The correct answer is 1. It is also answered with the statement that begins by saying that the child is asymptomatic. The error seems to me to be a misconception because for the study of a murmur an ECG is not usually requested but an echocardiography. Heart failure is a complication of Wolf-Parkinson-White syndrome and rarely a debut form of the disease.

[HIDDEN] It is also answered with the statement that begins by saying that the child is asymptomatic. The error seems to me to be a misconception because for the study of a murmur an ECG is not usually requested but an echocardiography. Heart failure is a complication of Wolf-Parkinson-White syndrome and rarely a debut form of the disease.

A 9-year-old boy, asymptomatic with an innocent murmur, undergoes an ECG that documents Wolf-Parkinson-White Syndrome. Which of the following statements is FALSE?

She may present with paroxysmal supraventricular tachycardia.

The 2D-Doppler ultrasound will rule out its association with Ebstein's disease.

It is convenient to perform a 24-hour ECG (Holter) and ergometry.

In certain patients, ablation of the accessory pathway with radiofrequency constitutes the therapeutic action.

[Tachycardia-induced syncopes].

In 50% of the patients presenting with a syncope, the cause is cardiac. The incidence of sudden death with 24% is high in this group. Since most of the tachycardia-induced syncopes are due to ventricular tachycardia (VT), a careful diagnostic approach must be used. The possibility of a VT to end in a fibrillation is great, especially in the presence of a organic heart disease, which leads to a bad prognosis in such patients. The aim of a careful anamnesis and clinical history is to establish the presence of a cardiac disease. A Wolff-Parkinson-White syndrome, a long QT, an old myocardial infarction or a coronary artery disease (CAD) can be assessed by echocardiography (ECG). Stress testing is useful in evaluating a CAD and can possibly lead to a diagnosis when a VT or a supraventricular tachycardia (SVT) is induced. ECG is used to assess the cardiac ejection fraction and in the evaluation of a suspected right or left cardiomyopathy. The ambulatory ECG allow a diagnosis only in 2 to 3% of the cases. Nevertheless, the presence of more than 10 PVC/h and/or asymptomatic nonsustained VT is a predictor for sudden death in syncopy patients. Detection of late potentials has a sensitivity of 50 to 83% and a sensibility of 89 to 91% for the prediction of inducible sustained VT during electrophysiological studies (EPS) in patients with syncope. However, the usefulness of this technique is not fully established, since there is no significant difference in survival or recurrence of syncope between patients with and without late potentials. The EPS is an invasive technique and therefore used at the end of the investigations. The cardiovascular mortality is low (4%) in patients with a negative EPS. A treatment is mandatory in tachycardia-induced syncopes even when the cause is a SVT. Antiarrhythmic drugs are useful for the treatment of SVT. However, radiofrequency ablation of the accessory pathway is preferable, since the success rate is over 90%, and the side effects of chronic ingestion of antiarrhythmic drugs can therefore be avoided. Some VT can be treated successfully with drugs under the control of an EPS, but most of the patients must have the implantation of an internal cardiac defibrillator (ICD).

[Location of atrial and ventricular insertions of accessory atrioventricular pathways using surface ECG mapping and its importance in catheter ablation therapy].

The modern non-pharmacological therapy of the WPW syndrome by means of catheter ablation is based on the interruption of the accessory pathway(-s) by radiofrequency current energy. Destruction of the morphologic substrate of the arrhythmia alters the activation wave spread in the heart. It was the aim of this report to demonstrate the diagnostic potential of BSM in localizing both overt and concealed accessory pathways. Presented study analyzes the alterations of the cardioelectric field by means of body surface ECG mapping in two female patients with accessory pathways before and after their successful curative treatment by radiofrequency catheter ablation. Five patients were analyzed prior and after RF catheter ablation by BSM, two of them were selected for this presentation. One patient with WPW syndrome suffered from frequent supraventricular tachycardia due to in one female patient with an overt accessory pathway. The other patient was for several years incessantly in permanent junctional reentry tachycardia due to a concealed accessory pathway. The examination comprised 12-lead ECG, orthogonal vectorcardiogram according to Frank, BSM using a regular 80-electrode-array system and signal-averaged ECG. The RF ablation was successful in both patients and their arrhythmia was abolished. By means of a detailed analysis of the ventricular activation prior RF ablation in the patient with WPW syndrome the precise site of the ventricular insertion of the accessory pathway in the left lateral free wall was predicted. Furthermore, alterations of the terminal QRS complex were observed when comparing pre- versus post-ablation maps. In the second patient the atrial insertion of the accessory pathway with retrograde and decremental conduction was successfully localized to the right septal region by means of pre-ablation BSM. Both ventricular and atrial activation can be in detail analyzed by means of BSM. Such analysis offers more precise information on the spatial component of the activation wave spread. This case report gives further evidence that BSM is a useful method for precise localization of both ventricular and atrial insertion sites of accessory pathways in patients with paroxysmal tachycardias due to this electrophysiologic abnormality. This information gained recently clinical impact since it can be directly used for faster arrhythmogenic substrate targeting during ablation therapy. (Fig. 5, Ref. 17.)

[Usefulness of transesophageal electrophysiological study during the ergometric test in the evaluation of supraventricular paroxysmal tachycardia occurring during exertion].

Transesophageal electrophysiologic study has recently been proposed for the evaluation of supraventricular arrhythmias. In this report we present 13 cases, with palpitations occurring only during effort, due to a suspected supraventricular tachycardia, in which the usefulness of the transesophageal electrophysiologic study performed during stress test was evaluated. Of these 13 patients, nine were male and four were female, mean age was 29 yrs. Twelve cases had no heart disease, one had a moderate mitral valve insufficiency. Nine cases had a normal ECG, four had a WPW pattern. In 9/13 cases no significant arrhythmia was ever documented, in 1/13 ventricular premature beats were present in the basal ECG, in 1/13 a atrial fibrillation and in 2/13 a supraventricular reciprocating tachycardia was recorded. In all cases a maximal exercise test and a 24-hour Holter monitoring were performed. In all pts a transesophageal electrophysiologic study was performed both at rest and during extra-stimuli and incremental atrial pacing. The end point of transesophageal study was the induction of a sustained (greater than 30") supraventricular tachycardia. RESULTS. Maximal exercise test was negative in 11/13 cases; it showed ventricular premature beats in one case and initiated a supraventricular tachycardia in one. The 24 hour Holter monitoring was negative in 12/13 cases while it showed frequent ventricular premature beats in one. Resting transesophageal electrophysiologic study revealed dual A-V nodal pathways in six pts: in one of them a junctional re-entry was induced; in two a single echo beat was observed, while in three no reentry was observed. In three cases a supraventricular tachycardia was induced which was sustained in one and unsustained (7" and 24") in two cases. In 4 cases transesophageal electrophysiologic study gave no information. Transesophageal stimulation during exercise induced a greater than 30" reciprocating tachycardia in all patients, at work loads of 30-180 watts. Six pts had an intranodal tachycardia (V-A less than 70 msec) a further six pts had a atrioventricular tachycardia involving a Kent bundle (V-A greater than or equal to 70 msec), which was concealed in two, and one had a atrial tachycardia. In four cases (3 with intranodal and 1 with atrioventricular tachycardia), exercise transesophageal study was repeated after chronic therapy with betablockers (sotalol 240 mg/die or metoprolol 200 mg/die). In all cases, after therapy, the induced tachycardia had a longer cycle and in two cases it was induced at a higher work load. In a further two cases flecainide (200 mg/die) was tested. In one case (with atrial tachycardia), the arrhythmia was no longer inducible after therapy, in another case (with intranodal tachycardia) the drug had no effect. CONCLUSIONS. In patients with paroxysmal supraventricular tachyarrhythmias occurring during effort the basal ECG is normal or shows a WPW pattern. The maximal exercise test and 24 hour Holter monitoring give no information in over 90% of cases.(ABSTRACT TRUNCATED AT 400 WORDS)

