PREDICTORS OF NEW-ONSET ATRIAL FIBRILLATION AFTER ST-SEGMENT ELEVATION MYOCARDIAL INFARCTION IN THE ELDERLY

Objective: The predictors and outcomes of new-onset atrial fibrillation (AF) were evaluated among elderly patients with acute ST elevation myocardial infarction (STEMI). Material and Method: Patients with STEMI who are older than 65 years were evaluated for new-onset AF and its complications. Patients with a previous history of AF and those found in AF at the time of admission were excluded. Results: Of the 102 patients with STEMI, AF was not observed in 74 patients (Group I) and was observed in 28 patients (Group II) during hospitalization. Those 28 patients with AF were further divided into two subgroups according to the onset time of AF (early <24 hours and late >24 hours). Anterior MI was observed in 49% of patients in Group I and 71.4% of patients in Group II (p<0.05). In late onset AF group; pulse rate, systolic and diastolic blood pressure were significantly higher than Group I at admission to the hospital (p<0.05). All patients in Group II had higher Killip class and TIMI risk scores than Group I patients (p<0.05). Left ventricular ejection fraction was 30.4 +/- 4.0% in the late onset group and 44.4 +/- 8.8% in Group I (p<0.05). There was a significant difference in mortality rate among groups during hospitalization period; 36% in Group II, 9% in Group I (p<0.05). Conclusion: AF is especially seen in elderly female patients with anterior MI and higher Killip Class. It is associated with higher rates of in-hospital mortality. Particularly, late-onset AFs are associated with lower LVEFs in older patients with STEMI and could be predictors of in hospital mortality.