Which Patient is Most Likely to Benefit from a Rate Responsive Pacemaker?

In order to provide information about indications for rate responsive pacing, we examined the exercise capacity of a typical collective of pacemaker patients. One hundred seven patients participated in the study, 50/107 (46.8%) suffered from sick sinus syndrome, 37/107 (34.6%) showed complete AV block, 12/107 (11.2%) had bradyarrhythmia and 8/107 (7.4%) had other diseases. Ali patients underwent treadmill exercise with increasing workloads up to the individual's maximum workload. We monitored heart rate, respiratory rate, workload, the subjective perception of stress according to the Borg scale, and the reason for the termination of exercise. Calculation of oxygen uptake was done according to an equation given by Givoni. During the tests, all implanted pacemakers have been programmed to VVI 70 mode. We found that all pacemaker patients showed a reduction of their exercise capacity compared to the age‐related normal values. Particularly in patients with AV block or bradyarrhythmia, the maximum achievable workload often did not even reach levels of everyday activities such as going upstairs; patients with sick sinus syndrome showed slightly better exercise capability, probably due to the higher increase of average heart rate. Despite objective differences of maximum workload, all patients had the same subjective perception at the end of the tests; the course of respiratory rate indicated that ail persons finished the tests in the range of individual maximum exercise capacity. We assume that patients who had to terminate exercise because of stenocardia. claudication, or joint pain even in the VVI 70 mode will not benefit much from rate adaptation. The effect of rate increase upon occurrence of dizziness is difficult to validate. Those who terminated the tests because of dyspnea, exhaustion, or muscular fatigue probably will benefit from rate adaptation during physical work. This group of patients represented 69% of ail examined patients; by excluding patients with AV block (who can be treated optimally by DDD pacemakers), about 46% of all pacemaker patients might benefit from rate responsive pacing.