From the Guidelines
The initial workup for dilated cardiomyopathy (DCM) should include a comprehensive clinical evaluation, laboratory tests, and cardiac imaging studies, as recommended by the most recent guidelines 1. The initial step in the workup should begin with a thorough history and physical examination, focusing on symptoms of heart failure, family history of cardiomyopathy, and risk factors like alcohol use or chemotherapy exposure, as emphasized in the 2013 ACCF/AHA guideline 1. Essential laboratory tests include:
- Complete blood count
- Comprehensive metabolic panel
- Thyroid function tests
- Iron studies
- B-type natriuretic peptide (BNP) to assess heart failure severity Cardiac biomarkers like troponin should be measured to rule out ischemic causes. Electrocardiogram (ECG) is necessary to identify arrhythmias and conduction abnormalities. Echocardiography is the cornerstone imaging study, providing assessment of ventricular size, wall thickness, ejection fraction, and valvular function, as highlighted in the European Heart Journal 1. Additional testing may include:
- Cardiac MRI for tissue characterization
- Coronary angiography to exclude coronary artery disease (especially in patients with risk factors)
- Genetic testing if familial DCM is suspected Endomyocardial biopsy may be considered in specific situations such as suspected myocarditis or infiltrative diseases. This comprehensive approach helps determine the underlying cause of DCM, which is crucial for guiding appropriate treatment strategies and providing prognostic information to patients, as noted in the American Heart Association scientific statement 1 and the systematic review of clinical practice guidelines and recommendations 1.
From the Research
Initial Workup for Dilated Cardiomyopathy
The initial workup for dilated cardiomyopathy (DCM) involves a comprehensive evaluation to determine the underlying cause and extent of the disease. The following are key components of the initial workup:
- Medical history and physical examination to identify signs and symptoms of heart failure, such as fatigue, dyspnea, and orthopnea 2
- Electrocardiogram (ECG) to assess for abnormalities, including left atrial enlargement, prolonged PR interval, left bundle branch block, and abnormal Q waves 3
- Echocardiography to evaluate left ventricular function, including ejection fraction, left ventricular end-diastolic diameter, and presence of mitral regurgitation 4
- Chest X-ray to assess for cardiomegaly and pulmonary congestion 2
- Laboratory tests, including complete blood count, electrolyte panel, and liver function tests, to identify potential underlying causes, such as anemia, electrolyte imbalances, and liver disease 2
- Cardiovascular magnetic resonance imaging (CMR) to assess for late gadolinium enhancement and right ventricular dysfunction, which are independent predictors of poor outcome in patients with DCM 5
Diagnostic Criteria
The diagnostic criteria for DCM include:
- Left ventricular dilation and impaired contractility, defined as a fractional myocardial shortening less than 25% and/or ejection fraction less than 45% 6
- Left Ventricular End Diastolic Diameter (LVEDD) greater than 117% excluding any known cause of myocardial disease 6
- Presence of symptoms and signs of heart failure, such as fatigue, dyspnea, and orthopnea 2
Prognostic Factors
Prognostic factors for DCM include: