Extent of MRI delayed enhancement of myocardial mass is related to right ventricular dysfunction in pulmonary artery hypertension

OBJECTIVE: The purpose of our study was to assess the presence and extent of delayed contrast enhancement of ventricular myocardium in pulmonary artery hypertension.

SUBJECTS AND METHODS: Fifteen patients (age, 45.6 +/- 13 years; 13 New York Heart Association class III) with pulmonary artery hypertension (11 idiopathic, four systemic sclerosis) were studied. All patients had undergone a comprehensive diagnostic workup, and pulmonary artery hypertension (mean pulmonary artery pressure, 54 +/- 16 mm Hg) was confirmed by cardiac catheterization. Cardiac MRI was performed on a 1.5-T scanner to determine ventricular volumes and mass. Delayed contrast enhancement of a mass was seen 10-20 minutes after the i.v. injection of 0.2 mmol/kg of gadopentetate dimeglumine using an inversion recovery gradient-echo sequence.

RESULTS: All patients showed delayed contrast enhancement at the insertion points of the right ventricular free wall to the interventricular septum (15 inferior, 13 anterior). The mean weight of the delayed contrast-enhanced myocardial mass was 3.1 +/- 1.9 g (size range, 0.3-3.9% of the total myocardial mass). The extent of the delayed contrast-enhancing myocardium was inversely related to the right ventricular ejection fraction (r = -0.63, p = 0.001), right ventricular stroke volume (r = -0.67, p = 0.006), and right ventricular end-systolic volume index (r = -0.51, p = 0.05) but not to any invasively measured hemodynamic index or N-terminal pro brain natriuretic peptide.

CONCLUSION: Myocardial delayed contrast enhancement occurs frequently in patients with severe symptomatic pulmonary artery hypertension and is inversely related to measures of right ventricular systolic function.