# Interventions for Hypertrophic Obstructive Cardiomyopathy: Defining the Gold Standard, Assessing Durability, and Guiding Patient Selection

## TL;DR

This paper reviews surgical and alternative treatments for a heart condition called hypertrophic obstructive cardiomyopathy, comparing their effectiveness and risks.

## Contribution

The paper provides a contemporary assessment of surgical septal myectomy as the gold standard treatment and highlights gaps in current evidence.

## Key findings

- Surgical septal myectomy achieves low residual heart flow obstruction and better long-term survival compared to alcohol septal ablation.
- Alcohol septal ablation has higher risks of re-intervention and permanent pacemaker implantation.
- Advancements like virtual surgical myectomy are expanding treatment options for high-risk patients.

## Abstract

Hypertrophic obstructive cardiomyopathy (HOCM) is a genetic disorder characterized by a dynamic left ventricular outflow tract (LVOT) obstruction and an increased risk of sudden cardiac death. For patients with symptoms refractory to medical management, or intolerant to the new selective myosin inhibitor, septal reduction therapy (SRT) with surgical septal myectomy (SM) is indicated. This narrative review provides a contemporary assessment of septal myectomy, integrating its historical development, technical advancements, and comparative long-term outcomes. SM is established as the current reference standard, offering extensive anatomical relief and favorable long-term survival in clinical registries. It consistently achieves residual LVOT gradients <10 mmHg and enables correction of complex accessory mitral pathologies, leading to significant reverse ventricular and atrial remodeling. In contrast, ASA, a less invasive alternative for high-risk surgical candidates, is limited by incomplete tissue necrosis. This results in higher residual gradients (15–20 mmHg), increased rates of re-intervention (10–20%) and incidence of permanent pacemaker implantation (10–17.4%) and an associated greater risk of long-term all-cause mortality (>5 years). The disparity in long-term survival and the risk associated with sequential septal reduction procedures underscore the critical need for precise patient selection guided by institutional expertise. Furthermore, advancements like virtual surgical myectomy and transapical beating-heart septal myectomy are expanding the scope of intervention. This review synthesizes comparative contemporary data on HOCM management, highlighting the need for prospective, multicenter studies to address enduring knowledge gaps concerning equitable access, genotype integration, and long-term comparative effectiveness as current evidence remains dominated by retrospective studies.