Ambulatory electrocardiograms obtained by Holter monitoring system in patients with permanent demand pacemakers.

Ventricular inhibited demand pacemakers (VVI) were implanted in 27 patients with complete A-V block and pacemaker arrhythmias were analyzed by Holter system ambulatory electrocardiograms and conventional electrocardiograms. With Holter ECG, 13 patients showed myopotential inhibition, 5 patients had sensing failure and premature ventricular contractions (PVC) were observed in all patients. On the contrary, myopotential inhibition and sensing failure were not detected by conventional ECG and the detection rate of PVC was only 30%. The transient recovery of A-V conduction was observed in 14 of 27 patients with Holter ECG, but was not detected by conventional ECG. The Holter system ambulatory electrocardiogram clearly demonstrated the complex cardiac arrhythmias. Therefore, it is useful for monitoring arrhythmias caused by VVI pacemakers.