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of or relating to the myocardium

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/09/08 13:19:14」(JST)

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A myocardial bridge occurs when one of the coronary arteries tunnels through the myocardium rather than resting on top of it. Typically, the arteries rest on top of the heart muscle and feed blood down into smaller vessels that populate throughout the myocardium. But if the muscle grows around one of the larger arteries, then a myocardial bridge is formed. As the heart squeezes to pump blood, the muscle exerts pressure across the bridge and constricts the artery. This defect is present from birth. It can lead to uncomfortable, powerful heartbeats and angina. The incidence of the condition in the general population is estimated at 5% based on autopsy findings,^[1] but significance when found in association with other cardiac conditions is unknown.^[2]

The condition is diagnosed on a scaled based on what percentage of obstruction occurs. If there is less than 50% blockage, then the condition is probably benign. A result of at least 70% usually causes some pain. Small amounts of myocardial bridging often are undetectable, as the blood usually flows through the coronary while the heart is relaxing in diastole.

This condition can cause complications such as vasospasm, angina pectoris, arrhythmia, Vtach. Additionally many patients express discomfort in specific positions, (i.e. lying on the left side for a prolonged period of time).

Case study

Figure 1: Angiogram showing myocardial bridging resulting in arterial compression.

Figure 1 shows a series of angiographic images with a bridge on the left anterior descending coronary artery (LAD) in a male patient of 65 years.

A1) Right anterior oblique view taken at end systole. The compressed vessel segment is indicated by the two arrows.

B1) Left anterior oblique view taken nearly at the same instant.

A2) Same view as in A1, but taken 133 ms later. The tunneled segment is no longer compressed.

B2) Same view as in B1 but 133 ms later.

References

^ Pelliccia, Antonio (2009), Sports Cardiology Casebook, Springer, p. 141, ISBN 978-1-84882-041-8
^ Ragosta, Michael (2009), Cardiac Catheterization: An Atlas and DVD, Elsevier Health Sciences, p. 146, ISBN 978-1-4160-3999-0

External links

Harlan Krumholz, M.D. discusses myocardial bridging
Medical definition of myocardial bridge
Myocardial bridge summary by the Texas Heart Institute

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UpToDate Contents

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1. 冠動脈の心筋架橋 myocardial bridging of the coronary arteries
2. 狭心症：心筋虚血による胸痛 angina pectoris chest pain caused by myocardial ischemia
3. 先天性および小児冠動脈異常 congenital and pediatric coronary artery abnormalities
4. 肥大型心筋症における心室性不整脈および突然の心停止 ventricular arrhythmias and sudden cardiac arrest in hypertrophic cardiomyopathy
5. 特殊な問題の治療を含む肥大型心筋症のマネージメントの概要 overview of hypertrophic cardiomyopathy management including treatment of special problems

English Journal

Clinical situations in which coronary CT angiography confers superior diagnostic information compared with coronary angiography.

Kantarcı M, Doğanay S, Karçaaltıncaba M, Karabulut N, Erol MK, Yalçın A, Duran C, Dursun M, Karakaya A, Tatlı S.SourceDepartment of Radiology, Atatürk University School of Medicine, Erzurum, Turkey.
Diagnostic and interventional radiology (Ankara, Turkey).Diagn Interv Radiol.2012 Jun;18(3):261-9. Epub 2012 Jan 19.
In this review, we aimed to outline the clinical and pathological conditions for which multidetector computed tomography coronary angiography (MDCT-CA) should be the preferred method because of its advantages over conventional coronary angiography (CCA). A consistent body of literature s
PMID 22261852

Bridging cardiogenic shock patients with short-term ventricular support at a community hospital to long-term ventricular support at a tertiary hospital.

González-Costello J, Yang J, Sims DB, Kossar AP, Murray LK, Colombo PC, Takayama H, Mancini D, Naka Y, Jorde UP, Uriel N.SourceDivision of Cardiology, Department of Medicine, Columbia University Medical Center, New York, New York; Servei de Cardiologia, Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain.
The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation.J Heart Lung Transplant.2012 Jun;31(6):618-24. Epub 2012 Feb 9.
BACKGROUND: Patients in cardiogenic shock require immediate circulatory support. Outcomes of patients who underwent short-term ventricular assist device (STVAD) implantation in a community hospital (CH) as a bridge to a long-term VAD (LTVAD) were compared with those who received both implants at the
PMID 22325690

Japanese Journal

Variant Angina Associated with Coronary Artery Endothelial Dysfunction and Myocardial Bridge: A Case Report and Review of the Literature

Nardi Federico,Verna Edoardo,Secco Gioel Gabrio,Rognoni Andrea,Bongo Angelo Sante,Iraghi Gabriele,Bertuol Stefano,Lupi Alessandro
Internal Medicine 50(21), 2601-2606, 2011
… The association of variant angina (VA) and myocardial bridges is a rare finding. … We describe a case of VA with recurrent coronary spasm triggered by different stimuli at the site of a myocardial bridge. … The interplay of endothelial dysfunction, coronary vasoconstriction and myocardial bridging was detected by intracoronary acetylcholine test and IVUS. …
NAID 130001288620

Long-Term Clinical Course of Patients With Isolated Myocardial Bridge

KIM Sung-Soo,JEONG Myung Ho,KIM Hyun Kuk,KIM Min Chul,CHO Kyung Hun,LEE Min Goo,KO Jum Suk,PARK Keun Ho,SIM Doo Sun,YOON Nam Sik,YOON Hyun Ju,PARK Hyung Wook,KIM Ju Han,HONG Young Joon,AHN Young Keun,CHO Jeong Gwan,PARK Jong Chun,KANG Jung Chaee
Circulation journal : official journal of the Japanese Circulation Society 74(3), 538-543, 2010-02-25
… Background: Myocardial bridge (MB) is regarded as a common benign lesion on coronary angiography (CAG). … At a mean follow-up of 37 months, 92 patients (13.3%) were re-admitted because of 79 recurrent chest pain refractory to medication (11.5%), 8 myocardial infarctions (1.2%), 1 life-threatening arrhythmia (0.1%) and 4 deaths (0.6%). … Conclusions: This study suggests that MB on non-occlusive CAG is not benign and may cause recurrent chest pain, myocardial infarction or life-threatening arrhythmia. …
NAID 10025943675