What is the most appropriate diagnostic test for a patient with abdominal distension, dyspnea, orthopnea, elevated Jugular Venous Pressure (JVP), pitting edema, hepatomegaly, and bibasilar crackles, with echocardiogram showing dilated atria and normal ventricles?

Cardiac CT Scan Has the Highest Diagnostic Value

In this patient with biventricular heart failure with preserved ejection fraction, biatrial enlargement, elevated JVP that fails to descend with inspiration (Kussmaul's sign), and massive systemic congestion, cardiac CT scan is the most appropriate diagnostic test to differentiate constrictive pericarditis from restrictive cardiomyopathy—the two most likely diagnoses that require fundamentally different management approaches. 1

Clinical Reasoning

This patient presents with a classic constellation of findings suggesting either constrictive pericarditis or restrictive cardiomyopathy:

• Preserved LVEF (60%) with normal ventricular size but dilated atria 1
• Kussmaul's sign (JVP elevation during inspiration) - highly specific for constrictive physiology 1
• Massive systemic congestion (hepatomegaly, ascites, peripheral edema) out of proportion to pulmonary congestion 1
• Normal heart sounds (no murmurs to suggest valvular disease) 1

The echocardiogram has already been performed and shows the characteristic features of diastolic heart failure: biatrial dilation with normal ventricles and preserved systolic function 1. While transthoracic echocardiography is the appropriate initial test for dyspnea of cardiac origin 1, it has limited ability to definitively distinguish constrictive pericarditis from restrictive cardiomyopathy 1.

Why Cardiac CT is Superior

Cardiac CT is the definitive imaging modality for pericardial disease because it:

• Directly visualizes pericardial thickness - the hallmark finding in constrictive pericarditis (thickening >4mm) that cannot be reliably assessed by echocardiography 1
• Detects pericardial calcification - present in 25-30% of constrictive pericarditis cases and pathognomonic when present 1
• Provides comprehensive morphologic assessment of both pericardium and myocardium to exclude infiltrative diseases 1, 2
• Has superior spatial resolution compared to echocardiography for evaluating pericardial anatomy 1

The ACR Appropriateness Criteria specifically rates cardiac CT with IV contrast as highly appropriate (rating 7/9) for dyspnea due to suspected pericardial disease with excluded ischemia 1. The ACC/AHA guidelines emphasize that cardiac CT and CMR provide complementary information with respect to morphologic and functional features of the diseased pericardium that echocardiography cannot provide 1.

Why Other Options Are Inappropriate

Holter Monitor

• Not indicated - there is no clinical suspicion of arrhythmia as the primary problem 1
• The patient has normal heart sounds and the presentation is dominated by congestive symptoms, not palpitations or syncope 1
• Holter monitoring would be appropriate if arrhythmogenic right ventricular cardiomyopathy or ventricular tachycardia were suspected, but this patient lacks those features 1

Coronary Angiogram

• Not appropriate - ischemic heart disease is extremely unlikely given the clinical presentation 1
• The patient has preserved systolic function, no anginal symptoms, and a presentation dominated by right heart failure 1
• The ACR Appropriateness Criteria rates coronary angiography as usually not appropriate (rating 2/9) for dyspnea due to suspected nonischemic heart failure with excluded ischemia 1
• Invasive catheterization would only be considered if hemodynamic measurements were needed after imaging, not as the initial diagnostic test 1

Exercise ECG Testing

• Contraindicated - this patient has decompensated heart failure with massive volume overload 1
• Exercise testing is inappropriate in patients with clinical signs of elevated central venous pressure and systemic congestion 1
• The patient has orthopnea and dyspnea at rest, making exercise testing both unsafe and non-diagnostic 1

Critical Diagnostic Distinction

The fundamental clinical question is: Does this patient have constrictive pericarditis (potentially curable with pericardiectomy) or restrictive cardiomyopathy (requiring medical management)? 1

Both conditions present with:

• Biatrial enlargement with normal ventricles 1
• Preserved ejection fraction 1
• Elevated filling pressures and systemic congestion 1
• Characteristic Doppler patterns on echocardiography 1

Only cardiac CT can reliably differentiate these conditions by directly visualizing pericardial thickening and calcification 1. This distinction has profound therapeutic implications: constrictive pericarditis may be surgically curable, while restrictive cardiomyopathy requires medical management and has a worse prognosis 1.

Common Pitfalls to Avoid

• Do not rely solely on echocardiography - while it can suggest constriction through Doppler patterns and septal motion abnormalities, it cannot definitively diagnose it without visualizing the pericardium 1
• Do not assume this is simply "heart failure" and treat empirically - the underlying etiology fundamentally changes management 1
• Do not order invasive catheterization first - non-invasive imaging should establish the diagnosis before considering hemodynamic assessment 1
• Do not dismiss pericardial disease because the initial echocardiogram was performed - echocardiography has well-recognized limitations in evaluating the pericardium 1