[Two types of exercise-induced abnormal blood pressure response in hypertrophic cardiomyopathy]

Objective: Insufcient exercise blood pressure response(blunted ABPR) and lower blood pressure during the recovery period (LBP)after exercise are common abnormalities in patients with hypertrophic cardiomyopathy (HCM). The purpose of this study was to analyze the related factors of these two types of abnormal blood pressure response in HCM patients and their relationship with cardiopulmonary function. Methods: A total of 219 consecutive HCM patients who underwent CPET in Fuwai hospital were recruited from April 1, 2018 to Jan 31, 2020 with a complete clinical assessment, including electrocardiography, HOLTER, rest echocardiography and cardiac MRI. One hundred and eleven healthy age- and gender-matched volunteers enrolled as control group. Results: The incidences of blunted ABPR and LBP in HCM patients were much higher than normal control group (8.7% vs 1.8%, P=0.016; 6.8% vs 0.0%, P=0.003, respectively). In HCM group, patients with blunted ABPR combined more coronary artery disease (CAD) (P=0.029), pulmonary hypertension (PH) (P=0.002) and atrial fibrillation/flutter (P=0.036) compared with patients without blunted ABPR. Compared with HCM patients without LBP, the patients with LBP had higher rest left ventricular outflow tract (LVOT) gradient (P=0.017) and left ventricular ejection fraction (P=0.043), more incidence of LVOT obstructive (P=0.015) and systolic anterior motion (P=0.022). After Logistic regression analysis, CAD and PH were independent factor of blunted ABPR, while LBP was only independently associated with rest LVOT gradient. Blunted ABPR was associated with lower Peak VO₂, peak heart rate and hear rate reserve, and higher NT-proBNP (P=0.019), VE/VO₂ (P=0.000). LBP was not associated with any index of cardiopulmonary function. Conclusion: The incidences of blunted ABPR and LBP in HCM patients were much higher than normal control group. In HCM patients, CAD and PH were independent determinants of blunted ABPR, while LBP was only independently associated with rest LVOT gradient. Patients with blunted ABPR had lower cardiopulmonary function, but LBP was not associated cardiopulmonary function.