Approach

There is no curative treatment for hypertrophic cardiomyopathy (HCM). Therapies are advocated in select patient populations in order to reduce symptoms (which may occur secondary to subaortic obstruction, diastolic dysfunction, or ischaemia) and to reduce the risk of sudden cardiac death (SCD). Patient care requires the collaboration of different specialties and coordination between different levels of care; a shared care approach between cardiomyopathy specialists and general adult cardiology centres is strongly recommended.[1]

Initial assessment and approach to treatment in all patients

On initial evaluation, patients must be classified as asymptomatic or symptomatic. They must also undergo risk stratification to further define their risk of SCD.[1][2]​​ Only patients with symptoms related to outflow tract obstruction, diastolic dysfunction, or systolic dysfunction require medical therapy. Only certain patients at high risk for SCD warrant implantable cardioverter-defibrillator (ICD) placement.

Arrhythmic risk calculators may be useful in predicting the risk of SCD and have been validated in large populations.[63][64]​​​ One study, however, evaluated the 2014 European Society of Cardiology SCD risk model for HCM. The prognostic score was applied retrospectively to a large independent cohort of patients with HCM and was found to be generally unreliable for prediction of future SCD; most patients who had experienced SCD or undergone appropriate ICD interventions were misclassified as low risk.[39]

Consensus recommendations have previously restricted all athletes with HCM from all competitive sports; however, US and European guidelines now advise that participation in high-intensity exercise/competitive sports may be considered for some individuals after comprehensive evaluation and shared discussion.[2][65]​​​​ A large prospective cohort study found that among individuals with HCM, or those who are genotype positive/phenotype negative, who are treated in experienced centres, those exercising vigorously do not experience a higher rate of death or life-threatening arrhythmias than those exercising moderately or those who are sedentary.[66] 

Asymptomatic patients

Asymptomatic patients (genotype-positive/phenotype-negative) are usually identified incidentally at the time of routine heart examination or family screening.[1][2]​​​ These patients require ongoing monitoring for development of clinical HCM. US guidelines recommend serial clinical assessment, ECG, and cardiac imaging every 1-2 years in children and adolescents and every 3-5 years in adults.[2]

Genotype-positive/phenotype-negative patients are not considered at high risk of SCD and ICD placement is not required.[2]

Participation in competitive sport of any intensity is reasonable in genotype-positive/phenotype-negative patients; they should be regularly assessed for change in clinical status.[2]​​[65]​​​ 

Patients at high risk of sudden death

SCD is the most common mode of death in young people with HCM, occurring with an incidence of 1% per year.[67] The proposed mechanism of SCD is ventricular tachycardia (VT) or ventricular fibrillation (VF) secondary to ischaemia.[4] SCD typically occurs in the setting of extreme exertion. No medical or surgical treatment has been shown to lessen the risk of sudden death in large populations, thus ICD therapy is first-line therapy in those patients in whom the risk of SCD is considered significant.[1][2]For details of risk stratification, see Diagnostic approach.

No randomised controlled trials (RCTs) studying the effect of ICD placement have been performed in patients with HCM, although there is evidence from observational studies.[2][68]

Guidelines recommend ICD placement for patients with HCM and previous documented cardiac arrest or sustained ventricular arrhythmia causing syncope or haemodynamic compromise in the absence of reversible causes.[1][2]​​​​ Comprehensive SCD risk stratification is recommended in all patients at initial presentation, then at 1-2 year intervals or whenever there is a change in clinical status.[1][2]

A single marker of high risk for sudden cardiac arrest may be sufficient to consider prophylactic ICD placement in selected patients.[1][2]​​​​​​​[68]​ Patients in whom this would apply include those with one or more first-degree or close relatives 50 years or less with sudden death presumably caused by HCM, patients with a maximum LV wall thickness greater than or equal to 30 mm, patients with one or more recent episodes of syncope suspected to be arrhythmic, LV apical aneurysm, LV systolic dysfunction with ejection fraction <50%, and extensive late gadolinium enhancement on cardiac magnetic resonance imaging.[1][2]​​​ Complications following ICD placement have been reported to occur at a rate of 3.4% per year.[69] Contact sports should be avoided after ICD implant.[70]

Patients and carers should be fully informed and participate in decision-making regarding ICD placement.[2] They should be counselled on the risk of inappropriate shocks, implant complications, and the social, occupational, and driving implications of the device. Implantation of a cardioverter defibrillator is only recommended in patients who have an expectation of good-quality survival >1 year.[1]

