Myocardial bridging

Ventricular septal rupture caused by myocardial bridge, solved by interventional closure device

Myocardial bridging is a common coronary anomaly, which is generally described as a benign phenomenon. However, a growing number of studies consider this anomaly a relevant pathophysiological phenomenon with serious pathological consequences. Here we report on the case of an 88-year-old woman suffering from myocardial infarction and ventricular septal rupture, lacking any recognizable coronary disease except for a myocardial bridge causing the systolic compression of the left anterior descending coronary artery. A wide range of diagnostic procedures, including coronarography, echocardiography, and magnetic resonance imaging were used. The septal rupture was finally closed by using a percutaneous closure device. This event indicates that myocardial bridges - at least in some cases - may have notable clinical relevance.

Myocardial bridging: what have we learned in the past and will new diagnostic modalities provide new insights?

The clinical significance of myocardial bridging has been a subject of discussion and controversy since the introduction of coronary arteriography (CAG) in the early 1960s. More recently computed tomography coronary angiography (CTCA) has made it possible to visualise the overlying muscular bands and appears to have a higher sensitivity for detecting myocardial bridging than CAG. Combining CTCA with invasive techniques such as CAG should make it possible to improve our understanding of the pathophysiology of myocardial bridging and to provide answers to hitherto unresolved questions. This paper critically reviews the outcomes of previous studies and defines remaining questions that should be answered to optimise the management of the presumably fast growing number of patients in whom a diagnosis of myocardial bridging has been made.

Atherosclerosis and myocardial bridging: Not a benign combination. An autopsy case report

Myocardial bridging is a congenital coronary anomaly with a variety of clinical manifestations. Traditionally, myocardial bridging has been considered a benign condition, but some cases of myocardial ischemia, infarction and sudden cardiac death due to myocardial bridging have been reported. Various studies have suggested that in their intramyocardial segments, these vessels are protected from obstructive atherosclerosis, with atherosclerosis being present in the proximal part of the artery. We report a case in a 45-year-old male who had a 2.5-cm long myocardial bridging over the left anterior descending artery, with obstructive atherosclerosis being present in the proximal as well as the intramyocardial part (part of the artery below the myocardial bridge). Atherosclerosis occurring in the intramyocardial segment is a rare occurrence, and combined with systolic narrowing by the myocardial bridge can lead to ischemia of the cardiac musculature.

Myocardial bridging is a potential risk factor of very late stent thrombosis of drug eluting stent

Drug eluting stents have been implanted worldwide and used in nearly 90% of percutaneous coronary interventions in China. Although many randomized trials have confirmed the efficacy and safety profile of drug eluting stents, they were not powered to detect or exclude the effect of drug eluting stents on rare events such as stent thrombosis. Several mechanisms of very late stent thrombosis have been postulated, but are not widely accepted. Virchow’s triad describes the 3 main factors of thrombus formation – stasis of blood flow, endothelial injury and hypercoagulability. Myocardial bridging is a common congenital anomaly. Modern anatomy and angiography regard myocardial bridging as widespread, but its pathophysiological response is always ignored. According to Virchow’s triad, myocardial bridging negatively affect endothelial function, and the turbulent shear stress and intimal trauma predispose the vessel toward thrombus formation. Therefore, we question whether a relationship between myocardial bridging and very late stent thrombosis of drug eluting stents exists. Also, we propose that myocardial bridging might be a potential risk factor of very late stent thrombosis of drug eluting stents; coronary artery bypass grafting might be a promising and novel choice in the treatment of myocardial bridging with severe stenosis in the coronary artery.

Prevalence of Congenital Coronary Artery Anomalies and Variants in 2697 Consecutive Patients Using 64-Detector Row Coronary CTAngiography

BACKGROUND

Coronary artery anomalies are not common, but could be very serious.

OBJECTIVES

This study determines the frequency of coronary anomalies and normal variants by multi-detector-row computed tomography (MDCT).

PATIENTS AND METHODS

The results of cardiac MDCT study in 2697 consecutive patients were analyzed retrospectively. Acquisition was performed by a 64-detector row CT machine. Imaging results were assessed by experienced radiologists.

RESULTS

Myocardial bridging was by far the most frequent coronary variant (n = 576, 21.3%). Eighty-three subjects (3.1%) showed other coronary anomalies and variants. Anomalies of origination and course of the left main coronary artery (LMCA) were detected in 1.09% of the subjects. The frequency of these anomalies in the right coronary artery (RCA), left circumflex artery (LCx), left anterior descending artery (LAD), posterior descending artery (PDA) and obtuse marginal (OM) artery were 1.24%, 0.33%, 0.1%, 0.07% and 0.03%, respectively. The single coronary pattern was seen in 0.18% and coronary fistulas in 0.07%.

