Non-invasive Diagnosis of Pulmonary Heart Disease, February 8, 2001

Non-invasive Diagnosis of Pulmonary Heart Disease, February 8, 2001

Characteristics of pulmonary circulation: low pressure, low resistance, high capacity. Average pulmonary arterial pressure > 20 mmHg; pulmonary arterial pressure between 20–30 mmHg is mild; 30–50 mmHg is moderate; 50–70 mmHg is severe. Since these diagnoses were first made through cardiac catheterization, they are considered invasive. Non-invasive diagnostics include:

① Chest X-ray: Chronic bronchitis, emphysema with bulging of the pulmonary artery segment, right ventricular enlargement, and a pear-shaped heart silhouette. The main branch of the pulmonary artery is markedly enlarged, especially the lower lobe branch of the right lung, sometimes exceeding 1.5 cm in diameter. At the same time, peripheral pulmonary arteries suddenly narrow, contrasting sharply with the expansion of the main branches—a phenomenon known as truncation or rat-tail phenomenon, visible as increased pulsation at the pulmonary hilum under fluoroscopy.

② Electrocardiogram: Clockwise rotation, rightward deviation of the electrical axis. RV1+SV5>1.05 mV, aVR∶R/S>1—these two features indicate right ventricular hypertrophy; pulmonary-type P wave: P wave>0.22 mV, or P wave>0.2 mV, appearing as a sharp peak.

③ Vectorcardiography: No obvious right ventricular hypertrophy.

④ Nuclear medicine examination: Lung ventilation-perfusion imaging, radionuclide ventriculography.

⑤ Echocardiography: A non-invasive diagnostic technique developed over the past 30 years, allowing clear visualization of the heart and nearby major blood vessels from the body surface.

⑥ Pulmonary impedance-flow graph and differential graph: A method using bioimpedance to measure pulmonary vascular volume. These six aspects constitute non-invasive examinations for pulmonary heart disease. Usually, X-rays and electrocardiograms are sufficient for diagnosis, but they are qualitative rather than quantitative.