IMPORTANCE OF THE TIME OF ONSET OF SUPRAVENTRICULAR TACHYARRHYTHMIAS ON PROGNOSIS OF PATIENTS WITH ACUTE MYOCARDIAL-INFARCTION

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 in farction (AMI). However, little is known about the relationship betwee n the time of onset of supraventricular tachyarrhythmias (SVTs) and mo rtality. Therefore, this study was carried out in a 48-month period on 131 patients with AMT who presented with SVT during hospitalization. Of these, 53 patients (40.5%) had arrhythmia within < 12 h of MI, whil e 78 patients (59.5%) had arrhythmia between 12 h and 4 days. The arrh ythmias studied were atrial fibrillation, atrial flutter, and paroxysm al supraventricular tachycardia. The patients were similar for age, ge nder, coronary risk factors, creatine kinase-MB peak, cardioversion an d LV function. Angiographic features for patients with the < 12-h onse t 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 less than or equal to 0.05) of the respective lesions. Inferior wall myocardial in farction was more frequent among patients with the earlier onset (60.4 %), while patients with the later onset presented more anterior wall i nfarctions (50.0%). Only 11.3% of the patients with the earlier onset presented with severe in-hospital congestive heart failure (Killip cla sses III-IV), versus 62.8% of the patients with the later onset (p les s than or equal to 0.0001). Patients with the earlier onset of arrhyth mia had fatality rates of 7.6 and 15.1% during the first month and sub sequent 47 months post-MI, respectively, while the other set of patien ts presented rates of 37.2 (p less than or equal to 0.0003) and 24.4% (p less than or equal to 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 s evere coronary artery disease in these patients.