Heart failure during first inferior acute myocardial infarction

BACKGROUND: Inferior acute myocardial infarctions (AMI) have better in-hospital prognosis than do anterior AMI. Authors of several studies reported that patients with inferior AMI complicated by atrioventricular block, concomitant precordial ST-segment depression and involvement of right ventricle have larger infarctions and a worse prognoses than do patients without these features. OBJECTIVE: To analyse the incidence, clinical course and in-hospital prognosis of patients with heart failure and first inferior AMI. METHODS: We analysed in 257 consecutive patients with first inferior AMI who had been admitted to the coronary care unit during January 1991 and March 1995. The clinical and electrocardiographic characteristics, as well as the morbidities and in-hospital mortalities, of groups of patients with and without heart failure during inferior AMI were compared. RESULTS: Symptoms and signs of heart failure were noted for 49 patients (19%). We found that patients who had suffered heart failure during inferior AMI were older (62.1 +/- 9.86 versus 58.78 +/- 10.58 years, P < 0.05) than those who had not suffered heart failure. There was no significant difference between patients' sex, history of diabetes mellitus, hypertension, smoking status, thrombolytic therapy, involvement of right ventricle and QRS score for these two groups. We found a greater prevalence of ST-segment depression (ST-segment depression > or = 1 mV in more than one precordial lead with maximal ST-segment depression in leads V4-V6) of V4-V6 precordial leads (57 versus 26%, P = 0.00002) and a lesser prevalence of no ST-segment depression (ST-segment depression < 0.1 mV in each precordial lead; 14 versus 38%, P = 0.001) among patients who had suffered heart failure. We found greater incidences of serious ventricular arrhythmias (53 versus 26, P = 0.0002) and ventricular tachycardiafibrillation (16 versus 7%, P = 0.03) among patients who had suffered heart failure than we did among those who had not. Third-degree atrioventricular block was more often found in patients who had suffered heart failure (23 versus 12%, P = 0.07) but this difference was not statistically significant. We found that the in-hospital mortality among patients who had suffered heart failure was much higher than that among those who had not (24.5 versus 3.8%, P = 0.000001). CONCLUSION: We found that heart failure occurs primarily in old patients, and in those with precordial ST-segment depression, especially in leads V4-V6. The patients who suffer heart failure have worse in-hospital prognosis due to serious ventricular arrhythmias and cardiogenic shock.