Question

What laboratory or diagnostic imaging can determine if the patient has RVH?

Answer 1

Right ventricular hypertrophy (RVH) is an abnormal enlargement or pathologic increase in muscle mass of the right ventricle in response to pressure overload, most commonly due to severe lung disease.

Chest Radiograph

Chest radiographs of patients with severe TR reveal cardiomegaly due to right ventricular enlargement. A prominent cardiac silhouette is observed on the right with the pulmonary artery view, and the enlarged right ventricle fills in the retrosternal space on the lateral film. Additional findings may include right atrial enlargement, the presence of an azygos vein, an upwardly displaced diaphragm, or the presence of pleural effusions.

When the cause of the TR is pulmonary hypertension secondary to a left-sided cardiac abnormality, other radiographic findings may be seen, particularly prominent right and left pulmonary artery hilar segments.

ECG

Right axis deviation (axis greater than 90 to 100 degrees) is often present with right ventricular hypertrophy. There also may be associated right atrial overload and ST-segment and T-wave abnormalities in the right precordial leads (formerly called “RV strain”), reflecting subendocardial ischemia or repolarization abnormalities of the right ventricular myocardium.

Echocardiogram

Diagnostic testing is indicated whenever PH is suspected. The purpose of the diagnostic testing is to confirm that PH exists, determine its severity, and identify its cause.

Cardiovascular Magnetic Resonance

Cardiovascular magnetic resonance (CMR) imaging may be helpful if the echocardiographic evaluation is suboptimal or inconclusive for assessment of TR severity and right ventricular size and function. CMR enables quantitative assessment of tricuspid regurgitant volume, a regurgitant fraction (the ratio of TR volume to stroke volume), right ventricular volumes, and ejection fraction as well as evaluation of associated LV and mitral disease.

Cardiac Catheterization and Angiography

Cardiac catheterization and contrast right ventriculography are not helpful for the diagnosis or evaluation of TR in most patients. However, RHC of measurement of pulmonary pressures and pulmonary vascular resistance is appropriate in patients with TR when clinical and noninvasive data regarding pulmonary pressures are discordant. Left heart catheterization may be helpful to assess potential causes of functional TR (left-sided valve or myocardial disease with an elevated left atrial pressure). On the other hand, a diagnosis of PH requires RHC. PH is confirmed when the mean pulmonary artery pressure is 25 mm Hg or greater at rest..

Right Heart Catheterization

RHC is necessary to confirm the diagnosis of PH and accurately determine the severity of the hemodynamic derangements. RHC is also helpful in distinguishing patients who have PH due to left heart diseases, such as systolic dysfunction, diastolic dysfunction, or valvular heart disease.

Pulmonary Function Tests

Pulmonary function tests are performed to identify and characterize underlying lung disease that may be contributing to PH.

Overnight Oximetry

Overnight oximetry can identify nocturnal oxyhemoglobin desaturation. It is common in patients with PH and may prompt supplemental oxygen therapy during sleep.

Polysomnography

Polysomnography is the gold standard diagnostic test for sleep-related breathing disorders such as obstructive sleep apnea. It should be performed when the clinical suspicion for OSA is high or the results of overnight oximetry are discordant with clinical expectation.

Exercise Testing

Exercise testing is usually performed using the six-minute walk test, stress echocardiography, or cardiopulmonary exercise testing. The latter can be performed with gas exchange measurements, echocardiography, and/or RHC..

Ventilation-Perfusion Scanning

Ventilation-perfusion (V/Q) scanning is the preferred imaging study to evaluate patients for CTEPH. A normal V/Q scan accurately excludes chronic thromboembolic disease with a sensitivity of 96% to 97% and a specificity of 90% to 95%. When the V/Q scan suggests that chronic thromboembolic disease exists, pulmonary angiography is necessary to confirm the positive V/Q scan and to define the extent of disease. V/Q scans are an important part of the diagnostic evaluation because PH due to chronic thromboembolic disease is potentially reversible with surgery.