Qualitative and quantitative characteristics of the passive compartment underneath the myocardial bridge comprising the blood vessel adventitia and the perivascular connective tissue / Características cualitativas y cuantitativas del compartimento pasivo debajo del puente miocárdico que comprende la adventicia del vaso sanguíneo y el tejido conectivo perivascular

SUMMARY: Myocardial bridges are inborn anomalies frequently found in authopsies. Although tipically clinically silent, they are occasionally associated with severe clinical manifestations, e.g. myocardial ischemia or even sudden death. The pathophysiology and risk factors for these manifestations have not yet been completely elucidated. The connective tissue underneath the bridge has been considered as one of the factors the symptoms depend on. Thus, the aim of this research was to determine the histological characteristics of the connective tissue lying underneath the myocardial bridge and to contribute to a better understanding of the protective effects this passive compartment might have in prevention of severe clinical manifestations of myocardial bridging. The study was carried out on twenty hearts with myocardial bridges. Length of the bridge was determined using a precise electronic caliper. Sections of the myocardial bridges with the underlying connective tissue were obtained and prepared for qualitative and quantitative analysis. The connective tissue underneath the bridges was composed of adipose tissue and loose connective tissue in different ratios. The tissue underneath thin bridges was predominantly composed of adipose tissue, while loose connective tissue was the dominant component under thick bridges. The myocardial bridges had an average thickness of 0,98 ± 0.44 mm and an average length of 15,25±5,65 mm. We found a strong positive correlation between the myocardial bridge thickness and length (r = 0,860, p = 0,0001). The thickness of the passive connective tissue compartment under the myocardial bridges was 0,58±0,22 mm, and there was no correlation between this parameter and the myocardial bridge thickness (r = -0,011; p = 0,963). In the clinical evaluation of patients with these anomalies it is necessary to take into account independently the myocardial bridge thickness and length on one side and the thickness of the connective tissue lying underneath it on the other.

Los puentes miocárdicos son anomalías congénitas que se encuentran con frecuencia en las autopsias. Aunque típicamente éstos son clínicamente silenciosos, ocasionalmente se asocian con manifestaciones clínicas graves, como isquemia miocárdica o incluso muerte súbita. La fisiopatología y los factores de riesgo de estas manifestaciones aún no se han dilucidado por completo. El tejido conectivo debajo del puente se ha considerado como uno de los factores de los que dependen los síntomas. Por lo tanto, el objetivo de esta investigación fue determinar las características histológicas del tejido conectivo que se encuentra debajo del puente miocárdico y contribuir a una mejor comprensión de los efectos protectores que este compartimento pasivo podría tener en la prevención de manifestaciones clínicas graves de puente miocárdico. El estudio se llevó a cabo en veinte corazones con puentes miocárdicos. La longitud del puente se determinó utilizando un calibrador electrónico preciso. Se obtuvieron secciones de los puentes miocárdicos con el tejido conjuntivo subyacente y se prepararon para análisis cualitativo y cuantitativo. El tejido conectivo debajo de los puentes estaba compuesto de tejido adiposo y tejido conectivo laxo en diferentes proporciones. El tejido debajo de los puentes delgados estaba predominantemente compuesto de tejido adiposo, mientras que el tejido conectivo laxo era el componente dominante debajo de los puentes gruesos. Los puentes de miocardio tenían un espesor promedio de 0,98 ± 0,44 mm y una longitud promedio de 15,25 ± 5,65 mm. Encontramos una fuerte correlación positiva entre el grosor y la longitud del puente miocárdico (r = 0,860, p = 0,0001). El grosor del compartimiento de tejido conectivo pasivo debajo de los puentes miocárdicos era de 0,58±0,22 mm, y no hubo correlación entre este parámetro y el grosor del puente miocárdico (r = -0,011; p = 0,963). En la evaluación clínica de pacientes con estas anomalías es necesario tener en consideración de forma independiente el grosor y la longitud del puente de miocardio por un lado y el grosor del tejido conectivo que se encuentra debajo del mismo por el otro.

