Macroscopical and microscopical study on frequency of myocardial bridge (a cause of sudden death) in coronary artery of sheep heart


1 Departmenof Basic Sciences, Faculty of Veterinary Medicine, Shahrekord University, Shahrekord- Iran

2 Graduated from the Faculty of Veterinary Medicine, Shahrekore University, Shahrekord- Iran


BACKGROUND: Myocardial bridge (MB) is generally defined as a superfacial muscular band that forms sporadic or multiple across the coronary artery in dog, cat, sheep, and human. OBJECTIVES: From the view of embryology MB is a preformatted structure with coronary artery during  forming. The type of study in human is during sonography and angiography examination, but in veterinary science the study on MB is  done after death examination. METHODS: This study was performed on over 50 sheep hearts that were prepared from slaughterhouse of Shahr e kord. First, pericardium was opened and the heart brought out of the pericardial cavity and then the hearts were studied with concentrated light and lens on both sides. After the M B recognition,  their length and width were measured by a ruler. In both sides of the heart,the MB was  divided into 1/3 proximal, 1/3 middle and 1/3 distal. In all of the studied hearts, only 10 samples (20%) had M B. RESULTS: The average length of recognised MBs was 1.55±1.17 (SD) cm and  with width of 1.09±.092 (SD) cm. The positive samples were transferred to histology laboratory for preparation of cross section of heart and were stained with  H&E staining.CONCLUSIONS: The longitudinal section showed the long fibers of myocardium with continual narrow fibers and intercalated discs were located between them.


Agirbasli, M., Martin, G.C., Stout, J.B., Jenings, H.S., Les, J.W., Dixson, J.H. (1997) Myocardial bridge as a cause of thrombus formation and myocardial infarction in a young athlet. Clin Cardiol. 20: 1032-1036.
Bombonao, P.P., Domingo, C.D.O., Mariana, A.N.B., d Carneiro-e-silra, F.O. (1994) Incidence of myocardial bridges in pigs. Braz J Vet Res Anim Sci. 31: 111-115.
Gowda, R.M., Khan, I.A., Ansari, A.W., Cohen, R.A. (2003) Acute ST segment elevation myocardial infarction from myocardial bridging of left anterior descending coronary artery. Int J Cardiol. 90: 117-118.
Koch, H.J.L., Kearney, P., Gorge, G., Haude, M., Meyer, J. (1994) Comparision of intravascular ultrasound and angiography In the assesment of myocardial bridging. Circ. 89: 1725-1732.
Lozano, I., Baz, J.A., Lopez, P.R. (2002) Long-term prognosis of patients with myocardial bridge and angiographic milking of the left anterior descending coronary artery. Rev Esp Cardiol. 55: 359-364.
Krandis, A.J., Salachas, A.J., Antonellis, I.P., Kappos, K.G., Patsilinakos, S.P., Zamanis, N.J., Margaris, N.G., Tavernarakis, A.G., Anthropolous, L.P. (1997) Transesophageal echocardiograohic doppler study of coronary flow in apatient with myocardial bridging. A case report. Ang. 48: 1007-1111.
Laurent, G., Cottin, Y., Andre, F., Pichon, E., Piszker, G., Gerard, C., Gabrielle, F., Ravisy, J., Louis, P., Wolf, J.E. (1996) Sympatomatic myocardial bridge. Apropos of 6 cases Arch. Mal Coeur Viss. 89: 883-887.
Nie, C.J., van Vincentm, J.G. (1989) Myocardial bridges in animals. Anat Histol Embryol. 18: 45-51.
Severino, R.S., Bombonato, P.P. (1992) Occurence of myocardial bridge in Gir Guzera Nelore and Indo Brazilian Cattle. Braz J Vet Res  Anim Sci. 29: 15-30.
Tang Kawattana, P., Muto, M., Kakayama, T., Karkoura, A., Yamano, S., amaguchi, M. (1997) Prevalence, Vasculature, and innervation of myocardial bridges in dogs. Am J Vet Res. 58: 1209-1215.
Yamaguchi, M., Tangkawattana, P., Hamilin, R.L. (1996) Myocardial bridging as a factor in heart disorders.Critical review and hypothesis. Acta Anat (Basel). 157: 248-60.
Yamaguchi, M., Tangkawattana, P., Muto, M., Nakade, T., Taniyama, H., Miyata, Y., Nakayama, T., Hamilin, R.L. (1996) Myocardial bridge muscle on the left anterior descending coronary artery differ from subepicardial myocardium of the left ventricle in dogs. Acta Anat. 157: 238-247.