ABSTRACT
The ambulatory electrocardiographic examinations were performed in 31 patients (mean age of 59.4+/-9.3 yrs : male 16 cases, female 15 cases) with ischemic heart disease to evaluate the clinical features of ST segment more than 1 mm persisting for 45 seconds or longer. The incidence of associated disease are angina pectoris 14 cases, acute myocardial infarction 3 cases, old myocardial infarction 7 cases, hypertension 19 cases, diabetes mellitus 5 cases, cerebrovascular disease 4 cases, aortic regurgitation 2 cases, ventricular arrhythmia 1 case and chronic renal faliure 1 case. 93.7% of 252 monitored episodes of transient myocardial ischemia were silent. The incidence and duration of transient myocardial ischemia were 8.1+/-6.7 episodes/day (7.6+/-6.5episodes/day for silent myocardial ischemia, 0.5+/-0.9 episodes/day for silent ischemia, 7.6+/-14.1mins/day for symptomatic ischemia). The heart rate at the onset of ST segment depression is higher in symptomatic episode than silent episode (94.6+/-19.7 vs 82.1+/-17.4/min,. p<0.05). But duration of ST segment depression is longer in silent episode than symptomatic episode(32.4+/-97.7 vs 14.8+/-10.2/min,. p<0.01). Maximal ST segment depression was similar between silent and symptomatic episode (1.61+/-0.65 mm, 1.97+/-0.84 mm, repectively). 55.5% of silent episodes occurred during sleep or resting state and 60% of symptomatic episodes occurred during strenuous effort, exercise or eating (p<0.01). Transient myocardial ischemia developed not more frequently in the morning probably because the 24 hour Holter electrocadiographic examination was performed during hospitalization in the majority of cases.