[Non-invasive evaluation of a population with WPW syndrome].

Evaluation of a WPW Syndrome population by non invasive methods; identification of the sudden death risk; results of treatment and patient selection for Electrophysiologic Studies (EPS). Retrospective study. Arrhythmology Outpatients Clinic from a Cardiac Department. Successive patients older than 12 years with a WPW pattern on the ECG and history of paroxysmal tachycardia followed-up for a period of 46 +/- 29 months. The clinical, ECG, Holter, stress test and echocardiographic data from 32 patients, were analysed. A study evaluating clinical follow up and the results of treatment was done. The group of patients was very symptomatic. The main complaint was a feeling of tachycardia (84.4%). Orthodromic tachycardia was documented in 7 cases and atrial fibrillation with rapid ventricular rate in five. Intermittent delta wave pattern was found in 21 patients, with 11 cases identified by Holter and 4 by stress test. A predominant left accessory pathway was found (47%), but the anteroseptal location was frequent too (25%). The echocardiogram was not useful in any case. Eighty per cent of the patients became asymptomatic with medical treatment. Beta blockers and amiodarone (the last chance) were the most useful drugs. No mortality was found in the study group. EPS was considered for the 5 patients with paroxysmal atrial fibrillation and the 7 cases resistant to medical treatment. The difficulty to define the risk of a population with WPW Syndrome by non invasive methods was demonstrated. Eighteen one cases were included in a low risk group, due to the intermittent WPW pattern in the ECG. A high risk group was considered for the 5 patients with atrial fibrillation with fast ventricular rate. The risk was not established in 9 cases. Most of the patients became asymptomatic by medical treatment.

[15-year-old patient with decompensated heart failure and tachycardia with negative P-waves in inferior ECG recordings. An indication for heart transplantation?].

A 15-year-old girl was admitted with signs of severe cardiac failure. There were no symptoms of cardiac insufficiency 4 weeks before hospital admission. She presented with permanent supraventricular tachycardia with negative P-waves in leads II, III and aVF, the heart rate was 150 beats per minute. The electrophysiological examination showed a permanent junctional reentry tachycardia. A postero-septal accessory pathway could be eliminated successfully by radiofrequency catheter ablation. Immediately after the procedure cardiac function deteriorated with slight decrease of the strongly reduced cardiac output. Intensive care and application of dobutamine led to clinical stability. During a follow-up of two years the young patient showed permanent sinus rhythm and an age related physical strain. This case report documents the rapid and severe manifestation of cardiac failure owing to permanent junctional reentry tachycardia in a 15-year-old girl. She was referred for consideration of heart transplantation. Invasive electrophysiological treatment led to permanent sinus rhythm with improvement of left ventricular function.

Electocardiographic features in Ebstein's disease.

Ebstein's disease (ED) is a rare and heterogeneous congenital heart disease affecting the tricuspid valve and the right ventricle. Few studies have analyzed the electrocardiographic features of this disease. To describe the electrocardiographic features observed in Ebstein's disease. We conducted a retrospective descriptive study that enrolled 26 patients followed for ED. The mean age of discovery of the ME was 103.5±99 months [0-31 years]. The diagnosis of ME is most often made between 5 and 10 years. We noted right atrial hypertrophy in 11 patients (42%), right ventricular hypertrophy in half of the patients. Right axial deviation was noted in 11 patients (42%). Eight patients (30%) had wide QRS≥ 120 ms. Seven of these 8 patients (27%) had a fragmented QRS appearance. A right bandle block was noted in 22 patients (84%), it was a complete block in 7 cases (27%). A preexcitation was found in 6 patients (23%). The localization of accessory pathway was right postero-septal in all cases. Rhythmic disorders were noted in 9 patients (34%). It was a junctional tachycardia in 3 patients (11%), atrial flutter in 4 patients (15%) and atrial fibrillation in 2 patients (7%). A second degree atriventricular block was observed in one patient, it was Mobitz I type. Two cases of postoperative rhythm disturbances were recorded: paroxysmal atrial fibrillation and junctional tachycardia related to Wolf Parkinson White (WPW) syndrome. Surface ECG in the ED is often pathological with prevalence of rhythm disturbances related to WPW syndrome.

Supraventricular tachycardia

Supraventricular tachycardia (SVT) is an umbrella term for fast heart rhythms arising from the upper part of the heart. This is in contrast to the other group of fast heart rhythms - ventricular tachycardia, which start within the lower chambers of the heart. There are four main types of SVT: atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia (PSVT) and Wolff–Parkinson–White syndrome. The symptoms of SVT include palpitations, feeling of faintness, sweating, shortness of breath, and/or chest pain. These abnormal rhythms start from either the atria or atrioventricular node. They are generally due to one of two mechanisms: re-entry or increased automaticity. Diagnosis is typically by electrocardiogram (ECG), holter monitor, or event monitor. Blood tests may be done to rule out specific underlying causes such as hyperthyroidism or electrolyte abnormalities.

[Wolff-Parkinson-White syndrome in Ebstein's anomaly].

The abnormal development of the tricuspid valve in patients with Ebstein's anomaly results in several activation abnormalities including delayed intraatrial conduction, right bundle branch block, and ventricular preexcitation. In the present review, the aim was to define the ECG characteristics before and after ablation of an accessory A-V pathway in patients with Ebstein's anomaly. In a series of 224 patients studied at the Instituto Nacional de Cardiologia "Ignacio Chávez", Sixty-four patients (28%) had documented tachycardia. Thirty-three patients with recurrent tachycardia were found to have a single right-sided AP that was successfully ablated. Only 21 of 33 patients (62%), had typical of ECG pattern of preexcitation. In addition, none of the patients had an ECG pattern of RBBB during sinus rhythm. Radiofrequency catheter ablation resulted in appearance of RBBB in 94% patients. The absence of RBBB in patients with Ebstein's anomaly and recurrent tachycardia had a 98% sensitivity and 92% specificity for the diagnosis of an AP. One third of patients with Ebstein's anomaly and symptomatic tachyarrhythmias have minimal or absent ECG features of ventricular preexcitation. In these patients, the absence of RBBB pattern is a strong predictor of an AP.

