Abstract 17186: Left Atrial Strain Predicts Adverse Outcomes in Hypertrophic Cardiomyopathy

Abstract

Introduction: Hypertrophic cardiomyopathy (HCM) patients are at increased risk for heart failure (HF), stroke, death, and paroxysmal atrial fibrillation (PAF) development. There is no consensus whether atrial fibrillation (AF) is a marker or mediator of adverse outcomes in HCM patients. Hypothesis: We hypothesized that PAF and left atrial (LA) remodeling predict adverse outcomes in HCM. Methods: Echocardiography (2D and speckle tracking) was used to assess LA size, function, and mechanics in a cohort of HCM patients with history of PAF (PAF group, n=45) and age/gender-matched HCM patients without history of AF (No-AF group; n=59). AF was diagnosed by review of EKGs, event recorder/holter monitor data, and ICD interrogation. Patients were followed for a mean of 53 months for development of the composite endpoint of HF, death, and stroke. Results: Clinical/demographic characteristics were similar in the 2 groups; 67% of PAF group had a CHADS 2 VASC score ≤ 1. The PAF group had higher LA volume, lower LA ejection fraction, and higher E/A ratio (reflecting LV diastolic dysfunction) compared to the No-AF group. LA contractile and reservoir strain/strain rate (SR) were significantly lower in the PAF group (Table 1). Male gender, LA reservoir and conduit strain/SR (not PAF presence) were associated with the development of the composite endpoint in univariate analysis. Only LA conduit and reservoir strain/SR independently predicted the composite endpoint in a multivariate model. Kaplan Meier survival analysis showed greater event-free survival among HCM patients with LA conduit strain >10.2% (Figure 1a) and LA reservoir strain >23.8% (p < 0.01) (Figure 1b). Conclusions: PAF is associated with greater degree of LA myopathy in HCM. LA myopathy assessed by conduit and reservoir strain/SR may be useful for risk stratification for HF, stroke, and death in HCM.