Hypertrophic Obstructive Cardiomyopathy During Pregnancy: A Report of Two Cases

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy caused by pathogenic variants in sarcomeric proteins and defined by left ventricular (LV) wall thickness ≥15 mm at end diastole in the absence of abnormal loading conditions. Hypertrophic obstructive cardiomyopathy (HOCM) is the obstructive phenotype of HCM characterized by dynamic left ventricular outflow tract (LVOT) obstruction, most often driven by septal hypertrophy and systolic anterior motion (SAM) of the mitral valve, frequently with mitral regurgitation. Pregnancy is generally well-tolerated in women with HCM; however, outcomes may be worse when significant left ventricular outflow tract obstruction (LVOTO) is present. Pregnancy-related increases in heart rate and reductions in systemic vascular resistance may intensify dynamic LVOTO, particularly when preload or afterload decreases. In severe symptomatic cases, pregnancy may be contraindicated (modified World Health Organization (mWHO) class IV, an extremely high-risk category in which pregnancy is generally discouraged) and therefore requires individualized counseling and specialized multidisciplinary care. This report describes two cases (a two-patient case series) of pregnant women with HOCM who required close hemodynamic monitoring and optimized peripartum management.