The Drug And Pace Health cliNical Evaluation (DAPHNE) study: a randomized trial comparing sotalol versus beta-blockers to treat symptomatic atrial fibrillation in patients with brady-tachycardia syndrome implanted with an antitachycardia pacemaker. A randomised, controlled study of rate versus rhythm control in patients with chronic atrial fibrillation and heart failure: (CAFÉ-II Study) A comparison of single-lead atrial pacing with dual-chamber pacing in sick sinus syndrome. Incidence of atrial fibrillation and thromboembolism in a randomised trial of atrial versus dual chamber pacing in 177 patients with sick sinus syndrome AAIR versus DDDR pacing in the bradycardia tachycardia syndrome: a prospective, randomized, double-blind, crossover trial. Effects of cardiac resynchronization therapy on heart rate variability in patients with chronic systolic heart failure and intraventricular conduction delay. Ventricular pacing or dual-chamber pacing for sinus-node dysfunction. Cardiac resynchronization in chronic heart failure. High incidence of pacemaker syndrome in patients with sinus node dysfunction treated with ventricular-based pacing in the Mode Selection Trial (MOST). Effects of multisite biventricular pacing in patients with heart failure and intraventricular conduction delay. Adenosine: a clinical experience and comparison with verapamil for the termination of supraventricular tachycardias. Progression of heart failure in right univentricular pacing compared to biventricular pacing. Quality of life and clinical outcomes in elderly patients treated with ventricular pacing as compared with dual-chamber pacing. Pacemaker Selection in the Elderly Investigators. Upgrading from single chamber right ventricular to biventricular pacing in permanently paced patients with worsening heart failure: The RD-CHF Study. Pacemaker dependency after transcatheter aortic valve implantation with the self-expanding Medtronic CoreValve System. Rate adaptive pacing in sick sinus syndrome: effects of pacing modes and intrinsic conduction on physiological responses, arrhythmias, symptomatology and quality of life. Clinical efficacy of cardiac resynchronization therapy using left ventricular pacing in heart failure patients stratified by severity of ventricular conduction delay.
BACKGROUND Atrial tachyarrhythmias ( ATAs ) are mainly treated by pharmacologic therapy for rate control or rhythm control . The aim of our study was to compare sotalol ( S ) versus beta-blocking agents ( BB ) in terms of prevention of ATA , cardioversions ( CVs ) , and cardiovascular hospitalizations ( H ) in patients paced for bradycardia-tachycardia form of sinus node disease ( BT-SND ) . METHODS One hundred thirty-five patients ( 67 males , aged 73 + /- 7 years ) were enrolled in a prospect i ve , parallel , r and omized , single-blind , multicenter study . All patients received a dual chamber rate adaptive pacemaker ; after 1 month , 66 patients were r and omly assigned to BB ( 62 + /- 26 and 104 + /- 47 mg/d for atenolol and metoprolol , respectively ) and 69 patients to S ( 167 + /- 66 mg/d ) . RESULTS After an observation period of 12 months , the percentage of patients free from ATA recurrences was 29 % in both BB and S group . Cardioversion and H were significantly ( P < .01 ) fewer in the 12 months after implantation than in the 12 months before both in patients treated with S ( CV 69.4 % vs 22.2 % , H 91.7 % vs 33.3 % ) and in patients treated with BB ( CV 58.5 % vs 17.1 % , H 82.9 % vs 26.8 % ) . Kaplan-Meier survival analysis showed a nonsignificant trend toward a lower incidence of the composite end point ( CV + H ) among BB patients . CONCLUSIONS In the complex context of " hybrid therapy " in patients with BT-SND implanted with a modern dual chamber rate adaptive pacemaker device delivering atrial antitachycardia pacing , no differences were found between the use of beta-blocker and the use of S , at the relatively low dose achieved after clinical titration , in terms of prevention of cardiovascular H or need for atrial CV Background : Atrial fibrillation ( AF ) and heart failure ( HF ) often coexist . The aim was to investigate whether restoring sinus rhythm ( SR ) could improve cardiac function , symptoms , exercise capacity and quality of life ( QoL ) in patients with chronic heart failure . Methods : Patients with HF and persistent AF receiving guideline -recommended treatments , including anticoagulants , were eligible for the study . Patients were r and omised to either rhythm ( treated with amiodarone for at least 3 months prior to attempting biphasic external cardioversion and continued amiodarone long-term if SR was restored ) or rate control . Anticoagulants were continued throughout the study regardless of rhythm , unless contraindications developed . Both groups were treated with beta blockers and /or digoxin to reduce the heart rate to < 80 bpm at rest and < 110 bpm after walking . Symptoms , walk distance ( 6-minute corridor walk test , 6MWT ) , QoL and cardiac function were