How previous angina influences early prognosis of patients with acute myocardial infarction.

Abstract

Background: There is little information about how previous angina influences the complications of myocardial infarction and also contradictory results have been reported.

Objective: To compare the risk factors for myocardial infarction, complications, performance of left ventricle, and coronary angiography findings of patients who had suffered acute myocardial infarction with those for patients who had not.

Methods: We studied 600 patients diagnosed to have suffered acute myocardial infarction. Patients are grouped into those having previously had angina for at least 1 month preceding acute myocardial infarction (group I, n = 308 patients; 223 men and 85 women, mean age 60.4 +/- 10.6 years) and those who had not had angina (group II, n = 292 patients; 221 men and 71 women, mean age 58 +/- 9 years). The risk factors, complications (cardiogenic shock, heart failure, disturbances of rhythm and conduction, cardiac rupture and death), left-ventricle ejection fraction, and echocardiography and coronary angiographic findings during hospitalization are compared.

Results: There was no difference with respect to localization of myocardial infarction (anterior, inferior, and non-Q) between groups I and II (P> 0.05). Hypertension in members of group I was higher (P < 0.05). There was no statistically significant difference with respect to diabetes mellitus, hypercholesterolemia and cigarette smoking (P > 0.05). Heart failure (P< 0.05), cardiogenic shock (P< 0.01), incidence of ventricular premature systole > 3/min (P< 0.001) and atrial fibrillation (P< 0.05) were seen more prevalently in group II than they were in group I. There was no difference between the two groups with respect to bundle-branch blockage and third-degree atrioventricular blockage. Incidences of ventricular fibrillation, rupture of interventricular septum (IVS) and death in hospital were higher in group II (6.2 versus 3.6%, 6.2 versus 3.2%, 2.1 versus 0.6%) but were not statistically significant. Coronary angiography detected no statistically significant difference with respect to disease in left main coronary artery, and one-vessel and two-vessel disease; but three-vessel disease was significantly more prevalent in group II (P < 0.01).

Conclusion: Heart failure, cardiogenic shock, arrhythmia (more than three VPS within 1 min and atrial fibrillation), and three-vessel disease detected by coronary angiography were found more often in the myocardial infarct patients without previous angina and these differences were statistically significant. In-hospital mortality and cardiac rupture were also found more commonly in this group and ejection fractions measured by echocardiography were found to be less, but these differences were statistically insignificant.