Symptomatic patients: predominantly left ventricular outflow tract obstruction (LVOTO) with preserved systolic function (ejection fraction ≥50%)

In symptomatic patients with LVOTO, the aim is to improve symptoms by using pharmacological therapy, surgery, or alcohol septal ablation. A symptomatic patient with resting or provocable LVOTO is initially treated with negative inotropic or chronotropic therapy; beta-blockers are preferred, with non-dihydropyridine calcium-channel blockers (diltiazem, verapamil) as alternatives.[2] Tachyphylaxis to drugs is common, and the dosage must be adjusted over time. In the absence of many RCTs, pharmacological therapy is mostly administered on an empirical basis to improve functional capacity and reduce symptoms.[1]

Addition of mavacamten (a cardiac myosin inhibitor) or disopyramide (a type Ia anti-arrhythmic) is considered if symptoms persist despite treatment with a beta-blocker or non-dihydropyridine calcium-channel blocker. Septal reduction therapy is also an option for eligible patients with persistent symptoms.[1][2] ​​

Low-dose diuretics may be used with caution in patients who have persistent dyspnoea with clinical evidence of volume overload and high left-sided filling pressures despite other HCM guideline-directed medical therapy. Aggressive diuresis can worsen LVOTO.[1][2]

Beta-blockers

  • Beta-blockers are beneficial due to their negative inotropic and chronotropic properties. Non-vasodilating beta-blockers are considered first-line therapy for symptomatic HCM due to LVOTO. In standard doses, they are usually well tolerated. Reported side effects include fatigue, impotence, sleep disturbances, and bradycardia.

  • Substantial experience suggests that beta-blockers can mitigate symptoms and reduce outflow tract obstruction in those patients with LVOTO occurring with exercise. There is little evidence to suggest a beneficial effect on resting outflow tract gradients; however, one small RCT found that metoprolol reduced LVOTO at rest and during exercise, provided symptom relief, and improved quality of life in patients with obstructive HCM. Maximum exercise capacity remained unchanged. This is the first RCT in over 50 years to address the use of beta-blockers in HCM.[71][72]

  • Beta-blocker may be of benefit in patients with HCM and symptoms suggestive of ischaemia.

Non-dihydropyridine calcium-channel blockers

  • Used for relief of symptoms, including those with a component of chest pain.[2] Verapamil and diltiazem have vasodilating properties as well as negative inotropic and chronotropic effects.[2] Short-term oral administration may increase exercise capacity, improve symptoms, and normalise or improve LV diastolic filling without altering systolic function.[1]

  • Verapamil can be used when beta-blockers are contraindicated or ineffective, but it is potentially harmful in patients with obstructive HCM and severe dyspnoea at rest, hypotension, and very high resting gradients (e.g., >100 mmHg), and infants <6 weeks.[2] Verapamil has been reported to cause death in a few patients with HCM and severe LVOTO or elevated pulmonary arterial pressure as it may provoke pulmonary oedema.[1] It should therefore be used with caution in these patients.[1]

  • Diltiazem should be considered in patients who are intolerant or have contraindications to beta-blockers and verapamil.[1]

Disopyramide

  • Negative inotrope and a type Ia anti-arrhythmic agent. Consider addition of disopyramide for patients with LVOTO and persistent severe symptoms despite therapy with beta-blockers or non-dihydropyridine calcium-channel blockers.[1][2]

  • US guidelines recommend that disopyramide is used in combination with an agent that has atrioventricular nodal blocking properties (i.e., beta-blocker or non-dihydropyridine calcium-channel blocker), as it may enhance conduction through the atrioventricular node, which could lead to rapid conduction with the onset of atrial fibrillation.[2]

  • European guidelines also advise that disopyramide may be considered as monotherapy in patients who are intolerant of or have contraindications to beta-blockers and non-dihydropyridine calcium-channel blockers.[1]

  • Disopyramide decreases resting LVOTO. In one multicentre study it was shown that 75% of patients with obstructive HCM who were managed with disopyramide had amelioration of symptoms in association with a 50% reduction in LV outflow gradient. This beneficial effect was sustained for the study period of 3 years.[73]

  • Dose-limiting anticholinergic side effects include dry eyes and mouth, urinary hesitancy or retention, and constipation. The ECG QT interval should be monitored for prolongation.[1]

