title: Sustained improvement in exercise tolerance following physiological cardiac pacing.
abstract: Fifty-three patients have received 'physiological' pacemakers, 37 with atrioventricular (AV) block having atrial synchronous units (VAT or VDD) implanted and the remaining 16 patients with both AV block and sick sinus syndrome having 'universal' (DDD) pacemakers. Effort tolerance was assessed by serial bicycle ergometry and in 16 patients direct comparisons between ventricular pacing and atrial synchronous pacing could be made acutely. Physiological pacemakers were found to increase maximum effort tolerance by 43% compared to pre-pacing values (P less than 0.01). The increase was sustained over a mean of 33 months post pacing. The atrial synchronous mode increased maximum effort tolerance by 34% acutely compared to ventricular inhibited pacing. Dual chambered 'physiological' pacemakers represent a significant therapeutic advance over standard ventricular inhibited pacemakers.
mesh_terms: D000328:Adult; D000368:Aged; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D005080:Exercise Test; D005260:Female; D006327:Heart Block / Q000503:physiopathology / Q000628:therapy*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D012804:Sick Sinus Syndrome / Q000503:physiopathology / Q000628:therapy