assessed at baseline and 1 year . Results : 61 patients with HF and persistent AF ( median duration 14 months ( IQR 5 to 32 ) ) were r and omly assigned to a rate or rhythm control strategy . Of patients assigned to rhythm control ( n = 30 ) , 66 % were in SR at 1 year , and 90 % of those assigned to rate control ( n = 31 ) achieved the heart rate target . At 1 year , NYHA class ( p = 0.424 ) and 6MWT distance ( p = 0.342 ) were similar between groups but patients assigned to rhythm control had improved LV function ( p = 0.014 ) , NT-proBNP concentration ( p = 0.046 ) and QoL ( p = 0.019 ) compared with those assigned to rate control . Greatest improvement was seen in patients in whom SR was maintained . Conclusion : Restoring SR in patients with AF and heart failure may improve QoL and LV function when compared with a strategy of rate control AIMS In patients with sick sinus syndrome , bradycardia can be treated with a single-lead pacemaker or a dual-chamber pacemaker . Previous trials have revealed that pacing modes preserving atrio-ventricular synchrony are superior to single-lead ventricular pacing , but it remains unclear if there is any difference between single-lead atrial pacing ( AAIR ) and dual-chamber pacing ( DDDR ) . METHODS AND RESULTS We r and omly assigned 1415 patients referred for first pacemaker implantation to AAIR ( n = 707 ) or DDDR ( n = 708 ) pacing and followed them for a mean of 5.4 ± 2.6 years . The primary outcome was death from any cause . Secondary outcomes included paroxysmal and chronic atrial fibrillation , stroke , heart failure , and need for pacemaker reoperation . In the AAIR group , 209 patients ( 29.6 % ) died during follow-up vs. 193 patients ( 27.3 % ) in the DDDR group , hazard ratio ( HR ) 1.06 , 95 % confidence interval ( CI ) 0.88 - 1.29 , P = 0.53 . Paroxysmal atrial fibrillation was observed in 201 patients ( 28.4 % ) in the AAIR group vs. 163 patients ( 23.0 % ) in the DDDR group , HR 1.27 , 95 % CI 1.03 - 1.56 , P = 0.024 . A total of 240 patients underwent one or more pacemaker reoperations during follow-up , 156 ( 22.1 % ) in the AAIR group vs. 84 ( 11.9 % ) in the DDDR group ( HR 1.99 , 95 % CI 1.53 - 2.59 , P < 0.001 ) . The incidence of chronic atrial fibrillation , stroke , and heart failure did not differ between treatment groups . CONCLUSION In patients with sick sinus syndrome , there is no statistically significant difference in death from any cause between AAIR pacing and DDDR pacing . AAIR pacing is associated with a higher incidence of paroxysmal atrial fibrillation and a two-fold increased risk of pacemaker reoperation . These findings support the routine use of DDDR pacing in these patients . CLINICAL TRIAL REGISTRATION URL http://www . clinical trials.gov . Unique identifier : NCT00236158 Objective : To analyse the occurrence of atrial fibrillation ( AF ) and thromboembolism in a r and omised comparison of rate adaptive single chamber atrial pacing ( AAIR ) and dual chamber pacing ( DDDR ) in patients with sick sinus syndrome and normal atrioventricular ( AV ) conduction , in which left atrial dilatation and decreased left ventricular fractional shortening had been observed in the DDDR group . Methods : 177 consecutive patients with sick sinus syndrome ( mean ( SD ) age 74 ( 9 ) years , 104 women ) were r and omly assigned to treatment with one of three pacemakers : AAIR ( n = 54 ) , DDDR with a short rate adaptive AV delay ( n = 60 ) ( DDDR-s ) ; or DDDR with a fixed long AV delay ( n = 63 ) ( DDDR-l ) . Analysis was intention to treat . Results : Mean follow up was 2.9 ( 1.1 ) years . AF at one or more ambulatory visits was significantly less common in the AAIR group ( 4 ( 7.4 % ) v 14 ( 23.3 % ) in the DDDR-s group v 11 ( 17.5 % ) in the DDDR-l group ; p = 0.03 , log rank test ) . The risk of developing AF in the AAIR group compared with the DDDR-s group was significantly decreased after adjustment for brady-tachy syndrome in a Cox regression analysis ( relative risk 0.27 , 95 % confidence interval ( CI ) 0.09 to 0.83 , p = 0.02 ) . The benefit of AAIR was highest among patients with brady-tachy syndrome . Brady-tachy syndrome and a thromboembolic event before pacemaker implantation were independent predictors of thromboembolism during follow up ( relative risk 7.5 , 95 % CI 1.6 to 36.2 , p = 0.01 , and relative risk 4.7 , 95 % CI 1.2 to 17.9 , p = 0.02 , respectively ) . Conclusions : During a mean follow up of 2.9 years AAIR was associated with significantly less AF . The beneficial effect of AAIR was still significant after adjustment for brady-tachy syndrome . Brady-tachy syndrome was associated with an increased risk of thromboembolism In 19 patients paced and medicated for bradycardia tachycardia syndrome ( BTS ) , AAIR and DDDR pacing were compared with regard to quality of life ( QoL ) , atrial tachyarrhythmia ( AFib ) , exercise tolerance , and left ventricular (LV)function .  