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 .
AAIR versus DDDR pacing in the bradycardia tachycardia syndrome: a prospective, randomized, double-blind, crossover trial.
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
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 .