VVI pacemaker (ventricular unicameral).

82-year-old woman with chronic atrial fibrillation of 10 years of evolution and preserved biventricular systolic function who presents with episodes of symptomatic complete atrioventricular block, so it is decided to implant a definitive cardiac pacing system. Which of the following is indicated:

AAI pacemaker (single-chamber atrial pacemaker).

Ventricular resynchronization therapy (CRT).

Current concepts in pacing 2010-2011: the right and wrong way to pace.

Over five decades have passed since the first permanent cardiac pacemakers were introduced into clinical medicine. Evolving technology and falling costs have demanded adaptation to clinical practice and implantation trends and, with the advent of evidenced-based medicine, the specific roles and benefits of individual pacemaker technologies have never been so carefully scrutinized. Pacing mode choice continues to be a subject of great controversy, and there are great regional variations in practice. We believe that single chamber atrial pacing use (AAI/R) has become an anachronism that should generally be abandoned (obviously with rare exceptional cases) and be replaced by dual chamber pacemakers (DDD/R) equipped with modern pacing algorithms that minimize patient exposure to ventricular pacing. Also, in patients with atrioventricular (AV) block, randomized clinical trials have failed to show improvement in clinically relevant outcomes such as mortality, stroke, and heart failure, particularly in the elderly, which has led some to advocate that DDD/R devices should never be offered to elderly AV block patients. However, we believe that the elderly, like the young, come in many "shapes and sizes" and individualized medicine compels us to consider each pacemaker candidate as unique. Implanting DDD/R devices in chronologically older, yet physiologically younger, patients is justifiable and good medical practice. Where right ventricular (RV) pacing is necessary and unavoidable, physicians should consider routinely placing RV leads on the RV mid- or outflow tract septum because these location are as good, if not better, for patients than the current practice of RV apical lead placement. In patients with AV block and asymptomatic yet moderate to severely depressed left ventricular systolic function, primary cardiac resynchronization therapy (CRT) should be strongly considered. Compelling clinical trial evidence does not yet exist to indicate that CRT should be the standard of care in patients with AV block and intact left ventricular systolic function. Right ventricular septal lead placement remains a reasonable option.

Pacemakers of the 1980s. An overview.

Methods and devices for permanent cardiac pacing remained relatively stable for over two decades with use of the single-chamber ventricular demand (VVI) pacemaker. However, changes have occurred in the 1980s and are expected to continue with the availability of more advanced technology and with increasing knowledge about cardiac pacing. The physiologic benefit of the newer dual-chamber atrial synchronous (VDD) and fully automatic, universal (DDD) pacemakers over the VVI pacemaker in patients with permanent complete heart block and normal sinus node function has been established. These newer units not only reestablish atrioventricular synchrony but also are physiologically rate-responsive. The VDD pacemaker is expected to be phased out in favor of the DDD pacemaker. When the atrial rate or interval is lower than the lower rate limit, the VDD pacemaker functions as a VVI, whereas the DDD pacemaker functions as an atrioventricular sequential (DVI) pacemaker to maintain continuous atrioventricular synchrony. Contrary to general belief, patients with complete heart block and normal sinus node function may gain very little physiologic benefit, if any, from DVI pacing. The sinus node will compete with the pacemaker's atrial stimulation when the sinus rate is faster than the DVI pacemaker rate (which usually occurs during activity). Also, the ventricular pacing rate will not vary with physiologic change. The DVI and atrial demand (AAI) pacemakers have been used in some patients with sinus node dysfunction. Increasing exercise tolerance should not be expected in the majority of patients because they are not pacemaker-dependent during activity, ie, their heart rate is higher than the pacemaker rate. However, these pacemakers appear to help in eliminating pacemaker syndrome, which does not infrequently occur with VVI pacemakers. Patients with sinus node dysfunction but without atrioventricular block do not gain more physiologic benefit with a DDD than with a DVI pacemaker. Whether these patients have severe sinus node dysfunction all the time or adequate sinus node function most of the time during follow-up, the DDD pacemaker will function as a noncommitted DVI with atrial sensing (DDI). The early report of DVI pacemaker-induced atrial fibrillation during follow-up has been refuted by more recent works. If the DDD pacemaker is significantly more expensive than the DVI pacemaker, the latter type may be a good alternative for this condition.

[30 years cardiac pacemaker therapy: a status evaluation].

Antibradycardiac pacemaker therapy has become established as one of the most effective forms of cardiological therapy for the indications AV-block, sick sinus syndrome, bradyarrhythmia, and hypersensitive carotid sinus. About 220,000 systems are implanted per year worldwide, about 32,000 in West Germany. Of the pacing modes, the fixed-rate ventricular single chamber systems (VVI) dominate with a share of almost 90%. Prognostic importance: For AV-block, the improvement of the prognosis by pacemaker therapy is unquestionable, since it increases the cumulative survival rates to 81% and 95% after 1 year and 50% to 65% after 5 years. For sick sinus syndrome, VVI-pacing proves to be a symptomatic measure, no prognostic importance can be proven. It is not conclusively clarified at present whether physiological pacing modes (AAI, DDD) have any such importance. Pacemaker therapy also has no prognostic importance for bradyarrhythmia. Hemodynamic importance: Numerous hemodynamic studies show that fixed-rate VVI-pacing fails to produce a long-term hemodynamic improvement for either an AV-block or a sick sinus syndrome. In sick sinus syndrome hemodynamic improvement can only be achieved by physiological pacing modes (AAI, DVI, DDD), whereby the increase in cardiac output is between 11% to 30%. For AV-block a long-term hemodynamic improvement can only be obtained by atrial triggered pacing modes (VAT, VDD, DDD); this is higher than the values of fixed-rate VVI-pacing by 7-25% at rest, or 10-40% under exercise. Similar results with improvements of the exercise hemodynamics between 22% and 66% are reported for rate-modulated single-chamber pacing (VVIR) for AV-block. Future trends: In the fourth decade of pacemaker therapy, developments point toward the "smart pacemaker", toward rate-modulated systems with combinations of parameters, toward rate-modulated dual-chamber systems and universal antibradycardiac and antitachycardiac systems.

[Use of dual-chamber pacemaker. Short and long-term results].