Patients had a PQ interval < or = 240 ms during sinus rhythm , no second or third degree AV block , no bundle branch block , or bifascicular block . In DDDR mode , AV delay was optimized using the aortic time velocity integral . After 3 months , QoL was assessed by question naires , patients were investigated by 24-hour Holter , cardiopulmonary exercise testing ( CPX ) was performed , and LV function was determined by echocardiography .  QoL was similar in all dimensions , except dizziness , showing a significantly lower prevalence in AAIR mode . The incidence of AFib was 12 episodes in 2 patients with AAIR versus 22 episodes in 7 patients with DDDR pacing ( P = 0.072 ) . In AAIR mode , 164 events of second and third degree AV block were detected in 7 patients ( 37 % ) with pauses between 1 and 4 seconds . During CPX , exercise duration and work load were higher in AAIR than in DDDR mode ( 423+/-127 vs 402+/-102 s and 103+/-31 vs 96+/-27 Watt , P < 0.05 ) . Oxygen consumption ( VO2 ) , was similar in both modes . During echocardiography , only deceleration of early diastolic flow velocity and early diastolic closure rate of the anterior mitral valve leaflet were higher in DDD than in AAI pacing ( 5.16+/-1.35 vs 3.56+/-0.95 m/s2 and 69.2+/-23 vs 54.1+/-26 mm/s , P < 0.05 ) . As preferred pacing mode , 11 patients chose DDDR , 8 patients chose AAIR . Hence , AAIR and DDDR pacing seem to be equally effective in  BTS patients . In view of a considerable rate of high degree AV block during AAIR pacing , DDDR mode should be preferred for safety reasons C resynchronization therapy ( CRT ) by atriobiventricular pacing has been proposed to treat severe heart failure in patients with intraventricular conduction delay result ing in ventricular mechanical discoordination . The clinical efficacy of CRT was recently demonstrated in a single-blind , r and omized , crossover trial , namely the MUltisite STimulation In Cardiomyopathies ( MUSTIC ) study .1 The purpose of this sub study was to assess the effect of CRT on heart rate variability ( HRV ) and to analyze its correlation with clinical efficacy . • • • All patients provided written informed consent before enrollment . All had severe heart failure due to idiopathic or ischemic left ventricular systolic dysfunction , left ventricular ejection fraction 35 % , and end-diastolic diameter 60 mm . All patients were in sinus rhythm with a QRS interval 150 ms and no classic indication for pacemaker implantation.2 Patients had been in New York Heart Association ( NYHA ) class III for 1 month before inclusion while receiving individually optimized treatment , including diuretics and angiotensin-converting enzyme inhibitors at the maximum tolerated dose . Exclusion criteria have been already reported.1 The study included a 6-month r and omized crossover phase during which atriobiventricular ( active ) pacing was compared with inhibited ( inactive ) ventricular pacing at the basic rate of 40 beats/min , each for a period of 3 months in r and om order ( Figure 1 ) . Implantation was performed after a 1-month observation period to verify the stability of heart failure .  Pacemakers were programmed as inactive after implantation . Patients were r and omly assigned to experimental groups within the following 2 weeks after verification of pacemaker proper performance . Treatment order r and omization followed a block design with stratification according to center . The single-blind , crossover phase was followed by a complementary 6-month period during which the pacing system was programmed according to patients ’ preferences . All leads were implanted transvenously . The left ventricular lead was placed in a tributary of the coronary sinus according to a previously described method .3 Specially design ed electrodes were used . The preferred target site was the lateral wall . The pacemakers were triple-output devices using st and ard dual-chamber technology , with built-in adapters to synchronize pacing in both ventricles . Pacemakers were programmed as either active or inactive at r and omization . The baseline pacing rate was set at 40 beats/min and the upper rate limit at 85 % of the highest predictable heart rate according to patients ’ age and gender . Each patient underwent Doppler echocardiography to determine their optimal atrioventricular delay ( electrical delay between atrial and ventricular excitation ) during atriobiventricular pacing . No modification of medical treatment except diuretic dose adjustment was permitted between enrollment and the end of the crossover phase of the study . Twenty-four-hour ambulatory electrocardiograms with a 2-channel recorder ( ELA Medical , le PlessisRobinson , France ) were obtained in all subjects during normal activity at baseline , at r and omization , at the end of each of the 2 crossover periods , and at the end of each longitudinal follow-up period ( 9 and 12 months ) . Tapes were replayed through a Elatec analyzer ( ELA Medical ) . HRV analysis used specifically vali date d software.4 Ambulatory electrocardiographic recordings  that lasted 16 hours and whose analyzable proportion