Symptomatic versus asymptomatic ischemic episodes during Holter monitoring: patterns of high resolution trend recordings of ST segment and heart rate

Abstract

Knowledge about the high incidence of asymptomatic ischemic episodes in patients with coronary artery disease is based on ST segment analysis of Holter recordings (1–4, 10, 11). Most investigators define ST segment elevations and downsloping or horizontal ST segment depressions ⩾ 0.1 mV persisting for at least 30 s (9) or 60 s (4) as ischemic episodes. The detection of such episodes is generally based on visual analysis. But even for experienced operators, visual analysis of the ST segment at 60 or more times normal speed is a potential source of error, especially if the resting ECG is altered. In addition, the determination of onset and offset of the ischemic episodes remains problematic. Gallino et al. (6) reported a computer system which was based on trend recordings of heart rate and QRST parameters with high temporal resolution. This system, however, is not generally available, and its use seems to be time consuming.