Continuous improvement of dual chamber DDD pacemakers, electrode stability and programmed sequential stimulation changed the prognosis of patients implanted with these devices. To report our experience with the use of dual chamber pacemakers. One hundred seventy six patients (116 male), aged 13 to 91 years old, who received a dual chamber pacemaker implant, are reported. Patients were followed for a mean of 2.6 years. Indications for DDD pacemaker were complete atrioventricular block in 43%, sick sinus syndrome in 32%, paroxysmal A-V block in 24%. All pacemakers were Siemens-Pacesetter and were provided with an automatic sensing and threshold device. J shaped atrium electrodes were used in 78% of patients and screw-in electrodes in 22%. Post operative complications were displacement of atrial electrode in 8 patients, of ventricular electrode in 6 patients, infection in two patients and a hematoma in one. Chronic parameters, measured after six months, were within expected ranges and allowed a good reprogramming of pacemakers. Long term programming aimed to reduce battery depletion, enhance device performance and improve hemodynamic conditions. Normal sequential stimulation was achieved in 154 patients (87%), 14 (85) patients died of cardiovascular disease not related to pacemaker function. Eight patients were in atrial fibrillation and were reprogrammed to VVI and DDI modes. DDD pacemakers are reliable and afford symptomatic relief in a broad spectrum of patients.

Deleterious effects of long-term single-chamber ventricular pacing in patients with sick sinus syndrome: the hidden benefits of dual-chamber pacing.

Nine hundred fifty patients who received three modes of primary pacemaker systems (581 dual-chamber universal [DDD], 84 atrioventricular-sequential ventricular-inhibited [DVI] and 285 ventricular-inhibited [VVI]) over 12 years were studied retrospectively to determine the effect of pacing mode on patient longevity and the subsequent development of chronic atrial fibrillation or flutter. All patients were followed up continuously for 7 to 8 years. Patients were classified according to indication for permanent pacing (sick sinus syndrome or other indication), age at pacemaker implantation (less than or equal to 70 or greater than 70 years) and history of atrial tachyarrhythmia. Fourteen percent of patients developed atrial fibrillation at some time during the study period. Of those, 4% had a DDD pacemaker, 8% had a DVI pacemaker and 19% had a VVI pacemaker. At 7 years, atrial fibrillation was significantly more frequent in the VVI group than in the DDD and DVI groups. In patients with sick sinus syndrome, the incidence rate was even higher in the VVI group but approximately the same in the DDD and DVI groups. Patients in the VVI and DVI groups who had had previous atrial tachyarrhythmia had a significantly higher incidence of atrial fibrillation at 7 years than did those in the DDD group. During the entire period there were 130 deaths in the study group, including 22% of patients with a DDD pacemaker, 38% of those with a DVI pacemaker and 50% of those with a VVI pacemaker. Patient survival at 7 years was lower in the VVI group than in the DDD or DVI groups.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pacemaker therapy in patients with atrial fibrillation].

Pacemaker therapy in patients with atrial fibrillation means the best current pacemaker therapy for patients with bradycardias with the aim to avoid the onset of atrial fibrillation and to establish DDD pacing despite of a history of atrial tachyarrhythmias. The newer application of pacing is the suppression of atrial arrhythmias in patients with medical refractory atrial tachyarrhythmias. Patients with slow ventricular rates and permanent atrial fibrillation should receive a VVI-pacemaker, if the bradycardias causes syncope, dizziness or a decrease of their exercise tolerance. In case of chronotropic incompetence the pacemaker should provide rate responsive pacing. Patients with sick sinus syndrome should receive an atrial (AAI) or dual-chamber (DDD) pacemaker, because patients with these in contrast to VVI-pacemakers develop less often atrial fibrillation and subsequent complications such as atrial thromboembolism. A dual-chamber or VDD-pacemaker--the latter connected to a VDD-single-lead--is indicated in patients with advanced AV-block. Atrial fibrillation occurs in 3 to 6% of the patients with no history of arrythmia and is, if pacemakers have no automatic mode switch, an often reason to program the devices to the VVI-pacing mode. Nowadays, most DDD(R)-pacemakers provide an automatic mode switch: During an atrial tachycardia the pacemaker switches to a VVI/VVIR mode and restores the initial DDD(R)-pacing mode with termination of the arrhythmia. In respect to the newer applications, one approach to prevent atrial tachyarrhythmias is permanent atrial pacing. As lower pacing rates of 80 to 90 ppm are usually needed and many patients hardly tolerate these pacing rates, new algorithms are under clinical investigation. Another approach is the simultaneous depolarization of the right and left atrium. Biatrial pacing is performed with one lead in the high right atrium and another lead in the coronary sinus. Another solution is bifocal atrial pacing with leads placed in the high right atrium and in the coronary sinus ostium. One effect of the new pacing techniques is to shorten interatrial conduction times. Therefore, biatrial pacing has become a therapy to prevent atrial arrhythmias deriving from delayed interatrial conduction times. As atrial reentry circuits seem to be important in atrial fibrillation, multisite atrial pacing is also performed in patients with medical refractory paroxysmal atrial fibrillation. Preliminary results suggest a more effective prevention of atrial fibrillation; nevertheless, these techniques should be still restricted to patients enrolled in clinical studies.

[Retrospective analysis of 1650 permanent pacemaker implantations experience over two different consecutive time periods in a single cardiology clinic].

Indications for pacing, pacing modes, and demographics of patients who underwent pacemaker implantation between two different time periods were compared in this study. Pacemaker registry of our cardiology department was used to evaluate these changes from 1986 to 2007 (First period: 1986-1996, second period: 1997-2007) retrospectively. Registry revealed 776 implantations in the first and 874 implantations in the second period. The percentages of first implantation were 89% and 70.1% respectively. Nearly 50% of the patients in both periods were female. Main indications for pacing were atrioventricular (AV) block, sick sinus syndrome (SSS) and slow ventricular rate during atrial fibrillation in both periods. Implantation of VVI-AAI pacemakers have decreased (77.8%/1.5% to 51%/0.3%, p=0.05) and implantation of DDD-VDD pacemakers have increased (19.3%/1.3% to 42.3%/6.3%, p=0.05) during the second period compared to the first period. Permanent pacemaker implantation for SSS has decreased significantly from 31.1% in the first period to 12.0% (p=0.05) in the second period. Implantation for AV block has increased significantly from 63.3% to 79.7% (p=0.05) in the second period. Our data revealed temporal changes in pacemaker implantation practice during last twenty years in the cardiology department of a teaching hospital. Implantation of VVI-AAI pacemakers have decreased significantly during the second period. Permanent pacemaker implantation for AV block has also decreased during the last period.