Utility of transesophageal atrial pacing in the diagnostic evaluation of patients with unexplained syncope associated or not with palpitations.

Noninvasive studies are often negative in patients with syncope, normal surface ECG and without heart disease. The purpose of the study was to determine the diagnostic impact of an esophageal electrophysiological study performed during a consultation. A total of 154 patients aged from 16 to 87 years were consecutively recruited for unexplained syncope; they had a normal ECG in sinus rhythm, no documented arrhythmia and no patent heart disease. Half of them complained of palpitations. Electrophysiologic study was performed during a consultation by transesophageal route: rate of 2nd d AV block occurrence during atrial pacing and sinus node recovery time were determined; programmed atrial stimulation using one and two atrial extrastimuli were delivered in control state and then after infusion of 0.02-1 microg/min of isoproterenol; arterial blood pressure was monitored. (1) Electrophysiologic study was positive in 107 patients (69%); (2) sinus node dysfunction was noted in 9 patients (6%); (3) atrioventricular conduction disturbances were noted in 2 patients (1%); (4) vasovagal reaction which associated a junctional bradycardia and a fall of arterial blood pressure and which reproduced spontaneous symptoms was provoked by isoproterenol infusion in 21 patients (14%); (5) sustained atrial fibrillation was induced in 23 patients (15%); and (6) paroxysmal junctional tachycardia was induced in 52 patients (34%). Patients with negative study were younger (44+/-21.5 years) than those with sinus node dysfunction or atrial fibrillation (71+/-9 and 63+/-14 years, respectively). The treatment was guided by these data: patients with inducible atrial fibrillation were treated by antiarrhythmic drugs and those with inducible paroxysmal junctional tachycardia by the radiofrequency ablation of reentrant circuit. Syncope disappeared in all patients but 2. Esophageal electrophysiologic study performed during a consultation was a safe, rapid and economic means to detect an arrhythmia (sinus node dysfunction or supraventricular tachycardia) in patients with dizziness/syncope and palpitations in half cases. Supraventricular tachycardia was clearly an underestimated cause of syncope in this population.

Electrocardiography

An esophogeal lead can be inserted to a part of the esophagus where the distance to the posterior wall of the left atrium is only approximately 5–6 mm (remaining constant in people of different age and weight). An esophageal lead avails for a more accurate differentiation between certain cardiac arrhythmias, particularly atrial flutter, AV nodal reentrant tachycardia and orthodromic atrioventricular reentrant tachycardia. It can also evaluate the risk in people with Wolff-Parkinson-White syndrome, as well as terminate supraventricular tachycardia caused by re-entry. An intracardiac electrogram (ICEG) is essentially an ECG with some added intracardiac leads (that is, inside the heart). The standard ECG leads (external leads) are I, II, III, aVL, V1, and V6. Two to four intracardiac leads are added via cardiac catheterization. The word "electrogram" (EGM) without further specification usually means an intracardiac electrogram.

Wolff-Parkinson-White Syndrome -- Treatment / Management

In general, patients with asymptomatic WPW pattern are considered at low-risk of a cardiac arrest. Those patients who have had a cardiac arrest usually almost always experience preceding tachycardia related symptoms. Thus, most asymptomatic patients may be managed by reassurance and close watchful clinical monitoring. Patients may be advised to notify their clinician urgently in case of rapid palpitations or syncope. Alternatively, an additional risk stratification strategy may be utilized.  Risk stratification of asymptomatic WPW pattern may be performed either invasively or by non-invasive means. Neither risk-stratification scheme is 100% perfect due to some false positives or false negatives. Non-invasive evaluation is usually a preferred initial modality. Patients can undergo exercise treadmill testing, ambulatory ECG monitoring, or sodium channel blocker challenge.  The presence of an abrupt and clear loss of preexcitation at faster sinus rates on electrocardiogram suggests a weak or low-risk pathway. These pathways thus are unlikely to result in life-threatening ventricular rates during AF. They can usually be managed with watchful monitoring alone without subjecting them to an invasive EP study. On the other hand, if preexcitation persists at faster heart rates during exercise testing, or is persistent during the entire ambulatory monitoring period, then it may suggest that an invasive evaluation may be further needed. However, it does not necessarily mean that the pathway is "high-risk."

Antidromic Atrioventricular Reentry Tachycardia with Wolff Parkinson White Syndrome: A Rare Beast.

Orthodromic atrioventricular reentrant tachycardia (AVRT) is the second-most-common form of supraventricular tachycardia (SVT) and is inducible in approximately 55% of individuals with Wolff Parkinson White (WPW) syndrome. Antidromic AVRT, where the accessory atrioventricular connection is used as the antegrade limb and the atrioventricular node serves as the retrograde limb of the circuit, has been clinically documented in less than 5% of patients with WPW syndrome and may be induced in less than 10% of these WPW cases in the electrophysiology laboratory. Left lateral pathways are considered more frequent and septal locations are less common when associated with antidromic AVRT. We report a case of 21-year-old male with a history of WPW syndrome who had undergone a prior electrophysiology study in 2010 at an outlying facility, documenting an anteroseptal accessory pathway near the His bundle along with an unsuccessful attempt at radiofrequency ablation at that time. No supraventricular tachycardia was induced at that previous study. The surface electrocardiogram (ECG), at this time, was consistent with the anteroseptal WPW pattern. The patient now presented with a complaint of intermittent palpitations with no definitive trigger. He also described a recent syncopal episode while walking inside his home. His physical exam and all lab work were within normal limits for his age. He underwent a repeat electrophysiology (EP) study where the baseline PR interval was 62 milliseconds and the QRS duration was 172 milliseconds in a pre-excited pattern. There was found to be an antegrade-only conducting accessory pathway at the anteroseptal region near the His bundle. Antegrade AVRT was induced with a single ventricular extra stimulus while on 2 mcg/min isoproterenol. Cryoablation was performed in a position slightly posterior to the His bundle, which successfully resolved the accessory pathway conduction. First-degree atrioventricular (AV) block was noted in the sinus rhythm with a PR interval of 226 milliseconds post-cryoablation. There was no recurrence of accessory pathway conduction on follow-up ECG 24 hours post-cryoablation. Antidromic AVRT is a very rare finding in WPW syndrome during an EP study. Catheter ablation is the treatment of choice for patients who have symptomatic WPW syndrome. Catheter ablation can be especially challenging when the accessory pathway is in close proximity to the normal conduction pathways. The prognostic significance of inducible antidromic AVRT is controversial in asymptomatic patients and limited data indicate it may be a poor prognostic sign in children. In adults, the prognostic significance is not well-established. Cryoablation is an option for the ablation of accessory pathways that are close to the normal conduction pathways. "Cryomapping" is designed to have precise ablation and to reassure the absence of complications.