CONCLUSION

Based on the fact that coronary CT-angiography using MDCT can display different coronary anomalies, this study shows similar results to other reports on the subject. Future advances in the performance of CT machines will further improve the quality of CT-based cardiac imaging.

Graft occlusion after coronary artery bypass grafting and stent deformation and in-stent restenosis after succedent stenting in a patient with deep position myocardial bridging

We present a case of deep position myocardial bridging in a patient who had early graft occlusion after coronary artery bypass grafting and had stent deformation and in-stent restonesis after succedent stenting.

Myocardial bridging assessed by multidetector computed tomography: likely cause of chest pain in younger patients with low prevalence of dyslipidemia

INTRODUCTION AND OBJECTIVES

The relationship between myocardial bridging and symptoms is still unclear. The purpose of our study was to assess the relationship between myocardial bridging detected by multidetector computed tomography and symptoms in a patient population with chest pain syndrome.

METHODS

The study enrolled 393 consecutive patients without previous coronary artery disease studied for chest pain and referred to multidetector computed tomography between January 2007 and December 2010. Noninvasive coronary angiography was performed using multidetector computed tomography. Myocardial bridging was defined as part of a coronary artery completely surrounded by myocardium on axial and multiplanar reformatted images.

RESULTS

Mean age was 64.6 (12.4) years and 44.8% were male. Multidetector computed tomography detected 86 myocardial bridging images in 82 of the 393 patients (20.9%). Left anterior descending was the most frequent coronary artery involved (87.2%). The prevalence of myocardial bridging was significantly higher in patients without significant atherosclerotic coronary stenosis on multidetector computed tomography (24.9% vs 15.0%; P=.02). Patients with myocardial bridging were younger (60.3 [13.8] vs 65.8 [11.9]; P<.001), had less prevalence of hyperlipidemia (29.3% vs 41.8%; P=.03), and more prevalence of cardiomyopathy (6.1% vs 1.6%, P=.02) compared with patients without myocardial bridging on multidetector computed tomography.

CONCLUSIONS

Multidetector computed tomography is an easy and reliable tool for comprehensive in vivo diagnosis of myocardial bridging. The results of the present study suggest myocardial bridging is the cause of chest pain in a subgroup of younger aged patients with less prevalence of hyperlipidemia and more prevalence of cardiomyopathy than patients with significant atherosclerotic coronary artery disease on multidetector computed tomography. Full English text available from:www.revespcardiol.org.

The regenerative capacity of the zebrafish heart is dependent on TGFβ signaling

Mammals respond to a myocardial infarction by irreversible scar formation. By contrast, zebrafish are able to resolve the scar and to regenerate functional cardiac muscle. It is not known how opposing cellular responses of fibrosis and new myocardium formation are spatially and temporally coordinated during heart regeneration in zebrafish. Here, we report that the balance between the reparative and regenerative processes is achieved through Smad3-dependent TGFβ signaling. The type I receptor alk5b (tgfbr1b) is expressed in both fibrotic and cardiac cells of the injured heart. TGFβ ligands are locally induced following cryoinjury and activate the signaling pathway both in the infarct area and in cardiomyocytes in the vicinity of the trauma zone. Inhibition of the relevant type I receptors with the specific chemical inhibitor SB431542 qualitatively altered the infarct tissue and completely abolished heart regeneration. We show that transient scar formation is an essential step to maintain robustness of the damaged ventricular wall prior to cardiomyocyte replacement. Taking advantage of the reversible action of the inhibitor, we dissected the multifunctional role of TGFβ signaling into three crucial processes: collagen-rich scar deposition, Tenascin C-associated tissue remodeling at the infarct-myocardium interface, and cardiomyocyte proliferation. Thus, TGFβ signaling orchestrates the beneficial interplay between scar-based repair and cardiomyocyte-based regeneration to achieve complete heart regeneration.

Increase in mean platelet volume in patients with myocardial bridge

AIM

Myocardial bridge is associated with atherosclerosis altered in shear stress and endothelial dysfunction. Mean platelet volume (MPV), a determinant of platelet activation, is shown to be related with atherosclerosis and endothelial dysfunction. In this study, we aimed to evaluate platelet function assessed by MPV in patients with myocardial bridge.

METHODS

Forty-two patients with myocardial bridge in the left anterior descending artery (LAD) and 43 age- and gender-matched healthy participants were included in the study. Myocardial bridging was defined as an intramyocardial systolic compression or milking of a segment of an epicardial coronary artery on angiography. For the entire study population, MPV was measured using an automatic blood counter.