[Relative contribution of standard and physiologic stimulation for maximal work capacity in patients with complete atrioventricular block].

The influence of heart rate on the maximal work capacity was investigated in 18 patients (mean age 55 years) with a physiological pacemaker implanted on account of chronic complete atrioventricular block of different aetiology. Twelve patients with a dominating atrial sinus activity had a dual chamber DDD pacemaker and six patients with dominating atrial fibrillation or flutter had a single chamber QTVVIR pacemaker. The exercise test was made on a bicycle ergometer using three stimulation regimes in randomized order and without the patient's knowledge of the programmed mode of pacing: 1. VVI pacing with frequency of 30/min exercise on AV block, 2. VVI pacing with a frequency of 70/min, 3. Uhysiological DDD or QT pacing. Patients with atrioventricular block attained an average heart rate of 54 + 9/min and a work capacity of 81 + 31 W. During VVI pacing a mean frequency of 73 +/- 9/min was achieved (+35%, P less than 0.002) and a work capacity of 100 +/- 45 W (+24%, P less than 0.008). The load during physiological stimulation led to an increased heart rate, i.e. to 140 +/- 15/min (+169%, P less than 0.002) and work capacity to 130 +/- 52 W (+61%, P less than 0.002). The increment of work capacity was thus 2.5 times greater during physiological than during standard ventricular pacing (P less than 0.005), when compared with the work capacity of patients during AV block. A more extensive investigation is needed to identify patients who will benefit maximally from physiological pacing.

[Long-term clinical assessment of single-lead VDD electric stimulation].

During the last decade single lead VDD pacing has been progressively affirmed as an electrotherapy of choice in patients with advanced atrioventricular block without alterations of the sinus function. It combines the benefits of P-synchronous ventricular pacing with an easy implant procedure when compared to the conventional DDD approach. The aim of this study was to evaluate the validity of such an approach in a large population of patients, all implanted in a single center. From 1987 up to now, 317 patients, all affected by advanced atrioventricular block and without sinus node dysfunction, were implanted in our center with a single lead VDD pacemaker. During follow-up the persistence of a proper atrioventricular synchronization was assessed and evaluated. The mean follow-up was 3.9 +/- 2.7 years/patient (range 6-138 months). The 94.6% of implanted systems maintained the normal VDD pacing function. Permanent reprogramming in VVI mode was necessary in 17 patients (5.36%); in 12 (3.78%) because of chronic atrial fibrillation and in 5 (1.63%) for loss of atrial sensing. The percentage of atrial synchronization was optimal (> 98%) and acceptable (> 95%) in 81% and 19% of patients, respectively. Episodes of paroxysmal atrial fibrillation occurred in 3 patients. Neither inhibition by myopotentials nor occurrence of sinus node disease was observed during follow-up. These results are in accordance with those reported by previous studies, performed on a smaller population or on a multicenter basis, and are comparable with the results reported for conventional DDD pacemaker. Our results confirm the high reliability of the single lead VDD pacing system concerning the long-term persistence of a proper atrioventricular synchronization. Data showed above enforce our opinion that this pacing approach should be considered the treatment of choice in patients with advanced atrioventricular block and preserved sinus node function.

Adverse effects of long-term right ventricular apical pacing and identification of patients at risk of atrial fibrillation and heart failure.

In patients needing a pacemaker (PM) for bradycardia indications, the amount of right ventricular (RV) apical pacing has been correlated with atrial fibrillation (AFib) and heart failure (HF) in both DDD and VVI mode. RV pacing was linked with left ventricular (LV) dyssynchrony in almost 50% of patients with PM implantation and atrioventricular (AV) node ablation for AFib. In patients with normal systolic function needing a PM, apical RV pacing resulted in LV ejection fraction (LVEF) reduction. These negative effects were prevented by cardiac resynchronization therapy (CRT). Algorithms favoring physiological AV conduction are possible useful tools able to maintain both atrial and ventricular support and limit RV pacing. However, when chronic RV pacing cannot be avoided, it appears necessary to reconsider the cut-off value of basic LVEF for CRT. In HF patients, RV pacing can induce greater LV dyssynchrony, enhanced by underlying conduction diseases. In this context, a more deleterious effect of RV pacing in implantable cardioverter-defibrillator (ICD) patients with low LVEF can be expected. In some major ICD trials, DDD mode was correlated with increased mortality/HF. This negative impact was attributed to unnecessary RV pacing >40-50%, virtually absent in VVI-40 mode. However, some data suggest that avoiding RV pacing may also not be the best option for patients requiring an ICD. In patients with impaired LV function, AV synchrony should therefore be ensured. The best pacing mode in ICD patients with HF should be defined on an individual basis.

[Atrial fibrillation before and after pacemaker implantation (WI and DDD) in patients with complete atrioventricular block].

Atrial fibrillation (AF) is a frequent problem of patients with pacemakers, and depends not only on disease but also on stimulation method. The aim of the study was to estimate the prevalence of AF before and after pacemaker implantation as well as to assess the influence of VVI and DDD cardiac pacing on onset of AF in patients with complete atrioventricularblock (AVB). We included 155 patients controlled between 2000 and 2008 in Pacemaker Clinic because of AVB III degree, treated with VVI or DDD pacemaker implantation. Information about the health status of the patients was gathered from medical documentation and analysis of clinical ambulatory electrocardiograms. The study group comprised of 68 women and 87 men, mean age 68.7 +/- 13.9 years during implantation. 69% of patients had VVI pacemaker. There were 72.3% of patients with sinus rhythm before pacemaker implantation. During follow-up 4 +/- 2.8 years in 19.6% cases onset of atrial fibrillation de novo was diagnosed (in 31.3% in VVI mode vs. 2.2% in DDD mode; p = 0.00014). Mean time to AF since implantation was approximately 2.5 years. In VVI group (21 persons) amounted 32.1 months, while in 1 patient with DDD pacemaker 18 months. Between group with AF after implantation and with sinus rhythm preserved there was no statistically significant difference in age or gender (p = 0.89512 and p = 0.1253, respectively). Prevalence of atrial fibrillation after pacemaker implantation increased to 40%. Atrial fibrillation is frequent in patients before and after pacemaker implantation, especially in patients stimulated in VVI mode. Major possibility of atrial fibrillation onset after pacemaker implantation should result in more attention during routine ECG examination.

