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 .
Adverse Effect of Ventricular Pacing on Heart Failure and Atrial Fibrillation Among Patients With Normal Baseline QRS Duration in a Clinical Trial of Pacemaker Therapy for Sinus Node Dysfunction
Background Dual‐chamber ( DDDR ) pacing preserves AV synchrony and may reduce heart failure ( HF ) and atrial fibrillation ( AF ) compared with ventricular ( VVIR ) pacing in sinus node dysfunction ( SND ) . However , DDDR pacing often results in prolonged QRS duration s ( QRSd ) as the result of right ventricular stimulation , and ventricular desynchronization may result . The effect of pacing‐induced ventricular desynchronization in patients with normal baseline QRSd is unknown . Methods and Results Baseline QRSd was obtained from 12‐lead ECGs before pacemaker implantation in MOST , a 2010‐patient , 6‐year , r and omized trial of DDDR versus VVIR pacing in SND .  Cumulative percent ventricular paced ( Cum%VP ) was determined from stored pacemaker data . Baseline QRSd < 120 ms was observed in 1339 patients ( 707 DDDR , 632 VVIR ) . Cum%VP was greater in DDDR versus VVIR ( 90 % versus 58 % , P=0.001 ) . Cox models demonstrated that the time‐dependent covariate Cum%VP was a strong predictor of HF hospitalization in DDDR ( hazard ratio [ HR ] , 2.99 [ 95 % CI , 1.15 to 7.75 ] for Cum%VP > 40 % ) and VVIR ( HR 2.56 [ 95 % CI , 1.48 to 4.43 ] for Cum%VP > 80 % ) . The risk of AF increased linearly with Cum%VP from 0 % to 85 % in both groups ( DDDR , HR 1.36 [ 95 % CI , 1.09 , 1.69 ] ; VVIR , HR 1.21 [ 95 % CI 1.02 , 1.43 ] , for each 25 % increase in Cum%VP ) . Model results were unaffected by adjustment for known baseline predictors of HF hospitalization and AF . Conclusions Ventricular desynchronization imposed by ventricular pacing even when AV synchrony is preserved increases the risk of HF hospitalization and AF in SND with normal baseline QRSd . ( Circulation . 2003;107:2932‐2937 .
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 .