Microscopic analysis of the myocardial bridges and their relationship with atheromatous plaque / Análisis microscópico de los puentes miocárdicos y su relación con la placa ateromatosa

SUMMARY: Most histopathological studies have reported that the segment of the coronary artery below the myocardial bridge does not present atheromatous plaque, while the segment proximal to the myocardial bridge may have it. The aim of this study was to evaluate the microscopic environment of myocardial bridges. This descriptive study was carried out with 60 hearts of individuals who underwent autopsy at the National Institute of Legal Medicine and Forensic Sciences in Bucaramanga-Colombia. For each specimen, the coronary arteries and their branches were dissected, removing the subepicardial adipose tissue to identify the myocardial bridges and obtain histological sections of the compromised arterial branches. The presence of myocardial bridges was observed in 22 hearts (36.7%) with a length of 17.31 + 4.41 mm and a thickness of 904.57 + 312.27 mm. The coronary vessel caliber at the prepontine level was 246.57 + 49.33 mm and was significantly higher than in the pontine (188.92 + 60.55 mm) and postpontin (190.40 + 47 mm) segments (p=0.001 for both values). Atheromatous plaque was observed in the prepontine segment in 12 cases (46.15 %) and in 8 samples (30.76%) at the pontine level, but in this segment, there was slight damage to the vascular endothelium, or phase I level. The thickness of the tunica intima in the cases with atheromatous plaque was 15.68 + 13.39 mm and that of the plaque-free segments was 5.10 + 4.40 mm (p=0.005), and in the pontine segment the overlying periarterial adipose tissue had a thickness of 72.01 + 69.44 mm, which was higher than the other three locations (p=0.005). The morphometry of the perivascular fat pad and the presence of phase I atheromatous plaque are the main contributions of this study to the histology of myocardial bridges.

RESUMEN: La mayoría de los estudios histopatológicos han reportado que el segmento de la arteria coronaria debajo del puente miocárdico no presenta placa ateromatosa, mientras que el segmento proximal al puente miocárdico puede tenerla. El objetivo de este estudio fue evaluar el entorno microscópico de los puentes miocárdico. Este estudio descriptivo se realizó con 60 corazones de individuos a quienes se les práctico autopsia en el Instituto Nacional de Medicina Legal y Ciencias Forenses de Bucaramanga-Colombia. Para cada espécimen se realizó disección de las arterias coronarias y sus ramas, eliminando el tejido adiposo subepicárdico para identificar los puentes miocárdicos y obtener secciones histológicas de las ramas arteriales comprometidas. Se observó presencia de puentes miocárdicos en 22 corazones (36,7 %) con una longitud de 17.31 + 4.41 mm y un espesor de 904.57 + 312.27 mm. El calibre del vaso coronario a nivel prepontino fue 246.57 + 49.33 mm y fue significativamente mayor que en el segmento pontino (188.92 + 60.55 mm) y pospontino (190.40 + 47 mm) (p=0.001 para ambos valores). Se observó placa ateromatosa en el segmento prepontino en 12 casos (46.15 %) y en 8 muestras (30.76%) al nivel pontino, pero en este segmento, correspondieron a fase I, con ligero daño en el endotelio vascular. El espesor de la túnica íntima en los casos con placa ateromatosa fue de 15.68 + 13.39 mm y de los segmentos libres de placa fue 5.10 + 4.40 mm (p=0.005) y en el segmento pontino el tejido adiposo periarterial suprayacente presento un espesor de 72.01 + 69.44 mm, el cual fue mayor a las otras tres ubicaciones (p=0.005). La morfometría de la almohadilla adiposa perivascular y la presencia de placa ateromatosa en fase I son los principales aportes de este estudio a la histología de los puentes miocárdicos.

