Importance of the time of onset of supraventricular tachyarrhythmias on prognosis of patients with acute myocardial infarction

Abstract

It is known that left ventricular (LV) function, severity of coronary artery disease, and the presence of ventricular arrhythmias are major determinants of prognosis in patients surviving an acute myocardial infarction (AMI). However, little is known about the relationship between the time of onset of supraventricular tachyarrhythmias (SVTs) and mortality. Therefore, this study was carried out in a 48-month period on 131 patients with AMI who presented with SVT during hospitalization. Of these, 53 patients (40.5%) had arrhythmia within < 12 h of MI, while 78 patients (59.5%) had arrhythmia between 12 h and 4 days. The arrhythmias studied were atrial fibrillation, atrial flutter, and paroxysmal supraventricular tachycardia. The patients were similar for age, gender, coronary risk factors, creatine kinase-MB peak, cardioversion and LV function. Angiographic features for patients with the < 12-h onset of arrhythmia were: 86.7% of the patients had uniarterial lesions, 8.9% had biarterial lesions, and 4.4% had triarterial lesions. Patients with the 12-h-4-day onset had 16.1%, 53.2%, and 30.6% (p≤0.05) of the respective lesions. Inferior wall myocardial infarction was more frequent among patients with the earlier onset (60.4%), while patients with the later onset presented more anterior wall infarctions (50.0%). Only 11.3% of the patients with the earlier onset presented with severe in-hospital congestive heart failure (Killip classes III-IV), versus 62.8% of the patients with the later onset (p≤0.0001). Patients with the earlier onset of arrhythmia had fatality rates of 7.6 and 15.1% during the first month and subsequent 47 months post-MI, respectively, while the other set of patients presented rates of 37.2 (p≤0.0003) and 24.4% (p≤0.01), respectively. These data suggest that the relationship between SVT occurrence between 12 h and 4 days after MI and poor prognosis is apparently linked to the occurrence of more severe coronary artery disease in these patients.