Abstract 15258: New Onset Atrial Fibrillation Predicts Malignant Arrhythmias in Post Myocardial Infarction Patients. A Cardiac Arrhythmias and Risk Stratification After Acute Myocardial Infarction (CARISMA) Substudy
Background: After myocardial infarction the risk of sudden cardiac death due to arrhythmias is substantial. The purpose of this study was to investigate if new onset atrial fibrillation (AF) was predictive for the development of potential malignant brady- and tachyarrhythmias after an acute myocardial infarction.
Methods: The study included 283 post myocardial infarction patients from the CARISMA study with left ventricular ejection fraction ≤ 40 %, NYHA class I, II or III and no history of AF. All patients were implanted with an implantable cardiac monitor (ICM), an ICD or a pacemaker within 5 to 21 days after the acute myocardial infarction and followed every three months for two years. Arrhythmias were diagnosed using the ICM, pacemakers or ICDs. In the bradycardia analysis patients were censored at the time of pacemaker implantation. We conducted time-dependent Cox-regression analysis to test the predictive value of new onset AF for the development of bradyarrhythmias and ventricular tachyarrhythmias.
Results: New onset AF was associated with a significantly increased risk of bradyarrhythmias when adjusting for left ventricular ejection fraction and gender (HR =2.7 [CI; 1.3-5.7], p=0.006). Similarly, new onset AF predicted ventricular tachyarrhythmias when adjusting for NYHA class (HR=2.2 [CI: 1.1-4.4], p=0.02). However, when dividing ventricular tachyarrhythmias into subgroups of nonsustained ventricular tachycardia (VT), sustained VT and ventricular fibrillation (VF), new onset AF was only significantly associated with an increased risk of nonsustained and sustained VT but not VF (nonsustained VT: HR=3.5 [CI: 1.7-7.3], p=0.0007, sustained VT: HR=4.6 [CI: 1.3-16.6], P=0.02, VF: HR= 1.1 [CI: 0.2-5.8], p=0.872).
Conclusion: In patients surviving a myocardial infarction with reduced left ventricular systolic function, new onset AF is associated with a significantly increased risk of developing ventricular tachy- and bradyarrhythmias.
- © 2012 by American Heart Association, Inc.