RESULTS

The study population consisted of 42 patients with myocardial bridge (52.7 ± 10.2, 76.2% male) and 43 age- and sex-matched healthy control participants (52.1 ± 10.4, 74.4% male). Compared to the control group, MPV value was significantly higher in patients with myocardial bridge (8.9 ± 1.24 vs 8.3 ± 0.78; P = .01). Further, there were no significant differences between groups regarding hemoglobin level, platelet count, fasting blood glucose, and creatinine levels.

CONCLUSIONS

Our study findings indicated that myocardial bridge is associated with elevated MPV values. Our results might partly explain the increased cardiovascular events in patients with myocardial bridge.

Myocardial bridging on coronary CTA: an innocent bystander or a culprit in myocardial infarction?

Myocardial bridging describes the clinical entity whereby a segment of coronary artery is either partially or completely covered by surrounding myocardium. It represents the most frequent congenital coronary anomaly and has an estimated prevalence of ≤13% on angiographic series. With the emergence of cardiac computed tomography and its ability to simultaneously image the coronary arteries and also the myocardium, there has been an apparent increase in the detection rates of myocardial bridges (prevalence as high as 44%). It has now become important to evaluate their clinical significance. Myocardial bridging is generally considered a benign entity with survival rates of 97% at 5 years; however, there is now emerging evidence that certain myocardial bridge characteristics may be associated with cardiovascular morbidity. The length and depth of myocardial bridges have been associated with increased atherosclerosis, whereas the degree of systolic compression has been associated with ischemia on myocardial perfusion single-photon emission tomography. On the basis of current evidence, it appears that limiting further testing for ischemia to symptomatic patients with long and/or deep myocardial brides would be appropriate.

What is Sudden Cardiac Death?

Sudden cardiac death (SCD) is a rapid, unexpected death due to cardiac causes. The differential diagnosis includes diseases from all four structural divisions of the heart: the blood vessels, myocardium, valves, and conduction system. Although ischemic heart disease is a common cause of SCD, acute myocardial infarcts and/or coronary thromboses are not always detected and are not required to make the diagnosis of death due to atherosclerotic coronary disease. Some people die suddenly from heart disease with a grossly and microscopically normal heart. Molecular analysis of some of these autopsy-negative, sudden unexplained deaths (SUD) may detect putative cardiac channel mutations.

There are three SCD scenarios that are of particular interest to forensic pathologists: sudden cardiac deaths in young athletes, during criminal altercations (homicide by heart attack), and in other hostile environments. In young athletes, most sudden deaths involve cardiac disease and include cardiomyopathies, congenital coronary artery anomalies, myocarditis, and channelopathies. One must, however, consider other causes in these deaths (e.g., commotio cordis, hyperthermia, sickle cell trait). Homicide-by-heart-attack deaths are those in which the cause of death is an acute exacerbation of underlying cardiac disease, however, the manner is homicide because a criminal act triggered the lethal pathologic cascade. A sudden cardiac arrest may occur in hostile locations with resultant trauma (e.g., while driving a motor vehicle). When the event occurs in the bathtub or other body of water, the question of whether the person died naturally from heart disease or unnaturally from trauma (e.g., drowning) often arises. One should not be mislead by the initial physical surroundings of the death (i.e., in a motor vehicle collision, or swimming pool) and fail to distinguish a natural sudden death from an accidental one.

Myocardial bridging with a coronary artery aneurysm and left ventricular stunning

The authors present a case demonstrating the unusual combination of myocardial bridging with a coronary artery aneurysm complicated by acute transient left ventricular dysfunction due to myocardial stunning. The pathophysiology and current insights into myocardial bridging, coronary aneurysms and myocardial stunning are briefly discussed. The literature reveals only one other reported case of coronary aneurysms associated with myocardial bridging. In addition, although there are several reports of angina and myocardial infarction complicating bridging, there is only 1 other report of myocardial stunning specifically.

Myocardial bridges: A review

Much has been written regarding the potential clinical significance of myocardial bridges. As such bridging is often seen in normal individuals, it is clear that not all arteries bridged by myocardial segments produce clinical symptoms thereby suggesting that this feature may simply be an anatomical variant. However, some authors who have considered these bridges as the cause of cardiac ischemia have suggested two potential mechanisms for their pathophysiology. The first is a phasic systolic compression of the bridged segment with persistent mid-to-late diastolic reduction in arterial diameter and the second proposes a reduction in arterial flow. Both mechanisms may contribute to a reduced reserve in coronary blood flow. In this review, we discuss the evidence that exists regarding myocardial bridging and the potential for bridging to cause myocardial ischemia.