Mavacamten

  • A cardiac myosin inhibitor approved for the treatment of adults with symptomatic New York Heart Association (NYHA) class II-III obstructive HCM to improve functional capacity and symptoms.[1][74][75]​ It works by inhibiting cardiac myosin adenosine triphosphatase (ATPase), thus reducing actin-myosin cross-bridge formation; this reduces contractility and improves myocardial dynamics.[1]

  • Consider addition of mavacamten for patients with LVOTO and persistent severe symptoms despite therapy with beta-blockers or non-dihydropyridine calcium-channel blockers.[1][2]​ In the US, mavacamten is currently available in the US through a Risk Evaluation and Mitigation Strategy (REMS) programme, designed to monitor patients periodically with echocardiograms for early detection of systolic dysfunction and to screen for drug interactions prior to each prescription.[76]

  • European guidelines stipulate that in the absence of evidence to the contrary, mavacamten should not be used with disopyramide, but may be coadministered with beta-blockers or non-dihydropyridine calcium-channel blockers.[1] UK guidelines differ, stating that it can be added‑on to individually optimised standard care that includes beta‑blockers, non-dihydropyridine calcium-channel blockers, or disopyramide, unless these are contraindicated.[75]

  • In patients with contraindications or known sensitivity to beta-blockers, non-dihydropyridine calcium-channel blockers, and disopyramide, mavacamten may be considered as monotherapy.[1]

  • Up-titration of drug treatment to a maximum tolerated dose should be monitored in accordance with licensed recommendations using echocardiographic surveillance of LV ejection fraction.[1]

  • In the EXPLORER-HCM phase 3 trial, treatment with mavacamten improved exercise capacity, LVOTO, NYHA functional class, and health status (symptoms, physical and social function, and quality of life) compared with placebo in patients with symptomatic obstructive HCM.[77][78][79] The drug was well tolerated and has a good safety profile; only a small subset of patients developed transient LV systolic dysfunction, which resolved after temporary discontinuation of the drug.

  • A secondary analysis found favourable changes in cardiac structure and function through 30 weeks of therapy, including improvement in echocardiographic markers of LV filling pressures, LVOT gradients, and systolic anterior motion. Reductions in NT-proBNP were also seen, further supporting the benefit of mavacamten on functional improvement and favourable remodelling.[80]​ 

  • Interim data from a long-term extension study, analysed at a median follow-up of 62.3 weeks, showed that mavacamten was associated with clinically important and sustained improvements of LVOT gradients, NYHA class, and NT-proBNP levels that were consistent with those observed in the parent trial. Treatment was generally well tolerated over 315 patient-years of exposure.[76]

  • In the VALOR-HCM phase 3 trial, patients who were assigned to mavacamten, as well as those who initially received placebo for 16 weeks and then crossed over to mavacamten, had a significantly reduced need for septal reduction therapy after 56 weeks compared with placebo.[81]

  • In another randomised trial (EXPLORER-CN), Chinese patients with symptomatic obstructive HCM who received treatment with mavacamten had a significant reduction in Valsalva LV outflow tract peak gradient, compared with those treated with placebo[82]

  • Open-label, follow-up studies evaluating the long-term efficacy and safety of mavacamten in these trials, as well as real-world experience, will provide more information on the durability of improvements and the safety profile of the drug.

Surgical myectomy (septal reduction therapy)

  • If severe symptoms persist despite optimal medical therapy, consideration should be given to surgical myectomy, which reduces septal mass, thereby relieving obstruction.​[2] Patients are generally considered to be eligible for septal reduction therapy when they have severe dyspnoea or chest pain (New York Heart Association class III or IV) or exertional recurrent syncope, resting or provocable outflow tract gradient of ≥50 mmHg, and appropriate anatomy.[1][2]

  • Myectomy abolishes or substantially reduces LV outflow tract gradients in over 90% of cases, reduces systolic anterior motion-related mitral regurgitation, and improves exercise capacity and symptoms.

  • Long-term symptomatic benefit is achieved in >80% of patients, with a long-term survival comparable to that of the general population.

  • Preoperative determinants of a good long-term outcome are: age <50 years; left atrial size <46 mm; absence of AF; and male sex.[1] Older age and increased severity of comorbidities are predictive of poor surgical outcomes.[83]​ 

  • Surgical myectomy has not been conclusively shown to affect the incidence of sudden death.

