Left atrial mechanical dysfunction and the risk for ischemic stroke in HCM patients without prior atrial fibrillation or stroke

Abstract

Abstract Background Patients with hypertrophic cardiomyopathy (HCM) are at high risk of atrial fibrillation (AF) and ischemic stroke. Left atrial enlargement and dysfunction that characterize atrial myopathy may precede and promote AF and cardiac thromboembolism. In HCM patients without prior AF or stroke, whether left atrial mechanical dysfunction can improve ischemic stroke prediction is unknown. Method Patients with prior AF or stroke (n = 121) were excluded and 653 consecutive patients with HCM (mean age 47.3 ± 12.3 years, 71% male) who underwent cardiac magnetic resonance (CMR) at Fuwai Hospital between January 2012 and December 2013 were finally enrolled. LA ejection fraction, strain and strain rate indices on reservoir, conduit and booster-pump phases that represent LA mechanical function were analyzed. The primary endpoint was ischemic stroke. The secondary endpoint was new-onset AF. Result At 7.6 ± 2.4 years of follow-up, 24 (3.7%) had ischemic stroke and 73 (11.2%) had new-onset AF. Patients with stroke had an older age (p = 0.014), higher incidence of hypertension (p < 0.001), more LGE presence (p = 0.006) and LGE extent (p = 0.007). For LA size and function, patients with stroke showed significantly higher LA volume index and lower LA ejection fraction and LA strain (all p < 0.01). Age, hypertension, LGE presence, LGE extent and all LA mechanical indices were univariably associated with stroke. On multivariate model, LA reservoir strain was associated with stroke (Hazard Ratio = 0.91. 95%CI 0.85-0.97, p = 0.005) independent of Age (p = 0.292), hypertension (p = 0.002), LGE extent (p = 0.003) and LA volume (p = 0.737). In addition, LA reservoir strain was also associated with new-onset AF (Hazard Ratio = 0.93. 95%CI 0.89-0.96, p < 0.001) independent of Age (p < 0.001), hypertension (p = 0.607), LGE extent (p = 0.882) and LA volume (p = 0.002). Conclusion In HCM patients without prior AF or stroke, LA mechanical dysfunction was a strong predictor for stroke and new-onset AF independent of LA enlargement, age, hypertension and LGE extent.