What is the diagnosis for a patient presenting with a soft parasternal lift, apical S4, and a 1cm difference in leg circumference with shortness of breath (SOB)?

Diagnosis: Pulmonary Arterial Hypertension with Right Ventricular Failure

The clinical presentation of a soft parasternal lift (right ventricular heave), apical S4, unilateral leg edema with 1cm circumference difference, and shortness of breath strongly suggests pulmonary arterial hypertension (PAH) with early right ventricular dysfunction and possible concurrent deep venous thrombosis. 1, 2

Key Diagnostic Features Supporting PAH

Cardiovascular Examination Findings

• Left parasternal lift (described as "soft parasternal lift") indicates right ventricular hypertrophy and pressure overload, present in patients with elevated pulmonary artery pressure 1, 2

• Apical S4 gallop represents a right ventricular fourth heart sound, audible in 38% of PAH patients, reflecting high right ventricular filling pressure and decreased ventricular compliance 1

• The combination of parasternal lift with S4 specifically points to right ventricular pressure overload rather than volume overload 1, 2

Asymmetric Leg Swelling: Critical Differential Point

• The 1cm difference in leg circumference (right > left) raises concern for concurrent deep venous thrombosis (DVT), which could indicate chronic thromboembolic pulmonary hypertension as the underlying etiology 1, 3

• Bilateral symmetric peripheral edema would suggest pure right heart failure, but unilateral predominance mandates evaluation for DVT 4, 5

• This finding is particularly important because it suggests a potentially treatable cause of PAH (chronic thromboembolic disease) 1, 3

Distinguishing PAH from Left Heart Disease

Why This is NOT Primarily Left Heart Failure

• Absence of orthopnea and paroxysmal nocturnal dyspnea argues against left-sided heart disease with elevated pulmonary venous pressure 6, 7

• An S4 at the apex in the context of a parasternal lift represents a right ventricular S4, not a left ventricular S4, because the hypertrophied right ventricle can transmit sounds to the apex in PAH 1

• Left heart failure typically presents with pulmonary crackles, which are notably absent in isolated PAH 2

Expected Additional Findings in PAH

You should specifically assess for:

• Accentuated pulmonary component of second heart sound (loud P2) at the left second intercostal space, present in 90% of IPAH patients 1, 2

• Elevated jugular venous pressure with prominent "a" waves indicating high right ventricular filling pressure 1, 4, 2

• Tricuspid regurgitation murmur (holosystolic at lower left sternal border, augmented with inspiration) suggesting elevated right ventricular pressures 1, 2

Immediate Diagnostic Workup Required

First-Line Testing

• Transthoracic echocardiography is the essential first diagnostic test to estimate pulmonary artery systolic pressure, assess right ventricular size and function, evaluate for tricuspid regurgitation, and exclude left heart disease 1, 2

• Electrocardiogram should demonstrate right axis deviation (79% sensitive) and right ventricular hypertrophy (87% sensitive in established PAH) 1

• Chest radiograph may show prominent pulmonary arteries with peripheral pruning, though can be normal in early disease 1

Critical Additional Testing

• Bilateral lower extremity venous duplex ultrasound is mandatory given the asymmetric leg swelling to evaluate for DVT 1, 3

• D-dimer levels will likely be elevated if thromboembolic disease is present 1, 3

• Ventilation-perfusion scan or CT pulmonary angiography to evaluate for chronic thromboembolic pulmonary hypertension, particularly given the unilateral leg swelling 1, 3

Definitive Diagnosis

• Right heart catheterization remains the gold standard for confirming PAH diagnosis, defining hemodynamics (mean PA pressure >25 mmHg, pulmonary vascular resistance >3 Wood units), and excluding left heart disease (pulmonary capillary wedge pressure ≤15 mmHg) 1, 2

Common Diagnostic Pitfalls to Avoid

Do NOT Assume This is Simple Heart Failure

• The presence of unilateral leg swelling should never be attributed to heart failure alone without excluding DVT 1, 3

• Starting diuretics without establishing the diagnosis could mask important clinical signs and delay appropriate PAH-specific therapy 1

Do NOT Miss Underlying Etiology

• Digital clubbing would argue AGAINST idiopathic PAH and should prompt evaluation for pulmonary veno-occlusive disease, congenital heart disease, or interstitial lung disease 1, 4, 2

• Screen for connective tissue disease (scleroderma, lupus) with appropriate serologies, as PAH-associated with connective tissue disease requires different management 1, 6

• Evaluate for portopulmonary hypertension if liver disease stigmata present 2

Prognostic Implications

• The presence of right ventricular S4 with parasternal lift indicates established PAH with right ventricular hypertrophy, not just early disease 1

• Shortness of breath as the presenting symptom occurs in 60% of PAH patients at presentation and indicates the need for prompt evaluation and treatment 6

• If chronic thromboembolic pulmonary hypertension is confirmed, pulmonary thromboendarterectomy may be curative, making accurate diagnosis critical 1, 3