Myocardial bridging. The role of microcirculation, coronary reserve and systolic endothelial injury]

BACKGROUND: The relationship between myocardial bridging (MB) and ischemic heart disease is still controversial. However, a recent new evidence suggests that this relation is not by chance. PURPOSE: The purpose of our study was to review in a critical manner, the evidence for the relationship between MB and myocardial ischemia and its possible consequences. METHODS: We present 2 cases of our series and review the medical literature from January 1966 to January 1998 published and included in Medline and Current Contents. RESULTS AND CONCLUSIONS: The principal findings after this review were: 1) MB is not a normal variant; 2) The clinical impact of MB depends on its anatomical extension and degree of compressive effect; 3) The MB muscle is not similar to myocytes from other cardiac areas; 4) The environment surrounding coronary artery may be a crucial factor in determining whether the MB influences the induction of heart disorders or not; 5) The overshoot due to compressive effect on coronary artery might determine endothelial injury in the microcirculation post-MB; 6) In some cases, the systolic endothelial injury may contribute to release factors that are able to reduce the coronary reserve, resulting in myocardial ischemia; 7) The possible role of PTCA in this disorder still has to be proven. Surgical treatment should be considered when important myocardial ischemia had been demonstrated, even in those asymptomatic cases.