Case Report: Myocardial Bypass in Left Descending Artery - A Rare Congenital Anomaly

Abstract Myocardial bypass (MB) is known to have scientific relevance and is present in several studies with great statistical significance regarding its clinical manifestations and complications. There are still questions about MB in its relationship with heart disease and repercussion in life-threatening conditions. We present a case report of a MB in the left anterior descending coronary artery, whose objective is to identify this rare congenital anomaly and to highlight the patient's clinical outcome in order to elicit greater contributions about the presence of this variant in the emergency room, its diagnosis by angiography and therapeutic management.

Puente miocárdico largo en la arteria descendente anterior como causa de síndrome coronario agudo / Long myocardial bridging in the left anterior descending artery causing acute coronary syndrome

RESUMEN Las arterias coronarias principales generalmente tienen un trayecto epicárdico. En algunos casos, pequeños segmentos de éstas se introducen en el interior del miocardio formando los denominados puentes miocárdicos. Esta particularidad anatómica puede producir un estrechamiento sistólico súbito del trayecto tunelizado (fenómeno de milking) y afectar el flujo coronario tanto en sístole como en diástole, con la consiguiente reducción de la reserva coronaria. Afecta principalmente a la arteria descendente anterior en sus segmentos medio y distal. Su presentación clínica puede ir desde un cuadro anginoso hasta la muerte súbita. Hasta el momento, parece ser, que el uso de betabloqueadores y anticálcicos es la opción terapéutica más efectiva en los casos sintomáticos. Se expone un caso en el que un síndrome coronario agudo fue la forma de presentación de esta variante anatómica y el oportuno diagnóstico angiográfico permitió realizar los reajustes terapéuticos necesarios para mejorar la sintomatología del paciente.

ABSTRACT Coronary arteries usually run along the outer surface of the heart. In some cases, small segments of them take a "tunneled" intramuscular course forming the so-called myocardial bridging. This anatomical feature may lead to a sudden systolic narrowing of the "tunneled" segment (milking effect), thereby impairing coronary blood flow in both systole and diastole; which further reduces coronary reserve. Myocardial bridging mainly affects the middle-distal segments of left anterior descending (LAD) artery and may cause anything from chest pain to sudden death. So far, it seems that the use of beta-blockers and anti-calcium agents is the most effective therapeutic option for symptomatic cases. We now report a case where the clinical presentation of this anatomical feature was an acute coronary syndrome. Timely, accurate angiographic diagnosis allowed for adequate therapeutic adjustments to improve the patient's symptomatology

Correlation between Coronary Artery Tortuosity and Stenosis in Patients with Myocardial Bridge / 中国医学科学院学报

Objective To analyze the correlation between tortuosity and stenosis in patients with myocardial bridge(MB)on the left anterior descending artery(LAD). Methods Data of patients with MB on the LAD,which was discovered by coronary computed tomography angiography(CCTA),in the Affiliated Hospital of North China University of Science and Technology from October 2015 to December 2018 were retrospectively analyzed.Among them 278 patients with tortuosity on LAD and 278 patients without tortuosity were selected.The clinical charateristics(age,gender,hypertension,hyperlipidemia,diabetes,smoking history,and family history)as well as the incidence and severity of stenosis of LAD were recorded and compared. Results The incidence of coronary artery stenosis in the non-tortuosity group(57.6%)was significantly lower than that in the tortuosity group(71.9%)($\bar{χ}$=12.608,

Muerte súbita cardíaca asociada a puente miocárdico / Sudden cardiac death associated with myocardial bridge

La muerte súbita cardíaca en deportistas genera un gran impacto social y familiar, afortunadamente su incidencia es baja. En atletas menores de 35 años las causas más frecuentes son las anomalías genéticas y las miocardiopatías. Presentamos el caso de un paciente masculino de 17 años que presentó muerte súbita reanimada mientras realizaba actividad física. El electrocardiograma post animación evidenció una injuria subepicárdica en cara anterior, encontrándose en la cinecoronariografía como único hallazgo, la existencia de un puente muscular en tercio medio de la arteria descendente anterior.

