Obstructive HCM with Left Ventricular Outflow Tract Gradient ≥50 mmHg: Next Step When Maximum Medical Therapy Has Not Improved Symptoms

This protocol applies to patients with hypertrophic cardiomyopathy whose symptoms remain attributable to left ventricular outflow tract obstruction (LVOTO), with a resting or provoked gradient of ≥50 mmHg, after maximum tolerated medical therapy has failed to achieve the target of symptom improvement.

Clinical Scenario

Symptoms are attributable to LVOTO. The resting or provoked left ventricular outflow tract gradient meets or exceeds 50 mmHg — the accepted threshold above which invasive intervention is considered. Despite medical optimisation, the goal of symptom improvement has not been reached.

Prior Therapy — Goal Not Reached

The preceding treatment step involved disopyramide (added to a beta-blocker, or with verapamil or diltiazem) or the cardiac myosin ATPase inhibitor mavacamten (added to a beta-blocker, or with verapamil or diltiazem), each titrated to maximum tolerated dose. The target outcome — improvement of symptoms — was not achieved, indicating escalation to this protocol.

Next-Step Approach

At this stage, the protocol moves to an interventional approach centred on septal reduction. The applicable procedure and the specific factors that guide its selection depend on individual patient characteristics. The complete protocol — including procedure selection criteria and clinical goals — is available via the link below.

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References

DOI: 10.1093/eurheartj/ehad194

By convention, LVOTO is defined as a peak instantaneous Doppler LV outflow tract gradient of >=30 mmHg, but the threshold for invasive treatment is usually considered to be >=50 mmHg.

SRT to improve symptoms is recommended in patients with a resting or maximum provoked LVOT gradient of >=50 mmHg who are in NYHA/Ross functional class III-IV, despite maximum tolerated medical therapy.

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