Cardiomyopathy in Northwestern Mexico: Clinical Spectrum, Morphological Variants, and Sarcomere Gene Mutations

Hypertrophic cardiomyopathy (HCM) is a common genetic heart disease characterized by left ventricular (LV) hypertrophy that cannot be fully explained by abnormal loading conditions.

To describe the clinical spectrum, morphological variants and sarcomere gene mutations in patients with HCM from northwestern Mexico.

We conducted a prospective, cross-sectional study of patients diagnosed with HCM by echocardiography. Morphological variants were classified as: asymmetric septal, concentric, mid-cavity, lateral, and apical according to the location of the greatest LV thickening. Next-generation sequencing was performed with a predesigned panel of 19 genes associated with HCM.

A total of 110 patients (47.3% women; median age 58) were enrolled. Apical HCM was the most frequent morphological variant (42%), followed by asymmetric septal HCM (35%). Patients with apical HCM were older than those with other variants (p = 0.002). Patients with asymmetric septal hypertrophy had a higher septal/posterior wall thickness ratio (1.85 ± 0.6, p = 0.0001) and a larger left atrial anteroposterior diameter (48 ± 9, p = 0.0001). LV outflow obstruction, systolic anterior motion, and severe mitral regurgitation were more prevalent in patients with asymmetric septal HCM (p = 0.0001). Patients with concentric HCM had the greatest E/e' ratio (16.3 ± 8, p = 0.01). Among genotyped patients, 44% had a sarcomeric gene mutation, most commonly MYBPC3 (24%) and MYH7 (7%), with no significant differences across morphological variants.

Apical HCM was the most frequent morphological variant of HCM in the studied population. Consistent with global reports, MYBPC3 and MYH7 were the most commonly identified gene mutations.