Cardiac arrest in athletes has a high impact in family and society, fortunately its incidence is low. In athletes younger than 35 years old the most frequent causes are genetic anomalies and cardiomyopathies. We report the case of a 17 years old male patient who presented cardiac arrest and reanimation while doing physical activity. The post-reanimation electrocardiogram showed a subepicardial injury in the anterior face, detecting in cinecoronariography as only finding the presence of myocardial bridging in the middle third of anterior descending artery.

A parada cardíaca em atletas tem um alto impacto na família e na sociedade, felizmente sua incidência é baixa. Em atletas menores de 35 anos as causas mais freqüentes são anomalias genéticas e cardiomiopatías. Relatamos o caso de um paciente do sexo masculino de 17 anos de idade que apresentou parada cardíaca e reanimação durante atividade física. O eletrocardiograma pós-reanimação mostrou lesão subepicárdica na face anterior, detectar na cinecoronariografia como apenas encontrar a presença de ponte miocárdica no terço médio da artéria descendente anterior.

Assessment of the Relationship between Monocyte to High-Density Lipoprotein Ratio and Myocardial Bridge / Avaliação da Relação entre a Razão de Monócitos para Lipoproteínas de Alta Densidade e a Ponte Miocárdica

Abstract Background: Assessing the monocyte to high-density lipoprotein ratio (MHR) is a new tool for predicting inflamation, which plays a major role in atherosclerosis. Myocardial bridge (MB) is thought to be a benign condition with development of atherosclerosis, particularly at the proximal segment of the brigde. Objective: To evaluate the relationhip between MHR and the presence of MB. Methods: We consecutively scanned patients referred for coronary angiography between January 2013- December 2016, and a total of 160 patients who had a MB and normal coronary artery were enrolled in the study. The patients' angiographic, demographic and clinic characteristics of the patients were reviewed from medical records. Monocytes and HDL-cholesterols were measured via complete blood count. MHR was calculated as the ratio of the absolute monocyte count to the HDL-cholesterol value. MHR values were divided into three tertiles as follows: lower (8.25 ± 1.61), moderate (13.11 ± 1.46), and higher (21.21 ± 4.30) tertile. A p-value of < 0.05 was considered significant. Results: MHR was significantly higher in the MB group compared to the control group with normal coronary arteries. We found the frequency of MB (p = 0.002) to increase as the MHR tertiles rose. The Monocyte-HDL ratio with a cut-point of 13.35 had 59% sensitivity and 65.0% specificity (ROC area under curve: 0.687, 95% CI: 0.606-0.769, p < 0.001) in accurately predicting a MB diagnosis. In the multivariate analysis, MHR (p = 0.013) was found to be a significant independent predictor of the presence of MB, after adjusting for other risk factors. Conclusion: The present study revealed a significant correlation between MHR and MB.

Resumo Fundamento: A avaliação da razão de monócitos para lipoproteínas de alta densidade (MHR, sigla em inglês) é uma nova ferramenta para se prever o processo inflamatório, o qual desempenha um papel importante na aterosclerose. A ponte miocárdica (PM) é considerada uma condição benigna com desenvolvimento de arteriosclerose, particularmente no segmento proximal da ponte. Objetivo: Avaliar a relação entre a MHR e a presença de PM. Métodos: Examinamos concecutivamente pacientes encaminhados para angiografia coronariana entre janeiro de 2013 e dezembro de 2016, e um total de 160 pacientes, uma parcela dos quais com PM, e outra com artérias coronárias normais, foram incluídos no estudo. As características angiográficas, demográficas e clínicas dos pacientes foram revisadas a partir de registros médicos. Monócitos e colesteróis HDL foram medidos através de hemograma completo. A MHR foi calculada como a razão entre a contagem absoluta de monócitos e o valor do colesterol HDL. Os valores de MHR foram divididos em três tercis, da seguinte forma: tercil inferior (8,25 ± 1,61); tercil moderado (13,11 ± 1,46); e tercil superior (21,21 ± 4,30). Considerou-se significativo um valor de p < 0,05. Resultados: A MHR foi significativamente maior no grupo com PM, em comparação com grupo controle com artérias coronárias normais. Verificamos que a prevalência de PM (p=0,002) aumentou à medida que se elevavam os tercis de MHR. A razão monócitos-colesterol HDL com ponto de corte de 13,35 apresentou sensibilidade de 59% e especificidade de 65,0% (área ROC sob a curva: 0,687, IC95%: 0,606-0,769, p < 0,001) na predição acurada do diagnóstico de PM. Na análise multivariada, a MHR (p = 0,013) mostrou-se um preditor independente significativo da presença de PM, após ajustes para outros fatores de risco. Conclusão: O presente estudo revelou uma correlação significativa entre MHR e PM.