[Usefulness of electrophysiologic studies. Report of 224 cases].

Two hundred and twenty four electrophysiologic studies were performed in 194 patients during a two-year period. One hundred and six (54.6%) had tachyarrhythmias: 21 had atrial tachycardia, 28 had the Wolff-Parkinson-White syndrome. Of 51 patients with a normal electrocardiogram a concealed left Kent bundle was observed in 21 cases and only one concealed right Kent bundle; functional James fibers were seen in 7 patients and Mahaim fibers in two. In 15 patients A-V nodal reentry was diagnosed and functional ectopy was observed in 5 patients. The sick-sinus-syndrome was seen in 24 patients and atrial arrest in three. Thirty patients underwent a second electrophysiologic study to evaluate proper antiarrhythmic therapy. Atrioventricular conduction was evaluated in 52 patients. A "suprahisian" delay was found in 34%, troncular lesions were diagnosed in 31%, a distal delay in 25% and mixed conduction disturbances in 10%. We conclude that electrophysiologic studies are a useful procedure to: 1) establish the etiologic diagnosis of tachyarrhythmias; 2) evaluate their potential danger; 3) objectively evaluate antiarrythmic therapy; 4) establish the need for surgical treatment; 5) give the topographic diagnosis and severity of A-V conduction disturbances and 6) indicate the need for definitive pacemaker implant.

Atrioventricular reentrant tachycardia

Atrioventricular reentrant tachycardia (AVRT), or atrioventricular reciprocating tachycardia, is a type of abnormal fast heart rhythm and is classified as a type of supraventricular tachycardia (SVT). AVRT is most commonly associated with Wolff–Parkinson–White syndrome, but is also seen in permanent junctional reentrant tachycardia (PJRT). In AVRT, an accessory pathway allows electrical signals from the heart's ventricles to enter the atria and cause earlier than normal contraction, which leads to repeated stimulation of the atrioventricular node. Signs and symptoms An episode of SVT may present with palpitations, dizziness, shortness of breath, or losing consciousness (fainting). The electrocardiogram (ECG) would appear as a narrow-complex SVT. Between episodes of tachycardia the affected person is likely to be asymptomatic; however, the ECG would demonstrate the classic delta wave in Wolff–Parkinson–White syndrome. Pathophysiology

Diagnostic approach to cardiac arrhythmias.

The diagnostic approach to cardiac arrhythmias should be logical and starts with the clinical history, which provides two types of information: (a) the presence of symptoms, and (b) the clinical context, including the presence of an underlying heart disease. Clinical history and examination are helpful in the choice of pertinent invasive or noninvasive tests. The tolerance of the arrhythmia is not helpful in determining the type of arrhythmia because ventricular tachycardia, for example, may be well tolerated or even asymptomatic. The electrocardiogram (ECG) in sinus rhythm may be suggestive of the origin or etiology of arrhythmia as the presence, for example, of the Wolff-Parkinson-White pattern. An essential step in the diagnostic approach to arrhythmia is the ECG documentation. Ambulatory Holter monitoring, radiotelemetry, intermittent recorders, exercise testing, and electrophysiological testing will help in this endeavor. The latter is particularly useful in paroxysmal circus movement tachycardias. Once the tachycardia is recorded, a number of clues, including the regularity of the RR interval and the width of the QRS complex, may facilitate the diagnosis. In tachycardias with wide QRS complexes, preexcitation has to be excluded. The first step is then to look for atrioventricular dissociation, which is diagnostic of ventricular tachycardia. Other diagnostic clues (QRS duration, axis deviation, QRS morphology) may be useful. In case of difficulty because of preexisting bundle branch block or aberrancy, esophageal, right atrial, or His bundle recordings are indicated. If the tachycardia is not well tolerated, prompt termination with electrical DC shock should be performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Radiofrequency catheter ablation of accessory pathway in a patient with Ebstein's anomaly and atrial septal defect--a case report.

The authors report the case of a 57-year-old woman with Ebstein's anomaly and atrial septal defect. She was referred to their hospital for treatment of refractory paroxysmal wide QRS tachycardia. Her 12-leads ECG in sinus rhythm showed ventricular preexcitation of type B Wolff-Parkinson-White syndrome. In a baseline electrophysiological study, a wide QRS tachycardia with right bundle branch block configurations was induced. This tachycardia was orthodromic atrioventricular reciprocating tachycardia with a right inferior accessory pathway. Radiofrequency current was successfully delivered at the inferior site of the atrialized right ventricle. Radiofrequency catheter ablation seems to be useful for supraventricular tachycardia in patients with Ebstein's anomaly and atrial septal defect.

[Clinical and prognostic value of evaluation of atrial vulnerability in an electrophysiological endocavitary and transesophageal study].

Atrial fibrillation or flutter is frequently inducible during endocavitary or transesophageal electrophysiologic study. However, its clinic and prognostic significance has not yet been clarified. We studied 443 patients: 276 underwent endocavitary electrophysiologic study, 228 underwent transesophageal electrophysiologic study and 61 underwent both methods. In 343 of them a satisfactory echocardiogram was obtained. Patients were divided in three groups: gr. I, 93 patients with documented episodes of paroxysmal atrial fibrillation or flutter; gr. II, 257 patients with or without heart disease without clinical atrial fibrillation or flutter; gr. III, 93 symptomatic or asymptomatic Wolff-Parkinson-White patients without clinical atrial fibrillation or flutter. Gr. I included patients without overt heart disease (20), with WPW (11), mitral valve prolapse (4), and miscellaneous (58). Gr. II included patients without overt heart disease (49), with concealed Kent bundles (7), Mahaim (1) or James fibers (1) mitral valve prolapse (6), sick sinus syndrome (40), miscellaneous (91), or syncope of an unknown origin (62). Atrial vulnerability was evaluated both by endocavitary and transesophageal electrophysiologic study using two different protocols; the first protocol was moderately aggressive (prot. A), while the second was aggressive (prot. B). Endocavitary electrophysiologic study. Prot. A: single and double extrastimuli at the three heart rates (sinus, 100 and 150/m'), 10/m' incremental atrial pacing from 160 to 250/m; prot. B: prot. A + incremental atrial pacing from 260/m' up to 2:1 St-A block. Transesophageal electrophysiologic study. Prot. A: 10" atrial burst at 100-600/m' prot. B: prot. A + 6-9" increasing rate bursts from 200 to 800/m'. End point of all protocols: initiation of greater than 1' atrial fibrillation or atrial flutter. Endocavitary electrophysiologic study. A greater than 1' atrial fibrillation or atrial flutter was induced with the two protocols respectively in 67% (52/78) and 85% (51/60) of gr. I, in 17% (26/150) and 36% (38/105) of gr. II and in 35% (17/48) and 44% (21/48) of gr. III (gr. I vs gr. II p less than 0.001 for prot. A and p less than 0.01 for prot. B; gr. II vs gr. III p less than 0.001 for prot. A and NS for prot. B). Induced atrial fibrillation or atrial flutter using the two protocols had a greater than 5' duration respectively in 83 and 78% of gr. I, 62 and 42% of gr. II and in 41 and 38% of gr. III.(ABSTRACT TRUNCATED AT 400 WORDS)

