The predictive value of CHADS2 risk score in post myocardial infarction arrhythmias - A Cardiac Arrhythmias and RIsk Stratification after Myocardial infArction (CARISMA) substudy

BackgroundPrevious studies have shown substantially increased risk of cardiac arrhythmias and sudden cardiac death in post-myocardial infarction (MI) patients. However it remains difficult to identify the patients who are at highest risk of arrhythmias in the post-MI setting. The purpose of this study was to investigate if CHADS2 score (congestive heart failure, hypertension, age ≥ 75 years, diabetes and previous stroke/TCI [doubled]) can be used as a risk tool for predicting cardiac arrhythmias after MI.MethodsThe study included 297 post-MI patients from the CARISMA study with left ventricular ejection fraction (LVEF) ≤ 40%. All patients were implanted with an implantable cardiac monitor (ICM) within 5 to 21 days post-MI and followed every three months for two years. Atrial fibrillation, bradyarrhythmias and ventricular tachycardias were diagnosed using the ICM, pacemaker or ICD. Patients were stratified according to CHADS2 score at enrollment. Congestive heart failure was defined as LVEF ≤ 40% and NYHA class II, III or IV.ResultsWe found significantly increased risk of an arrhythmic event with increasing CHADS2 score (CHADS2 score = 1-2: HR = 2.1 [1.1-3.9], p = 0.021, CHADS2 score ≥ 3: HR = 3.7 [1.9-7.1], p < 0.001). This pattern was identical when dividing the arrhythmias into subgroups of atrial fibrillation, ventricular tachycardias and bradyarrhythmias. CHADS2 score was similarly associated with the development of major cardiovascular events defined as reinfarction, stroke, and hospitalization for heart failure or cardiovascular death.ConclusionIn the post-MI setting, CHADS2 score efficiently identifies populations at high risk for cardiac arrhythmias.