was 90 % were excluded to avoid bias linked to HRV circadian variations . After initial arrhythmia analysis and editing , the remaining normal-to-normal RR intervals in suitable recordings were measured and HRV time-domain analyses were performed according to published guidelines .5 For the purpose s of this study , 4 different time-domain HRV indexes were measured : ( 1 ) the SD of the normal-to-normal ( NN ) interval over the recording duration ( SDNN ) ; ( 2 ) the SD of the 5-minute mean NN interval over the entire recording ( SDANN [ milliseconds ] ) . Because SDANN values are obtained from successive 5-minute periods , they reflect heart rate changes caused by 5-minute cycles . They reflect long-term variations but provide no short-term variability data ; ( 3 ) the square root of the mean squared successive differences between adjacent RR intervals over the entire recording ( rMSSD [ milliseconds ] ) . This correlates more with the parasympathetic ( vagal ) activity ; ( 4 ) proportion of successive interval differences 50 ms as computed over the entire recording ( pNN50 [ percent ] ) . This also reflects parasympathetic activity . From the Departement de Cardiologie et Maladies Vasculaires , Centre Cardio-Pneumologique , Hopital Pontchaillou-CHU , Rennes , France . Dr. Daubert ’s address is : Departement de Cardiologie et Maladies Vasculaires , Centre Cardio-Pneumologique , Hopital PontchaillouCHU , 35033 Rennes Cedex , France . E-mail : jean-claude . daubert@chu-rennes.fr . Manuscript received August 23 , 2002 ; revised manuscript received and accepted January 23 , 2003 BACKGROUND Dual-chamber ( atrioventricular ) and single-chamber ( ventricular ) pacing are alternative treatment approaches for sinus-node dysfunction that causes clinical ly significant bradycardia . However , it is unknown which type of pacing results in the better outcome . METHODS We r and omly assigned a total of 2010 patients with sinus-node dysfunction to dual-chamber pacing ( 1014 patients ) or ventricular pacing ( 996 patients ) and followed them for a median of 33.1 months . The primary end point was death from any cause or nonfatal stroke . Secondary end points included the composite of death , stroke , or hospitalization for heart failure ; atrial fibrillation ; heart-failure score ; the pacemaker syndrome ; and the quality of life . RESULTS The incidence of the primary end point did not differ significantly between the dual-chamber group ( 21.5 percent ) and the ventricular-paced group ( 23.0 percent , P=0.48 ) . In patients assigned to dual-chamber pacing , the risk of atrial fibrillation was lower ( hazard ratio , 0.79 ; 95 percent confidence interval , 0.66 to 0.94 ; P=0.008 ) , and heart-failure scores were better ( P<0.001 ) . The differences in the rates of hospitalization for heart failure and of death , stroke , or hospitalization for heart failure were not significant in unadjusted analyses but became marginally significant in adjusted analyses . Dual-chamber pacing result ed in a small but measurable increase in the quality of life , as compared with ventricular pacing . CONCLUSIONS In sinus-node dysfunction , dual-chamber pacing does not improve stroke-free survival , as compared with ventricular pacing . However , dual-chamber pacing reduces the risk of atrial fibrillation , reduces signs and symptoms of heart failure , and slightly improves the quality of life . Overall , dual-chamber pacing offers significant improvement as compared with ventricular pacing BACKGROUND Previous studies have suggested that cardiac resynchronization achieved through atrial-synchronized biventricular pacing produces clinical benefits in patients with heart failure who have an intraventricular conduction delay . We conducted a double-blind trial to evaluate this therapeutic approach . METHODS Four hundred fifty-three patients with moderate-to-severe symptoms of heart failure associated with an ejection fraction of 35 percent or less and a QRS interval of 130 msec or more were r and omly assigned to a cardiac-resynchronization group ( 228 patients ) or to a control group ( 225 patients ) for six months , while conventional therapy for heart failure was maintained . The primary end points were the New York Heart Association functional class , quality of life , and the distance walked in six minutes . RESULTS As compared with the control group , patients assigned to cardiac resynchronization experienced an improvement in the distance walked in six minutes ( + 39 vs. + 10 m , P=0.005 ) , functional class ( P<0.001 ) , quality of life ( -18.0 vs. -9.0 points , P= 0.001 ) , time on the treadmill during exercise testing ( + 81 vs. + 19 sec , P=0.001 ) , and ejection fraction ( + 4.6 percent vs. -0.2 percent , P<0.001 ) . In addition , fewer patients in the group assigned to cardiac resynchronization than control patients required hospitalization ( 8 percent vs. 15 percent ) or intravenous medications ( 7 percent vs. 15 percent ) for the treatment of heart failure ( P<0.05 for both