How should I initially manage a patient with suspected pulmonary hypertension and right‑ventricular hypertrophy (incomplete right bundle branch block on ECG) who is breathing comfortably at rest?

Initial Management of Suspected Pulmonary Hypertension with Right Ventricular Hypertrophy

In a patient breathing comfortably at rest with suspected pulmonary hypertension and ECG evidence of right ventricular hypertrophy, immediately obtain transthoracic echocardiography to estimate pulmonary artery pressures and assess right ventricular function, followed by right heart catheterization to confirm the diagnosis before initiating any specific therapy. 1, 2

Immediate Diagnostic Workup

First-Line Imaging

• Perform transthoracic Doppler echocardiography immediately to estimate right ventricular systolic pressure, evaluate for right atrial enlargement, right ventricular enlargement, pericardial effusion, and assess left-sided cardiac abnormalities 1, 3
• Use contrast echocardiography to detect any intracardiac shunting 1
• Assess specifically for left ventricular systolic/diastolic dysfunction, chamber enlargement, and valvular disease to identify Group 2 pulmonary hypertension (left heart disease), which is the most common form 1, 2

Critical caveat: Echocardiography alone cannot provide a definitive diagnosis—the tricuspid regurgitant jet may be unobtainable in many patients, and qualitative signs have low predictive value without measurable velocities 2. Never initiate PAH-specific therapies based on echocardiography alone 4.

Essential Laboratory and Functional Testing

• Obtain routine biochemistry, complete blood count, thyroid function tests, liver function tests, and NT-proBNP to identify associated conditions and assess disease severity 3
• Perform serologies for hepatitis B/C and HIV 2
• Conduct autoimmune screening with ANA, and if positive, obtain extended autoantibody panel (up to 40% of idiopathic PAH patients have elevated autoantibodies) 2
• Measure arterial blood gas to assess oxygenation 1
• Perform 6-minute walk test with Borg dyspnea score to establish baseline exercise capacity and provide prognostic information 1, 3

Imaging to Determine Etiology

• Obtain ventilation-perfusion (V/Q) scanning in all patients to exclude chronic thromboembolic pulmonary hypertension (CTEPH)—a normal V/Q scan effectively excludes CTEPH with 96-97% sensitivity 1, 2
• Do not rely on CT pulmonary angiography alone to exclude CTEPH, as it has insufficient sensitivity and may miss the diagnosis 1, 2
• Perform high-resolution chest CT to detect parenchymal lung disease that may be missed by pulmonary function tests 2
• Obtain complete pulmonary function testing including spirometry, lung volumes, and DLCO measurement to evaluate for underlying lung disease (Group 3 pulmonary hypertension) 1
• Perform abdominal ultrasound to screen for portal hypertension 1, 2

Mandatory Invasive Confirmation

Right Heart Catheterization

Right heart catheterization is required in all patients with suspected pulmonary hypertension to confirm the diagnosis, establish specific hemodynamic classification, determine severity, and guide therapy. 1, 2 This is the only method that provides definitive hemodynamic diagnosis 2.

Essential measurements during catheterization include 2:

• Mean pulmonary artery pressure (mPAP ≥20 mmHg defines pulmonary hypertension per updated 2022 criteria)
• Pulmonary artery wedge pressure (PAWP)
• Cardiac output (thermodilution or Fick method)
• Calculated pulmonary vascular resistance
• Right atrial pressure

The distinction between pre-capillary PAH (PAWP ≤15 mmHg) and post-capillary PH (PAWP >15 mmHg) is critical, as it determines whether PAH-specific therapies can be used or are contraindicated 2, 4.

Management Based on Hemodynamic Classification

If Pre-Capillary PH is Confirmed (mPAP ≥20 mmHg, PAWP ≤15 mmHg)

• Immediately refer to an expert pulmonary hypertension center for severe disease, uncertain diagnosis, or persistent right ventricular dysfunction 2
• Perform acute vasoreactivity testing with inhaled nitric oxide to identify patients who may benefit from high-dose calcium channel blockers 2
• Conduct targeted evaluation for idiopathic PAH when no alternative cause is identified 2

If Post-Capillary PH is Identified (PAWP >15 mmHg)

• Optimize treatment of underlying left heart disease with guideline-directed medical therapy 2, 4
• Do not initiate PAH-specific therapies, as they are contraindicated in Group 2 PH 4
• If reduced LVEF is present, implement triple neurohormonal blockade (ACE inhibitor or ARB, beta-blocker, and mineralocorticoid receptor antagonist) 4

If PH is Not Confirmed

• Continue echocardiographic surveillance with repeat assessment if symptoms emerge or worsen 2

Critical Pitfalls to Avoid

• Never use calcium channel blockers empirically without documented acute vasoreactivity during right heart catheterization, as this can be harmful 1
• Never diagnose CTEPH on imaging alone—this contravenes guideline definitions and risks inappropriate therapy 2
• Do not perform lung biopsy routinely due to high risk; reserve only for cases where tissue diagnosis is essential 1
• Avoid non-dihydropyridine calcium channel blockers (diltiazem, verapamil) if reduced LVEF is present due to negative inotropic effects 4
• Ensure V/Q scanning is performed before relying on CT alone to exclude CTEPH, as CT has insufficient sensitivity 1, 2

Addressing the Incomplete Right Bundle Branch Block

The incomplete right bundle branch block on ECG reflects right ventricular hypertrophy and strain 5. While this finding supports the clinical suspicion of pulmonary hypertension, specific management of the conduction abnormality is not required unless complete heart block develops 4. Monitor for progression to complete AV block, but the primary focus should remain on diagnosing and treating the underlying pulmonary hypertension 4.