A new method for recording a three-lead electrocardiogram using a two-channel Holter system.

A technique for recording a three-lead electrocardiogram (ECG) without increasing the number of channels and electrodes in a commercially available two-channel Holter recorder was devised. On channel 1, a V5-like lead (CM5 lead) was recorded for 24 consecutive hours. On channel 2, the device could switch continuously between a V2-like lead (CM2 lead) and a II- or III- or a VF-like lead (CMf lead) every 30 sec. Fifty eight patients with angina pectoris were studied using this new device. There were 2 patients with variant angina pectoris, one of whom showed ST elevation in the CM2 lead coupled with ST depression in the CMf lead and the other ST elevation in the CMf lead coupled with ST depression in the CM2 lead. The number of patients having ST depression confined to the CM5 lead only, CM2 lead only and CMf lead only was 17, 2 and 3, respectively. In 41 patients, 127 transient episodes of ischemic type ST changes were observed during daily activity. Only 35 (28%) of these episodes were associated with anginal symptoms and the remaining 92 episodes occurred unrelated to such symptoms. Accordingly, 3-lead Holter monitoring using this device is useful, particularly for the detection of variant angina, and makes it less likely for asymptomatic ischemic ST changes to be overlooked as compared to the 2-lead conventional Holter monitoring system.