Title : Left atrial volume index and atrial arrhythmia outcomes in hypertrophic cardiomyopathy
Abstract:
Hypertrophic cardiomyopathy is an inherited myocardial disease characterised by overt left ventricular hypertrophy. Atrial fibrillation is a common complication. Due to the unique arrhythmogenic substrate, atrial ablation has limited efficacy, making predictors of outcome valuable. Left atrial size may predict the onset of atrial fibrillation, but traditional measurements of size have been variable and inaccurate. This study aims to establish the validity of left atrial volume index (LAVi) by area-length method in predicting outcomes. A retrospective medical notes review was conducted, including 233 patients with hypertrophic cardiomyopathy from the echocardiography database (mean age 53 years, 73% male, median follow-up 8.8 years). The prevalences of atrial arrhythmia and all-cause mortality were 31% and 12% respectively. On multivariate analysis, LAVi predicted incident atrial arrhythmia (HR 1.04 per 1ml/m2, p<0.0001) and intervention for atrial arrhythmia (composite of atrial ablation and pace-and-ablate, HR 1.02 per 1ml/m2, p=0.001). LAVi did not predict death. From a case series of 10 patients undergoing atrial ablation, none had freedom from arrhythmia recurrence or reintervention during the follow-up. Overall, atrial arrhythmia is prevalent, and LAVi predicted onset and intervention. Selection for atrial ablation should be extremely judicious, with perhaps a greater role of anti-arrhythmic drugs and pace-and-ablate.