Paroxysmal supraventricular tachycardia

Paroxysmal supraventricular tachycardia (PSVT) is a type of supraventricular tachycardia, named for its intermittent episodes of abrupt onset and termination. Often people have no symptoms. Otherwise symptoms may include palpitations, feeling lightheaded, sweating, shortness of breath, and chest pain. The cause is not known. Risk factors include alcohol, caffeine, nicotine, psychological stress, and Wolff-Parkinson-White syndrome, which often is inherited. The underlying mechanism typically involves an accessory pathway that results in re-entry. Diagnosis is typically by an electrocardiogram (ECG) which shows narrow QRS complexes and a fast heart rhythm typically between 150 and 240 beats per minute.

[Significance of isotopes in the study of pre-excitation and ventricular tachycardia].

In normal patients, Mac Carthy has demonstrated that there was a very close correlation between the ventricular contractile activity, evaluated by Fourier's isotopic phase analysis, and electrical depolarization, evaluated by endocardial mapping. It has therefore been possible to study asynchronisms or asymmetries of the ventricular contraction-depolarization and particularly the syndromes of ventricular pre-excitation and ventricular tachycardias. In Wolff-Parkinson-White syndromes (WPW), the mapping obtained by heart cavity tomography in addition to dual-plane gamma-angiography, provides most useful informations, due to additional section planes permitting tridimensional location of the earliest site of ventricular activation. It is quite useful to locate the bundle of Kent always difficult on surface electrocardiogram, or when the endocardial exploration does not permit to precisely locate the site of the excentric atrial activation in case of multiple bundles of Kent or without retrograde conduction. When the left bundle of Kent is barely identified, the isotopic image may be improved by oesophageal stimulation. Additional parameters (use of several harmonics, factorial analysis) will permit to improve the localization of accessory pathways, to be destroyed by fulguration or surgery. In case of ventricular tachycardias with limited functional tolerance, only gamma-angiography, lasting only 3 to 5 minutes, may be used. Combined with endocardial tomography or even gamma-angiography performed in sinus rhythm, not only the site of origin of the ventricular ectopy may be localized, but it also can be correlated with ventricular kinetics abnormalities and the cardiopathy in question may be identified. Most authors consider that there is a close relationship between isotopic site, electrocardiographic appearance and the site found by endocardial mapping or "pace-mapping". In patients with ventricular tachycardias of different morphologies, isotopic mapping permits to differentiate those originating from a same lesion (which may be treated by surgery of fulguration) from those originating in remote areas. Therefore, this technique is a non aggressive and rapid method providing accurate informations on severe rhythm disorders currently treated by eradication of their anatomical substratum.

[Inadequate, inappropriate sinus-node tachycardia. <i>An old cardiac arrhythmia in a new perspective</i>].

<iIntroduction:</i The inadequate, inappropriate sinus-node tachycardia is not a rare clinical syndrome, defined as a non-paroxysmal, increased sinus-rate at rest, and/or inadequate response to physical and/or emotional stress, and palpitations. <iAim:</i The aim of this study was to describe our experiences with the investigations of our inappropriate sinus-node tachycardia patients. <iMethod:</i In the last years, 104 patients (92 women, 12 men, mean age: 31 ± 10 years) were treated with this cardiac arrhythmia entity. All patients underwent 12 leads ECG, chest X-ray, echocardiography, Holter-monitoring and transtelephonic ECG observations. The quality of life score was estimated by using the European Heart Rhythm Association scale. <iResults:</i Patients had no structural heart disease (physical examination ECG, chest X-ray, echocardiography were normal), the laboratory values (TSH, blood count) were within normal limits, but the resting heart rates were repeatedly high (102 ± 8/min). The results of Holter recording (expressed as minimal-maximal [average] heart rate/min) without drug therapy showed high heart rate values (59 ± 8, 160 ± 14 [94 ± 6]/min). The standard bicycle ergometry showed an average loading capacity of 124 ± 23 watt (heart rate: control: 99 ± 12/min, top: 167 ± 13/min) with early, inadequate sinus tachycardia. To disclose the episodes of paroxysmal supraventricular tachycardia, beside the Holter-monitoring transtelephonic ECG system was used. This diagnostic modality was very useful for the exclusion of paroxysmal supraventricular tachycardia episodes during the palpitation symptoms. Out of 104 patients, 4 patients (3.8%) showed familiar occurrence, another 16 patients (15.2%) had previous slow-pathway radiofrequency ablation due to atrioventricular nodal reentry tachycardia. <iConclusions:</i Based on our clinical observations, it can be pointed out that inappropriate sinus-node tachycardia syndrome (1) occurs mainly in young women, mostly in students, inducing decreased quality of life scores (EHRA score: 2.3 ± 0.4); (2) the prevalence in our outpatient clinic was 0.7%; (3) the patient population is not homogeneous: familiar or postablation occurrence is possible in some patients; (4) transtelephonic ECG has been proved to be very useful to disclose episodes of paroxysmal supraventricular tachycardia in these patients. Orv Hetil. 2019; 160(37): 1464-1470.

[Possible mechanisms of false positive results of averaged ECG].

The objective of this retrospective study was to investigate the causes of high amplification (HA) ECG abnormalities detected in apparently healthy subjects. This study was based on 14 patients derived from a population of 167 admitted for assessment of malaise or supraventricular tachycardia and who had no apparent heart disease. The surface ECG showed fine QRS complexes (< 120 ms) with no left hemiblock on ECG. All of these subjects underwent a complete electrophysiological study and high amplification ECG using a 40 Hertz high-pass filter. For these 14 patients, the amplitude of the last 40 milliseconds (ms) of the mean QRS (RMS 40) was less than or equal to 20 microvolts (microV). Eight of them also had a duration of the terminal part of the QRS complex less than 40 microV (LAS) greater than 40 ms and 6 others had and LAS greater than 35 ms. The mean QRS interval was normal in all patients (< 120 ms). The usual causes for reduction of the RMS 40-were eliminated: programmed ventricular pacing using 3 extrastimuli under basal conditions and with isuprel remained negative. E chocardiography and the right ventricular angiography were normal. The surface ECG showed slight abnormalities: absence of Q wave in V6 without delay of the intrinsic-like deflection in 3 subjects, increased R wave in V1 in 2 subjects and especially deep S wave in V5-V6 with no left axis deviation in 10 patients. Programmed or increasing frequency atrial pacing induced RBB or LBB in 13 of these 14 subjects (RBB: 7, LBB : 3, RBB and LBB:3). Follow-up, ranging from 6 months to 3 years, did not reveal any cardiac events, but signs of RBB appeared in 3 patients and signs of LBB were observed in 1 patient. an abnormal high amplification ECG in apparently healthy subjects could be explained by minor conduction disorders essentially in the right branch. The presence of a deep S wave (> 2 mm) in V5-V6 is the commonest ECG sign in these subjects. This diagnosis can only be proposed after exclusion of right ventricular dysplasia in symptomatic patients.