Myocardial bridging causing ischemia and recurrent chest pain: a case report

Background

Myocardial bridging is present when a segment of a major epicardial coronary artery runs intramurally through the myocardium. It usually has a benign prognosis, but in some cases myocardial ischemia, infarction and sudden cardiac death have been reported. We are here reporting a case of myocardial bridging which was complicated with recurrent chest pain and transient ST-segment elevation during exercise treadmill test.

Case presentation

A 40 year-old-man presented with recurrent retrosternal chest pain of 2 months duration. He had history of smoking and was obese, otherwise no physical abnormalities were detected by examination. Electrocardiogram and blood tests were normal apart from impaired glucose tolerance with elevated triglycerides and decreased level of high density lipoprotein cholesterol. While doing exercise treadmill test, the patient developed chest pain and significant ST-segment elevation in almost all precordial leads that persisted for about 15 minutes through recovery. We decided to admit the patient to the coronary care unit for further management and to perform coronary angiogram. Myocardial bridging was observed in the mid segment of the left anterior descending coronary artery. Medical treatment was decided.

At one year follow up, our patient was healthy and had no cardiac complaints. In conclusion, myocardial bridging may predispose to coronary vasospasm that may leads to ischemic complications.

ST-segment elevation in non-atherosclerotic coronaries: a brief overview

The most common, clinically significant cause of ST elevation is an angiographically demonstrable occlusive disease due to atherosclerotic changes in coronary artery. Often, a patient presenting with non-specific complaints and ST-segment elevation on the electrocardiogram, is sent for a cardiac catheterization only to see no luminal stenosis on the angiogram. This clinical review is intended to inform emergency medicine physicians and internists about the conditions in which ST-segment elevation is accompanied with no atherosclerotic lesion on coronary angiography. These situations make a diverse array of conditions ranging from anomalous coronaries to anatomically normal coronaries with varied degrees of myocardial injury. These conditions are briefly reviewed in this article.

Exercise, heart and health

Regular physical activity provides a variety of health benefits, including improvement in cardiopulmonary or metabolic status, reduction of the risk of coronary artery disease or stroke, prevention of cancer, and decrease in total mortality. Exercise-related cardiac events are occasionally reported during highly competitive sports activity or vigorous exercises. However, the risk of sudden death is extremely low during vigorous exercise, and habitual vigorous exercise actually decreases the risk of sudden death during exercise. The cause of sudden death is ischemic in older subjects (≥35 years old), while cardiomyopathies or genetic ion channel diseases are important underlying pathology in younger (<35 years old) victims. The subgroup of patients who are particularly at higher risk of exercise-related sudden death may be identified in different ways, such as pre-participation history taking, physical examination and/or supplementary cardiac evaluation. Limitations exist because current diagnostic tools are not sufficient to predict a coronary artery plaque with potential risk of disruption and/or an acute thrombotic occlusion. Proper and cost-effective methods for identification of younger subjects with cardiac structural problems or genetic ion channel diseases are still controversial.

The role of myocardial perfusion imaging in evaluating patients with myocardial bridging

BACKGROUND

Myocardial bridging (MB) is a common, congenital coronary-abnormality that is found on average in one out of every three adults at autopsy (Moehlenkamp et al in Circulation, 106:2616-2622, 2002; Erbel et al in Circulation, 120:357-359, 2009). However, its clinical significance and impact on myocardial ischemia remains controversial and unclear. Myocardial perfusion imaging (MPI) is widely used to assess myocardial ischemia in patients with known or suspected coronary artery disease, and is frequently performed to evaluate the hemodynamic significance of MB. This study was undertaken to determine the use of MPI in evaluating MB and to identify the characteristics of MB associated with perfusion defects using MPI.

METHODS AND RESULTS

Thirty-nine patients with MB of the left anterior descending (LAD) artery as documented by coronary angiography (CA) were enrolled for this study. None of the patients exhibited other forms of heart disease as determined by both CA and stress-rest MPI, no later than 1 month prior to the study. Using MPI, eight patients (20.5%) were found to have perfusion defects in the corresponding myocardial areas. This frequency was significantly higher when compared with results obtained by stress electrocardiogram. The difference in the mean systolic narrowing of bridging segments was statistically significant between patients with and without ischemia. The positive rate of reversible defects in patients with severe systolic narrowing was significantly higher than in patients with mild-to-moderate systolic narrowing. However, there was no significant difference either between the mean length of the tunneled artery in patients with and without abnormal MPI or the positive rate of abnormal MPI in patients with different locations of the tunneled artery.

