Prognosis of new-onset of atrial fibrillation in acute coronary syndrome: Portuguese experience
Authors: Santos H , Santos M , Almeida I , Miranda H , Sa C , Chin J , Almeida S , Sousa C , Almeida L 
Published: May 2021

Abstract

Funding Acknowledgements
Type of funding sources: None.

OnBehalf
Portuguese Registry of Acute Coronary Syndromes

Background
Acute coronary syndrome (ACS) and atrial fibrillation (AF) are common diseases in developed countries and in some cases, the first episode of AF can occur during the ACS. A stressful event like an ACS can be a trigger for AF, being important to realize its impact and prognosis in the short and long term.

Objective
Evaluate the impact and prognosis of new-onset AF in ACS.

Methods
Multicenter retrospective study, based on the Portuguese Registry of ACS between 1/10/2010-4/09/2019. Patients were divided into two groups: A – patients without new-onset AF, and B – patients that presented new onset of AF. Were excluded patients without a previous cardiovascular history or clinical data during the admission and the follow-up period. Logistic regression was performed to assess if new-onset AF in ACS was a predictor of major adverse cardiac events and mortality. Kaplan-Meier test was performed to establish the survival rates and re-admission for one year of follow up.

Results
9687 patients suffered ACS and had follow-up at 1 year, 9264 in group A (95.6%) and 423 in group B (4.4%). Both groups were similar regarding dyslipidemia, diabetes mellitus, previous coronary artery disease, multivessel disease after the cardiac catheterization. Group A had more smokers (28.2 vs 17.8%, p &lt; 0.001) and left ventricular ejection fraction (LVEF) &gt;50% (69.2 vs 45.1%, p &lt; 0.001). On the other hand, group B was elderly (67 ± 14 vs 75 ± 12, p &lt; 0.001), female (26.9 vs 34.0%, p &lt; 0.001), arterial hypertension (70.5 vs 77.5%, p = 0.005), was more admitted directly to the cat lab (12.5 vs 17.7%, p = 0.002), ST-segment elevation myocardial infarction (40.2 vs 49.9%, p &lt; 0.001), Killip-Kimball classification &gt; I (12.8 vs 34.8%, p &lt; 0.001) and hybrid revascularization (0.7 vs 2.4%, p = 0.002). Logistic regression revealed that new-onset of AF in ACS patients was a predictor of congestive heart failure (odds ratio (OR) 1.75, p &lt; 0.001, confidence interval (CI) 1.47-2.09), cardiogenic shock (OR 3.08, p &lt; 0.001, CI 2.37-4.01), sustained ventricular tachycardia (OR 2.29, p &lt; 0.001, CI 1.61-3.25) and intrahospital mortality (OR 1.99, p &lt; 0.001, CI 1.51-2.63). Nevertheless, new-onset of AF was not associated with re-infarction (p = 0.361), mechanical complications (p = 0.319), atrioventricular block (p = 0.574), stroke (p = 0.131) and cardiac arrest (p = 0.060) during the hospitalization for ACS. Mortality rates at one year of follow-up showed significant differences, p &lt; 0.001, between the two groups (Figure 1). Similar results were found concerning re-admission for all causes, p = 0.021 (Figure 2), on the other causes, re-admission for cardiovascular causes do not reveal to be significant, p = 0.515.

Conclusions
New-onset of AF in ACS was a predictor of congestive heart failure, cardiogenic shock, sustained ventricular tachycardia and intrahospital mortality. AF was associated with higher mortality rates and re-admission for all causes at one year follow up.