[Analysis of arrhythmias using Holter electrocardiographic monitoring in patients with ventricular preexcitation].

It is known that patients with preexcitation of ventricles (PE) have a predisposition to paroxysmal supraventricular tachyarrhythmias (PSVT). There is a relatively small amount of knowledge concerning the occurrence and clinical significance of other disturbances of the cardiac rhythm in these patients. 1. To consider the possibility of utilization of Holter monitoring (HM) of electrocardiograms (ECG) in the detection of PSVT; 2. To find out the occurrence and evaluate the significance of other than paroxysmal tachycardias; 3. By means of correlation of subjective complaints with objectively documented arrhythmias to consider the extent, to which the subjective complaints are determined by disturbances of cardiac rhythm. 24-hour HM ECG was performed under clinical conditions in 50 patients, 23 male and 27 female patients at the average age of 35 +/- 13 (ranging 15-17) years, with manifestant PE on ECG. 21 (42%) patients with documented PSVT and/or atrial paroxysmal fibrillation (APF) constituted a group with Wolff-Parkinson-White (WPW) syndrome. 29 (58%) patients without these arrhythmias were ranked among the group with WPW pattern. 22 (44%) patients had concomitant organic heart disease (OHD). Each long-term electrocardiographic ECG recording was judged in order to specify the occurrence of individual types of arrhythmias and to perform their quantitative analysis per 24 hours. Subjective complaints presented by patients during HM were correlated with the objectively documented arrhythmias. Arrhythmias were recorded in HM in 35 (70%) of patients with PE. Supraventricular premature beats (SVPBs) occurred in 32 (64%) and ventricular premature beats (VPBs) in 15 (32%) patients with PE. When comparing the patients with PE and OHD with subjects with PE without OHD, no statistical differences in the occurrence of SVPBs and VPBs as well as in numbers per 24 hours were discovered. PSVT were recorded by HM only in 2 patients, and AV reciprocating echoes in another patient with WPW syndrome. Short runs of atrial tachycardia occurred in 2 patients with WPW syndrome.

[Respective interest of two techniques of electrophysiological study in patient without heart disease].

Electrophysiologic study (EPS) frequently is required to assess the prognosis of asymptomatic Wolff-Parkinson-White syndrome (WPW) or to prove the nature of no documented tachycardia. EPS usually is performed by intracardiac route and hospitalization is required. Similar data are given by an EPS performed by oesophageal route during a consultation. The purpose of the study was to evaluate the cost of both techniques in France. Transesophageal EPS was performed during a consultation in 100 patients with asymptomatic WPW syndrome and 100 patients with no heart disease, complaining of no documented tachycardias with abrupt beginning and end, suggesting a paroxysmal junctional re-entrant tachycardia (PJRT). The cost of transesophageal study including isoproterenol infusion is 127.75 euros. The cost of intracardiac EPS is at least 1460 euros, cost of hospitalization during only one day. In patients with WPW syndrome, 15 had a potentially malignant form with the induction of a tachycardia conducted through the accessory pathway at a high rate (> 240/min in control state, > 300/min with isoproterenol); radiofrequency catheter ablation was indicated in a second time. In the group with no documented tachycardia, PJRT was induced in 30 patients and indication of ablation was discussed. In other 155 patients with either a benign form of WPW syndrome or with a tachycardia unrelated to a PJRT, hospitalization was not required; in these patients, intracardiac study performed during one day of hospitalization would have costed 226,300 Euros. The cost for the esophageal EPS and a similar diagnosis was 19,801 Euros, with a save money of 206,499 Euros. In 45 patients in whom hospitalization was indicated in a second time to perform catheter ablation of the arrhythmia, the cost related to esophageal EPS was 5749 Euros. In the total group, considering the final diagnosis and the need of hospitalization in 45 patients, the save money related to the use of esophageal EPS was 206,499 E-5749 E = 200,750 euros. We should take into account the cost studies, when various techniques could be used for a similar diagnosis. There are important differences in the cost of diagnostic methods and it is easy to decrease this cost.

[Radiofrequency catheter ablation in patients with Mahaim-type slow-conduction accessory right atrioventricular pathway].

In some cases undergoing radiofrequency catheter ablation (RFCA) of accessory pathway (AP), a Mahaim-like right-sided atrioventricular AP (M-AP) showing slow and decremental conduction is observed. Among 200 consecutive patients referred to our Institution up to September 1993 for arrhythmias related to an AP and undergoing RFCA, 8 patients (6 males, 2 females; mean age 24 +/- 8 years, range 8-35) showed a M-AP. Seven out of 8 patients have been complaining episodes of palpitation for 13 +/- 7 years (range 1-20), while 1 subject was an asymptomatic young athlete. In 2/8 patients an Ebstein disease (Eb) was present and they had previously undergone right-sided Kent bundle (Kb) ablation elsewhere. During sinus rhythm, QRS was normal in 1 patient, while it showed ventricular preexcitation due to right-sided Kb in 3 patients and right bundle branch block in another 4 patients. A left bundle branch block morphology (LBBBM) reentrant tachycardia (RT) was observed in 7 patients (in 1, only after RFCA of a right-sided Kb); 3 showed also orthodromic RT. In the asymptomatic young athlete, a preexcitation atrial fibrillation with very rapid ventricular response was inducible. All patients underwent diagnostic electrophysiologic (EP) study and RFCA in the same session. In 2/8 patients M-AP was manifest only after right-sided Kb RFCA. In all patients, associated EP abnormalities were noted: in 5/8 patients a dual A-V node pathway was present and in 5/8 patients 6 right-sided Kbs were associated. Patients have been divided in 3 groups, according to the mechanism involving the M-AP in the RT. In the 2 Group I patients showing also Eb, antidromic LBBBM RT and orthodromic RT involving the M-AP anterogradely and retrogradely, respectively, were observed; both arrhythmias were abolished by ablating the M-AP. The 3 Group II patients showed only antidromic LBBBM RT, involving a fast A-V node pathway retrogradely; also in these patients, the M-AP was the target of RFCA. This was performed only in 1 patient, in whom A-V node RT was also observed and ablated after RFCA of M-AP; as to the other 2 patients, in 1 the ablation of M-AP was not considered mandatory, since it was responsible for inducible not sustained LBBBM RT observed only after RFCA of a Kb in the same EP session, while in the other it was not possible because of a prolonged traumatic conduction block through the M-AP.(ABSTRACT TRUNCATED AT 400 WORDS)

Arrhythmias and conduction abnormalities in children after repair of tetralogy of Fallot.

