2024 ACC/AHA/Multisociety Guidelines for Management of Hypertrophic Cardiomyopathy Released

2024 ACC/AHA/Multisociety Guidelines for Management of Hypertrophic Cardiomyopathy is now available online with free access at JACC website. Both PDF and HTML versions are available and you can choose either depending on your reading preference. The PDF version runs into 82 pages and is a 4.49 MB download. As it is a ‘Just Accepted’ paper which is yet to become part of a full issue, page numbers are not for citation. I was quite happy to see the name of my friend Seshadri Balaji representing Heart Rhythm Society among the writing committee members. Prof. Balaji is originally from Tamil Nadu, South India.

Those who are in a hurry could go through the 2024 Hypertrophic Cardiomyopathy Guideline-at-a-Glance which is a five page document which summarises top ten take home messages from the guidelines. As you would have imagined, I went through that first! I found the central illustration of the article quite interesting. It is titled as “Encouraging exercise for HCM patients”, with a subtitle which reads “Recent evidence demonstrates benefits outweigh risks in many patients with appropriate assessment”. I presume that everyone will be interested as undetected HCM is an important cause of sudden cardiac death in athletes. Mild to moderate recreational exercise without competition is tagged green, vigorous recreational activities as yellow and competitive sports as orange, with Class I, IIa and IIb recommendations respectively. Of course, the wording ‘with appropriate assessment’ is of topmost importance. As you are aware, exercise is not for everyone with HCM! Role of exercise in HCM has been discussed as take home point number ten.

The newly available cardiac myosin inhibitors for treatment of symptomatic obstructive hypertrophic cardiomyopathy has come as take home point number six. They are a new class of agents which inhibit actin-myosin interaction, thereby decreasing myocardial contractility and left ventricular outflow tract obstruction. Mavacamten is a first-in-class reversible cardiac myosin inhibitor which has been evaluated in the EXPLORER-HCM trial for symptomatic hypertrophic obstructive cardiomyopathy. MAVERICK-HCM trial evaluated mavacamten in nonobstructive hypertrophic cardiomyopathy. USFDA has approved Mavacamten for the treatment of adults with symptomatic NYHA class II-III hypertrophic obstructive cardiomyopathy to improve exercise capacity and symptoms.

Extended ambulatory monitoring for those at risk of atrial fibrillation which was given a Class IIa recommendation in 2020 guidelines has been upgraded to Class I recommendation in the 2024 guidelines. A new Class I recommendation has appeared in 2024 guidelines for paediatric HCM regardless of symptom status for exercise stress testing to determine functional capacity and provide prognostic information.

Adding myosin inhibitor for adult patients symptomatic with HOCM despite beta blockers or nondihydropyridine calcium channel blockers is a new Class I recommendation in pharmacotherapy. Other options of disopyramide in combination with atrioventricular nodal blocking agent and septal reduction therapy performed at experienced centers for such patients remain at Class I level as in 2020 guidelines. Cardiac myosin inhibitors have to be discontinued in those who develop persistent left ventricular systolic dysfunction. Cardiac myosin inhibitors are contraindicated in pregnant women due to potential teratogenic effects.

Another new recommendations is for valsartan in younger patients with nonobstructive HCM due to a pathogenic or likely pathogenic cardiac sarcomere genetic variant and mild phenotype as it may slow adverse cardiac remodeling. But that comes only as a Class IIb recommendation. Another interesting statement is Class III recommendation for universal restriction from vigorous physical activitiy and competitive sports. As discussed initially, such activity has been suggested to be considered after comprehensive evaluation as Class IIb. With this brief introduction in mind, please proceed to the full text of the 2024 guidelines with free access to everyone.