Korean Circ J.  2003 Oct;33(10):901-908. 10.4070/kcj.2003.33.10.901.

Fate of Atrial Myocardium in Severe Mitral Regurgitation in the Aspect of Programmed Cell Death

• Cho EJ
• Youn HJ
• Park CS
• Chung HO
• Jeon HK
• Kim CJ
• Rho TH
• Kim SY
• Kim JP
• Kim JH
• Choi KB
• Hong SJ
• Sim SB
• Lee SH
• Seo EJ

• KMID: 1938805
• DOI: http://doi.org/10.4070/kcj.2003.33.10.901

Abstract

BACKGROUND AND OBJECTIVES
From the view point of the molecular aspects, the fate of long standing pressure and volume overloaded atrium in severe MR has not been evaluated. This study was performed to elucidate whether apoptosis of right atrial myocytes is related to atrial changes.
SUBJECTS AND METHODS
The medical records of 16 patients (M: F=8: 8, mean age=52+/-12), with severe MR having undergone valve replacement surgery, were retrospectively reviewed. The subjects were divided into 2 groups according to the duration of their symptoms (group I, symptom duration less than 12 months, n=10 and group II, more than 12 months, n=6). Using the atrial myocardium specimens obtained during surgery, TUNEL assays and immunohistochemical staining were performed for the expressions of Fas, Bax and the Bcl family.
RESULTS
Apoptotic indices of TUNEL assay were 31.1+/-12.6 and 4.9+/-4.3% in groups I and II, respectively (p<0.01). The Fas expressions were 42.1+/-14.4 and 27.8+/-10.5% in groups I and II, respectively (p<0.05), but in group I, with atrial fibrillation (AF), was 49.3+/-6.9%, which was higher than the 29.2+/-12.5% in group I without AF and group II (p<0.001). The Bax expression in group I patients with a left atrial size less than 4 cm was 19.2+/-10.7%, which was higher than the 7.2+/-6.2% in group I with a left atrial size more than 4 cm and group II (p<0.05).
CONCLUSION
Programmed cell death of the atrial myocardium, in severe MR, might be an early molecular pathological change rather than the late sequelae. The causality between programmed cell death and electrical and structural changes of the atrium should be further investigated.

Keyword

Mitral valve insufficiency; Atrial fibrillation; Apoptosis

MeSH Terms

Apoptosis
Atrial Fibrillation
Cell Death*
Humans
In Situ Nick-End Labeling
Medical Records
Mitral Valve Insufficiency*
Muscle Cells
Myocardium*
Retrospective Studies