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KEY FEATURES

ESSENTIALS OF DIAGNOSIS

  • Neurologic symptoms usually precede cardiac symptoms

  • Gait ataxia and dysarthria

  • Echocardiography shows concentric left ventricular hypertrophy

  • ECG may show left or right ventricular hypertrophy and nonspecific ST-T changes

GENERAL CONSIDERATIONS

  • An autosomal recessive disorder, characterized by ataxia, areflexia, and extremity muscle weakness due to degeneration of the spinocerebellar tracts

  • Found in 1:40,000 population and caused by trinucleotide expansion in the gene encoding frataxin (FXN)

  • Cardiac hypertrophy is the most common heart manifestation and may lead to sudden death

  • Cardiac manifestations appear with or up to 20 years after neurologic symptoms

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

  • Ataxia and dysarthria

  • Dyspnea

  • Palpitation

PHYSICAL EXAM FINDINGS

  • Absent tendon reflexes, diminished sensation, scoliosis

  • Left ventricular lift

  • S4 or S3 if heart failure

  • Harsh systolic outflow tract murmur

DIFFERENTIAL DIAGNOSIS

  • Hypertrophic cardiomyopathy (asymmetric septal hypertrophy may occur, but myocardial fiber disarray as described in genetic hypertrophic cardiomyopathy is rare)

  • Other causes of dilated cardiomyopathy in the later stages

DIAGNOSTIC EVALUATION

ELECTROCARDIOGRAPHY

  • Almost all patients have ECG abnormalities; the most common in order of prevalence are:

    • – Nonspecific ST-T–wave changes

    • – Right-axis deviation and other signs of right ventricular hypertrophy

    • – Left ventricular hypertrophy

    • – Supraventricular tachyarrhythmias

    • – Inferolateral Q waves

    • – Ventricular tachyarrhythmias are uncommon

IMAGING STUDIES

  • Echocardiogram may show:

    • – Concentric left ventricular hypertrophy

    • – Asymmetric septal hypertrophy

    • – Global hypokinesis

    • – Diastolic dysfunction

    • – Dilated cardiomyopathy with systolic dysfunction

TREATMENT

CARDIOLOGY REFERRAL

  • Suspected cardiac disease

HOSPITALIZATION CRITERIA

  • Heart failure

  • Syncope

  • Tachyarrhythmias

MEDICATIONS

  • Symptomatic management of arrhythmias

  • Pharmacologic management of heart failure

  • No specific therapy exists

THERAPEUTIC PROCEDURES

  • Automatic implanted cardioverter-defibrillator in selected patients

  • Heart transplantation is usually not indicated because the neuromuscular disease is progressive

MONITORING

  • ECG monitoring in hospital patients as appropriate

DIET AND ACTIVITY

  • Low-sodium diet if heart failure is present

  • Restricted activity as appropriate for cardiac disease

ONGOING MANAGEMENT

HOSPITAL DISCHARGE CRITERIA

  • Resolution of heart failure

  • Successful device placement

FOLLOW-UP

  • As appropriate for cardiac condition

COMPLICATIONS

  • Heart failure

  • Syncope

  • Progressive neuromuscular debilitation

  • Sudden cardiac death

PROGNOSIS

  • Because the neuromuscular disease cannot be arrested, it usually causes death; however, some patients develop a malignant form of dilated cardiomyopathy

PREVENTION
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