Histopathological Study of Left and Right Atria in Isolated Rheumatic Mitral Stenosis With and Without Atrial Fibrillation

Abstract

In rheumatic MS, SR is associated with myocyte hypertrophy whereas AF is associated with myocytolysis. Endocardial inflammation is more common in left atrial appendage irrespective of rhythm. Interstitial fibrosis is seen in >90% of patients distributed in both the atria and is independent of the rhythm. Amyloid and Aschoff bodies are uncommon and the rest of the changes are uniformly distributed across both the atria.

A histological study of the atria in patients with isolated rheumatic mitral regurgitation with and without atrial fibrillation

“…18 Myocyte hypertrophy was the most common histological finding in our study; however, glycogen deposits were not seen. We also noted the severity of the myocyte hypertrophy being more on the right than the left side of the heart, which is a unique finding not seen in our previous study in patients with isolated MS 7 and warrants additional evaluation in a bigger sample size for an explanation.…”

“…The details of the operative procedure have been described before. 7 The surgeons (Ravikumar N. Kalyani and Giridhar Kamalapurkar) performed the surgery through a standard median sternotomy under general anesthesia, aortobicaval cannulation, cardiopulmonary bypass, systemic heparinization, and moderate hypothermia, and cold sanguineous hyperkalemic cardioplegia. Through a paraseptal incision left atrium (LA) was opened.…”

“…The histological findings were graded as mild, moderate, or marked/severe as described previously. 7,12 Myocyte hypertrophy was graded as mild if four or fewer erythrocytes could be placed across the widest myocyte diameter, moderate if five erythrocytes could be identified across myocyte, and marked/severe if six or more erythrocytes could be placed across the widest myocyte diameter.…”

“…A histopathologic study has shown that rheumatic MS in sinus rhythm (SR) is associated with biatrial myocyte hypertrophy, whereas MS with AF is associated with myocytolysis. 7 Endocardial inflammation in the left atrial appendage (LAA) is noted irrespective of the underlying rhythm, with widespread interstitial fibrosis in >90% of patients. [8][9][10] We report the results of a histopathological examination of biopsies obtained from the right and left atria during surgery in patients with isolated rheumatic MR in SR and AF.…”

Is left atrial fibrosis an independent determinant of atrial fibrillation in mitral stenosis?

“…Bois et al 10 in their study of 149 consecutive patients with AF, found that DGE within LA walls was uncommon and when present, did not correlate with AF type or risk of AF recurrence. Shenthar et al 11 conducted histological studies of left and right atria in rheumatic MS. They found that sinus rhythm was associated with myocyte hypertrophy whereas AF was associated with myocytolysis.…”