Relationship between left atrial/left ventricular diameter ratio and outcomes in patients with hypertrophic cardiomyopathy

Background: Although diastolic dysfunction is the main pathophysiological feature of hypertrophic cardiomyopathy (HCM), it remains to be clarified whether parameters of diastolic function can reliably determine HCM prognosis. In patients with reduced left ventricular (LV) distensibility, chronic elevation of LV diastolic pressure is seen with a smaller than expected LV size. Accordingly, patients with HCM with severe LV diastolic dysfunction typically demonstrate left atrial (LA) dilation and a disproportionately smaller left ventricle. Therefore, we investigated the relationship between LA/LV diameter ratio, as a potential indicator of disease progression, and outcomes in patients with HCM.

Methods: We included 468 patients in whom LA and LV end-diastolic diameter were successfully evaluated by echocardiography at the initial assessment. We divided the patients into two groups: those with an LA/LV diameter ratio > 1 and those with an LA/LV diameter ratio ≤ 1. We compared the HCM-related death rates between the two groups.

Results: Of the 468 patients, 96 patients (20.5 %) with HCM showed an LA/LV diameter ratio > 1. In the univariate analysis, patients with an LA/LV diameter ratio > 1 had a significantly greater likelihood of HCM-related death than patients with an LA/LV diameter ratio ≤ 1 (log-rank p = 0.002). In the multivariate Cox proportional hazards analysis, when including LA/LV diameter ratio > 1 and imbalanced baseline variables, an LA/LV diameter ratio > 1 was an independent determinant of HCM-related death (adjusted hazard ratio: 1.87, 95 % confidence interval: 1.08-3.24; p = 0.024).

Conclusion: LA/LV diameter ratio can be easily evaluated and may be useful for risk stratification of HCM-related death in patients with HCM.