Role of Global Longitudinal Strain in Predicting Outcomes in Hypertrophic Cardiomyopathy.

Global longitudinal strain (GLS) is a sensitive indicator of global left ventricular function particularly in those with normal ejection fraction. We examined the potential value of GLS in predicting outcomes in hypertrophic cardiomyopathy (HC). Conventional and strain echocardiography was performed in 400 patients with HC followed for a median 3.1 years (interquartile range 1.2 to 5.6). Peak systolic strain from 3 apical views was averaged to calculate GLS. Patients were divided based on a previously published cutoff value of -16%. Additionally, we identified 4 HC subgroups based on GLS: GLS ≤ -20%, -20% < GLS ≤ -16%, -16% < GLS ≤ -10%, and GLS > -10%. The primary end point was a composite of new-onset sustained ventricular tachycardia/fibrillation, heart failure, cardiac transplantation, and all-cause death. Patients with GLS > -16% had significantly more events (17% vs 7%, p = 0.002). In the 4-group analysis, event rates increased with worsening GLS (5%, 7%, 14%, and 33%, respectively, p = 0.001). Event-free survival was significantly superior in those with GLS ≤ -16% versus GLS > -16% (p = 0.004); similarly, GLS > -10% portended a significantly worse event-free survival compared with each of the other 3 groups (p <0.01 for all pairwise comparisons). By univariate and multivariate Cox regression analysis, GLS remained significantly associated with the composite end point. GLS > -10% had 4 times the risk of events compared with GLS ≤ -16% (p = 0.006). In conclusion, echo-based GLS is independently associated with outcomes in HC. Patients with GLS > -10% have significantly higher event rates.