How does morphology impact on diastolic function in hypertrophic cardiomyopathy? A single centre experience

Objectives: It is unclear if morphology impacts on diastole in hypertrophic cardiomyopathy (HCM). We sought to determine the relationship between various parameters of diastolic function and morphology in a large HCM cohort. Setting: Tertiary referral centre from Stanford, California, USA. Partecipants: 383 patients with HCM and normal systolic function between 1999 and 2011. A group of 100 prospectively recruited age-matched and sexmatched healthy participants were used as controls. Primary and secondary outcome measures: Echocardiograms were assessed by two blinded boardcertified cardiologists. HCM morphology was classified as described in the literature (reverse, sigmoid, symmetric, apical and undefined). Results: Reverse curvature morphology was most commonly observed (218 (57%). Lateral mitral annular E′<12 cm/s was present in 86% of reverse, 88% of sigmoid, 79% of symmetric, 86% of apical and 81% of undefined morphology, p=0.65. E/E′ was similarly elevated (E/E′: 12.3±7.9 in reverse curvature, 12.1±6.1 in sigmoid, 12.7±9.5 in symmetric, 9.4±4.0 in apical, 12.7±7.9 in undefined morphology, p=0.71) and indexed left atrial volume (LAVi)>40 mL/m2 was present in 47% in reverse curvature, 33% in sigmoid, 32% in symmetric, 37% in apical and 32% in undefined, p=0.09. Each morphology showed altered parameters of diastolic function when compared with the control population. Left ventricular (LV) obstruction was independently associated with all three diastolic parameters considered, in particular with LAVi>40 mL/ m2 (OR 2.04 (95% CI 1.23 to 3.39), p=0.005), E/E′>15 (OR 4.66 (95% CI 2.51 to 8.64), p<0.001) and E′<8 (OR 2.55 (95% CI 1.42 to 4.53), p=0.001). Other correlates of diastolic dysfunction were age, LV wall thickness and moderate-to-severe mitral regurgitation. Conclusions: In HCM, diastolic dysfunction is present to similar degrees independently from the morphological pattern. The main correlates of diastolic dysfunction are LV obstruction, age, degree of hypertrophy and degree of mitral regurgitation.