What are the management options for a patient with cardiomyopathy?

Management of Cardiomyopathy

Begin with nonvasodilating beta-blockers as first-line therapy for all symptomatic cardiomyopathy patients, titrated to a resting heart rate of 60-65 bpm, regardless of whether left ventricular outflow tract obstruction is present. 1

Initial Pharmacological Management

First-Line Therapy: Beta-Blockers

• Nonvasodilating beta-blockers (metoprolol succinate, bisoprolol, carvedilol) are the Class I recommended initial treatment for symptomatic patients with hypertrophic cardiomyopathy (HCM). 1
• Titrate to maximum tolerated dose targeting resting heart rate of 60-65 bpm to achieve physiologic beta-blockade. 1, 2
• Beta-blockers reduce left ventricular outflow tract (LVOT) gradients, alleviate dyspnea, improve exercise tolerance, and enhance quality of life. 1
• For nonobstructive cardiomyopathy with preserved ejection fraction, beta-blockers remain first-line for symptoms of exertional angina or dyspnea. 3

Alternative First-Line: Non-Dihydropyridine Calcium Channel Blockers

• Verapamil or diltiazem are reasonable alternatives if beta-blockers are not tolerated, but use with caution due to vasodilating properties that may worsen obstruction. 2
• These agents slow ventricular response and improve diastolic filling, particularly beneficial in patients with preserved ejection fraction. 3
• Avoid in patients with severe LVOT obstruction or hemodynamic instability. 3

Second-Line and Advanced Therapies

Mavacamten (Cardiac Myosin Inhibitor)

• Mavacamten is a Class I recommendation for adults with persistent NYHA class II-III symptoms despite optimal beta-blocker or calcium channel blocker therapy. 1
• Improves LVOT gradients, functional capacity, and quality of life in 30-60% of patients with obstructive HCM. 1, 2
• Requires mandatory REMS program monitoring due to risk of left ventricular ejection fraction reduction <50%. 1
• This represents the first FDA-approved medication specifically targeting HCM pathophysiology. 4

Disopyramide

• Add disopyramide to beta-blocker or calcium channel blocker therapy as third-line option for patients with persistent symptoms and LVOT obstruction. 1, 2
• Must be combined with AV nodal blocking agent to prevent rapid ventricular response if atrial fibrillation develops. 2
• Requires careful QTc interval monitoring due to proarrhythmic potential. 2
• Particularly effective in patients with LVOT obstruction, can abolish basal gradients and improve exercise tolerance. 3

Critical Medications to AVOID

Contraindicated Vasodilators

• Discontinue ALL vasodilators immediately: ACE inhibitors, ARBs, dihydropyridine calcium channel blockers (nifedipine, amlodipine), digoxin, alpha-blockers, nitrates, and hydralazine. 1, 2
• These agents worsen LVOT obstruction by reducing afterload and increasing gradient severity. 1
• Dihydropyridine calcium channel blockers are Class III: Harm recommendations for patients with resting or provocable LVOT obstruction. 1

Other Contraindications

• Avoid Class IC antiarrhythmics (flecainide, propafenone) as they prolong QRS duration, increase QT interval, and may increase ventricular rate due to conversion to atrial flutter with 1:1 conduction. 3
• Avoid digoxin in patients with LVOT obstruction and normal ejection fraction. 3

Atrial Fibrillation Management in Cardiomyopathy

Anticoagulation Strategy

• All patients with cardiomyopathy and atrial fibrillation (paroxysmal, persistent, or permanent) require oral anticoagulation with direct oral anticoagulants (DOACs) as first-line, independent of CHA₂DS₂-VASc score. 3, 1
• The traditional CHA₂DS₂-VASc score is NOT recommended for stroke risk calculation in HCM patients, as they have inherently high stroke risk. 3
• Vitamin K antagonists (warfarin) are acceptable alternatives, particularly in patients with moderate-severe mitral stenosis or mechanical prosthetic valves. 3
• For dilated cardiomyopathy (DCM), use CHA₂DS₂-VASc score ≥2 in men or ≥3 in women to guide anticoagulation. 3
• Left atrial appendage closure (percutaneous or surgical) is reasonable for patients with contraindication to anticoagulation or high hemorrhagic risk. 3

Rate and Rhythm Control

• Ventricular rate control using beta-blockers or non-dihydropyridine calcium channel blockers (alone or in combination) targeting resting heart rate <100 bpm. 3
• Assess adequacy of rate control during exercise, not just at rest. 3
• For rhythm control, amiodarone is often the only effective option for preventing AF recurrences, though sotalol has a better side-effect profile. 3
• In hemodynamically unstable patients, perform direct current cardioversion immediately. 3
• For hemodynamically stable patients with severe symptoms, use intravenous beta-blockers or amiodarone. 3
• Consider AV node ablation with permanent pacing when adequate rate control cannot be achieved medically. 3

