Left Atrial Function by Cardiovascular MRI Independently Predicts Life Threatening Arrhythmias in Patients Referred for Primary Prevention ICD

ABSTRACT Background In this study we aimed to investigate left atrial function, measured from routine cine cardiovascular magnetic resonance (CMR) imaging, to determine its value for the prediction of sudden cardiac death (SCD) or appropriate ICD shock in patients receiving primary prevention ICD. Methods 203 patients with ischemic or idiopathic non-ischemic dilated cardiomyopathy undergoing CMR imaging prior to primary prevention ICD implantation were studied. Left atrial (LA) volumes were measured at end-diastole and end-systole from 4- and 2-chamber cine images, and LA emptying function (LAEF) calculated. Patients were followed for the primary composite endpoint of SCD or appropriate ICD shock. Results Mean age was 61±12 years with a mean left ventricular ejection fraction of 24±7%. The mean LAEF was 27±15% (range 0.9 to 73%). At a median follow-up of 1639 days, 35 patients (17%) experienced the primary composite outcome. LAEF was strongly associated with the primary outcome (p=0.001); patients with an LAEF ≤30% experiencing a cumulative event rate of 26.1% versus 5.7% (HR 5.5, p Conclusions LAEF is a simple, powerful and independent predictor of SCD in patients being referred for primary prevention ICD.