Recurrent attack of acute myocardial infarction complicated with ventricular fibrillation due to coronary vasospasm within a myocardial bridge: a case report.

BACKGROUND: Myocardial bridge (MB) often an inoffensive condition that goes in one or more of the coronary arteries through the heart muscle instead of lying on its surface. MBs sometimes leads to myocardial ischemic symptoms such as chest pain, even an occurrence of myocardial infarction. However, reports of severe and recurrent cardiac adverse events related to the MBs are rare. CASE PRESENTATION: A 44-year-old male patient who suffered from a four-hour crushing chest pain ten years ago, was diagnosed as acute anterior ST-elevation myocardial infarction (STEMI). The initial findings of coronary angiography (CAG) showed MB was located in the middle part of the left anterior descending coronary artery (LAD). The patient was managed medically. Another re-attack of similar previous chest pain characteristics occured just after 3 days of discharge. Supra-arterial myotomy and CABG were the next adopted management. Postoperative progression was uneventful. However, 32 months after surgical treatment, the patient experienced an abrupt onset of chest pain accompanied by loss of consciousness. The ECG showed ventricular fibrillation (VF). After electrical cardioversion, an immediate CAG followed by CTA was performed which excluded thrombus or acute occlusion in the native coronary artery and an occlusion was observed at the end of the left internal mammary artery. An implantable cardioverter-defibrillator (ICD) was successfully performed for prevention of malignant arrhythmia. During ten years of follow-up, no complications have been identified. CONCLUSIONS: Although MB is mostly benign, it may lead to significant cardiovascular consequences. Supra-arterial myotomy is an appropriate treatment option for this patient who failed to optimal medical therapy. Furthermore, ICD implantation must be considered in order to prevent malignant ventricular arrhythmia caused by continuous spasm resulting in ischemia. Further investigations are required to confirm the clinical effectiveness of these procedures.

The Outcome of Percutaneous Coronary Intervention for Significant Atherosclerotic Lesions in Segment Proximal to Myocardial Bridge at Left Anterior Descending Coronary Artery.

This study aimed to evaluate the efficacy of percutaneous coronary intervention (PCI) for significant atherosclerosis lesions proximal to myocardial bridge (MB) at left anterior descending coronary artery (LAD).A total of 330 consecutive patients with LAD significant stenosis, diagnosed as acute coronary syndrome (ACS), were included. Based on whether combined with MB, the patients were divided into the MB group (MB, n = 48) and non-MB group (NMB, n = 282). Drug eluting stents (DES) were successfully implanted in the stenostic segments prior to MB. All patients were followed up during the hospital stay, 30 days and 12 months after PCI, to evaluate the major adverse cardiac events (MACEs).There was no difference in the incidence of MACEs between the two groups (6.2% versus 2.1%, P = 0.254) when in the hospital. During the follow-up of 30 days and 12 months after PCI, the rate of MACEs was significantly higher in the MB group than in the NMB group (18.2% versus 6.4% and 43.8% versus 17.0%, respectively, P < 0.001). Stent restenosis occurred in four patients in the MB group; whereas, in five patients in the NMB group, the rate of stent restenosis was higher in the MB group than in the NMB group (8.3% versus 1.8%, P = 0.036). Cox proportional hazards regression analysis revealed that the presence of MB was an independent predictor of MACEs (hazard ratio (HR) = 1.781, 95% confidence intervals (95% CI) = 1.108-2.863, P = 0.017).DES implantation for significant atherosclerosis stenosis in the segments proximal to MB have higher incidence of MACEs. MB appears to be associated with a higher incidence of stent restenosis after PCI and is a significant factor in the occurrence of MACEs.