Myocardial infarction in the practices of a group of private physicians. IV. Factors related to the longevity of patients with myocardial infarction during the first five years

Myocardial infarction in Malmö during the 10-year period 1963--1972

Myocardial infarctions in Malmö during the 10-year period 1963--1972 have been studied. The mortality from myocardial infarction decreased significantly among men during this period but not among women. The incidence of hospital-treated infarction increased significantly among men, mainly due to an increase in primary infarctions. The one-year survival in this hospital material did not improve during the period. The number of days of sick-leave during 12 months before primary infarction was significantly higher than expected. The duration of sick-leave during the year after primary infarction remained unchanged throughout the period. The mortality figures relate to all age groups, comprising 2 111 men and 1 409 women. The hospital incidence relates to men and women aged 65 years or below and comprises 1 323 men and 279 women during the period concerned. The reduced mortality and increased incidence of hospital-treated infarction are probaby explained by the fact that more men seek hospital treatment, leading to a better prognosis. The long duration of sick-leave after infarction is probably due to causes other than strictly medical factors.

Absence of secular changes in the prognosis of patients with an initial myocardial infarction

A community-based study was conducted in metropolitan Baltimore in which secular trends in the in-hospital and long-term prognosis of 935 male and female patients hospitalized with an initial myocardial infarction were examined for the two periods of 1966-1967 and 1971. The in-hospital case fatality rate among males in both periods remained unchanged (19.0% vs 19.0%), whereas there was a decrease over time among women hospitalized in 1966-1967 as compared to those in 1971 (37.2% vs 26.6%) (p less than 0.10). For patients discharged alive from the hospital and followed up for as long as 10 years, no significant differences in overall survival were observed between male patients discharged in 1966-1967 and 1971 or between female patients discharged in these two periods. These findings may reflect the lack of major therapeutic advances in the care of the acute coronary patient between the two study periods and, therefore, support continuing efforts directed at the primary and secondary prevention of the atherosclerotic process.

Which postinfarction ventricular arrhythmias should be treated?

There is still no consensus on which arrhythmias should be treated in the 6- to 12-month high-risk period after acute myocardial infarction. To examine this question, we analyzed 24-hour ECG recordings in 430 patients who survived for at least 2 weeks after myocardial infarction and studied these patients for at least 1 year. During the year after infarction, 63 cardiac deaths occurred. High ventricular premature depolarization (VPD) frequency increased the risk of dying; 26% of the patients had greater than or equal to 10 VPDs/hr and were 2.6 times as likely to die within a year as those with lower frequencies. Repetitive VPDs (pairs or ventricular tachycardia) also were strongly associated with mortality. Thirty-one percent had repetitive VPDs, and these patients were 3.2 times as likely to die as those who lacked this characteristic. Frequent or repetitive VPDs were strongly associated with many other important postinfarction risk factors (e.g., left ventricular dysfunction or digitalis treatment). Nevertheless, frequent or repetitive VPDs contributed significantly to death in the first year after infarction independent of other risk factors; about 90% of these arrhythmias can be controlled satisfactorily with antiarrhythmic drugs. As yet, no definitive trial has been conducted to show whether controlling frequent or repetitive VPDs will significantly reduce the mortality in the first year after infarction. The principal design features for such a trial are discussed.

Deaths and non-fatal reinfarctions during two years' follow-up after myocardial infarction

Since 1968 special units for registering and following up all myocardial infarction patients have been in operation in Góteborg. The present paper reports on the deaths and non-fatal reinfarctions among 440 men and women below 67 years of age followed for two years after hospitalization for myocardial infarction. Of the 359 men, 299 had their first infarction and 60 a recurrent infarction. During two years 13% of men with a first infarction, and 37% of men with a recurrent infarction died. Deaths were significantly more common during the first than during the second year. There was no significant difference in mortality between men and women. The incidence of non-fatal reinfarctions was of similar magnitude and showed similar time relationships. Two thirds of the deaths were sudden (within 24 hours after onset of new symptoms) and half of the deaths occurred outside hospital. The autopsy rate was 92%. Two thirds of the deaths were caused by a fresh morphological infarct. In one fourth of the deaths where no cause was found at autopsy, death was ascribed to malignant arrhythmias. Heart weights were higher among patients dying after recurrent infarction at entry to the study. No distinctive pattern was found when autopsy findings were correlated to the interval between the onset of symptoms and death. Deaths due to fresh infarction and without an identifiable cause were more common among those who died within 24 hours of onset of symptoms compared to those dying after longer intervals.