Role of previous angina pectoris and collateral flow to preserve left ventricular function in the presence or absence of myocardial infarction in isolated total occlusion of the left anterior descending coronary artery.

The aim of this study was to determine whether previous angina pectoris and collateral circulation influenced myocardial function after isolated coronary occlusion. In 58 consecutive patients, coronary angiography showed a complete isolated occlusion of the left anterior descending coronary artery; 43 patients (74%) had previous myocardial infarction. Duration of previous angina pectoris was defined as the time from the first ischemic symptom to the date of myocardial infarction or of coronary angiography in the absence of myocardial infarction. Left ventricular ejection fraction was measured on the 30 degrees right anterior oblique projection of the left ventricular angiogram. Collateral circulation was graded as follows: none or filling limited to side branches (group 1) and partial or complete filling of the epicardial arterial segment (group 2). Group 2 (40 patients) had higher ejection fraction (57 vs 38%; p less than 0.0001) and longer duration of previous angina pectoris (11 vs 0.1 months; p less than 0.002) than group 1 (18 patients). A longer duration of previous angina pectoris probably allows collateral development before coronary occlusion in 1-vessel coronary artery disease, thereby limiting myocardial damage.