To find out types and frequency of cardiac arrhythmias and conduction abnormalities in the group of children who underwent surgery for tetralogy of Fallot (TOF). Forty-six pedicatric patients who underwent a complete repair of TOF at the age of 1 to 13 (mean 2.89+/-2.36) were studied Thirty-eight (82.60%) had total correction and 8 (17.40%) had palliative operation first, and total correction afterwards. Twenty-four-hour Holter ECG monitoring was performed in all 46 pediatric patients aged from 1 to 16 yrs (mean 6.48+/-4.04) after surgery as follows: in 1 patient (2.17%) after a year, in 20 patients (43.477%) after 2 to 5 years and in 25 patients (54.34%) after 5 years. Mean age of patients on Holter monitoring was 9.25+/-4.39 (range 4-19). Twenty of them (43.47%) were girls and 28 (56.53%) were boys. All the patients were evaluated by standard methods (clinical signs, clinical findings, ECG before surgery, ECG before Holter monitoring and 2D Doppler echocardiography. Types of heart rhythm found out by Holter monitoring were: sinus nodus dysfunction in 1 child (2.17%), significant premature atrial contraction (PAC) in 8 (17.39%), supraventricular paroxysmal tachycardia in 3 (6.535), transient nodal rhythm in 2 (4.34%), premature ventricular contraction (PVC) Lown grade 1-III in 9 (19.56%) and Lown grade IV in 2 (4.34), atrioventricular (AV) block grade I in 2, right bundle branch block (RBBB) in all 46 (100%) and RBBB + left anterior hemiblock (LAH) in 4 (8.96%). There was no presence of atrial flutter, ventricular tachycardia or complete A V block. None of them experienced sudden death. Using cross procedure statistical methods, it was found that all the patients with PVC had right ventricular dilatation. There was no relation of other types of arrhythmia found on Holter monitoring to the other parameters from echocardiography, neither to the other standard methods. Children did not need the pace-maker, but 36.95% of the them required antiarrhythmic drugs. Twenty-four hour Holter ECG is a noninvasive and very sensitive method for discovering heart rhythm disturbances in children after the repair of tetralogy of Fallot, especially in asymptomatic patients. The patients after the repair of this congenital heart disease needed a long-term follow-up for early recognition of serious heart rhythm disturbances and their treatment.

[Who should be referred for electrophysiologic studies?].

Prerequisite of a rational antiarrhythmic therapy is the correct diagnosis of the given cardiac rhythm disorder. The majority of intermittent and latent cardiac arrhythmias can be reliably induced and analyzed during the electrophysiologic study (EPS). In case of bradyarrhythmias, the method is indicated in patients with suspected sinus node disease or high-grade AV conduction disturbances, as far as the cause of clinical symptoms cannot be settled by Holter recordings. Since patients with paroxysmal supraventricular tachycardias (WPW syndrome and AV nodal reentrant tachycardia) can be cured by transvenous ablation techniques, EPS is indicating in this setting in all symptomatic patients for the diagnosis and the treatment of the given arrhythmia. In patients with recurrent ventricular tachyarrhythmias, EPS should be performed to establish the diagnosis and to control medical treatment; in addition, EPS is a prerequisite for nonpharmacologic treatment modalities such as defibrillator therapy and transvenous or surgical ablation techniques. In survivors of cardiac arrest without new Q-wave myocardial infarction, persistent ventricular tachyarrhythmias can be induced in some 50% of the patients. Patients should be evaluated by EPS in case the reasons for significant clinical symptoms cannot be determined otherwise, given the likelihood, that brady- or tachyarrhythmias are the cause of the clinical symptoms; this includes patients with organic heart disease and with unexplained syncopes.

Diagnosis and cure of the Wolff-Parkinson-White syndrome or paroxysmal supraventricular tachycardias during a single electrophysiologic test.

We conducted this study to determine the feasibility of an abbreviated therapeutic approach to the Wolff-Parkinson-White syndrome or paroxysmal supraventricular tachycardia, in which the diagnosis is established and radiofrequency ablation carried out during a single electrophysiologic test. One hundred six consecutive patients were referred for the management of documented, symptomatic paroxysmal supraventricular tachycardias (66 patients) or the Wolff-Parkinson-White syndrome (40 patients). All agreed to undergo a diagnostic electrophysiologic test and catheter ablation with radiofrequency current. No patient had had such a test previously. Among the 66 patients with paroxysmal supraventricular tachycardias, the mechanism was found to be atrioventricular nodal reentry in 46 (70 percent) (typical in 44 and atypical in 2), atrioventricular reciprocating tachycardia involving a concealed accessory pathway in 16 (24 percent), atrial tachycardia in 2 (3 percent), and noninducible paroxysmal supraventricular tachycardia in 2 (3 percent). A successful long-term outcome was achieved in 57 of 62 patients (92 percent) with paroxysmal supraventricular tachycardia in whom ablation was attempted and in 37 of 40 patients (93 percent) with the Wolff-Parkinson-White syndrome. The only complications were one instance of occlusion of the left circumflex coronary artery, leading to acute myocardial infarction, and one instance of complete atrioventricular block. The mean (+/- SD) duration of the electrophysiologic procedures was 114 +/- 55 minutes. The diagnosis and cure of paroxysmal supraventricular tachycardia or the Wolff-Parkinson-White syndrome during a single electrophysiologic test are feasible and practical and have a favorable risk-benefit ratio. This abbreviated therapeutic approach may eliminate the need for serial electropharmacologic testing, long-term drug therapy, antitachycardia pacemakers, and surgical ablation.

[The mitral prolapse syndrome. Observation of 100 cases (author's transl)].