comparisons ) . Implantation of the device was unsuccessful in 8 percent of patients and was complicated by refractory hypotension , bradycardia , or asystole in four patients ( two of whom died ) and by perforation of the coronary sinus requiring pericardiocentesis in two others . CONCLUSIONS Cardiac resynchronization results in significant clinical improvement in patients who have moderate-to-severe heart failure and an intraventricular conduction delay OBJECTIVES We evaluated the incidence , predictors , and treatment of  pacemaker syndrome in patients with sinus node dysfunction treated with ventricular-based ( VVIR ) pacing in the Mode Selection Trial ( MOST ) . BACKGROUND Pacemaker syndrome , or intolerance to VVIR pacing , consists of cardiovascular signs and symptoms induced by VVIR pacing . METHODS The definition of pacemaker syndrome required that a patient with single-chamber VVIR pacing develop either congestive signs and symptoms associated with retro grade conduction during VVIR pacing or a > or=20 mm Hg reduction of systolic blood pressure during VVIR pacing , associated with reproducible symptoms of weakness , lightheadedness , or syncope . RESULTS Of 996 patients r and omized to VVIR pacing , 182 ( 18.3 % ) met criteria for pacemaker syndrome in follow-up . Pacemaker syndrome occurred early in most patients ( 13.8 % at 6 months , 16.0 % at 1 year , increasing to 19.7 % at 4 years ) . Baseline univariate predictors of pacemaker syndrome included a lower sinus rate and higher programmed pacemaker rate . Previous heart failure , ejection fraction , and drop in systolic blood pressure with VVIR pacing at implantation did not predict the development of pacemaker syndrome . Post-implantation predictors of pacemaker syndrome were a higher percentage of paced beats , higher programmed low rate , and slower underlying spontaneous sinus rate . Quality of life decreased at the time of diagnosis of pacemaker syndrome and improved with reprogramming to atrial-based pacing . CONCLUSIONS Severe pacemaker syndrome developed in nearly 20 % of VVIR-paced patients and improved with reprogramming to the dual-chamber pacing mode . Because prediction of pacemaker syndrome is difficult , the only way to prevent pacemaker syndrome is to implant atrial-based pacemakers in all patients BACKGROUND One third of patients with chronic heart failure have electrocardiographic evidence of a major intraventricular conduction delay , which may worsen left ventricular systolic dysfunction through asynchronous ventricular contraction . Uncontrolled studies suggest that multisite biventricular pacing improves hemodynamics and well-being by reducing ventricular asynchrony . We assessed the clinical efficacy and safety of this new therapy . METHODS Sixty-seven patients with severe heart failure ( New York Heart Association class III ) due to chronic left ventricular systolic dysfunction , with normal sinus rhythm and a duration of the QRS interval of more than 150 msec , received transvenous atriobiventricular pacemakers  ( with leads in one atrium and each ventricle ) . This single-blind , r and omized , controlled crossover study compared the responses of the patients during two periods : a three-month period of inactive pacing ( ventricular inhibited pacing at a basic rate of 40 bpm ) and a three-month period of active ( atriobiventricular ) pacing . The primary end point was the distance walked in six minutes ; the secondary end points were the quality of life as measured by question naire , peak oxygen consumption , hospitalizations related to heart failure , the patients ' treatment preference ( active vs. inactive pacing ) , and the mortality rate . RESULTS Nine patients were withdrawn from the study before r and omization , and 10 failed to complete both study periods . Thus , 48 patients completed both phases of the study . The mean distance walked in six minutes was 22 percent greater with active pacing ( 399+/-100 m vs. 326+/-134 m , P<0.001 ) , the quality -of-life score improved by 32 percent ( P<0.001 ) , peak oxygen uptake increased by 8 percent ( P<0.03 ) , hospitalizations were decreased by two thirds ( P<0.05 ) , and active pacing was preferred by 85 percent of the patients ( P<0.001 ) . CONCLUSIONS Although it is technically complex , atriobiventricular pacing significantly improves exercise tolerance and quality of life in patients with chronic heart failure and intraventricular conduction delay The efficacy and side-effects of adenosine for treatment of supraventricular arrhythmias were compared to verapamil therapy in patients presenting to the emergency room . Clinical variables and the time interval from the initiation of treatment to the termination of the supraventricular tachycardia , as well as the time from the initial effective dose of medication to the termination of supraventricular tachycardia were compared for adenosine and verapamil . Adenosine was given to a total of 44 patients , 16 patients in the electrophysiology laboratory , and 28 patients