What investigations are recommended for a patient with scleroderma and dermatomyositis, controlled on methotrexate (MTX), presenting with progressive palpitations, chest pain, and dyspnea, with a normal echocardiogram (echo) and no evidence of interstitial lung disease (ILD) on computed tomography (CT) chest?

Cardiac Evaluation is the Next Critical Step

Given the progressive palpitations, chest pain, and dyspnea with a normal echocardiogram and no significant ILD, you must urgently evaluate for cardiac involvement—specifically myocarditis, conduction abnormalities, and coronary microvascular dysfunction—which are common and potentially life-threatening complications in both dermatomyositis and scleroderma. 1

Immediate Investigations Required

Electrocardiogram (ECG)

• Obtain a 12-lead ECG immediately to assess for arrhythmias, conduction abnormalities (AV blocks, bundle branch blocks), and signs of myocardial injury 1
• ECG abnormalities are frequently present in dermatomyositis cardiac involvement, even when echocardiography appears normal 1

Cardiac Biomarkers

• Measure troponin (high-sensitivity troponin preferred) to detect myocardial injury 1
• Obtain NT-proBNP or BNP levels, as elevated values suggest cardiac dysfunction even with preserved ejection fraction 2
• These biomarkers can be elevated in inflammatory myocarditis associated with dermatomyositis 1

24-Hour Holter Monitoring

• Essential to capture paroxysmal arrhythmias that may not be present during a single ECG 1
• Palpitations in connective tissue disease patients frequently represent clinically significant arrhythmias including atrial fibrillation, ventricular tachycardia, or frequent premature ventricular contractions 1

Cardiac MRI with Gadolinium Enhancement

• This is the most sensitive test for detecting myocarditis and should be performed urgently 1
• Cardiac MRI can identify myocardial inflammation, fibrosis, and edema that are not visible on echocardiography 1
• Late gadolinium enhancement patterns are characteristic of inflammatory myocarditis in dermatomyositis 1
• Echocardiography has limited sensitivity for detecting early diastolic dysfunction and subtle systolic abnormalities that are common in dermatomyositis 1

Secondary Cardiac Considerations

Coronary Evaluation

• Consider coronary angiography or coronary CT angiography if symptoms suggest ischemia, as approximately 20% of patients with chest pain have normal epicardial coronaries but may have microvascular dysfunction 3
• Coronary vasomotor disorders including microvascular angina and coronary slow flow phenomenon can occur in connective tissue diseases 3

Pericardial Assessment

• While your echocardiogram was reported as normal, specifically review for pericardial effusion or pericarditis, which can occur in both scleroderma and dermatomyositis 1
• Consider pericardial friction rub on examination 1

Pulmonary Vascular Assessment

Right Heart Catheterization Consideration

• If there is any suspicion of pulmonary hypertension (even with normal echo), right heart catheterization is mandatory for definitive diagnosis 2
• Scleroderma patients are at high risk for pulmonary arterial hypertension, which can present with dyspnea and chest pain 2
• Never rely on echocardiography alone to exclude pulmonary hypertension, as the false-negative rate is significant 2

6-Minute Walk Test with Oxygen Saturation

• Perform 6-minute walk distance with continuous pulse oximetry to assess for exercise-induced desaturation 2
• A distance <333 meters in connective tissue disease patients increases diagnostic accuracy for pulmonary arterial hypertension 2

Repeat Pulmonary Function Testing

Complete PFTs with DLCO

• Repeat spirometry, lung volumes (TLC), and diffusion capacity (DLCO) 1
• A decline in FVC ≥10% or DLCO ≥15% from baseline suggests progressive disease even without radiographic changes 1
• Restrictive physiology can result from chest wall restriction due to skin involvement, respiratory muscle weakness from myositis, or early ILD not yet visible on CT 1

Respiratory Muscle Strength Testing

• Measure maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) to assess for respiratory muscle weakness from dermatomyositis 1
• Respiratory muscle weakness can cause dyspnea and restrictive physiology independent of ILD 1

Methotrexate-Related Considerations

Methotrexate Pneumonitis Evaluation

• Although your CT showed minimal GGOs present since before, methotrexate pneumonitis remains a consideration with new respiratory symptoms 4
• Methotrexate pneumonitis typically presents with dyspnea, cough, and new ground-glass opacities, but can be subtle 4
• Consider bronchoscopy with bronchoalveolar lavage if methotrexate pneumonitis is suspected, particularly to exclude infection 1

Critical Pitfalls to Avoid

• Do not attribute symptoms solely to anxiety or deconditioning without completing cardiac evaluation 1
• Do not assume a normal echocardiogram excludes significant cardiac disease in dermatomyositis—cardiac MRI is far more sensitive 1
• Do not delay cardiac evaluation, as myocarditis in dermatomyositis can progress rapidly and is a significant cause of mortality 1
• Do not miss pulmonary arterial hypertension by relying on echocardiography alone in a scleroderma patient 2

Multidisciplinary Consultation

• Urgent cardiology consultation is essential for interpretation of cardiac testing and consideration of endomyocardial biopsy if cardiac MRI suggests myocarditis 1
• Pulmonology consultation should be obtained if pulmonary hypertension is suspected or if there is unexplained dyspnea 2