Myocardial bridges: Overview of diagnosis and management

Abstract

A myocardial bridge is a segment of a coronary artery that travels into the myocardium instead of the normal epicardial course. Although it is general perception that myocardial bridges are normal variants, patients with myocardial bridges can present with symptoms, such as exertional chest pain, that cannot be explained by a secondary etiology. Such patients may benefit from individualized medical/ surgical therapy. This article describes the prevalence, clinical presentation, classification, evaluation, and management of children and adults with symptomatic myocardial bridges.intramyocardial coronary artery, myocardial bridge, myocardial ischemia, sudden cardiac death A myocardial bridge (MB) is defined as an intramyocardial segment of an epicardial coronary artery. Perhaps first described by Reyman in 1737, one of the first descriptions of an MB in the modern literature was published by Geiringer in 1951.1 Geiringer noted that, although this "trivial and slight deviation from normal" had been largely overlooked as a potential etiology for pathology, this altered anatomic course might influence the development of atherosclerosis. In an unselected human autopsy series of 100 patients, he identified myocardial bridging in 23 hearts, and detailed the myocardial fiber orientation and relative relationships among the coronary arteries, epicardial fat, and myocardium observed in these patients.The case examples reported in this series reflect observations made in subsequent reports, namely that MBs can range greatly in length as well as depth, that a coronary artery may have more than one bridged segment, and that the overlying fiber orientation may impact the functional significance of a bridge. Ferreira et al. reported a necropsy series of 90 consecutive hearts and found two distinctive patterns of fiber orientation. 2 In the more common superficial orientation, the myocardial fibers cross the artery transversely toward the apex of the heart at an acute angle or perpendicularly. In the deeper orientation, the fibers crossed the left anterior descending (LAD) coronary artery and surrounded it by a muscle bundle that arose from the right ventricular apical trabeculae and crossed the artery transversely, obliquely, or helically before terminating in the interventricular septum.They postulated that the deeper orientation could twist the vessel and compromise diastolic flow, resulting in ischemia.It is understood that MBs are common, however, the estimations of the prevalence of MBs vary. It is important to consider that estimations will vary at least in part as a result of several key variables, including the means of identification (eg, computed tomography (CT), intravascular ultrasound (IVUS), or autopsy), which vessels are examined, and which definition of a bridge is applied (eg, only a "deep" bridge vs both "superficial" and "deep" bridges). Perhaps the most fundamental variable is whether an MB is even considered. Unlike hypertrophic cardiomyopathy, which will usually be obvious to the pathologist, MBs c...

Myocardial bridge as a cause of repeated infarction

“…Los cuadros de infarto agudo de miocardio por un puente miocárdico son muy raros y poco (1,3,5) reportados. Generalmente se comportan de forma asintomática y su diagnóstico es casual .…”

“…Según la literatura, el tratamiento de los puentes musculares sintomáticos o con repercusión clínica se basa en la administración de beta bloqueantes. Son de primera elección por su efecto beneficioso en la disminución de la frecuencia cardíaca y el consiguiente aumento de la perfusión diastólica del corazón (1) más el efecto inotrópico negativo . En ciertos casos, se pueden asociar calcio antagonistas no dihidropiridínicos (verapamilo, diltiazem) que muestran efecto positivo adicional por acción (6) vasodilatadora .…”

“…El puente miocárdico es una anomalía congénita en la que una parte de la arteria coronaria (1) epicárdica se introduce en el espesor del músculo miocárdico . Esto ocasiona una especie de "tunelización" de la arteria en el miocardio, que pasa uno o más haces de fibras musculares por sobre la arteria en forma de "puente".…”

“…En cuanto a fisiopatología, se sabe que las principales arterias del corazón tienen un trayecto epicárdico. Cuando segmentos de estas arterias se introducen en el espesor del miocardio, sufren una estrechez súbita durante cada contracción del corazón (efecto milking), causando isquemias transitorias al miocardio, cuya severidad depende de 2 factores principales: la profundidad y la (1,2) longitud del puente muscular .…”

Myocardial bridge characteristics and coronary atherosclerotic markers

“…Myocardial bridge (MB) is an anatomical variant of coronary artery course in which a segment of the artery is enclosed by band of myocardial muscle fi bers most commonly in the left anterior descending artery (LADA) and rarely in the left circumfl ex artery (LCx) and right coronary artery (RCA). 1,2 In the literature, the prevalence of MB varies between 5% to 86% depending on the type of study and modality used (postmortem examination versus coronary CT versus intracoronary US versus conventional angiography) to assess MB presence. As such, autopsy series have estimated a high prevalence of MB as approximately 80% while coronary angiographic studies have shown a less prevalence of MB as approximately 5%.…”