Left atrial mechanics in hypertrophic cardiomyopathy: discriminating hypertrophy and predicting fibrosis

Abstract BACKGROUND : Hypertrophic cardiomyopathy (HCM) and left ventricular hypertrophy (LVH) secondary to systemic hypertension (HTN) may be associated with left atrial (LA) functional abnormalities. We aimed to characterize LA mechanics in HCM and HTN and determine any correlation with the extent of fibrosis measured by cardiac magnetic resonance (CMR) in HCM patients. METHODS: Two-dimensional speckle tracking-derived longitudinal LA function was acquired from apical views in 60 HCM patients, 60 HTN patients, and 34 age-matched controls. HCM patients also underwent CMR, with measurement of late gadolinium enhancement (LGE) extension. Association with LA strain parameters was analyzed. RESULTS: The mean LV ejection fraction did not differ across groups. The E/e’ ratio was only preserved in the control group and significantly impaired in the HCM group. LA mechanics were significantly reduced in HCM, compared to the HTN group. LA strain rate in systole (LA-SRs) and late diastole (LA-SRa) were the best discriminators of HCM, with an area under the curve (AUC) of 0.8, followed by LA strain in systole (LA ɛsys) (AUC 0.76). LA-SRs and LA-SRa had high specificity (89% and 91%, respectively) and LA ɛsys had sensitivity of 80%. LA strain rate in early diastole (LA-SRe) was moderately correlated with the extension of LGE (r 2 0.42, p=0.027) CONCLUSIONS: LA-SRs and LA-SRa were the best discriminators for LVH secondary to HCM. LA-SRe was best correlated with the degree of fibrosis assessed by CMR. These findings suggest that LA mechanics can be potential predictors of disease severity in HCM.