ECG markers of atrial abnormalities are not associated with new onset atrial fibrillation in patients with acute ST-segment elevation myocardial infarction

Abstract

Abstract Introduction New onset AF is a known complication in patients with acute ST-segment elevation myocardial infarction (STEMI). However, whether new-onset AF is linked to atrial structural abnormalities or has different underlying mechanisms is not fully clarified. Purpose We aimed to assess the association of P wave indices as ECG markers of atrial structural abnormalities with new-onset AF in STEMI patients undergoing primary percutaneous intervention (PCI). Methods Study sample comprised of 2277 consecutive patients with STEMI admitted to a tertiary care hospital for primary PCI from 2007 to 2010. SWEDEHEART registry was used as the source of information regarding clinical characteristics and events during index admission, including new-onset AF. The closest available ECGs prior to STEMI (median 448, interquartile rate 25–75% 112–1390 days before STEMI) were extracted from the regional electronic ECG databases and automatically processed using Glasgow algorithm. Patients with sinus rhythm ECGs were included in the current analysis (n=1481, mean age 68±12 years, 33% females). P-wave duration, PR interval, P-wave frontal axis and P terminal force in lead V1 (PTF-V1) were assessed. PTF-V1 >40 mm*ms was considered abnormal. Results Paroxysmal AF prior to STEMI was known in 77 patients (5.2%). Among patients without pre-existing AF (n=1404), new-onset AF during hospital admission was identified in 102 patients (6.9%). Patients with new-onset AF were older than those without AF history (74±9 vs 67±12 years, p<0.001), but did not differ in regard to other clinical characteristics. In univariate logistic regression analysis P wave duration as continuous variable, P wave duration >120 ms and PR interval were significantly associated with new onset AF (Table 1). However, after adjustment for age both, P wave duration >120 ms (odds ratio (OR) 1.20, 95% CI 0.77–1.89, p=0.418) and PR interval (OR 1.01, 95% CI 1.00–1.01, p=0.068), failed to demonstrate the significant association with new onset AF while age (OR 1.06, 95% CI 1.04–1.08, p<0.001) remained an independent risk factor for AF development. Conclusion In patients with acute STEMI new onset AF developed during hospital admission is common and strongly associated with age. P wave indices failed to demonstrate the significant association with new onset AF thus indicating that atrial structural abnormalities are unlikely the underlying cause of AF development in acute STEMI. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Scholarship grant from Swedish Institute. Table 1