A Relation between Transient Myocardial Ischemia and Ventricular Arrhythmias on Holter Monitoring after Acute Myocardial Infarction

BACKGROUND: Transient myocardial ischemia that is recorded on Holter monitoring after a myocardial infarction is known to be a risk factor of myocardial reinfarction or death. However, it is still uncertain whether transient myocardial ischemia is a cause of ventricular arrhythmias or is simply an indicator of severe coronary artery disease. Therefore, we have studied the relation of ventricular arrhythmias to transient myocardial ischemia detected on Holter monitoring after a myocardial infarction. METHOD: We studied 40 patients with acute myocardial infarction who were performed Holter monitoring, 7 to 14 days after an attack. On Holter monitoring, we analyzed the prevalence, characteristics of transient myocardial ischemia and its relation to ventricular arrhythmias. RESULTS: 1) Among 40 patients(32 men, 8 women, mean age 53+/-13), transient myocardial ischemia was recorded in 13 patients(33%). ST elevation was observed in 2 patients, and ST depression, in 11 patients. Total episodes of transient myocardial ischemia were 65, of which only one episode was accompanied by chest pain, and total daily episodes were 4.8+/-1.4. Total daily duration of transient myocardial ischemia was 61.4+/-15.5 minutes and the duration of each transient myocardial ischemia was 15.8+/-2.1 minutes. 2) There were no significant differences in frequencies of single ventricular premature beast, bigeminy, trigeminy, ventricular couplets, and ventricular tachycardias between two groups with and without transient myocardial ischemia. CONCLUSION: It is concluded that transient myocardial ischemia on Holter monitoring after myocardial infarction is not a cause of ventricular arrhythmias.

Relation between Ischemia on Exercise Testing and on Holter Monitoring

BACKGROUND: The relation between treadmill exercise testing and ambulatory ST segment monitoring in detection of ischemia in patients with coronary artery disease has not been well established, with pathophysiologic mechanisms underlying the development of ischemia in the ambulatory setting not being well elucidated. This study was performed to determine the relation between myocardial ischemic indexes on exercise testing and on Holter monitoring. METHODS: We analized 25 patients with stable angina and angiographically documented coronary artery disease, who exhibited ischemia both on a Bruce protocol exercise test and on 24-hr Holter monitoring while receiving routine antianginal medications. RESULTS: Mean heart rate at the onset of 1mm ST segment depression during exercise testing(74.4 VS 114.1 beats/min, p<0.01). Overall the correlations between ischemic indexes on both test were weak. But heart rate at the onset of ischemic episodes during Holter monitoring had a good correlation with heart rate at 1mm ST depression during exercise test. And the number of ischemic episodes on Holter monitoring revealed a weak negative correlation with duration of exercise during treadmill test. CONCLUSION: Ischemic indexes on exercise testing cannot accurately predict ischemic indexes on Holter monitoring in patients with coronary artery disease. In that regard, Holter monitoring may provide other clinical information in addition to that obtained by exercise testing in selected patients.