Transient mitral regurgitation in acute glomerulonephritis.

During an epidemic of acute glomerulonephritis (AGN) 15 patients were studied by M-mode, cross-sectional, and Doppler echocardiography. All 15 patients had the classical signs of the disease including hematuria, proteinuria, edema, and consistent laboratory findings. There were 10 boys and five girls with a mean age of 8 years. Ten of the 15 patients had an enlarged left atrium and five of these 10 also had transient mild to moderate mitral regurgitation. In the five patients with mitral regurgitation the ratio of left atrium/aorta was 1.48; in the five patients with an enlarged left atria without evidence of mitral regurgitation the left atrium/aorta ratio was 1.34. All the patients had normal left ventricular dimensions, as well as ejection and shortening fractions. The findings of left atrial enlargement and mitral regurgitation disappeared gradually in all patients within 3 months. There was no correlation between the level of systemic blood pressure and the development of mitral regurgitation. A possible cause for these changes is fluid overload in the oliguric phase of the acute glomerulonephritis. The changes are transient and probably functional. There was no significant mitral valve or left atrial anomaly 3 and 6 months after hospital discharge.