What treatment options are available for heart failure in patients with muscular dystrophy?

Treatment Options for Heart Failure in Muscular Dystrophy Patients

ACE inhibitors or ARBs should be started by 10 years of age in Duchenne muscular dystrophy (DMD) patients, even before ventricular dysfunction develops, to delay onset of heart failure and improve mortality. 1, 2

First-Line Pharmacological Therapy

ACE Inhibitors/ARBs

• Early institution of ACE inhibitors has been shown to delay the onset of LV dysfunction and improve mortality in DMD patients 1
• Should be initiated by age 10 in all DMD patients, barring contraindications 1, 2
• Earlier therapy may be considered given the relatively low risk profile of these medications 2
• ARBs can be substituted for patients who are intolerant of ACE inhibitors 1

Beta-Blockers

• Should be added after ACE inhibitor/ARB initiation 2
• Typically initiated based on:
  • Presence of ventricular dysfunction
  • Elevated heart rate
• Multiple retrospective and prospective open studies suggest benefit in DMD cardiomyopathy 1
• A prospective open study showed improvement in LV ejection fraction with ACE inhibitors alone or in combination with beta-blockers within 12 months of treatment 1

Mineralocorticoid Receptor Antagonists

• Eplerenone has demonstrated attenuation of decline in LV function (measured by circumferential strain) in a randomized prospective study 1
• Should be considered as part of the heart failure management regimen, though optimal timing remains unclear 1

Glucocorticoids

• Long-term glucocorticoid use in DMD has shown improvement in all-cause mortality, primarily through improved cardiac outcomes 1
• Human DMD data suggests steroids have a protective effect on the heart, with longer duration correlating with greater improvement in LV function 1

Advanced Heart Failure Therapies

Implantable Cardioverter Defibrillators (ICDs)

• Should be considered for patients with LV ejection fraction <35%, following adult heart failure guidelines 1
• Studies show appropriate shocks for ventricular tachycardia can occur in DMD patients with ICDs 3
• Important consideration: Severe kyphoscoliosis and respiratory muscle weakness may increase risks associated with ICD placement 1

Left Ventricular Assist Devices (LVADs)

• Can be effective in select DMD patients with advanced heart failure 3
• One study showed 75% survival at 1 year post-LVAD implantation 3
• Can serve as destination therapy or bridge to transplantation 1, 3

Heart Transplantation

• Viable option for select DMD patients with end-stage heart failure 4
• Post-transplant survival in MD patients is comparable to matched cardiomyopathy patients 4
• Careful patient selection is crucial given the systemic nature of muscular dystrophy 4

Monitoring and Diagnostic Approaches

Preferred Imaging Modality

• Cardiac MRI (CMR) is preferred over echocardiography when possible 1, 2
• CMR provides superior information on:
  • Tissue characteristics
  • Chamber dimensions
  • Myocardial function
  • Late gadolinium enhancement (indicator of fibrosis)
• Early detection of cardiac involvement allows timely initiation of cardioprotective therapies 5

Arrhythmia Management

• Regular cardiac assessment should include ECG and consideration of Holter monitoring in patients with decreased LVEF or symptoms 2
• Arrhythmias in advanced DMD cardiomyopathy include atrial fibrillation/flutter, ventricular tachycardia, and ventricular fibrillation 1, 6
• Greater burden of late gadolinium enhancement on CMR is associated with increased arrhythmia risk 1

Clinical Pearls and Pitfalls

• Sinus tachycardia is a frequent finding in DMD patients and often precedes cardiac dysfunction - consider it a useful biomarker 2
• Early detection of cardiomyopathy can be challenging due to the long subclinical phase and difficulties in assessing cardiovascular symptoms in non-ambulatory patients 5
• The natural history of rhythm abnormalities in DMD is not well documented, making arrhythmia management an understudied area 1
• When considering advanced therapies, factor in respiratory muscle involvement which can impact quality of life and outcomes 6
• For mechanical circulatory support, discussions about goals of therapy should ideally occur before the urgent need for device placement 1