  • The rate of postoperative complications is estimated at 5.9% in most experienced centres. The most common complications are complete heart block in patients without previous conduction abnormality (3% to 10%), left bundle branch block (40% to 56%), and ventricular septal defect (1%).[83][84]

Alcohol septal ablation (ASA)

  • May be performed as an alternative to surgical myectomy.

  • Involves the delivery of alcohol into a target septal perforator branch of the left anterior descending coronary artery, for the purpose of producing a myocardial infarction and reducing septal thickness.[1]

  • Septal remodelling and relief of obstruction after ASA occurs over several months, resulting in a smaller reduction in resting gradient compared with surgical myectomy, but a similar reduction in patient symptoms.[85][86]

  • Complications include ventricular arrhythmias (2.2%), coronary dissection (1.8%), and complete heart block (>10%) necessitating permanent pacemaker placement.[87]​ There is an increased need for permanent pacemaker implantation post-procedure compared with surgical myectomy.[88]

  • Mortality from all-cause or sudden cardiac death is low after ASA.[89]

  • ASA has not been conclusively shown to affect the incidence of sudden death.

  • While data comparing the later outcomes of ASA and surgical myectomy are lacking, a retrospective, observational study compared long-term mortality of patients with obstructive HCM following both procedures. It concluded that ASA was associated with increased long-term all-cause mortality compared with septal myectomy. This finding remained after adjustment for confounding factors (patients undergoing ASA tend to be older with more comorbidities and reduced septal thickness, compared with patients undergoing septal myectomy), but may still be influenced by unmeasured confounders.[90]

Management of complications

Myocardial ischaemia

Patients may develop symptoms or signs of ischaemia. Ischaemia in HCM is multifactorial and thus not easily treated. Decreasing myocardial oxygen demand with negative inotropic and chronotropic agents may prove beneficial. Aetiology of the ischaemia should be identified (i.e., increased LV outflow tract obstruction, coronary artery disease, or myocardial bridging).

For patients with anomalous coronary artery, surgical unroofing of myocardial bridging (tunnelling of coronary arteries into heart muscle) has been reported to yield symptomatic improvement in select patients, but data are limited.[30][91]​​​​​ Moreover, myocardial bridging is frequently identified in HCM and has not been conclusively linked to SCD.[92][93]​​​​​ Therefore, the risks of the procedure need to be considered when advising surgical intervention.

For patients with concomitant epicardial coronary artery disease consider PCI or CABG. See Chronic coronary disease.

Ventricular arrhythmias

As described above, implantation of an ICD is recommended for secondary prevention in patients with HCM who have survived a cardiac arrest due to VT or VF, or who have spontaneous sustained ventricular arrhythmia causing syncope or haemodynamic compromise in the absence of reversible causes. It should also be considered in patients presenting with haemodynamically tolerated VT, in the absence of reversible causes.[1] In patients with HCM and pacing-capable ICDs, programming antitachycardia pacing is recommended to minimise risk of shocks.[2]​ Although data are lacking, anti-arrhythmics such as beta-blockers (e.g., sotalol) and amiodarone should be considered for patients with recurrent, symptomatic ventricular arrhythmia, or recurrent ICD shocks.[1] Catheter ablation in specialised centres may be considered in select patients with recurrent, symptomatic sustained monomorphic VT (SMVT), or recurrent ICD shocks for SMVT, in whom anti-arrhythmics are ineffective, contraindicated, or not tolerated.[2][94]​​​​​

Atrial arrhythmias

Atrial arrhythmias, including atrial fibrillation (AF), are common, particularly in older patients with HCM. Prevalence of AF among patients with HCM is estimated at 17% to 39%, with an annual incidence of 2.8% to 4.8%.[1] AF is often poorly tolerated in patients with HCM.[2] As a result, an aggressive strategy for maintaining sinus rhythm may be warranted. Paroxysmal or persistent AF are linked to left atrial enlargement.[4] AF is independently associated with heart-failure-related death, and occurrence of fatal and non-fatal stroke, as well as long-term progression of heart failure symptoms. Management of AF is as per patients without HCM. However, digoxin is not typically used for atrial rate control if the patient has significant hypertrophy, as there is a theoretical concern that it could exacerbate LVOTO due to a positive inotropic effect.[2] In addition, traditional stroke risk scoring systems used in the general population, such as CHA2DS2-VASc (congestive heart failure or left ventricular dysfunction, hypertension, age ≥75 [doubled], diabetes, stroke [doubled]-vascular disease, aged 65-74 years, sex category [female]) are not predictive in patients with HCM, with evidence suggesting that they may perform suboptimally.[1][2]​​​​​​[95]​​ For this reason, although there are no RCTs evaluating the role of anticoagulation in patients with HCM, given the high incidence of stroke, prophylactic anticoagulation is recommended in all patients with HCM and AF (if no contraindication).[1] A direct oral anticoagulant (DOAC) is recommended first-line option, and a vitamin K antagonist (usually warfarin) second-line option.[1][2]​​[95]​​​ See New-onset atrial fibrillation and Chronic atrial fibrillation.