Artificial cardiac pacemaker

From this the basic ventricular "on demand" pacing mode is VVI or with automatic rate adjustment for exercise VVIR – this mode is suitable when no synchronization with the atrial beat is required, as in atrial fibrillation. The equivalent atrial pacing mode is AAI or AAIR which is the mode of choice when atrioventricular conduction is intact but the natural pacemaker the sinoatrial node is unreliable – sinus node disease (SND) or sick sinus syndrome. Where the problem is atrioventricular block (AVB) the pacemaker is required to detect (sense) the atrial beat and after a normal delay (0.1–0.2 seconds) trigger a ventricular beat, unless it has already happened – this is VDD mode and can be achieved with a single pacing lead with electrodes in the right atrium (to sense) and ventricle (to sense and pace). These modes AAIR and VDD are unusual in the US but widely used in Latin America and Europe. The DDDR mode is most commonly used as it covers all the options though the pacemakers

Pacemaker programming in patients with first-degree AV-block: Programming pattern and possible consequences.

The optimal way of pacing in patients with an indication for pacing and concomitant first-degree atrioventricular (AV)-block is not known, and consequently, firm guidelines on this topic are lacking. This study explored the current pacemaker programming pattern in patients with first-degree AV-block who have a dual chamber pacemaker without cardiac resynchronization. The study was a retrospective chart review conducted at Duke University Hospital. Patients receiving a pacemaker due to sinus node dysfunction with coexistent first-degree AV-block were studied. Baseline demographics and characteristics, as well as pacemaker programming parameters and follow-up data, were collected through chart review. Preimplantation and postimplantation electrocardiograms were analyzed. A total of 74 patients were included (mean age, 75 ± 11 y; 53% men). The mean ± SD preimplant PR interval and QRS duration was 243 ± 46 and 110 ± 30 milliseconds, respectively. A history of atrial fibrillation was present in 49% of the patients, and 77% had a normal left ventricular ejection fraction. The majority of patients (65%) had their pacemakers programmed to atrial pacing (AAI/DDD +/-R), whereas 32% and 2.7% of the pacemakers were programmed to AV-sequential pacing (DDD) and ventricular pacing (VVI), respectively. There were no significant differences in baseline characteristics or electrocardiogram measures between patients programmed to the 3 pacing modes. Patients with pacemakers programmed to AAI had a lower ventricular pacing percentage at follow-up (8 vs 55, and 46% [DDD and VVI, respectively]; P < .001). There was no evident association between baseline characteristics and programmed pacing mode in patients with first-degree AV-block. The choice of pacing mode affects long-term pacing burden, which in turn has been shown to influence outcome.

[Clinical efficacy of permanent cardiac pacing in patients with bradysystolic forms of disturbances of cardiac rhythm and conduction].

From 1996 to 2002 primary implantations of pacing systems because of bradysystolic disturbances of cardiac rhythm and conduction had been carried out in 311 patients. Indications were disturbances of atrioventricular conduction in 168 and sick sinus syndrome in 143 patients. According to type of permanent pacing patients were divided into 3 groups: with single-chamber ventricular on demand pacing (VVI, n=215), with single-chamber atrial pacing (AAI, n=39), and with dual-chamber pacing (DDD, n=57). As characteristics illustrating long term clinical results of permanent pacing we used development of the pacemaker syndrome; development of permanent atrial fibrillation; risk of thromboembolic complications and strokes; progression of heart failure; total, cardiovascular mortality and their structure; 7 year survival.

[DDD dual chamber pacemakers. Initial experience].

Our preliminary experience with dual-chamber DDD pacemakers is reported. Technological innovations of the device, atrio-ventricular electrode stability and sequential stimulation have contributed to improve the conditions of patients previously submitted to VVI pacemaker implantation. Primary indications for DDD pacemaker implantation in our series included 7 patients with complete atrio-ventricular (A-V) block, 3 with Mobitz type II second-degree A-V block and 2 with sick sinus syndrome. In six of the 12 patients (50%) additional indications included: ventricular tachycardia in 4 patients, atrial fibrillation in one and pacemaker syndrome in one. Other cardiac conditions were diagnosed: dilated cardiomyopathy in 3 patients, ischemic heart disease in 2 patients, valvular heart disease in 2 patients, congenital heart disease in 1 patient and hypertrophic cardiomyopathy in one patient. The implanted pacemakers were: 5 Genesis, 4 Ultra CPI and 3 Versatrax. J-shaped atrial electrodes were used in 8 patients and in 4 instances a screw-in electrode was employed. Improvement of hemodynamic function was achieved by frequent follow up and reprogramming of DDD pacemaker in every patient. While 4 patients died with progressive deterioration of cardiac function, eight patients survived with adequate sequential stimulation. We conclude that DDD pacemakers are reliable and afford symptomatic relief in a broad spectrum of patients.

[Clinical safety and efficacy of single-chamber atrial pacing in sick sinus syndrome: long-term follow-up].

Although atrial pacing is a more physiological mode of stimulation in sinus node dysfunction, the pacing modes most often are used DDD and VVI. The aim of our study was to demonstrate that AAI/AAIR pacing is effective and safe by analyzing the complications and mortality of this pacing mode in a long-term follow-up study. Between 1982 and 2000 definitive AAI-mode pacemakers were implanted for sinus node dysfunction in mode AAI in 160 patients. We analyzed the clinical characteristics, evolution, and complications of the AAI pacing mode during a follow-up of 5.4 4.5 years. The sample was made up of 104 women and 56 men with an average age of 72 12 years. During follow-up, it was necessary to change the pacing mode for symptomatic bradycardia in 11 patients (annual incidence 1.2%), which was caused by second or third-degree atrioventricular block in 7 patients (annual incidence 0.8%), and chronic atrial fibrillation with bradycardia in 4 patients (annual incidence 0.4%). During follow-up, atrial arrhythmias occurred in 32 patients (annual incidence 3.7%), stroke in 4 patients (annual incidence 0.4%), and 27 patients (annual incidence 3.1%) died. The AAI/AAIR pacing mode was safe and effective in sinus node dysfunction, with a low percentage of pacing changes required for progression to atrioventricular block, low incidence of atrial arrhythmias, stroke and low mortality during long term follow-up.

