Left Atrial Volumes and Strain by Cardiac Magnetic Resonance Are Associated With Long Term Outcomes in Patients With Hypertrophic Cardiomyopathy

Introduction: We sought to evaluate left atrial (LA) morphology, function and strain by cardiac magnetic resonance (CMR) in hypertrophic cardiomyopathy (HCM) patients and the association of these parameters with long-term clinical outcomes. Methods: We retrospectively evaluated 50 HCM patients and 50 patients without significant cardiovascular disease (controls) who underwent clinically-indicated CMR. We performed a multivariate regression analysis adjusting the model for age, coronary artery disease, NYHA class, late gadolinium enhancement and LV EF with endpoints of ventricular tachyarrhythmias (VTA) and heart failure hospitalization (HFH). LA indexed volumes (LAVi), LA EF, expansion index, reservoir (εR), conduit (εCD), and contractile strain (εCT) were measured. Results: The mean age for HCM patients was 59.6 ± 16.3 (54% males) versus 50.9 ± 14.6 (36% male) for controls. Median follow up was 15.6 months. HCM patients had significantly higher LV mass, LV wall thickness, LAVi and lower LA strain compared to controls. On multivariate analysis, LA εCT, minimum and maximum LAVi were significantly associated with the composite outcome (p = 0.05). Cox proportional hazard models (figure) showed a clear difference in the outcomes around median εCT and maximum LAVi. Conclusion: HCM patients had significantly higher LAVi and lower LA strain compared to controls. LA εCT, minimum and maximum LAVi were significantly associated with the composite outcome of VTA or HFH.