Indications for permanent pacemaker implantation

Permanent pacemaker implantation is indicated in patients with symptomatic sinus node dysfunction and HCM, and in patients with high-grade atrioventricular (AV) block who are symptomatic, or who have arrhythmias such as AF or ventricular arrhythmias that are worsened by bradycardia or prolonged pauses.[96][70]​​

Symptomatic patients: predominantly non-obstructive with preserved systolic function (ejection fraction ≥50%)

Patients with non-obstructive HCM commonly have dyspnoea and exertional angina.[2] Symptoms are related to diastolic dysfunction, with impaired filling resulting in reduced output and pulmonary congestion. Presence of obstructive CAD should be excluded.[2] Patients are more symptomatic when heart rate is higher, as diastolic filling is further compromised; a negative chronotropic agent may therefore be beneficial in this setting.[4]

First-line options for patients with non-obstructive HCM and preserved ejection fraction are beta-blockers or non-dihydropyridine calcium-channel blockers.[1][2] Non-dihydropyridine calcium-channel blockers are thought to improve symptoms, secondary to their beneficial effect on myocardial relaxation and ventricular filling. They are also negative inotropes, which may aid in relief of symptoms. Beta-blockers may improve diastolic filling due to their negative chronotropic effect. 

Oral diuretics may be added to treatment in patients who have persistent dyspnoea despite beta-blockers or non-dihydropyridine calcium-channel blockers or volume overload; diuretics should be used with caution to avoid hypotension or hypovolemia.[2]  Disopyramide is not recommended, as it may decrease cardiac output more than the other therapies in this setting. Mavacamten is not approved for use in non-obstructive HCM; studies are ongoing.

US guidelines note that in addition to pharmacological therapies, physical activity and control of comorbidities including hypertension, diabetes, obesity, and obstructive sleep apnoea can provide optimal reduction of symptom burden.[2]

Surgery may be considered in highly selected patients with apical HCM and severe dyspnoea or angina despite maximal medical therapy; but this is limited to centres of excellence with the highest volumes, surgical experience and expertise.[2]

Management of complications

Myocardial ischaemia

If the patient develops symptoms or signs of ischaemia, decreasing myocardial oxygen demand with negative inotropic and chronotropic agents may prove beneficial. Aetiology of the ischaemia should be identified (i.e., increased LV outflow tract obstruction, coronary artery disease, or myocardial bridging). Surgical unroofing of myocardial bridging has been reported to yield symptomatic improvement in select patients, but data are limited.[30][91]​ 

Oral nitrates can be used cautiously for relief of angina.[1] Ranolazine can be considered to improve symptoms in patients with angina-like chest pain and no evidence of left ventricular outflow tract obstruction, even in the absence of obstructive coronary artery disease.[1] See Chronic coronary disease.

Ventricular arrhythmias

As in patients with LVOTO, implantation of an ICD is recommended for secondary prevention in patients with nonobstructive HCM who have survived a cardiac arrest due to VT or VF, or who have spontaneous sustained ventricular arrhythmia causing syncope or hemodynamic compromise in the absence of reversible causes. It should also be considered in patients presenting with hemodynamically tolerated VT, in the absence of reversible causes.[1] In patients with HCM and pacing-capable ICDs, programming antitachycardia pacing is recommended to minimise risk of shocks.[2] Although data are lacking, anti-arrhythmics such as beta-blockers (e.g., sotalol) and amiodarone should be considered for patients with recurrent, symptomatic ventricular arrhythmia, or recurrent ICD shocks.[1] Catheter ablation in specialised centres may be considered in select patients with recurrent, symptomatic sustained monomorphic VT (SMVT), or recurrent ICD shocks for SMVT, in whom anti-arrhythmics are ineffective, contraindicated, or not tolerated.[2][94]

