Differential diagnosis of rhythm disturbances induced by endocardial pacing

Rhythm disturbances induced by endocardial pacing were studied in 15 patients. Atrial extrasystoles were found in 8, ventricular extrasystoles in 5, ventricular tachycardia in 1 and ventricular fibrillation in 1 patient. In all cases, an implanted pacemaker EKS-222 was used working in VVI regime. The connection of the above-mentioned rhythm disturbances with pacing is deduced from the stability of the coupling interval with the earlier induced complex, and from the presence of a negative P wave in standard leads II and III. A reliable criterion is in the authors' view, the disappearance of rhythm disturbances after the implanted pacemaker has been switched off.