Significance of pre-infarction angina for occurrence of post-infarction angina.

We evaluated the factors determining the occurrence of post-infarction angina in 41 patients who had intra-coronary thrombolysis within 6 h of the onset of acute myocardial infarction. Pre-infarction angina was considered to be present if it occurred more than one week before acute myocardial infarction. Post-infarction angina was defined as typical chest pain occurring within 10 days following the infarction. Collateral flow to the infarct zone was determined to be present if any portion of the infarct-related epicardial artery or side branches was visualized. In cases of successful thrombolysis, the prevalence of post-infarction angina was not significantly influenced by pre-infarction angina and the extent of collateral circulation. However, in patients without recanalization, pre-infarction angina and collateral blood flow supply to the area at risk caused a high prevalence of angina after infarction. It is concluded that pre-infarction angina indicative of myocardial ischemia is associated with post-infarction angina especially in patients with conventional therapy, because the jeopardized myocardium is salvaged substantially by collateral circulation with a limited flow reserve.