Atrial pacing should be used more frequently in sinus node disease.

Single lead atrial (AAI(R)) pacing for sick sinus syndrome provides physiological pacing and is less expensive than a dual chamber system. Compared with ventricular-based pacing, it maintains the normal cardiac depolarization sequence, is associated with less atrial fibrillation and heart failure, and avoids pacemaker syndrome. We sought whether it is possible to select patients for AAI(R) pacing with a low likelihood of subsequent ventricular pacing, and whether this approach was cost-effective. A retrospective review was conducted of AAI(R) pacemaker implantations. Patients requiring a further procedure for insertion of a ventricular lead (for DDD(R) or VVI(R) pacing) were compared with those who remained atrially paced. 2.7% (117 of 4,366) of implants were AAI(R), compared with less than 1% overall for New Zealand and Australia. During follow-up of 3.5 (2.3, 7.7) years, insertion of a ventricular lead was required in 14 (12%), and was more likely in those with pre-existing PR interval >0.20 seconds (odds ratio 7.8, P = 0.003) or left bundle branch block (LBBB, odds ratio 17, P = 0.037). Right bundle branch block, left anterior fascicular block, or history of paroxysmal atrial fibrillation were not more frequent in the group requiring ventricular pacing, and preimplantation Wenckebach point was not different. The most efficient strategy was initial AAIR implantation in all except those with LBBB or PR interval >0.20 seconds. Compared with routine DDDR implantation, cost was reduced by 20%, with a 1.4% annual incidence of further procedures. AAIR is the appropriate pacing choice for sick sinus syndrome without LBBB or PR interval >0.20 seconds.

Artificial cardiac pacemaker

Biventricular pacing Cardiac resynchronization therapy (CRT) is used for people with heart failure in whom the left and right ventricles do not contract simultaneously (ventricular dyssynchrony), which occurs in approximately 25–50% of heart failure patients. To achieve CRT, a biventricular pacemaker (BVP) is used, which can pace both the septal and lateral walls of the left ventricle. By pacing both sides of the left ventricle, the pacemaker can resynchronize the ventricular contractions.

[Atrial-triggered and ventricular-inhibited ventricular VDD pacing with atrial and ventricular single catheter electrodes--the Phymos MPS pacemaker].

Optimal treatment from the haemodynamic aspect in complete atrioventricular block is dual-chamber DDD pacing. It makes possible atrioventricular sequence and adaptability of the frequency of ventricular pacing to the load under the control of the sinoatrial node. DDD pacing calls, however, for an atrial and ventricular electrode on two leads. Italian authors developed in 1984 a pacemaker (PM) PHYMOS (MEDICO ITALIA) which makes possible atrial triggered ventricular VDD pacing by means of a single pass lead with a tripolar electrode. As the first ones in the post-communist countries the authors implanted to six patients a PM PHYMOS MPS. They confirmed that the advantages of the VDD system, as compared with DDD, are the use of a single pass lead. This makes the implantation quicker, simpler and safer and reduces the time of X-ray irradiation and the incidence of electrodes dislocations. Another advantage is the lower incidence of atrial fibrillation and probably also pacemaker mediated tachycardias. The disadvantages of the VDD system are that atrial stimulation is impossible and that the diameter of the single pass lead is somewhat larger. According to data in the literature and the so far small experience of the authors, when the indication is correct--atrioventricular block grade III or II with intact function of the sinoatrial node--the advantages of VDD pacing with a single pass lead, as compared with DDD pacing, predominate over disadvantages.

Development of atrial fibrillation in patients with atrioventricular block after atrioventricular synchronized pacing.

Many studies have evidenced an increased incidence of AF in patients receiving single chamber ventricular pacing (VVI) when compared with those undergoing an atrial-based system (AAI or DDD). However, the difference in incidence of AF between two atrial-based systems (VDD, DDD) in patients with AV block was still controversial. This study was conducted to compare the development of AF between different modes of pacemakers (VDD and DDD) in patients with symptomatic AV block. A retrospective review was conducted of the detailed records of all consecutive patients who received permanent pacemakers due to symptomatic bradycardia from March 1995 to March 2000. The occurrence of AF was documented when there was presence of AF in the free-run or 12-lead ECG, any ECG strips, or persistent AF on 24-hour Holter ECG during the follow-up. The study included 152 patients (44 women, 108 men; mean age 73). The patients were divided into two groups: VDD (n = 100) and DDD (n = 52). The mean follow-up was 48.9 +/- 22.9 months. The incidence of AF was 7.9%. A higher incidence of AF was noted in the DDD group (15.4%) when compared with the VDD group (4.0%, P = 0.023). The incidence of development of AF in patients with AV block was higher in those receiving DDD cardiac pacing when compared with those who received the VDD system. The authors suggest that VDD pacing may be a better choice than the DDD system for patients with AV block, but without clinical evidence of sinus node dysfunction, and if an atrial lead is required, it should be placed close to the Bachmann's bundle.

Managed ventricular pacing compared with conventional dual-chamber pacing for elective replacement in chronically paced patients: results of the Prefer for Elective Replacement Managed Ventricular Pacing randomized study.

Several studies have shown that unnecessary right ventricular pacing has detrimental effects. To evaluate whether minimization of ventricular pacing as compared with standard dual-chamber pacing (DDD) improves clinical outcomes in patients referred for pacemaker or implantable cardioverter-defibrillator (ICD) replacement. In an international single-blind, multicenter, randomized controlled trial, we compared DDD with managed ventricular pacing (MVP), a pacing mode developed to minimize ventricular pacing by promoting intrinsic atrioventricular conduction. We included patients referred for device replacement with >40% ventricular pacing, no cardiac resynchronization therapy upgrade indication, no permanent atrial fibrillation (AF), and no permanent complete atrioventricular block. Follow-up was for 2 years. The primary end point was cardiovascular hospitalization. The intention-to-treat analysis was performed by using Kaplan-Meier method and the log-rank test. We randomized 605 patients (556 referred for pacemaker and 49 referred for ICD replacement; mean age 75 ± 11 years; 365 [60%] men, at 7.7 ± 3.3 years from first device implantation) to MVP (n = 299) or DDD (n = 306). We found no significant differences in the primary end point cardiovascular hospitalization (MVP: 16.3% vs DDD: 14.5%; P = .72) and the secondary end point persistent AF (MVP: 15.4% vs DDD: 11.2%; P = .08), permanent AF (MVP: 4.1% vs DDD: 3.1%; P = .44), and composite of death and cardiovascular hospitalization (MVP: 23.9% vs DDD: 20.2%; P = .48). MVP reduced right ventricular pacing (median 5% vs 86%; Wilcoxon, P < .0001) as compared with DDD. In patients referred for pacemaker and ICD replacement with clinically well-tolerated long-term exposure to >40% ventricular pacing in the ventricle, a strategy to minimize ventricular pacing is not superior to standard DDD in reducing incidence of cardiovascular hospitalizations.