Heart Failure Management in Cardiomyopathy

Systolic Dysfunction (EF <50%)

• In patients with cardiomyopathy and ejection fraction <50%, treat similarly to other heart failure patients with guideline-directed medical therapy (GDMT): ACE inhibitors/ARBs, beta-blockers, mineralocorticoid receptor antagonists, and SGLT2 inhibitors. 3
• An ejection fraction <50% in HCM connotes significantly impaired systolic function and identifies individuals with poor prognosis and increased sudden cardiac death risk. 3
• Consider advanced treatment options including cardiac resynchronization therapy, left ventricular assist device, and transplantation for progressive disease. 3

Diastolic Dysfunction with Preserved EF

• Focus on symptom management with beta-blockers or non-dihydropyridine calcium channel blockers. 3
• Diuretics for volume management, but use cautiously to avoid excessive preload reduction. 3

Special Consideration: Ivabradine

• For dilated cardiomyopathy patients with heart failure, LVEF ≤35%, sinus rhythm with heart rate ≥70 bpm despite maximally tolerated beta-blocker doses, ivabradine reduces hospitalization for worsening heart failure. 5
• Initiate at 5 mg twice daily, titrate to 7.5 mg twice daily or decrease to 2.5 mg twice daily to maintain resting heart rate 50-60 bpm. 5

Cardiometabolic Risk Factor Management

Obesity and Hypertension

• Intensive management of obesity is crucial, as it is present in >70% of adult HCM patients and independently associated with increased left ventricular hypertrophy burden, more symptoms, and worse outcomes. 1
• Aggressively treat hypertension, as cardiometabolic risk factors are highly prevalent and associated with poorer prognosis in cardiomyopathy. 1
• Screen for and treat obstructive sleep apnea, which is common in HCM and contributes to symptom burden. 2

Lifestyle Modifications

• Moderate-intensity recreational exercise has not been associated with increased risk of ventricular arrhythmia events in recent studies and should be encouraged for general health benefits. 3
• More rigorous exercise/training requires comprehensive shared discussion between patient and expert HCM care team regarding potential risks, though exercise-related risk cannot be individualized. 3
• Manage comorbidities including physical inactivity, alcohol misuse, and hyperthyroidism to reduce AF burden. 3

Subtype-Specific Considerations

Restrictive Cardiomyopathy and Cardiac Amyloidosis

• Reverse remodeling is NOT a therapeutic goal in restrictive cardiomyopathy (RCM). 3
• Cardiac output is crucially dependent on heart rate; beta-blockers may not be tolerated due to negative chronotropic and inotropic effects. 3
• Coordinate care with hematologists for cardiac amyloidosis, and with nephrology, hepatology, neurology when systemic disease is present. 3

Anthracycline-Induced Cardiomyopathy

• Requires preliminary multidisciplinary discussion with oncologists about treatments with best efficacy and limited cardiotoxic effects. 3
• Monitor with cardiology during chemotherapy for cardiomyopathy development. 3
• Treat with standard heart failure GDMT if cardiomyopathy develops. 3

Peripartum Cardiomyopathy

• Coordinate care with high-risk obstetricians, intensivists, cardiac anesthesiologists, family planning counselors, and neonatologists. 3
• Management determined by active pregnancy status, clinical condition, and desire for future pregnancies. 3

Genetic Cardiomyopathies

• Valsartan may be beneficial for younger patients (≤45 years) with pathogenic sarcomere variants and mild phenotype to slow adverse cardiac remodeling (Class 2b recommendation). 1
• Coordinate care with genetic counselors and DNA storage facilities for family screening. 3

Sudden Cardiac Death Risk Stratification

• All patients with cardiomyopathy require sudden cardiac death risk stratification using major noninvasive risk markers to identify candidates for implantable cardioverter-defibrillator placement. 1
• This assessment should be performed at initial diagnosis and periodically during follow-up. 1

Referral to Specialized Centers

• Refer to multidisciplinary HCM centers for challenging treatment decisions, weak recommendations (Class 2b), particularly nuanced cases, and consideration of invasive procedures specific to cardiomyopathy. 3, 2
• Septal reduction therapies (surgical myectomy, alcohol septal ablation) performed by experienced teams at dedicated centers have significantly improved safety and efficacy. 3

Common Pitfalls to Avoid

• Never use vasodilators in obstructive cardiomyopathy—this is the most critical error that worsens LVOT obstruction and can precipitate hemodynamic collapse. 1, 2
• Do not rely on CHA₂DS₂-VASc score alone for anticoagulation decisions in HCM with atrial fibrillation—these patients require anticoagulation regardless of score. 3
• Avoid aggressive diuresis in restrictive cardiomyopathy, as stroke volume is fixed and cardiac output depends on heart rate. 3
• Do not overlook cardiometabolic risk factors—obesity, hypertension, and sleep apnea significantly impact outcomes and are modifiable. 1, 2