Effect of experimental coronary sinus ligation on myocardial structure and function in the presence or absence of structural heart disease: an insight for the interventional electrophysiologist.

Aims: To study the effect of coronary sinus (CS) occlusion on normal hearts and hearts with structural disease.

Methods And Results: We included 32 dogs, divided into 4 groups: (1) CS ligation (CSL): subjected to CSL; (2) control group: no intervention; (3) MI-CSL group: subjected to myocardial infarction (MI) induction followed by CSL after 1 week; and (4) MI-control group: subjected to MI induction, then open thoracotomy after 1 week without CSL. Electrocardiography, echocardiography, histopathology, and immunohistochemistry were done before and after CSL. In CSL group, there were no significant electrocardiographic or echocardiographic changes after CSL, although there was interstitial oedema that decreased after 1 week with the appearance of Thebesian vessels and positive staining for vascular endothelial growth factor. In MI-CSL group, there was significant increase in left ventricular (LV) end-systolic diameter (P = 02), decrease in LV fractional shortening (P = 0.0001), and LV ejection fraction (P = 0.002) in comparison with MI-control group, associated with severe myocardial degeneration.

Conclusion: Acute CS occlusion could be compensated in normal hearts, but may be detrimental in the presence of structural heart disease.