COMPARISON OF DUAL-CHAMBER AND VENTRICULAR RATE-RESPONSIVE PACING IN PATIENTS OVER 75 WITH COMPLETE HEART-BLOCK

Objective-To compare symptoms and exercise tolerance during dual chamb er universal (DDD) and ventricular rate response (VVIR) pacing in elde rly (greater than or equal to 75) patients. Design-Randomised, double blind, crossover study. Setting-Regional cardiac department. Patients- Twenty elderly patients (mean age 80.5 (1) years) with high grade atri oventricular block and sinus rhythm. Patients with pre-existing risk f actors for the pacemaker syndrome and chronotropic incompetence were e xcluded. Intervention-After four weeks of WI pacing following pacemake r implantation, patients underwent consecutive two week periods of VVI R and DDD pacing. Main outcome measures-Patient preference, symptom sc ores, ''daily activity exercises,'' and perceived level of exercise (B org score). Results-Eleven patients preferred DDD mode to either VVI o r VVIR mode. Mean (SE) total symptom scores during VVI, VVIR, and DDD pacing were 5.9 (1.1), 6.1 (1.0), and 3.5 (0.9) respectively (P < 0.01 ). The corresponding mean (SE) pacemaker syndrome symptom scores were 4.8 (0.7), 5.2 (0.8), and 2.9 (0.8) (P < 0.05). Symptom scores during VVI and VVIR pacing were not significantly different. Exercise perform ance and Borg scores were significantly worse during VVI pacing compar ed with VVIR or DDD pacing but did not significantly differ between VV IR and DDD modes. Conclusions-In active elderly patients with complete heart block both DDD and VVIR pacing are associated with improved exe rcise performance compared with fixed rate VVI pacing. The convenience and reduced cost of VVIR systems, however, may be offset by a higher incidence of the pacemaker syndrome. In elderly patients with complete heart block VVIR pacing results in suboptimal symptomatic benefit and should not be used instead of DDD pacing.