Abstract P607: Interplay Between Post-Myocardial Infarction Left Ventricular Systolic Dysfunction and Atrial Fibrillation: Prognostic Implications for Post-Myocardial Infarction Acute Ischaemic Stroke

Introduction: Acute myocardial infarction (MI) and acute ischaemic stroke (AIS) are leading causes of morbidity and mortality. There is scarce data examining the interplay between post-MI left ventricular systolic dysfunction (LVSD), with or without atrial fibrillation (AF), and subsequent AIS, especially in patients with milder degrees of LVSD (ejection fraction 40-49%). Evidence of an association would be helpful in developing new strategies of reducing AIS after MI. As such, we sought to study this relationship in a real-world population-based registry. Methods: This study involved linking national-level data from the Singapore Myocardial Infarction Registry with the Singapore Stroke Registry from 1st January 2007 to 31st December 2018. Both data sets have similar definitions for patient demographics. The ejection fraction (EF) and AF status were recorded during the MI episode. The outcome studied was the first instance of AIS that developed after the MI episode. We also studied the relationship between EF, AF and the severity of AIS as measured by the NIH Stroke Scale (NIHSS). Results: There were 64,512 patients available for analysis. The median age was 65.7 (IQR 56.1-76.5) and 69.5% were male. The median duration post-MI to develop AIS was 16.9 (IQR 1.6-46.1) months. There was an independent association between LVSD and the outcome of AIS (adjusted HR 1.18, 95% CI 1.10-1.27); this was evident even in mild forms of LVSD (adjusted HR 1.16, 95% CI 1.06-1.27). AF was not a statistically significant predictor of AIS in post-MI patients with LVSD. Amongst patients without AF, post-MI LVSD was associated with a more severe stroke and higher NIHSS. Conclusion: Post-MI LVSD is associated with the occurrence of subsequent AIS. Although this relationship was independent of AF status, patients with LVSD but no AF had suffered a more severe AIS. These findings support the need to develop effectives therapies to prevent AIS post-MI, especially among those with LVSD.