Successful surgical resection of a muscular bridge in a patient with nonobstructive hypertrophic cardiomyopathy--a case report

Myocardial bridging: A 'forgotten' cause of acute coronary syndrome - a case report

During a stress test, an asymptomatic 40-year-old man showed an ST depression above 4 mm and a horizontal ST depression above 2 mm in the V3 to V6 precordial leads during the recovery phase, without symptoms related to myocardial ischemia. After several days, he experienced recurrent episodes of oppressive retrosternal pain with radiation to the interscapular region, associated with stress dyspnea. Stress myocardial scintigraphy using technetium sestamibi was performed, which showed a modest push-pull deficit of perfusion in the septal-anterior basal area associated with a small deficit of perfusion in the apical region.The patient was admitted to hospital with a diagnosis of unstable angina. Repeated episodes of chest pain appeared during this period, which were partially relieved with the administration of sublingual nitrate. There were no significant changes in the electrocardiogram or cardiac enzyme levels. Coronary angiography showed initial parietal hypertrophy with normal segmentary kinesis and global systolic function and, most importantly, the presence of a systolic narrowing (myocardial bridging) of the middle one-third of the left anterior descending artery from the likely intramyocardial route. There was no significant stenosis of the remaining coronary tracts.Myocardial bridges have traditionally been considered a benign condition, but recent studies have demonstrated that the clinical complications can be dangerous; these complications include acute coronary syndromes, arrhythmias (including supraventricular tachycardia and ventricular tachycardia), exercise-induced atrioventricular conduction blocks, transient ventricular dysfunction and sudden death.

The effect of intracoronary nicorandil on coronary myocardial bridging

Medical treatments of coronary myocardial bridging (CMB) generally include beta-blockers and calcium channel blockers. Nitrates are avoided because symptoms may worsen. Nicorandil is a hybrid of a nitrate and a potassium channel opener. However, the effect of nicorandil on CMB is unknown. We analyzed nicorandil reactivity at the site with CMB in 51 patients. Maximal and minimal diameters of CMB were measured by quantitative angiography at baseline and at 60 seconds after intracoronary administration of 200 mg nicorandil. The maximal diameter during diastole increased from 2.15 + 0.42 mm to 2.34 + 0.44 mm after administration of nicorandil (P < .001), and the minimal diameter during systole increased from 1.24 + 0.63 mm to 1.67 + 0.64 mm (P < .001). Thus, nicorandil reduced the percentage vessel narrowing from 44.0 + 26.1% to 30.3 + 21.2% (P < .001). In 22 patients, we also evaluated the effect of nitroglycerin. The maximal diameter during diastole increased from 2.25 + 0.47 mm to 2.51 + 0.44 mm after administration of nitroglycerin (P < .019), and the minimal diameter during systole decreased from 1.28 + 0.64 mm to 1.14 + 0.60 mm (P = .276). Thus, nitroglycerin augmented the percentage vessel narrowing from 44.9% + 25.0% to 56.0% + 23.5% (P = .023). These results indicate that intracoronary administration of nicorandil could dilate coronary arteries during diastole as well as systole in patients with CMB during coronary angiography.

Drug eluting stent implantation for the treatment of symptomatic myocardial bridging is associated with favorable peri-procedural results and short-term outcomes

Myocardial bridging is the most common congenital coronary abnormality, and is frequently found on post-mortem cardiac examination. Although often asymptomatic, clinical presentation can vary from unstable angina to sudden cardiac death. Only isolated cases of using drug eluting stents (DES) for bridging segments have been described. Our objective was to retrospectively analyze a series of patients undergoing percutaneous coronary intervention (PCI) with DES for symptomatic myocardial bridging and follow post-procedure outcomes. Results revealed favorable peri-procedural angiographic and short-term clinical results with DES implantation. Although initial data regarding DES implantation for symptomatic myocardial bridging are promising, long-term follow up, particularly related to in-stent restenosis will be important.

Non-compaction cardiomyopathy associated with myocardial bridging: A frequently overlooked or misdiagnosed cardiomyopathy

Isolated ventricular non-compaction (IVNC) is an unclassified cardiomyopathy which occurs due to a morphogenetic abnormality involving an arrest of compaction of the loose myocardial meshwork during fetal ontogenesis. Despite recent advances in knowledge, diagnosis remains problematic because of its similarity to other diseases of the myocardium and endocardium. In this report, we describe a case of IVNC and myocardial bridging. The patient had been misdiagnosed with apical hypertrophic cardiomyopathy 2 years earlier. The correct diagnosis was established by transthoracic echocardiography and confirmed by cardiac catheterization and angiocardiography.

Myocardial bridging

Myocardial bridging, a congenital coronary anomaly, is a clinical condition with several possible manifestations, and its clinical relevance is debated. This article reviews current knowledge about the anatomy, pathophysiology, clinical relevance, and treatment of myocardial bridging. Myocardial bridging is present when a segment of a major epicardial coronary artery, the 'tunnelled artery', runs intramurally through the myocardium. With each systole, the coronary artery is compressed. Myocardial bridging has been associated with angina, arrhythmia, depressed left ventricular function, myocardial stunning, early death after cardiac transplantation, and sudden death. Evidence indicates that the intima beneath the bridge is protected from atherosclerosis, and the proximal segment is more susceptible to development of atherosclerotic lesions because of haemodynamic disturbances. New techniques (e.g. intravascular ultrasonography and intracoronary Doppler studies) have revealed new characteristics and pathophysiologic processes such as diastolic flow abnormalities. Medical treatment generally includes beta-blockers. Nitrates should be avoided because symptoms may worsen. Intracoronary stents and surgery have been attempted in selected patients. Additional research is needed to define patients in whom myocardial bridging is potentially pathologic, and randomized multicentre long-term follow-up studies are needed to assess the natural history, patient selection, and therapeutic approaches.