Diagnostics

• Indications

  • To confirm the diagnosis of suspected DCM

• Characteristic findings

  • Ventricular dilation with or without atrial dilation

  • Normal ventricular wall thickness [15]

  • ↓ Left ventricular ejection fraction (LVEF)

  • Wall motion abnormalities may be seen in some underlying etiologies (e.g., muscular dystrophy, acute myocarditis)

• CBC with differential

• Basic metabolic panel

• Liver chemistries

• TSH

• HIV testing

• Ferritin, transferrin saturation

• Diagnostics for congestive heart failure: in patients with concomitant heart failure

• Additional studies as needed for the underlying etiology as guided by clinical evaluation, such as:

  • Urine toxicology screen for suspected substance use

  • Inflammatory markers to detect autoimmune disease or myocarditis

  • Specific serologies (e.g., for Lyme disease, Chagas disease)

• Indications: to assess for complications and the underlying etiology

• Possible findings include:

  • Cardiomegaly: left-sided enlargement with a balloon appearance

  • Radiographic features of pulmonary edema secondary to decompensated heart failure

  • Findings of underlying disease, e.g., hilar lymphadenopathy in sarcoidosis [

• Indications

  • To assess for complications (e.g., AV block)

  • To rule out tachycardia-induced cardiomyopathy

• Possible findings include

  • Conduction disorders (e.g., AV block, LBBB)

  • Atrial fibrillation, other tachyarrhythmias

  • Reduced QRS voltage

  • ST-segment and T-wave abnormalities (e.g., T-wave inversions)

• Recommended in:

  • Patients with suspected familial or idiopathic DCM

  • Family members of patients with DCM and an associated genetic mutation

Refer patients for genetic counseling prior to ordering genetic testing for DCM

Cardiac MRI

• Indications

  • Suspected infiltrative DCM (e.g., due to hemochromatosis, amyloid)

  • DCM of unclear etiology after the initial evaluation

  • Evaluation of cardiac function and morphology

• Findings

  • Myocardial edema: in active myocarditis and sarcoidosis [8]

  • Disease-specific pattern of gadolinium enhancement: e.g., in muscular dystrophy, sarcoidosis, Chagas disease

Endomyocardial biopsy

• Indication: suspected underlying etiology that requires specific management (e.g., amyloidosis) and cannot be confirmed by other diagnostic methods

• Findings vary based on the underlying etiology.

• Interstitial fibrosis

• Altered cardiomyocyte appearance

  • Cell hypertrophy

  • Vacuole formation

  • Loss of myofibrils

  • Nuclear atypia