Reporte de un caso de puente intramiocárdico en arteria coronaria derecha / A case report of intramyocardial bridge on right coronary artery

Los puentes intramiocárdicos son una anomalía de la circulación coronaria. Estos suelen presentarse en el trayecto de la arteria descendente anterior y se clasifican en superficiales o profundos. Reportamos el hallazgo de un puente intramiocárdico en el trayecto de la arteria coronaria derecha, incluida su rama sinoauricular y descendente posterior durante la disección de rutina de un cadáver. El paciente al parecer no presentó signos relativos a insuficiencia coronaria y falleció debido a una insuficiencia respiratoria aguda causada por neumonía aspirativa. Debido a la presencia limitada de casos sobre puente intramiocárdico de la arteria coronaria derecha, realizamos una revisión de la literatura al respecto y planteamos algunas conclusiones.

Intramyocardial bridges are a coronary circulation anomaly. They usually occur on the path of the anterior descending artery and are classified as superficial or deep. During a routine autopsy, we found­and report­an intramyocardial bridge in large part of the right coronary artery pathway, including the sinoatrial and posterior descending branch. The patient did not show signs of coronary insufficiency, and died from an acute respiratory failure caused by aspiration pneumonia. Due to the infrequency of cases of intramyocardial bridges of the right coronary artery without concomitant clinical symptoms or signs, we conducted a literature review in this regard.

High Prevalence and Clinical Implication of Myocardial Bridging in Patients with Early Repolarization

PURPOSE: Recent evidence suggests that early repolarization (ER) is related with myocardial ischemia. Compression of coronary artery by a myocardial bridging (MB) can be associated with clinical manifestations of myocardial ischemia. This study aimed to evaluate the associations of MB in patients with ER. MATERIALS AND METHODS: In consecutive patients (n=1303, age, 61±12 years) who had undergone coronary angiography, we assessed the prevalence and prognostic implication of MB in those with ER (n=142) and those without ER (n=1161). RESULTS: MB was observed in 54 (38%) and 196 (17%) patients in ER and no-ER groups (p<0.001). In multivariate analysis, MB was independently associated with ER (odd ratio: 2.9, 95% confidence interval: 1.98–4.24, p<0.001). Notched type ER was more frequently observed in MB involving the mid portion of left anterior descending coronary artery (LAD) (69.8% vs. 30.2%, p=0.03). Cardiac event was observed in nine (6.3%) and 22 (1.9%) subjects with and without ER, respectively. MB was more frequently observed in sudden death patients with ER (2 out of 9, 22%) than in those without ER (0 out of 22). CONCLUSION: MB was independently associated with ER in patients without out structural heart disease who underwent coronary angiography. Notched type ER was closely related with MB involving the mid portion of the LAD. Among patients who had experienced cardiac events, a higher prevalence of MB was observed in patients with ER than those without ER. Further prospective studies on the prognosis of MB in ER patients are required.

