[The first non-Q myocardial infarct as a clinical manifestationn of acute coronary syndrome].

INTRODUCTION: Non-Q myocardial infarction is only one of the possible clinical manifestations of acute coronary syndromes. Acute coronary syndrome is the most frequent cause of hospitalization in everyday cardiological practice.

OBJECTIVES: 1. To evaluate the incidence of unstable angina and myocardial infarction in the group of patients admitted to hospital with diagnosis of acute coronary syndromes; 2. To evaluate the incidence of non-Q myocardial infarction in the group with index myocardial infarction; 3. To determine the frequency of different ECG changes in the subgroup with non-Q myocardial infarction.

MATERIAL AND METHODS: The study was conducted at the Institute of Cardiovascular Diseases in Sremska Kamenica in the period between Jan. 1, 1997 and Dec. 31, 1999. Hospitalized patients with acute coronary syndromes (n = 3.337) were divided into subgroups with unstable angina (chest pain, ECG changes and normal level of CK) and with myocardial infarction (chest pain, ECG with/without changes, elevation of cardiac enzymes). Myocardial infarction without Q waves on ECG was considered to be non-Q myocardial infarction. Initial ECG changes (ST elevation, ST depression, inverted T waves, abscence of changes) were evaluated in patients with non-Q myocardial infarction who were not treated with Streptase.

RESULTS: During a three-year period, 3.337 patients with acute coronary syndrome were hospitalized. 65.3% of them had unstable angina, while 34.7% suffered from myocardial infarction. In the group with myocardial infarction, 12.9% (280/2179) had reinfarction. 8.8% of patients were treated with thrombolytic agents, which prevented formation of Q waves in 24.6% of patients. In the group of patients who were not treated with thrombolytics, 196 patients (11.8%) fulfilled criteria for non-Q myocardial infarction. Incidence of initial ST elevation, ST depression and inverted T waves in those patients with non-Q myocardial infarction were 11.2%, 35.2% and 52.1% respectively, whereas 1.5% had no ECG changes.

CONCLUSION: Both incidence of unstable angina and non-Q myocardial infarction, as manifestations of acute coronary syndromes, and incidence of newly formed ST elevation, which is one of the forms of initial ECG changes in non-Q myocardial infarction, are significantly lower than those found in literature.