2020 AHA/ACC Guidelines on hypertrophic cardiomyopathy: a paradigm shift

Hypertrophic cardiomyopathy (HCM) is a complex and relatively common myocardial disorder characterised by primary left ventricular hypertrophy. This entity is well known for outstanding genetic, morphological and clinical heterogeneity. HCM is a particularly common cause of sudden cardiac death in young people and may cause death and disability in patients of all ages, although it is also frequently compatible with normal longevity.

In the last decades, novel treatment strategies targeting subgroups of patients with HCM have been introduced, however, causing controversy about their special indications and outcome.
The first international consensus document on hypertrophic cardiomyopathy (HCM) was presented by ACC and ESC experts ⁽¹⁾ and paved the path for further guidelines to be forged by the ACCF/AHA in 2011 ⁽²⁾ and ESC in 2014 ⁽³⁾. By the end of 2020 the newest addition to this line of recommendations has been presented by the AHA/ACC guidelines for the diagnosis and treatment of patients with HCM ⁽⁴⁾. These guidelines replace the previous 2011 ACCF/AHA guidelines for the diagnosis and treatment of hypertrophic cardiomyopathy and was developed on the basis of existing evidence for cardiovascular specialists as well as noncardiovascular clinicians.
Apart from topics on diagnostic and treatment issues, these guidelines involve recommendations initiating a paradigm shift in the management of patients with HCM.
A shared decision-making, meaning a dialogue between patient and care provider, including a full disclosure of all options, risks and benefits, as well as patient engagement to express their goals and expectations, is a novelty in the guidelines, which has not been seen before. Furthermore, the advent of multidisciplinary HCM centres, with the ability to offer high quality comprehensive management of patients, is being established, in contradiction to centres covering the primary care of patients with HCM. Multidisciplinary HCM centres should be trusted with the performance of septal reduction treatments as well as management of complex disease-related decisions.
For primary sudden cardiac death prevention in HCM, the new guidelines recommend a comprehensive, systematic non-invasive assessment with the aid of clinical risk factors. In patients with at least one major risk factor (sudden death in the family, massive left ventricular hypertrophy, recent syncope suspected to be arrhythmic, LV apical aneurysm, LV systolic dysfunction) the estimated five-year sudden death risk according to the ESC sudden cardiac death risk score in HCM is also taken into account for the decision to proceed with ICD implantation.
The septal reduction treatment for patients with obstructive HCM is also discussed in these guidelines (IIb recommendation) for patients who are mildly symptomatic but have additional adverse clinical factors (pulmonary hypertension, left atrial enlargement, impaired functional capacity) or for young patients with very high resting left ventricular outflow tract gradients or as an alternative to escalation of medical therapy after shared decision-making including risks and benefits of all treatment options.
Finally, these guidelines introduce an important lifestyle recommendation on physical activity and sports, which are encouraged for most patients with HCM who could gain some benefit from mild to moderate intensity recreational exercise.