Suspensión de la anticoagulación oral en pacientes con fibrilación auricular ante un procedimiento invasivo: ¿deben recibir un puenteo con anticoagulación parenteral durante su realización? / Suspension of oral anticoagulation in patients with atrial fibrillation before an invasive procedure: should they receive parenteral anticoagulation bridging during its implementation?

En la actualidad, muchos pacientes con fibrilación auricular son anticoagulados por largos períodos. Durante este tiempo pueden ser sometidos a procedimientos invasivos. A partir de una viñeta clínica, un médico se plantea el impacto de utilizar o no heparina de bajo peso molecular como puente farmacológico al momento de suspender la anticoagulación oral. Luego de realizar una búsqueda ad hoc, un ensayo clínico aleatorizado de no inferioridad demuestra que en pacientes con fibrilación auricular, con puntajes de riesgo tromboembólico (CHADS2) intermedios a bajos que requieren una interrupción temporal del tratamiento con warfarina para un procedimiento invasivo electivo, la estrategia de no reemplazar la anticoagulación oral con heparina de bajo peso molecular no resultó inferior (o menos efectiva) para la prevención de tromboembolismo arterial, y disminuyó además el riesgo de sangrado mayor en comparación al uso de un puente con esta medicación. (AU)

Many patients with atrial fibrillation are anticoagulated for long periods. During this time they may be subjected to invasive procedures. From a clinical vignette, a physician discusses the impact of using (or not) low molecular weight heparin as a pharmacological bridge at the time of suspending oral anticoagulation. After conducting a bibliographic search, a no inferiority randomized clinical trial showed that in patients with atrial fibrillation with intermediate to low thromboembolic risk (CHADS2) requiring a temporary interruption of warfarin therapy for an elective invasive procedure, the strategy of with holding low molecular weight heparin bridging was not inferior (or less effective) for the prevention of arterial thromboembolism than its use, also decreasing the risk of major bleeding. (AU)

Assessment of indirect inflammatory markers in patients with myocardial bridging

Introduction: Myocardial bridging (MB)is a congenital variant of the coronary artery in which a portion of the epicardial coronary artery takes an intramuscular course. Although it is considered a benign anomaly, it may lead to such complications as myocardial ischaemia, acute coronary syndrome, coronary spasm, exercise-induced dysrhythmias or even sudden death. MB may be related to increased inflammatory and atherosclerotic processes. This study was conducted with the aim of evaluating the relationship between neutrophil/lymphocyte ratio (NLR) and MB.Methods: Taking into consideration the inclusion criteria, 86 patients with MB and 88 with normal coronary angiographies (control group) were included in the study. The association between MB and laboratory and other clinical parameters was evaluated.Results: The platelet distribution width (PDW) (17.3 ± 0.40 vs 16.1 ± 0 .5; p < 0.05), NLR (3.2 ± 1.3 vs 2.2 ± 0.9; p < 0.05) and red cell distribution width (RDW) (14.3 ± 1.3 vs 13.1 ± 1.1; p < 0.05) were significantly higher in the MB group than in the control group.Conclusions: This study demonstrated that compared to normal coronary arteries, PDW, NLR and RDW were significantly higher in MB patients. Further studies are needed to clarify the increased inflammatory parameters in patients with MB

Myocardial bridging

Abstract Myocardial bridging is rare. Myocardial bridges are most commonly localized in the middle segment of the left anterior descending coronary artery. The anatomic features of the bridges vary significantly. Alterations of the endothelial morphology and the vasoactive agents impact on the progression of atherosclerosis of myocardial bridging. Patients may present with chest pain, myocardial infarction, arrhythmia and even sudden death. Patients who respond poorly to the medical treatment with β-blockers warrant a surgical intervention. Myotomy is a preferred surgical procedure for the symptomatic patients. Coronary stent deployment has been in limited use due to the unsatisfactory long-term results.