100 patients with mitral prolapse syndrome (MPS) were studied with electrocardiogram, phonocardiogram, thorax radiography and echocardiogram. In 44 of the patients, the effort test and dynamic electrocardiogram were performed; 25 underwent hemodynamic examination, and 10 underwent selective coronarography. The most frequent symptomatologies were palpitations and vertigo; the most-registered electrocardiographic alterations were ventricular extrasystoles and altered electrical repolarization in the inferior seat. The symptomatic patients with rhythm disturbances showed reduced work capacity (RWC) with aggravation of the effort arrhythmias. The phonocardiogram showed variability of the phonoauscultatory reports, not only from patient to patient, but also in the same patient. The apicocardiogram presented a characteristic systolic re-entry which coincided with the non-ejective click. In all cases, the echocardiogram demonstrated a systolic movement backwards from the mitralic strips with different aspects. The endocavitary pressures in the studied cases were normal or only slightly altered. The left ventriculography frequently demonstrated assynergic areas, and constantly, eversion of the posterior  mitralic strips in the left atrium. In most of the cases, the selective coronarography showed the absence of the ventricular atrial tract of the circumflex. The sustained role of the mixomatous degeneration in the pathogenetic mechanism of the MPS must be emphasized. The beta-blockers were the most effective drugs against arrhythmias, which in some cases showed themselves impervious to any medicinal treatment. MPS is considered a very diffuse disease which can run its course without detection or which can be accompanied by serious rhythm disturbances that can threaten the patient's life. The importance of echocardiography in the diagnosis of MPS is emphasized. The SPM patient showed undergo a series of wave tests which reveal malignant potentialities, so that the best therapeutic principles, both for the treatment and prevention of the arrhythmias, can be applied.

Successful radiofrequency current catheter ablation of accessory atrioventricular pathway after tricuspid replacement in Ebstein's anomaly.

A 15-year-old female with Ebstein's anomaly was referred to hospital for radiofrequency (RF) current catheter ablation of her refractory paroxysmal supraventricular tachycardia (PSVT) after tricuspid valve replacement. A surface ECG showed ventricular preexcitation of type B Wolff-Parkinson-White (WPW) syndrome. In a baseline electrophysiological study, two types of PSVT with left and right bundle branch block (LBBB and RBBB) configurations were induced. The LBBB type was antidromic and the RBBB type was orthodromic atrioventricular reciprocating tachycardia (AVRT) with a right posterolateral accessory pathway. RF current was successfully delivered at the posterolateral site above the prosthetic valve (V-delta interval = -30 msec). The patient has been free from arrhythmias during a follow-up period of 9 months. RF current ablation seems to be useful for AVRT patients with corrected Ebstein's anomaly.

[Idiopathic right ventricular tachycardia or arrhythmogenic right ventricular tachycardia?].

While cycling a 38-year-old man suddenly experienced palpitations associated with marked weakness. 90 min later his general practitioner, having diagnosed a ventricular tachycardia (VT) with a rate of 218/min, terminated it by a drug injection. Electrocardiography (ECG), echocardiography and biventricular cardiac catheterization with right ventricular contrast injection failed to provide any evidence of structural abnormality. However, ergometry and EPS with programmed ventricular stimulation induced VT of identical morphology (left bundle branch bloc [LBBB] with right axis deviation [RAD]). Idiopathic right-ventricular outflow tract tachycardia (IRVT) having been diagnosed, the patient was put on a maintenance dose of 50 mg/d atenolol. After 6 months without symptoms he again experienced several attacks of tachycardia. Resting ECG merely revealed an epsilon potential and negative T waves in V1-V3. Right ventricular contrast injection revealed inferolateral dyskinesia. EPS demonstrated both the known VT and a second, morphologically different one (LBBB with LAD). These findings indicated arrhythmogenic right-ventricular cardiomyopathy (ARCV). A cardioverter/defibrillator was implanted (ICD) and over the subsequent 8 months he had six episodes of VT which were quickly terminated by the ICD. At first presentation of right-ventricular outflow tract tachycardia it is often not possible to differentiate between IRVT and arrhythmogenic RV cardiomyopathy. The two being significantly different in prognosis and treatment, follow-up monitoring is essential to establish the definitive diagnosis.

The different electrophysiological characteristics in children with Wolff-Parkinson-White syndrome between those with and without atrial fibrillation.

Atrioventricular reciprocating tachycardia (AVRT) is known to be the most common supraventricular tachycardias in childhood. Because AF with rapid ventricular response may degenerate to ventricular fibrillation through conduction of accessory pathways (APs), it can be potentially life-threatening in some pediatric patients with WPW syndrome. However, information about WPW syndrome children associated with AF is limited. The purpose of this study was to investigate the specific electrophysiological characteristics in pediatric patients with WPW syndrome and AF. From July 1992 to February 2002, 51 pediatric patients with manifest WPW syndrome and documented AVRT underwent electrophysiological study and radiofrequency catheter ablation. In these patients, two (4%) were found to have several spontaneous episodes of AF recognized on 12-lead standard ECG or 24-hour Holter monitoring. Eleven (22%) patients had AF induced by rapid atrial pacing during the baseline procedure of electrophysiological study. The children with manifest WPW syndrome were divided into two groups: those with AF (group 1; n = 11) consisted of seven male and four female children (mean age 15 +/- 3 years, range 10-18), and those without AF (group 2; n = 40) consisted of 22 boys and 18 girls (mean age 16 +/- 3 years, range 7-18). The study excluded a patient who had Ebstein's anomaly associated with moderate tricuspid regurgitation and right atrial enlargement. The onset and duration of symptoms were not significantly different between the two groups. Comparing the electrophysiological characteristics, the atrial effective refractory period (ERP) was shorter in WPW syndrome children with AF (170 +/- 36 vs 190 +/- 38 ms, P = 0.041). This study demonstrated that the pediatric WPW syndrome patients with AF had different electrophysiological characteristics from those without AF.

[The diagnosis and ablation of accessory atrioventricular pathways in the initial electrophysiological exam: a new therapeutic modality in pre-excitation syndromes].

To describe the experience and results in the diagnosis and catheter ablation of atrioventricular accessory (AP) pathways during the initial electrophysiologic study. We performed catheter ablation at the time of an initial electrophysiologic study in 22 consecutive patients (12 W and 10 M, mean age 42 +/- 15) with Wolff-Parkinson-White syndrome or supraventricular tachycardia. Cardiology Department at University Hospital. The precise AP mapping was performed with the ablation catheter (4 mm distal electrode and deflectable tip) according to the earlier ventricular activation during sinus rhythm or the earlier atrial activation during ventricular pacing or orthodromic reentrant tachycardia. For left-sided pathways the ablation catheter was positioned on the mitral annulus retrogradely across the aortic valve, while for right-sided pathways it was positioned on the tricuspid annulus or near the coronary sinus os. Radiofrequency energy was applied for 20-60 segs with 55-65 Volts. Seventeen AP were manifest and five were concealed. AP were left lateral in 11 patients (50%), left posterior in 5, and right postero-septal, right posterior or antero-septal in 2 patients each. The ablation was initially successful in 18/22 (82%), with 9 +/- 8 radiofrequency applications. Mean duration of the entire procedure was 145 +/- 59 min and the fluoroscopy duration was 39 +/- min. There were no major complications. During 2-9 months of follow-up AP conduction returned in two patients. Radiofrequency catheter ablation of AP is effective and safe and can be performed at the time of an initial electrophysiologic test, avoiding the need for long-term antiarrhythmic drug therapy or surgical ablation.