Behind The Science: Midventricular Obstruction in HCM: An Overlooked High‑Risk Phenotype | JACC Author Interviews

Midventricular obstruction in hypertrophic cardiomyopathy (HCM) is rare—but clinically significant. In this episode of Behind the Science, Adith Arun and Alexander Schulz, MD break down new JACC findings showing why midventricular obstructive HCM should be recognized as a distinct, higher‑risk phenotype, rather than grouped with non‑obstructive disease. Through a focused discussion of echocardiographic criteria, intraventricular gradient assessment, Kaplan–Meier outcomes, heart failure risk, and sudden cardiac death signals, the authors explore how midventricular obstruction compares with classic LVOT obstruction—and why current phenotyping may be missing patients. The conversation also examines the implications for cardiac myosin inhibitors, ongoing clinical trials, and the potential value of targeted subgroup analyses to guide future therapy. Essential viewing for cardiologists managing HCM, particularly those interested in advanced imaging, risk stratification, and emerging treatments.