in the emergency room for evaluation and termination of their tachycardia . In the electrophysiology laboratory , 7 patients had AV node reentry , 5 had Wolff-Parkinson-White syndrome , 2 of whom had atrial flutter and fibrillation but no bypass tract reentry , 1 had concealed bypass tract reentry , 1 had Lown-Ganong-Levine syndrome , 1 had intraatrial reentry , and 1 had an automatic atrial tachycardia . Twenty-five patients received  adenosine in the emergency room and 3 patients in the hospital for 31 episodes of supraventricular arrhythmias . In the emergency room , 11 patients had supraventricular tachycardia due to AV node reentry , 3 had Wolff-Parkinson-White syndrome , 6 had atrial flutter or intra-atrial re-entry , 2 had ventricular tachycardia , and 3 had sinus tachycardia . In the hospital , 2 patients had atrial flutter and one had sinus tachycardia . The group of 14 patients with supraventricular tachycardia due to Wolff-Parkinson-White syndrome or AV node reentry presenting in the emergency room were compared in a retrospective manner to the patients treated with st and ard verapamil therapy with respect to time from initiation of therapy to termination of supraventricular tachycardia and time from effective dose of medication to the termination of supraventricular tachycardia , as well as side-effects . There was no significant difference between the two groups with respect to clinical variables .  Adenosine converted 18 of 18 episodes of supraventricular tachycardia in 14 patients 24.6 + /- 9.6 seconds from the administration of the effective dose ( 0.104 + /- 0.024 mg/kg ) and a mean of 4.4 + /- 2.0 minutes from the initiation of therapy . Verapamil converted 29 of 32 episodes of supraventricular tachycardia in 20 patients , 10.9 + /- 7 minutes from the administration of the effective dose , and a mean of 16.8 + /- 20 minutes from the initiation of therapy using a mean of 8.4 + /- 3.4 mg of IV verapamil . ( ABSTRACT TRUNCATED AT 400 WORDS BACKGROUND Cardiac resynchronization therapy ( CRT ) improves hemodynamics and symptoms of heart failure by reducing ventricular dyssynchronity . Conversely , recent studies have demonstrated that right univentricular pacing in patients with an ejection fraction below 40 % aggravates heart failure . In this retrospective study , we compared progression of disease in patients with mild to moderate heart failure that were treated with a right univentricular pacing device  and patients with congestive heart failure that were treated with a biventricular system .  METHODS 107 patients were included . 59 received a right ventricular pacing device and 48 a biventricular system . Patients were assessed after 1 and 6 months by NYHA class , echocardiographic parameters ( EF , LVEDD ) and hospitalization for heart failure . RESULTS Hospitalization for heart failure after implantation of the devices was more frequent in patients that received a conventional pacemaker with a single lead in the right ventricle than in patients that were treated with a CRT system ( 12 % vs. 6 % , p<0.05 ) , although heart failure was more advanced in the CRT group at baseline . Ejection fraction in the right ventricular pacing group further decreased from 43%+/-4 at baseline to 38%+/-4 after 6 months ( p<0.05 ) . Left ventricular enddiastolic diameter ( LVEDD ) was 51+/-7 mm and 58+/-6 mm ( p<0.05 ) at 6 months . In the CRT group , EF was 23%+/-4 at baseline and 31%+/-7 after 6 months ( p<0.05 . ) . LVEDD improved from 56+/-4 mm before implantation to 52+/-7 mm and 6 months ( p<0.05 ) . CONCLUSION Progression of heart failure symptoms in the right univentricular pacing group was more pronounced compared to the CRT group , despite the fact that patients assigned to the CRT group had more severe symptoms of heart failure at baseline . Biventricular pacing relieved symptoms of heart failure , whereas right univentricular pacing with subsequent conduction delay of the left ventricle further deteriorated pre-existing heart failure . Therefore , patients with an indication for pacemaker therapy because of bradycardia and co-existing mild to moderate heart failure might benefit from early implantation of a CRT system BACKGROUND St and ard clinical practice permits the use of either single-chamber ventricular pacemakers or dual-chamber pacemakers for most patients who require cardiac pacing .  Ventricular pacemakers are less expensive , but dual-chamber pacemakers are believed to be more physiologic . However , it is not known whether either type of pacemaker results in superior clinical outcomes . METHODS The Pacemaker Selection in the Elderly study was a 30-month , single-blind , r and omized , controlled comparison of ventricular pacing and dual-chamber pacing in 407 patients 65 years of age or older in 29 centers . Patients received a dual-chamber pacemaker that had been r and omly programmed to either ventricular pacing or dual-chamber pacing . The primary end point was health-related quality of life as measured by the 36-item Medical Outcomes Study Short-Form General Health Survey . RESULT The average age of the patients was 76 years ( range , 65 to 96 ) , and 60 percent were men .  