[The pacemaker and implantable cardioverter-defibrillator registry of the Italian Association Arrhythmology Cardiac Pacing and cardiac pacing - annual report 2013].

The pacemaker (PM) and implantable cardioverter-defibrillator (ICD) Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) monitors the main epidemiological data in real-world practice. The survey for the 2013 activity collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the Italian collaborating centers. The Registry collects prospectively national PM and ICD implantation activity on the basis of European cards. PM Registry: data about 25 419 PM implantations were collected (19 134 first implant and 6285 replacements). The number of collaborating centers was 275. Median age of treated patients was 80 years (74 quartile I; 86 quartile III). ECG indications included atrioventricular conduction disorders in 43.6% of first PM implants, sick sinus syndrome in 24.7%, atrial fibrillation plus bradycardia in 12.9%, other in 18.8%. Among atrioventricular conduction defects, third-degree atrioventricular block was the most common type (23.2% of first implants). Use of single-chamber PMs was reported in 27.2% of first implants, of dual-chamber PMs in 62.6%, of PMs with cardiac resynchronization therapy (CRT) in 1.8%, and of single lead atrial-synchronized ventricular stimulation (VDD/R PMs) in 8.4%. ICD Registry: data about 16 519 ICD implantations were collected (11 474 first implants and 5045 replacements). The number of collaborating centers was 430. Median age of treated patients was 71 years (63 quartile I; 77 quartile III). Primary prevention indication was reported in 76% of first implants, secondary prevention in 24.0% (cardiac arrest in 7.8%). A single-chamber ICD was used in 27.2% of first implants, dual-chamber in 35.9% and biventricular in 36.8%. The PM and ICD Registry appears fundamental for monitoring PM and ICD utilization on a large national scale with rigorous examination of demographics and clinical indications. The PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The use of CRT-PM regards a very limited number of patients. The ICD Registry documented a constant increase in prophylactic and biventricular ICD use, reflecting a favorable adherence to trials and guidelines in clinical practice.

Pacing for sinus node disease: a therapeutic rationale.

Symptomatic sinus node disease is a common indication for permanent pacemaker implantation. Single-chamber ventricular (VVI) pacing, single-chamber atrial (AAI) stimulation, and dual-chamber (DDD or DDI) systems are used to a varying extent at different implanting centers. Hemodynamic and clinical studies relevant to the choice of pacing mode in these patients are reviewed. The data currently available strongly support the use of pacing systems providing atrial stimulation. The choice between single-chamber atrial or dual-chamber pacing can be based on the relative importance assigned to a number of factors: Hemodynamic aspects, the risk of ventricular lead problems, cost, and complexity aspects favor AAI pacing, whereas patients with a substantial risk of developing atrioventricular block should receive a DDD or DDI unit.

Pacemaker crosstalk

Cause Crosstalk can only occur in dual chamber or biventricular pacemaker. It happens less often in more recent models of dual chamber pacemakers due to the addition of a ventricular blanking period, which coincides with the atrial stimulus. This helps to prevent ventricular channel oversensing of atrial output. Newer dual chamber pacemakers also use bipolar leads with a smaller pacing spike, and steroid eluting leads with lower pacing thresholds. Crosstalk is more common in unipolar systems since they require a larger pacing spike. Crosstalk is sometimes referred to as crosstalk inhibition, far-field sensing, or self-inhibition. In some cases, crosstalk can occur in the pulse generator circuit itself, though more common causes include atrial lead dislodgement into the ventricle, ventricular lead dislodgement into the atrium, high atrial output current, high ventricular sensitivity, and short ventricular blanking period.

[Predictors for need of antibradycardia and antitachycardia pacing after ICD implantation : Implications for the subcutaneous ICD].

Little is known about the incidence and risk factors for progression to pacemaker dependency or the need for cardiac resynchronization in typical patients with an implanted defibrillator with regard to an alternative implantation of a subcutaneous ICD (S-ICD). After retrospective analysis of 291 patients with first implantation of a transvenous single chamber ICD (VVI-ICD) from 2010-2016 and excluding those with an indication for pacemaker or lack of follow-up data, 121 patients were included and investigated with regard to the following endpoints: need for pacemaker stimulation, upgrade for cardiac resynchronization (CRT), and secondary occurrence and effectiveness of antitachycardia pacing (ATP). We compared the results with those of fundamental S‑ICD studies and tried to determine risk factors on the basis of medical history and pre-implant data. The study population and the rate of endpoints were significantly different to those of fundamental S‑ICD studies. Within a 2.2-year follow-up, 14.9 % of the patients developed a need for pacemaker stimulation and 0.8 % the need for cardiac resynchronization. Excluding patients who at implantation were already at high risk for pacemaker dependency, 7.4 % remained with a reached endpoint. We identified atrial fibrillation and bundle-branch-block as risk factors. All episodes of ventricular tachycardia (VT) could be terminated by ATP in 9.9 % of the patients. They more often had ischemic heart disease and a secondary prophylactic indication for an ICD. The low rate of conversions from S‑ICD to a transvenous ICD in case of pacemaker-dependency as stated in fundamental S‑ICD studies should not be transferred to other typical collectives of ICD recipients. The latter group is at significantly higher risk for developing pacemaker-dependency.

[The Pacemaker and Implantable Cardioverter-Defibrillator Registry of the Italian Association of Arrhythmology and Cardiac Pacing--Annual report 2014].