Impact of Myocardial Bridge-mural Coronary Artery on Myocardial Blood Supply / 中国医学科学院学报

Objective To explore the impact of myocardial bridge-mural coronary artery (MB-MCA) on myocardial blood supply. Methods The imaging data of 74 patients with the isolate MB in the left anterior descending artery undergoing 256-slice CT coronary angiography and myocardial perfusion imaging (MPI) were retrospectively analyzed. The subjects were divided into incomplete and complete MB types. The length of MB and the systolic stenosis degree of MCA were measured.The type and length of MB and the systolic stenosis degree of MCA (according to Noble grade) were compared between the normal and abnormal MPI groups. The clinical characteristics including age, gender, body mass index, hypertension, dyslipidemia, diabetes mellitus, and smoking history were also reviewed. Results There were 38 incomplete MB cases and 13 complete MB cases in the normal MPI group,and 5 and 18 in the abnormal MPI group (χ=18.134,P=0.000). The MB length in the normal and abnormal MPI group were (14.7±3.7) mm and (15.5±4.5) mm (t=0.804,P=0.424). However, the systolic stenosis degree of MCA showed significant difference (χ=17.839,P=0.000). The clinical characteristics were not significantly differentt between the normal and abnormal MPI groups (P>0.05). Conclusions The MB type and the systolic stenosis degree of MCA can affect myocardial perfusion.Patients with complete MB and the moderate-to-severe systolic stenosis degree of MCA are more susceptible to myocardial ischemia. However, the MB length is not correlated with myocardial ischemia.

A Totally Occluded Long Segment Myocardial Bridge: 10-year Follow-up after Percutaneous Coronary Intervention in a Patient with Hypertrophic Cardiomyopathy / 대한내과학회지

Intracoronary stent implantation can improve coronary hemodynamics and myocardial ischemia in patients with symptomatic bridging. However, percutaneous coronary intervention for this lesion is limited due to the high prevalence of restenosis and risk of complications. We present a case of a totally occluded long-segment myocardial bridge in a patient with hypertrophic cardiomyopathy who was successfully implanted with a bare metal stent under intravascular ultrasound guidance without complications. The patient has been free of ischemic symptoms with stent patency for 10 years.

Puentes de miocardio en corazones de avestruz (Struthio Camelus) / Miocardial bridge in ostrich heart (Struthio Camelus)

El término puente de miocardio es atribuido al conjunto de fibras musculares cardiacas, que a veces se sobreponen a un segmento subepicárdico de una determinada rama de las arterias coronarias derecha e izquierda. Polacek (1959) fue el primero en enfocar esta entidad desde el punto de vista muscular, de aquí nace el nombre de "puente de miocardio" siendo actualmente la más usada en clínica. La presencia de estos puentes, ha sido identificada tanto en humanos como en animales y basados en ello, se estudiaron 50 corazones de avestruz, de la clase African Black, cuyo objetivo fue determinar presencia de puentes de miocardio, número, longitud y principales arterias en donde se ubican. Hubo presencia de puentes de miocardio en 20 (40,0%) de los 50 corazones estudiados; el número total de puentes de miocardio fue de 34, de los cuales 30 (88,2%) se ubicaron sobre la arteria coronaria izquierda y sus ramas y 4 (11,8%) sobre la arteria coronaria derecha y sus ramas. El número de puentes varió de 1 a 4 por corazón. Los vasos donde se observaron con mayor frecuencia fueron: ramas ventriculares de la rama interventricular paraconal con 22 (64,7%) puentes y rama interventricular paraconal con 8 (23,5%) puentes. Los registros métricos de la extensión de los puentes de miocardio variaron entre 1,6 mm y 73,1 mm.

