Cardiomyopathy in Friedreich’s ataxia

Last updated March 25, 2024, by Lindsey Shapiro, PhD
Medically reviewed by David Lynch, MD, PhD

Abnormalities in cardiac structure or function are common in Friedreich’s ataxia (FA), with nearly all patients developing some degree of cardiac abnormality at some point in their lives. Cardiac complications are the leading cause of mortality in FA, estimated to account for about 60% of early deaths.

There is limited data about the natural history of cardiomyopathy in FA, especially in young patients, as heart involvement is not typically diagnosed until after neurological symptoms lead to a diagnosis. The progression of cardiac involvement in FA also varies and does not always correlate with the degree of neurological disease progression.

Cardiac findings in FA

For about 60% of FA patients, cardiomyopathy is hypertrophic, although evidence of hypertrophy may not be apparent at disease onset. Hypertrophic cardiomyopathy in FA may differ from classic forms of the condition due to their underlying causes.

Echocardiography remains the standard tool for monitoring cardiac involvement in FA. Common findings in patients with the disease include the following:

• Concentric left ventricular (LV) hypertrophy, usually evidenced by increased relative wall thickness.
• Possible diastolic dysfunction.
• Systolic function is often initially preserved in FA, but may decline later in the disease course. This may be characterized by dilated LV with reduced ejection fraction (LVEF).
• Outflow tract obstruction is uncommon, differing from classic hypertrophic cardiomyopathy.

Most FA patients will also exhibit abnormalities in electrocardiography (EKG) assessments, the most common of which are nonspecific ST-T wave changes, right axis deviation, and LV hypertrophy.

Complications

Many patients with evidence of cardiomyopathy are asymptomatic at the time of diagnosis, but will become symptomatic over time. Arrhythmias and heart failure are among the most common clinical manifestations of FA, particularly later in the course of disease, and both are associated with an increased mortality risk.

Arrhythmias

Arrhythmias are a common complication of FA-associated heart disease and may become clinically significant in advanced stages, with symptoms including palpitations or angina. Such arrhythmias are mainly supraventricular, including atrial fibrillation and flutter. Sustained ventricular arrhythmia with sudden death is rare.

Heart Failure

Heart failure from cardiomyopathy is the leading cause of death in FA. Initially, heart failure with preserved ejection fraction may be observed, but the ventricles may dilate and ejection fraction falls in later disease stages.

The presence of overt heart failure symptoms, such as dyspnea or fatigue, are generally associated with a reduced LVEF. Heart failure symptoms may not be as easily recognized in FA patients who are wheelchair-bound. The New York Heart Association (NYHA) heart failure classification scheme is commonly used to assess the severity of functional limitations due to heart failure, but may have limited utility in people with neuromuscular disorders such as FA.

Management

Monitoring

It is recommended that all FA patients undergo EKG evaluations as part of their initial evaluations and annually thereafter, regardless of initial findings. Cardiology consultations should be considered for all FA patients and should definitely occur if patients exhibit abnormalities in cardiac tests or cardiac symptoms. Symptoms suggestive of arrhythmia warrant 24-hour Holter monitoring and/or Loop monitoring.

Treatment

There are no solid guidelines for the specific management of cardiac disease in FA; thus, its management relies on guidelines from the American Heart Association/American College of Cardiology (AHA/ACC) that are used in the general population.

Management of arrhythmias may include:  [FARA 4.3]

• Antiarrhythmic therapies: AHA/ACC guidelines may be used.
• Rate-controlling agents: These are not the preferred method for long-term management, but may sometimes be appropriate. Beta blockers are the preferred options when there is a history of heart failure or reduced ejection fraction, but should be commenced slowly. Verapamil and diltiazem are contraindicated where there is a reduced LVEF.
• Antithrombotic therapy: This may be used for patients with atrial fibrillation and reduced LVEF or others with standard risk factors for thromboembolism. Oral anticoagulants are recommended rather than vitamin K antagonists unless there is a contraindication.
• Ablation therapy: This may be considered when atrial arrhythmias are not controlled with antiarrhythmic and/or rate control medications.

Management of heart failure may include the following:  [FARA 4.4]

• Pharmacological treatment: Heart failure medications are recommended when reduced LVEF is present. Medication management may follow AHA/ACC guidelines, with the recognition that there may be pathophysiological differences in FA cardiac disease.
• Lifestyle factors: Exercise, dietary changes, and fluid restrictions may be considered.
• Device therapy: Cardiac resynchronization therapy may be considered in FA patients who develop heart failure due to severe LV systolic dysfunction.
• Fluid and operative management: Careful monitoring of fluid balance is critical for patients undergoing stressful events such as surgery or hydration therapy. Advanced technologies for cardiac support should be accessible following surgery.

Proper management of diabetes and other cardiovascular risk factors is also important for managing heart disease in FA.
Next: Therapeutic management