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 .
High incidence of pacemaker syndrome in patients with sinus node dysfunction treated with ventricular-based pacing in the Mode Selection Trial (MOST).
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
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 .