Risk of atrial fibrillation recurrence after new-onset transient episode during ST-elevation myocardial infarction
Authors: Demidova M M , Baturova M A , Erlinge D , Platonov P G 
Published: October 2024

Abstract

Background
Atrial fibrillation (AF) often complicates ST-elevation myocardial infarction (STEMI) and is associated with major in-hospital complications and increased mortality. The data on AF recurrence after new-onset transient STEMI-associated AF is scarce, and electrocardiographic (ECG) predictors of AF recurrence are unknown.

Purpose
Our aim was to assess the risk of AF recurrence and to find out the predictors of AF recurrence after transient STEMI-associated AF.

Methods
STEMI patients admitted during 2007-2010 for primary percutaneous coronary interventions (PCI) were followed up until 2018. All ECGs ever recorded before, during or after STEMI (n=58907) were exported from regional database in digital format and processed using Glasgow algorithm. Clinical characteristics and mortality status were retrieved from the Swedish national registries. Information regarding AF was obtained from the national registries and the regional ECG database. STEMI-associated AF was defined as first-ever AF episode occurring between symptom onset and hospital discharge. Patients with pre-existing AF, AF after acute coronary artery bypass surgery and patients discharged with ongoing AF were excluded from analysis. P-wave indexes were assessed from the latest sinus rhythm ECG before discharge. The primary endpoint was the first documented AF episode after discharge. The secondary endpoints were total mortality and ischemic stroke. Cox regression analysis was adjusted for relevant clinical covariates.

Results
1) 1956 patients who were discharged alive on sinus rhythm were included in the analysis (age 65±12, 70% males), 127(6.5%) of them had transient STEMI-associated AF.
2) Patients with STEMI-associated AF were more likely to develop AF during follow-up (n=74 [58.3%]) than patients without AF before or during STEMI (No AF) (n=56 [3.1%], HR=4.80 95%CI 3.93-5.97) (Figure 1).
3) None of the clinical and demographic characteristics was associated with AF recurrence. P-wave duration, P-terminal force in V1 and P-voltage in lead I were associated with AF recurrence, however only reduced P-wave voltage in lead I &lt;93 µV (75th percentile) (HR=2.29 95% CI 1.21-4.35, p=0.011) remained independently associated with AF recurrence in adjusted analysis (Figure 2).
4) During follow-up, 134 patients had an ischemic stroke and 522 died. STEMI-associated AF was associated with higher long-term mortality risk comparing to No AF (HR=1.18 95%CI 1.02-1.36). The risk of stroke was not associated with STEMI-associated AF (HR=1.08 95%CI 0.79-1.49). In patients with STEMI-associated AF, occurrence of stroke did not differ between patients with and without AF recurrence (5[7%] vs 8 [15%] respectively, p=0.147).

Conclusion
STEMI-associated transient AF is associated with a 4.8-fold increased risk of AF after discharge, reaching 28% by 1 year after discharge. ECG-based P-wave indexes reflecting atrial remodeling can be used for the prediction of AF recurrence after discharge.