The term myocardial bridge is attributed to all cardiac muscle fibers, which sometimes overlap a subepicardial segment of a particular branch of the right and left coronary arteries. Polacek in 1959 was the first to approach this entity from the standpoint of muscle. From this arises the name of "myocardial bridge" and is currently the term most widely used clinically. The presence of these bridges, has been identified in humans and in animals and based on that, 50 African Black class ostrich hearts were studied, with the aim to determine the presence of myocardial bridges, number, length and main arteries where they are located. There was presence of myocardial bridges in 20 (40.0%) of the 50 hearts studied, the total number of myocardial bridges was 34, of which 30 (88.2%) were located on the left coronary artery and its branches and 4 (11.8%) over the right coronary artery and its branches. The number of bridges ranged from 1 to 4 by heart. The vessels most frequently observed were: ventricular branches paraconal interventricular branch with 22 (64.7%) and interventricular branch paraconal bridges with 8 (23.5%) bridges. Metrical records of the extent of myocardial bridges ranged between 1.6 mm and 73.1 mm.

Myocardial Ischemia by Aggravation of Myocardial Bridging

Myocardial bridging (MB) occurs when the myocardium covers a segment of a major epicardial coronary artery, resulting in a tunneled arterial segment. Although MB is generally considered benign, it has been associated with myocardial ischemia. A 70-year-old man with MB (50% luminal narrowing during systole) at the mid-left anterior descending artery (LAD) on previous coronary angiography (CAG) visited our hospital with worsening chest pain. His blood pressure (BP) was not well controlled because of poor compliance. Follow-up CAG showed that MB at the mid-LAD progressed to severe stenosis (>90% luminal narrowing during systole) and the total length of tunneled artery extended from 22.5 to 23.9 mm. His chest pain was relieved by BP control. This is the first report of myocardial ischemia secondary to progression of MB demonstrated by CAG in Korea.

Schwarz type C myocardial bridge unraveled post-thrombus aspiration in a patient with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy [HCM], a heterogenous disease with diverse pathology and variable clinical course has a high prevalence of myocardial bridging. Despite the high prevalence of myocardial bridging in HCM patients, acute ST-elevation myocardial infarction [STEMI] due to concomitant atherothrombosis proximal to Schwarz type C myocardial bridge unraveled during trans-radial primary percutaneous intervention has rarely been reported in medical literature. Herein, we report a case of Schwarz type C myocardial bridge unmasked postthrombosuction in a patient with HCM presenting with acute STEMI. He had atherothrombosis proximal to the tunneled left anterior descending artery which was successfully stented with drug-eluting stent without the aid of intravascular ultrasound

Association of myocardial bridge in the left anterior descending coronary with coronary atherosclerosis proximal to the bridge site in diabetic patients / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate whether myocardial bridging (MB) is an independent risk factor for coronary atherosclerosis proximal to the bridge site in the left anterior descending coronary artery (LAD) in diabetic patients.</p><p><b>METHODS</b>From March 2011 to December 2012, 9862 patients with suspected coronary disease underwent coronary computed tomography angiography (CCTA) using a dual-source CT scanner. The baseline clinical characteristics (age, gender, smoking history, presence of hypertension, dyslipidemia, diabetes mellitus, family history of heart attack and body mass index) and the results of CCTA were reviewed. Two radiologists evaluated the MB and coronary atherosclerosis stenosis (CAS) over 50% in the LAD and made a diagnosis by consensus. Significant independent risk factors for CAS were investigated by logistic regression analysis.</p><p><b>RESULTS</b>Of the 2345 patients identified to have diabetes mellitus, 1373 had MB, among whom 827 had coronary atherosclerosis proximal to the bridge site; 972 of the diabetic patients were free of MB, among whom 254 had coronary atherosclerosis at the equivalent site. None of the patients had CAS in the tunneled segment. After adjusted for clinical data, logistic regression analysis showed that MB in the LAD was significantly correlated with coronary atherosclerosis in the proximal LAD in diabetic patient (OR=3.91) and non-diabetic patients (OR=2.69) (P<0.05).</p><p><b>CONCLUSION</b>In diabetic patients, atherosclerosis occurred frequently in the segment proximal to MB in the LAD, and MB in the mid-LAD is an independent risk factor for CAS in the proximal LAD.</p>