Pulmonary arterial hypertension, evolution of tracings

ECG 5A : This tracing shows sinus rhythm, first degree atrioventricular block (PR interval 205 ms), narrow QRS, right axis deviation (116°), signs of right ventricular hypertrophy with a R/S ratio > 1 in V1 and repolarization disorders in the right precordial leads (V1 to V4);

ECG 5B: Tracing recorded 2 years after the initial tracing; slight increase in PR interval (228 ms); increase in right rotation (131°) and increase of the amplitude of the R wave in V1;

ECG 5C: Tracing recorded 6 years after the initial tracing; increase in the amplitude of the R wave in V1, V2, V3

Comments: Pulmonary arterial hypertension (PAH) is a rare and severe pulmonary vascular disease defined by an increase in pulmonary arterial resistance, which can progress to right heart failure. PAH can complicate various diseases (connectivitis, scleroderma, congenital heart disease with left-right shunt, portal hypertension, HIV infection), can be favored by intake of anorectics, can occur sporadically (idiopathic PAH) or in a familial setting with autosomal dominant transmission. Diagnosis should be evoked in the presence of an unexplained stress dyspnea, which is quasi-constant, possibly associated with signs of right heart failure, chest pain, palpitations, lipothymia or exercise syncope. The symptomatology is therefore relatively aspecific and polymorphous, which can explain a frequent delay in diagnosis and a likely underestimation. The delay between the first symptoms and diagnosis can therefore be relatively long. Diagnosis is suspected by cardiac ultrasound which allows screening, but should be confirmed systematically by right cardiac catheterization (elevation of mean pulmonary arterial pressure > 25 mmHg).

The electrocardiogram reveals abnormalities corresponding to the chronic increase of right-sided pressures in a majority of patients with chronic PAH, even though sensitivity is poor thus limiting its usefulness for diagnosis. On the other hand, the electrocardiogram allows to follow, in a given patient, the evolution of the disease.

In this patient, these 3 electrocardiograms performed over an extended period of 6 years allow observing a right axis rotation and an increase in R wave voltages in the right precordial leads testifying to the progression of the right ventricular hypertrophy. The absence of right atrial enlargement (pulmonary P-wave) indicates that the pressure increase in the right chambers has yet to affect the atrial cavity.

It should be noted that, in some patients with PAH who respond favorably to calcium channel blockers, the electrocardiogram may show a regression or even resolution of signs of right ventricular hypertrophy.

Take-home message: The electrocardiogram lacks sensitivity and specificity to be used as a standalone for the diagnosis of PAH. On the other hand, the electrical abnormalities allow to follow the evolution of the disease. The recording of electrocardiograms repeated over time can highlight the presence of a right axis rotation, a dominant R wave in V1 (> 0.5 mm, R/S ratio> 1 and progression of the R wave amplitude), a right bundle branch block, repolarization disorders with T-wave inversion in the right precordium.