The pacemaker (PM) and implantable cardioverter-defibrillator (ICD) Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) monitors the main epidemiological data in real-world practice. The survey for the 2014 activity collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the Italian collaborating centers. The Registry collects prospectively national PM and ICD implantation activity on the basis of European cards. PM Registry: data about 24 680 PM implantations were collected (19 480 first implant and 5200 replacements). The number of collaborating centers was 208. Median age of treated patients was 81 years (75 quartile I; 86 quartile III). ECG indications included atrioventricular conduction disorders in 45.3% of first PM implants, sick sinus syndrome in 23.1%, atrial fibrillation plus bradycardia in 11.7%, other in 19.9%. Among atrioventricular conduction defects, third-degree atrioventricular block was the most common type (22.7% of first implants). Use of single-chamber PMs was reported in 26.9% of first implants, of dual-chamber PMs in 63.6%, of PMs with cardiac resynchronization therapy (CRT) in 1.7%, and of single lead atrial-synchronized ventricular stimulation (VDD/R PMs) in 7.8%. ICD Registry: data about 17 116 ICD implantations were collected (11 274 first implants and 5842 replacements). The number of collaborating centers was 424. Median age of treated patients was 71 years (62 quartile I; 77 quartile III). Primary prevention indication was reported in 72.3% of first implants, secondary prevention in 27.7% (cardiac arrest in 10.1%). A single-chamber ICD was used in 32.2% of first implants, dual-chamber in 37.1% and biventricular in 30.7%. The PM and ICD Registry appears fundamental for monitoring PM and ICD utilization on a large national scale with rigorous examination of demographics and clinical indications. The PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The use of CRT-PM regards a very limited number of patients. The ICD Registry documented a large use of prophylactic and biventricular ICD, reflecting a favorable adherence to trials and guidelines in clinical practice.

[The pacemaker and implantable cardioverter-defibrillator registry of the Italian Association of Arrhythmology and Cardiac Pacing - Annual Report 2012].

The pacemaker (PM) and implantable cardioverter-defibrillator (ICD) Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) monitors the main epidemiological data in real-world practice. The survey for the 2012 activity collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the Italian collaborating centers. The Registry collects prospectively national PM and ICD implantation activity on the basis of European cards. PM Registry: data about 25 611 PM implantations were collected (18 870 first implant and 6741 replacements). The number of collaborating centers was 245. Median age of treated patients was 80 years (74 quartile I; 86 quartile III). ECG indications included atrioventricular conduction disorders in 41.9% of first PM implants, sick sinus syndrome in 26.0%, atrial fibrillation plus bradycardia in 13.7%, other in 18.4%. Among atrioventricular conduction defects, third-degree atrioventricular block was the most common type (21.7% of first implants). Use of single-chamber PMs was reported in 29.0% of first implants, of dual-chamber PMs in 61.3%, of PMs with cardiac resynchronization therapy (CRT) in 1.7%, and of single lead atrial-synchronized ventricular stimulation (VDD/R PMs) in 8.0%. ICD REGISTRY: data about 16 606 ICD implantations were collected (11 393 first implants and 5213 replacements). The number of collaborating centers was 427. Median age of treated patients was 71 years (62 quartile I; 77 quartile III). Primary prevention indication was reported in 68.6% of first implants, secondary prevention in 31.4% (cardiac arrest in 9.0%). A single-chamber ICD was used in 29.4% of first implants, dual-chamber in 37.6% and biventricular in 32.9%. The PM and ICD Registry appears fundamental for monitoring PM and ICD utilization on a large national scale with rigorous examination of demographics and clinical indications. The PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The use of CRT-PM regards a very limited number of patients. The ICD Registry documented a constant increase in prophylactic and biventricular ICD use, reflecting a favorable adherence to trials and guidelines in clinical practice.

[The Pacemaker and Implantable Cardioverter-Defibrillator Registry of the Italian Association of Arrhythmology and Cardiac Pacing - Annual report 2016].

The pacemaker (PM) and implantable cardioverter-defibrillator (ICD) registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) monitors the main epidemiological data in real-world practice. The survey for the 2016 activity collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the Italian collaborating centers. The registry collects prospectively national PM and ICD implantation activity on the basis of European cards. PM Registry: data about 23 496 PM implantations were collected (19 003 first implant and 4493 replacements). The number of collaborating centers was 204. Median age of treated patients was 81 years (75 quartile I; 86 quartile III). ECG indications included atrioventricular conduction disorders in 39.8% of first PM implants, sick sinus syndrome in 22.1%, atrial fibrillation plus bradycardia in 14.1%, other in 24.0%. Among atrioventricular conduction defects, third-degree atrioventricular block was the most common type (22.18% of first implants). Use of single-chamber PMs was reported in 26.9% of first implants, of dual-chamber PMs in 65.0%, of PMs with cardiac resynchronization therapy (CRT) in 1.5%, and of single lead atrial-synchronized ventricular stimulation (VDD/R PMs) in 6.6%. ICD Registry: data about 20 350 ICD implantations were collected (14 763 first implants and 5587 replacements). The number of collaborating centers was 430. Median age of treated patients was 72 years (63 quartile I; 78 quartile III]. Primary prevention indication was reported in 79.0% of first implants, secondary prevention in 21.0% (cardiac arrest in 7.9%). A single-chamber ICD was used in 32.2% of first implants, dual-chamber in 31.1% and biventricular in 36.7%. The PM and ICD Registry appears fundamental for monitoring PM and ICD utilization on a large national scale with rigorous examination of demographics and clinical indications. The PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The use of CRT-PM regards a very limited number of patients. The ICD Registry documented a large use of prophylactic and biventricular ICD, reflecting a favorable adherence to trials and guidelines in clinical practice.

[The Pacemaker and Implantable Cardioverter-Defibrillator Registry of the Italian Association of Arrhythmology and Cardiac Pacing - Annual report 2015].

