The A-R interval as exercise indicator: a new option for rate adaptation in single and dual chamber pacing

• Published in: Pacing and clinical electrophysiology Vol. 13; no. 12 Pt 1; p. 1656
• Main Authors: Ruiter, J H, de Boer, H, Begemann, M J, van Mechelen, R
• Format: Journal Article
• Language: English
• Published: United States 01-12-1990
• Subjects: Adult; Aged; Aged, 80 and over; Arrhythmias, Cardiac - drug therapy; Arrhythmias, Cardiac - physiopathology; Arrhythmias, Cardiac - therapy; Atrioventricular Node - physiopathology; Electrocardiography; Exercise Test; Female; Heart Rate; Humans; Male; Middle Aged; Pacemaker, Artificial
• ISSN: 0147-8389
• DOI: 10.1111/j.1540-8159.1990.tb06868.x

We investigated the possibility to use the interval from an atrial stimulus to the ventricular R wave (A-R interval) as an indicator of physical stress, in 16 patients with pacemakers implanted for severe atrial bradycardia but with intact AV conduction. The A-R interval was studied during incremental atrial pacing at rest and during exercise with a constant workload. In addition, the atrial pacing rate was kept constant just above spontaneous sinus rate and the dynamics of the A-R interval were studied during exercise with a low constant workload and during a maximal exercise test with increasing workload. Incremental atrial pacing prolonged the A-R interval and this response was blunted during exercise (P less than 0.003). Atrial pacing at a constant rate and during a constant workload resulted in an almost direct shortening of the A-R interval. When the workload was increased but the atrial rate kept constant, a pronounced shortening of the A-R interval was noted (P less than 0.0001). It is concluded that changes of the A-R interval during different kinds of exercise were prompt and predictable in patients with sinus node dysfunction but intact AV conduction. In these patients the shortening of the A-R interval during exercise may be a suitable indicator for rate adaptive atrial pacing.