Left ventricular dysfunction after acute myocardial infarction--the impact of cardiovascular risk factors

Left ventricular (LV) systolic function is an important prognostic factor in coronary heart disease. Left ventricular ejection fraction (LVEF) should be assessed in all patients after acute myocardial infarction (AMI). Although reperfusion therapy has been found effective in the reduction of complications of AMI, LVEF impairment is a common consequence of an acute coronary event. The aim of this study was to estimate the incidence of LVEF depression after ST-elevation myocardial infarction (STEMI) and to evaluate the effect of previous cardiovascular risk factors on the risk of LV dysfunction.

One hundred and forty-seven consecutive patients with a first STEMI were included in this study. Most patients were male (70.7%) and mean age was 60.7 years. LVEF was assessed by echocardiography (using the single-plane area-length method and automatic border detection). LV systolic function was considered depressed when ejection fraction was less than 45 %. The chi-square test was used in the statistical analysis to compare proportions and a logistic regression model was fitted to assess the independent effect of each variable.

Incidence of LV dysfunction was 55.8% in STEMI patients. No association was found between gender or age and LVEF impairment. The proportion of patients with diabetes was higher in the impaired LVEF group than in normal LVEF patients (44.7% vs. 31.7%, p = 0.12); the prevalence of smoking was also higher in patients with LV dysfunction (46.9% vs. 33.8%, p = 0.11). On the other hand, dyslipidemia was less common in patients with depressed LV function (35.4% vs. 56.9%, p = 0.01). Hypertension was not associated with impaired LVEF. After adjustment for ST-elevation location and number of vessels with critical stenosis, diabetes and smoking were associated with a significantly higher risk of LVEF impairment (diabetes: OR = 3.73, 95% CI 1.25-11.16; smoking: OR = 3.9, 95% CI 1.37-11.07) and dyslipidemia with a significantly lower risk of LV dysfunction (OR: 0.37, 95% CI 0.15-0.88).

In STEMI patients, previous cardiovascular risk factors have a significant impact on the likelihood of LV dysfunction and hence could influence long-term prognosis.