Hypercontractile phenotype in hypertrophic cardiomyopathy indicates unfavorable hemodynamics, coronary flow and prognosis

Aims Our aim was to assess the clinical and prognostic significance of the left ventricular (LV) hypercontractile phenotype (HP) in hypertrophic cardiomyopathy (HCM), which until now remains unclear. Methods and results We enrolled 1533 HCM patients (age 51 ± 15 years, 965 males, 63%) with ejection fraction (EF) ≥ 50%, referred for rest transthoracic echocardiography (TTE) in 27 laboratories from 13 countries. Two-dimensional volumetric TTE assessment included LV outflow tract gradient (LVOTG), LV EF, and LV force (systolic blood pressure + LVOTG/ESV, mmHg/mL). HP was defined as the highest quartile of the force (> 7.32 mmHg/mL). Survival analysis was performed in a subset of 1200 patients with follow-up information. Compared with non-HP patients, HP showed higher heart rate (72 ± 14 vs. 67 ± 14 beats per minute, P < 0.001), lower stroke volume (50 ± 22 vs. 67 ± 22 mL, P < 0.001), larger left atrial volume index (44 ± 16 vs. 40 ± 16 mL/m2, P = 0.011) and higher coronary flow velocity in the mid-distal left anterior descending artery (n = 325, 41 ± 12 vs. 37 ± 14 cm/s, P = 0.021). Force was moderately related to LV EF (r = 0.48, P < 0.001) and weakly to LVOTG (r = 0.36, P < 0.001). During a median follow-up of 87 months (interquartile range 45-143 months), 131 all-cause deaths occurred. At multivariable Cox analysis, a force > 7.32 mmHg (the fourth quartile for analyzed patients) was associated with a hazard ratio of 1.44 (95% Confidence intervals 1.00-2.07) for all-cause death, independently of LVOTG and LV EF. Conclusion HP in HCM is associated with a disadvantageous systemic, cardiac and coronary hemodynamic profile as well as lower survival in the long-term.