The pacemaker (PM) and implantable cardioverter-defibrillator (ICD) Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) monitors the main epidemiological data in real-world practice. The survey for the 2015 activity collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the Italian collaborating centers. The Registry collects prospectively national PM and ICD implantation activity on the basis of European cards. PM Registry: data about 24 285 PM implantations were collected (19 194 first implant and 5091 replacements). The number of collaborating centers was 218. Median age of treated patients was 81 years (75 quartile I; 86 quartile III). ECG indications included atrioventricular conduction disorders in 42.8% of first PM implants, sick sinus syndrome in 22.9%, atrial fibrillation plus bradycardia in 15.1%, other in 19.2%. Among atrioventricular conduction defects, third-degree atrioventricular block was the most common type (23.8% of first implants). Use of single-chamber PMs was reported in 26.9% of first implants, of dual-chamber PMs in 63.4%, of PMs with cardiac resynchronization therapy (CRT) in 1.8%, and of single lead atrial-synchronized ventricular stimulation (VDD/R PMs) in 7.9%. ICD Registry: data about 15 363 ICD implantations were collected (11 453 first implants and 3910 replacements). The number of collaborating centers was 434. Median age of treated patients was 71 years (63 quartile I; 78 quartile III]. Primary prevention indication was reported in 77.3% of first implants, secondary prevention in 22.7% (cardiac arrest in 8.0%). A single-chamber ICD was used in 29.3% of first implants, dual-chamber in 34.6% and biventricular in 36.1%. The PM and ICD Registry appears fundamental for monitoring PM and ICD utilization on a large national scale with rigorous examination of demographics and clinical indications. The PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The use of CRT-PM regards a very limited number of patients. The ICD Registry documented a large use of prophylactic and biventricular ICD, reflecting a favorable adherence to trials and guidelines in clinical practice.

[The Pacemaker and Implantable Cardioverter-Defibrillator Registry of the Italian Association of Arrhythmology and Cardiac Pacing - Annual report 2018].

The pacemaker (PM) and implantable cardioverter-defibrillator (ICD) Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) monitors the main epidemiological data in real-world practice. The survey for the 2018 activity collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the Italian collaborating centers. The Registry collects prospectively national PM and ICD implantation activity on the basis of European cards. PM Registry: data about 23 912 PM implantations were collected (20 084 first implants and 3828 replacements). The number of collaborating centers was 180. Median age of treated patients was 81 years (75 quartile I; 86 quartile III). ECG indications included atrioventricular conduction disorders in 34.5% of first PM implants, sick sinus syndrome in 18.3%, atrial fibrillation plus bradycardia in 13.0%, other in 34.2%. Among atrioventricular conduction defects, third-degree atrioventricular block was the most common type (19.2% of first implants). Use of single-chamber PMs was reported in 24.9% of first implants, of dual-chamber PMs in 67.6%, of PMs with cardiac resynchronization therapy (CRT) in 1.6%, and of single lead atrial-synchronized ventricular stimulation (VDD/R PMs) in 5.9%. ICD Registry: data about 18 353 ICD implantations were collected (13 944 first implants and 4359 replacements). The number of collaborating centers was 433. Median age of treated patients was 71 years (63 quartile I; 78 quartile III). Primary prevention indication was reported in 84.3% of first implants, secondary prevention in 15.7% (cardiac arrest in 5.3%). A single-chamber ICD was used in 27.9% of first implants, dual-chamber ICD in 31.9% and biventricular ICD in 40.2%. The PM and ICD Registry appears fundamental for monitoring PM and ICD utilization on a large national scale with rigorous examination of demographics and clinical indications. The PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The use of CRT-PM regards a very limited number of patients. The ICD Registry documented a large use of prophylactic and biventricular ICD, reflecting a favorable adherence to trials and guidelines in clinical practice. In order to increase and optimize the cooperation of Italian implanting centers, online data entry (http://www.aiac.it/riprid) should be adopted at large scale.

Artificial cardiac pacemaker

Automatic pacemakers are designed to be over-ridden by the heart's natural rate at any moment that it gets back to a non-pathologic normal sinus rhythm and can reinitiate influencing the electric activity in the heart when the pathologic event happens again. A "ventricular-demand pacemaker" produces a narrow vertical spike on the ECG, just before a wide QRS. The spike of an "atrial-demand pacemaker" appears just before the P wave. Comparably, a Triggered Pacemaker is activated immediately after an electrical activity is commenced in the heart tissue by itself. A "ventricular triggered pacemaker" produces the impulse just after a pulse is created in the ventricular tissue and it appears as a simultaneous spike with QRS. An "atrial triggered pacemaker" is the mode in which an impulse is produced immediately after an electrical event in the atrium. It appears as a discharge following the p wave but prior to the QRS which is commonly widened. Biventricular pacing

[The Pacemaker and Implantable Cardioverter-Defibrillator Registry of the Italian Association of Arrhythmology and Cardiac Pacing - Annual report 2017].

The pacemaker (PM) and implantable cardioverter-defibrillator (ICD) Registry of the Italian Association of Arrhythmology and Cardiac Pacing (AIAC) monitors the main epidemiological data in real-world practice. The survey for the 2017 activity collects information about demographics, clinical characteristics, main indications for PM/ICD therapy and device types from the Italian collaborating centers. The Registry collects prospectively national PM and ICD implantation activity on the basis of European cards. PM Registry: data about 23 457 PM implantations were collected (19 378 first implant and 4079 replacements). The number of collaborating centers was 185. Median age of treated patients was 81 years (75 quartile I; 86 quartile III). ECG indications included atrioventricular conduction disorders in 37.1% of first PM implants, sick sinus syndrome in 19.5%, atrial fibrillation plus bradycardia in 13.2%, other in 30.2%. Among atrioventricular conduction defects, third-degree atrioventricular block was the most common type (21.0% of first implants). Use of single-chamber PMs was reported in 25.6% of first implants, of dual-chamber PMs in 66.7%, of PMs with cardiac resynchronization therapy (CRT) in 1.4%, and of single lead atrial-synchronized ventricular stimulation (VDD/R PMs) in 6.3%. ICD Registry: data about 19 023 ICD implantations were collected (13 898 first implants and 5125 replacements). The number of collaborating centers was 437. Median age of treated patients was 71 years (63 quartile I; 78 quartile III). Primary prevention indication was reported in 81.8% of first implants, secondary prevention in 18.2% (cardiac arrest in 6.4%). A single-chamber ICD was used in 27.0% of first implants, dual-chamber in 33.6% and biventricular in 39.3%. The PM and ICD Registry appears fundamental for monitoring PM and ICD utilization on a large national scale with rigorous examination of demographics and clinical indications. The PM Registry showed stable electrocardiographic and symptom indications, with an important prevalence of dual-chamber pacing. The use of CRT-PM regards a very limited number of patients. The ICD Registry documented a large use of prophylactic and biventricular ICD, reflecting a favorable adherence to trials and guidelines in clinical practice. In order to increase and optimize the cooperation of Italian implanting centers, online data entry (http://www.aiac.it/riprid) should be adopted at large scale.