Comparison of different methods of ST measurementfor evaluation of myocardial ischaemia in Holter monitoring.

Long-term ambulatory electrocardiographic monitoring [AEM] of the ST segment is clinically the most practical test for the documentation and quantification of myocardial ischaemia. However, there is still some controversy about the validity of ST measurements in Holter monitoring. Therefore, in the present study, in a series of 26 patients with angiographically proven (> 70%) coronary heart disease and a positive exercise electrocardiogram, the number, duration and the severity of symptomatic and asymptomatic ischaemic episodes were measured by (1) the ST change at the J point, (2) the ST change 0.07–0.10 s after the J point (immediately before the T wave), (3) the change of the slope of the ST segment, and (4) the area under the ST segment, with a Reynolds Pathfinder III and compared with visual analysis. At the J point (1) there were a total of 264 episodes with a duration of 3947 min and a maximum of 0.35 mV, beforethe T wave (2) 276 episodes with a duration of 3440 min and a maximal change of 0.40 mV; looking at the slope of the ST segment (3) the figures were 118, 1041 min and regarding the area under the ST segment they were 198, 2385 min. In conclusion, ST deviations are safely detected by automated analysis of the ST segment. Compared with visual analysis (220 episodes), deviation ofthe ST1 (J point) and ST2 point (80 ms thereafter) overestimate the incidence of true ischaemic ST depression by about 20%. The presence of a negative slope and an area of ST deviation of more than 10 μVs underestimates the presence of ischaemic episodes by about 50% and 10%, respectively. The presence of ST1 deflection >0.1 mV plus ST2 deflection of <0.1 mV predicts the true ischaemic ST depression most accurately (compared with visual analysis). [ABSTRACT FROM PUBLISHER]