Phenotype-Based Classification of Obstructive Hypertrophic Cardiomyopathy Undergoing Myectomy.

This study partitioned variables derived from clinical and pathological information in patients who received septal reduction therapy to identify obstructive hypertrophic cardiomyopathy subtypes. Subtype 1 was characterized by a high percentage of sarcomere mutation carriers and the highest interventricular septal thickness. Subtype 2 was featured by left atrial enlargement and a high percentage of patients with atrial fibrillation. Subtype 3 was characterized by a high left ventricular outflow tract gradient, serious inflammatory cell infiltration, and a high incidence of postoperative adverse events. This finding has been well replicated in 2 validation cohorts with short- and long-term follow-up.