Atrial arrhythmias

Treat atrial arrhythmias, including AF, as described above for patients with predominant LVOTO, to maintain sinus rhythm. The risk of systemic thromboembolism in patients with HCM and AF is thought to be significant, and thus the threshold for initiation of anticoagulant therapy should be low.[1][2]  Anticoagulation is recommended for all patients with HCM and AF, with a DOAC first-line, and a vitamin K antagonist (usually warfarin) second-line.[1][2]

Indications for permanent pacemaker implantation

Permanent pacemaker implantation is indicated in patients with symptomatic sinus node dysfunction and HCM, and in patients with high-grade AV block who are symptomatic, or who have arrhythmias such as AF or ventricular arrhythmias that are worsened by bradycardia or prolonged pauses.[96][70]​

Symptomatic patients: with systolic dysfunction (ejection fraction <50%)

The average duration from onset of symptoms to end-stage disease is 14 years.[97] Systolic function deteriorates, and the left ventricle remodels and becomes dilated. The mechanism of end-stage HCM is likely to be diffuse ischaemic injury. Risk factors for end-stage disease include younger age at diagnosis, more severe symptoms, larger LV cavity size, and family history of end-stage disease. Mortality is high once this complication develops, with mean time to death or cardiac transplantation of 2.7 ± 2.1 years.[97]

Medical therapy

Patients with systolic dysfunction with ejection fraction <50% are treated with guideline-directed medical therapy (GDMT) for heart failure with reduced ejection fraction.[2][98] See Heart failure with reduced ejection fraction.

Diuretics should be used cautiously in these patients compared with patients with other causes of heart failure, due to possible impairment in preload.

US guidelines note that reduced ejection fraction is uncommon in patients with HCM, and therefore the patient should be evaluated for other causes of systolic dysfunction.[2] Mavacamten should be interrupted or discontinued in patients who develop LVEF <50%. Previously indicated negative inotropic agents (verapamil, diltiazem, or disopyramide) should also be discontinued.[2]

Evaluation for mechanical circulatory support and/or heart transplantation

If patients remain refractory to medical therapy, they should be referred for consideration for heart transplant.[2][98] Heart transplants have been shown to improve survival and quality of life for patients with end-stage heart failure secondary to HCM.[98] Presence of comorbidities, caretaker status, and goals of care should all be taken into account when considering patient eligibility for transplant.[98]​ Left ventricular assist device therapy may be considered as a bridge to transplantation.[2]

ICD

As described above, patients with HCM and systolic dysfunction with ejection fraction <50% are considered for ICD placement.[2]

Cardiac resynchronisation therapy (CRT)

US guidelines note that in patients with NYHA functional class II to class IV symptoms despite GDMT, and left bundle branch block, CRT can be beneficial to improve symptoms, reduce HF hospitalisations, and increase survival in patients. The benefit in patients with HCM is not established, but use of CRT may be considered in select patients.[2]

Considerations for additional common chronic comorbid conditions

Lifestyle and cardiovascular disease risk modification

  • Comorbidities such as hypertension, obesity, diabetes, hyperlipidaemia, and sleep-disordered breathing, and lifestyle factors, such as smoking and inactivity, may increase symptom burden and risk of heart failure and/or atrial fibrillation.[99][100]​​​ Primary prevention of cardiovascular disease (as per published guidelines) and management of risk factors is recommended in all (symptomatic and asymptomatic) patients.[1][99][101]

  • Obesity and hypertension have both been associated with increased risk of developing HCM in genotype-negative individuals. US guidelines suggest that weight loss interventions in patients with HCM and obesity have the potential to reduce symptoms and adverse outcomes.[99]

  • When treating patients with hypertension and obstructive HCM, beta-blockers or non-dihydropyridine calcium-channel blockers are preferred. Low-dose diuretics may also be considered. Vasodilating agents may exacerbate LVOTO and symptoms.[99]

  • Assessment for sleep-disordered breathing is recommended by US guidelines, with referral to specialist if symptoms are present.[99] The guidelines suggest that management of obstructive sleep apnoea could reduce symptoms and arrhythmic complications in patients with HCM, but evidence is needed.

  • Patients should refrain from high-intensity athletics.

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