Baseline characteristics of study population:
A total of 1793 patients were screened for eligibility. Of these, 1626 patients admitted with de novo acute MI were enrolled in this study. The mean (SD) age of the population was 61.5 (12.5) years and men made up 70.7% of the study population. Fifty-one (3.1%) patients were diagnosed with AF. Dramatically, the minority of patients were previously diagnosed with AF (14 patients, 27.4%) and only 1 out of every 5 AF patients (10 patients, 19.6%) was using oral anticoagulants (OAC). Demographic and clinical characteristics of the study population are presented in Table 1. Patients in the AF group were older than the non-AF group [mean 73.4 (9.4) vs. 61.0 (12.4) years, p<0.001]. The percentage of women in the AF group was also higher than that in the non-AF group (43.1% vs. 28.7%, p=0.027). Non-ST segment elevation MI (NSTEMI) presentation (68.6% vs. 53.2%, p=0.023) and prevalence of hypertension (64.7% vs. 48.5%, p=0.023) were more common in patients in the AF group. Conversely, fewer patients in the AF group smoked than in the non-AF group (39.2% vs. 58.6%, p=0.006). Median LV ejection fraction at admission was lower in AF patients than the non-AF patients [45.0% (30-50%) vs. 50.0% (35-55%), p=0.008]. Hemoglobin levels were also lower in the AF group [12.7 (2.2) vs. 13.7 (1.9) gr/dL, p=0.004]. A greater number of patients in the AF group were classified as Killip class 3 and 4 at admission (3.9% vs. 2.9%, p=0.001). Severe mitral regurgitation was more common in AF patients (11.7% vs. 1.7%, p<0.001). Although the STEMI rate was 46.0% for the entire study population, only 3.0% of the total population, none of which were in the AF group, received thrombolytic treatment as a reperfusion therapy before diagnostic coronary angiography. Oral P2Y12 inhibitor loading before the index emergency admission rate was higher in AF patients (96.0% vs. 91.8%, p=0.027). Clopidogrel was the most commonly used P2Y12 inhibitor in the study population (49.2%). On the other hand, the loading rate of oral P2Y12inhibitors other than clopidogrel was 31.3% in the AF and 47.6% in the non-AF group (p=0.004). Preexisting oral anticoagulant use was also higher in AF patients (19.6% vs. 1.0%, p<0.001) (Table 2).