Abstract 19806: Left Atrial Remodeling in Hypertrophic Cardiomyopathy and Markers for Atrial Fibrillation: Assessment by Cardiovascular Magnetic Resonance Imaging

Abstract

Introduction. Atrial fibrillation (AF) is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM), and an important determinant of clinical deterioration due primarily to heart failure and embolic stroke Hypothesis. Left atrial (LA) structural and functional parameters were assessed with high resolution cardiovascular magnetic resonance imaging (CMR) to provide imaging markers associated with the risk for developing AF in HCM patients. Methods. We studied 438 consecutive HCM patients (age 47 17 years) with CMR, including 57 with a history of paroxysmal AF, 13 in persistent AF, 368 without AF history, as well as 244 normal controls. The LA chamber was assessed for absolute and indexed end-diastolic volume (LAEDV) and end-systolic volume (LAESV), and % ejection fraction (LAEF). Results. Absolute LAEDV was significantly greater in HCM patients with AF (157 ± 73 ml) than in patients without AF (109 ± 39 ml), or normal controls (80 ± 24 ml; p < 0.001). LAEF was lower in HCM with AF (34 ± 17%) than in HCM without AF (46 ± 12%) or controls (55 ± 9%; p < 0.001), and decreased progressively from control values to HCM without AF to HCM with paroxysmal AF (37 ±16 ml), and to those patients with persistent/chronic AF (18 ±13%; p < 0.001). A multivariate model showed LAEF (< 40%) and LAEDV (> 125 ml), as well as age (> 46 years) each to be independently associated with occurrence of AF. Combining these 3 CMR variables most accurately discriminated the susceptibility to AF with the area under ROC curve = 0.805, and the accuracy = 82%. Conclusions. In HCM, % LAEF, as assessed by CMR, is a novel marker associated with AF, and in conjunction with increased LAEDV and older age.