Quality of life improved significantly after pacemaker implantation ( P<0.001 ) , but there were no differences between the two pacing modes in either the quality of life or prespecified clinical outcomes ( including cardiovascular events or death ) . However , 53 patients assigned to ventricular pacing ( 26 percent ) were crossed over to dual-chamber pacing because of symptoms related to the pacemaker syndrome . Patients with sinus-node dysfunction , but not those with atrioventricular block , had moderately better quality of life and cardiovascular functional status with dual-chamber pacing than with ventricular pacing . Trends of borderline statistical significance in clinical end points favoring dual-chamber pacing were observed in patients with sinus-node dysfunction , but not in those with atrioventricular block . CONCLUSION The implantation of a permanent pacemaker improves health-related quality of life . However , the quality -of-life benefits associated with dual-chamber pacing as compared with ventricular pacing are observed principally in the subgroup of patients with sinus-node dysfunction BACKGROUND Biventricular ( BiV ) stimulation lowers morbidity and mortality in patients with drug-refractory congestive heart failure ( CHF ) , depressed left ventricular ( LV ) function , and ventricular dyssynchrony in absence of indication for permanent cardiac pacing . This pilot , single-blind , r and omized , cross-over study examined the safety and efficacy of upgrading conventional pacing systems to BiV stimulation in patients with advanced CHF . METHODS We included 56 patients in New York Heart Association ( NYHA ) functional classes III or IV despite optimal drug treatment and ventricular dyssynchrony ( interventriclar delay > 40 ms or LV preejection delay > 140 ms ) in need of pacemaker replacement . We compared the patients ' functional status , arrhythmias , and st and ard echocardiographic measurements during 3 months of conventional , single right ventricular ( RV ) versus 3 months of BiV stimulation . RESULTS There were 44 patients in the cross-over phase . QRS duration was shortened by 23 % and LV preejection delay by 16 % with BiV stimulation .  NYHA functional class , 6-minute hall walk and quality of life score were significantly improved with BiV stimulation compared with single RV pacing by 18 % , 29 % , and 19 % , respectively . No significant difference was observed in the ventricular arrhythmia burden or LV reverse remodeling between the 2 periods . CONCLUSIONS This pilot study showed that upgrading from RV pacing to BiV pacing significantly improves symptoms and exercise tolerance in chronically paced patients with advanced CHF and mechanical dyssynchrony BACKGROUND / OBJECTIVES To determine pacemaker ( PM ) dependency at follow-up visit in patients who underwent new permanent pacemaker implantation ( PPI ) following transcatheter aortic valve implantation ( TAVI ) .  METHODS Single center prospect i ve observational study including 167 patients without previous PM implantation who underwent TAVI with the self-exp and ing Medtronic CoreValve System ( MCS ) between November 2005 and February 2011 . PM dependency was defined by the presence of a high degree atrioventricular block ( HDAVB ; second [ AV2 ] and third degree [ AV3B ] ) , or a slow ( < 30 bpm ) or absent ventricular escape rhythm during follow-up PM interrogation . RESULTS A total of 36 patients ( 21.6 % ) received a new PM following TAVI . The indication for PM was AV2B ( n=2 , 5.6 % ) , AV3B ( n=28 , 77.8 % ) , postoperative symptomatic bradycardia ( n=3 , 8.3 % ) , brady-tachy syndrome ( n=1 , 2.8 % ) , atrial fibrilation with slow response ( n=1 , 2.8 % ) and left bundle branch block ( n=1 , 2.8 % ) . Long term follow-up was complete for all patients and ranged from 1 to 40 months ( median ( IQR ) : 11.5 ( 5.0 - 18.0 months ) . Of those patients with a HDAVB , 16 out of the 30 patients ( 53.3 % ) were PM independent at follow-up visit ( complete or partial resolution of the AV conduction abnormality ) . Overall , 20 out of the 36 patients ( 55.6 % ) who received a new PM following TAVI were PM independent at follow-up . CONCLUSION Partial and even complete resolution of peri-operative AV conduction abnormalities after MCS valve implantation occurred in more than half of the patients An atrial-based pacing mode is superior to ventricular constant rate dem and pacing ( VVI ) mode in patients with sick sinus syndrome ( SSS ) by providing both rate adaptation and atrioventricular ( AV ) synchrony . The use of a non-atrial sensor to overcome chronotropic incompetence and preserve normal intrinsic AV conduction in pacemaker therapy for SSS was investigated in 15 consecutive patients ( mean age 66 + /- 2 years ) . All had intact AV conduction ( ante grade conduction capacity > 100 beats.min-1 and an atrial paced to intrinsic R interval of < or = 220 ms ) .  