Cardiac CT Scan Has the Highest Diagnostic Value
Cardiac CT scan (Option B) is the diagnostic test of choice for this patient, as it is the gold standard for evaluating pericardial thickness and identifying pericardial calcification, which is pathognomonic for constrictive pericarditis—the most likely diagnosis given the clinical presentation of right-sided heart failure with biatrial dilation and preserved ventricular function. 1
Clinical Reasoning
Why This Patient Likely Has Constrictive Pericarditis
This patient presents with the classic triad of constrictive pericarditis:
- Markedly elevated JVP that fails to descend during inspiration (Kussmaul's sign) - a hallmark finding in constrictive physiology 1
- Biatrial enlargement with normal ventricular size and preserved LVEF (60%) on echocardiography 1
- Right-sided heart failure symptoms including massive peripheral edema, hepatomegaly, and ascites 2
The echocardiographic findings are particularly telling: both atria are dilated while the ventricles remain normal in size with preserved systolic function. This pattern strongly suggests a restrictive filling disorder rather than primary myocardial dysfunction. 1
Why Cardiac CT Is the Definitive Test
Cardiac CT provides the critical anatomic information needed to distinguish constrictive pericarditis from restrictive cardiomyopathy, which can present with identical clinical and echocardiographic findings. 1
Key advantages of cardiac CT in this scenario:
- Directly visualizes and measures pericardial thickness - the defining anatomic feature of constrictive pericarditis 1
- Identifies pericardial calcification, which is pathognomonic for constrictive pericarditis and cannot be reliably assessed by echocardiography 1
- Provides definitive anatomic information that echocardiography cannot reliably assess 1
This distinction is clinically crucial because constrictive pericarditis is surgically curable with pericardiectomy, while restrictive cardiomyopathy requires medical management. 1 Making the correct diagnosis fundamentally changes the treatment approach and prognosis.
Why the Other Options Are Inappropriate
Holter monitor (Option A) would only detect arrhythmias and has no role in diagnosing the underlying structural cause of this patient's heart failure syndrome. 1
Coronary angiogram (Option C) is not indicated because:
- There are no clinical features suggesting acute coronary syndrome
- The preserved LVEF and normal ventricular size argue against ischemic cardiomyopathy
- This would not provide information about pericardial disease 1
Exercise ECG testing (Option D) is contraindicated in this patient with decompensated heart failure (WHO functional class IV equivalent with orthopnea and massive edema). 1 Additionally, exercise testing would not provide diagnostic information to distinguish constrictive from restrictive disease. 1
Clinical Pitfalls to Avoid
Do not rely solely on echocardiography to make the diagnosis of constrictive pericarditis. While echo can suggest the diagnosis through findings of biatrial enlargement and preserved ventricular function, it cannot reliably assess pericardial thickness or identify calcification. 1
Do not assume elevated JVP always reflects left-sided filling pressures. Right-left mismatch occurs in more than 1 in 4 patients with advanced heart failure, where right and left filling pressures are discordant. 3 However, in this patient, the combination of elevated JVP with pulmonary congestion (bibasilar crackles) suggests both sides are affected, consistent with constrictive physiology.
If cardiac CT findings are equivocal, right heart catheterization may be needed to confirm the hemodynamic pattern of constriction (equalization of diastolic pressures, square root sign). 1 Cardiac MRI can provide complementary tissue characterization if restrictive cardiomyopathy is ultimately confirmed. 1