DDDR pacemakers capable of being programmed into atrial rate adaptive ( AAIR ) , dual chamber rate adaptive ( DDDR ) and ventricular rate adaptive ( VVIR ) modes were used . Beginning with an acute study , arterial pressure was invasively assessed in each pacing mode during physiological stresses and low level exercise . In the ambulatory phase , the incidence of ventricular pacing and arrhythmias ( Holter recording ) , diurnal blood pressure changes ( ambulatory blood pressure recording ) , and symptom and quality of life level ( question naires and interviews ) were compared . Despite similar heart rate changes during acute physiological stresses , a higher blood pressure was recorded during AAIR or DDDR pacing compared with VVIR pacing . Systolic blood pressure over 24 h was lower in the VVIR mode ( 122 + /- 5 mmHg ) than AAIR/DDDR pacing ( 129 + /- 6/128 + /- 6 mmHg , P < 0.05 ) . VVIR pacing was associated with a higher frequency of atrial and ventricular ectopics , with two patients developing paroxysmal atrial fibrillation . Ventricular pacing was used in a higher percentage in the DDDR compared with the VVIR mode ( 64 + /- 11 and 39 + /- 7 % , P < 0.03 ) . VVIR pacing was associated with more palpitations , a lower level of general well being and depression . Despite the use of a sensor to overcome chronotropic incompetence , VVIR pacing is a less satisfactory pacing mode for SSS . Although AAIR/DDDR pacing may achieve similar haemodynamic and clinical status , in patients with intact AV conduction , AAIR pacing may be preferable by avoiding an abnormal ventricular activation pattern OBJECTIVES We assessed the clinical efficacy of single-site left ventricular ( LV ) pacing and determined the impact of baseline conduction delay severity on the magnitude of benefit . BACKGROUND Multisite biventricular pacing can improve heart failure ( HF ) symptoms in patients with an intraventricular conduction delay by resynchronizing abnormal ventricular contractions and improving LV systolic function . METHODS Eighty-six patients with at least New York Heart Association functional class II HF , chronic LV systolic dysfunction , normal sinus rhythm , and a QRS interval over 120 ms were implanted for atrial-synchronized LV pacing . The single-blinded , r and omized , controlled , crossover study stratified patients 1:1 by the baseline QRS interval into long ( QRS > 150 ms ) and short ( QRS 120 to 150 ms ) groups , which were compared during a three-month period of active ( univentricular ) pacing and a three-month period of inactive ( ventricular inhibited ) pacing . The primary end point was peak oxygen consumption ( VO(2 ) ) followed by anaerobic threshold , distance walked in 6 min , and quality -of-life question naire score . PATIENTS Twelve patients were withdrawn before r and omization and 17 could not complete both study periods . The short QRS group did not improve in any end point with active pacing . For the long QRS group , peak VO(2 ) increased 2.46 ml/min/kg ( p < 0.001 ) , the anaerobic threshold increased 1.55 ml/min/kg ( p < 0.001 ) , the distance walked in 6 min increased 47 m ( p = 0.024 ) , and the quality -of-life score improved 8.1 points ( p = 0.004 ) . CONCLUSIONS Left ventricular pacing significantly improves exercise tolerance and quality of life in patients with chronic HF , LV systolic dysfunction , and a QRS interval over 150 ms
No statistically significant difference was found between the pacing modes for mortality , heart failure , stroke , chronic atrial fibrillation or quality of life .
However , the risk of developing heart failure may vary with age and device .
The risk of heart failure may have an impact on the decision to use dual-chamber or single-chamber atrial pacemakers .
Results from an analysis based on age ( > 75 years or ≤ 75 years ) and risk of heart failure indicate that dual-chamber pacemakers dominate single-chamber atrial pacemakers ( i.e. are less expensive and more effective ) in older patients , whereas dual-chamber pacemakers are dominated by ( i.e. more expensive and less effective ) single-chamber atrial pacemakers in younger patients .
In patients with SSS without evidence of impaired AV conduction , dual-chamber pacemakers appear to be cost-effective compared with single-chamber atrial pacemakers .
BACKGROUND Bradycardia [ resting heart rate below 60 beats per minute ( b.p.m . ) ]
can be caused by conditions affecting the natural pacemakers of the heart , such as sick sinus syndrome ( SSS ) and atrioventricular ( AV ) blocks .
People suffering from bradycardia may present with palpitations , exercise intolerance and fainting .
The only effective treatment for patients suffering from symptomatic bradycardia is implantation of a permanent pacemaker .
OBJECTIVE To appraise the clinical effectiveness and cost-effectiveness of dual-chamber pacemakers compared with single-chamber atrial pacemakers for treating symptomatic bradycardia in people with SSS and no evidence of AV block .