CONCLUSIONS

MPI is an effective, noninvasive technique for the evaluation of patients with MB. The myocardial ischemia that resulted from bridging is associated more closely with the degree of systolic narrowing than with the length of tunneled artery or the location of MB.

Cardiac ischemia in pediatric patients

Cardiac ischemia in children is usually not an isolated disease in an otherwise normally formed coronary artery but is part of more complex congenital or acquired diseases. Although cardiac ischemia is not a frequent occurrence, it must be recognized as a serious, life-threatening event. This article lists and characterizes major causes of cardiac ischemia in children, describes signs and symptoms of each, and provides therapeutic considerations.

Myocardial bridging of the left anterior descending coronary artery: depiction rate and morphologic features by dual-source CT coronary angiography

Objective

To evaluate the depiction rate and morphologic features of myocardial bridging (MB) of the left anterior descending coronary artery (LAD) using dual-source CT (DSCT).

Materials and Methods

CT scans from a total of 1,353 patients who underwent DSCT were reviewed retrospectively for LAD-MB. Seventy-eight patients were excluded due to poor image quality or poor enhancement of the coronary artery. The length and depth of the MB were analyzed and classified as superficial or deep with respect to the depth (≤ 1 or > 1 mm) of the LAD tunneled segment. Superficial MB was subdivided into complete or incomplete types according to full or partial encasement of the myocardium.

Results

Of the 1,275 patients included in this study, 557 cases of MB were found from 536 patients (42%). Superficial MB was observed in 368 of 557 (66%) cases, and deep MB was seen in 189 of 557 (34%) cases. Superficial MB showed 2 types: complete (128 of 368, 35%) and incomplete (240 of 368, 65%). The mean length of a tunneled segment for superficial MB was 16.4 ± 8.6 mm. The mean length and depth of a tunneled segment for deep MB were 27.6 ± 12.8 mm and 3.0 ± 1.4 mm, respectively. The incidence of atherosclerotic plaques in a 2-cm-long segment proximal to MB was 16%.

Conclusion

The depiction rate of LAD-MB using DSCT in a large series of patients was 42%, with two-thirds of MB segments being the superficial type.

Unexpected death of a young woman: is myocardial bridging significant?--A case report and review of literature

Myocardial bridging (MB) refers to a congenital condition where a segment of a major coronary artery courses within the myocardium for a variable distance, and has been reported as an incidental finding in many cases. However, in some situations it has been shown to be associated with acute coronary syndromes, arrhythmias, myocardial ischemia and sudden death. We present the case of a 26-year-old Chinese woman with no previous history of disease who died unexpectedly in hospital. She had a 'common cold' with its associated symptoms. Autopsy revealed the presence of MB of the left anterior descending artery and microscopic examination showed associated cardiac lesions such as contraction band necrosis and interstitial fibrosis in the region supplied by the embedded artery. The coronaries were otherwise patent. Gross and microscopic examination of other organs was unremarkable. Toxicological analysis of body fluids and stomach content excluded death due to either drug intoxication or known poisonous substances. MB could have been responsible for death, but the disparate attitudes towards this phenomenon made this assumption open to discussion. We provide the case description and a short review of the literature on fatal and near- fatal cases involving MB.

Evaluation of myocardial bridges with optical coherence tomography

This study investigated the morphological characteristics of myocardial bridges (MBs) using optical coherence tomography (OCT) imaging compared with coronary artery angiography (CAG) and also evaluated atherosclerotic lesions in the proximal segments of MBs. Twelve patients (seven males, five females, age range 36 - 81 years) with MBs in the left anterior descending coronary artery were enrolled and examined. The mean +/- SD length of the MBs measured by OCT appeared significantly longer than when measured by CAG (20.5 +/- 4.2 mm versus 15.6 +/- 3.5 mm, respectively). The mean +/- SD maximal extent of MB stenosis appeared significantly smaller with OCT compared with CAG (48.7 +/- 4.8% versus 55.3 +/- 2.6%, respectively). Intimal thickening was observed only in the proximal 2 cm arterial segment of MBs. The morphological and intimal structure characteristics of MBs can be observed clearly with OCT.

Coronary artery perforation following implantation of a drug-eluting stent rescued by deployment of a covered stent in symptomatic myocardial bridging

We successfully rescued a patient whose coronary artery perforated following implantation of a drug-eluting stent (DES), by deploying a stent-graft in symptomatic myocardial bridging. Our case demonstrated that coronary perforation could be handled without difficulty when perforated myocardial bridging is confined to the interventricular groove

Long-term clinical course of patients with isolated myocardial bridge

BACKGROUND

Myocardial bridge (MB) is regarded as a common benign lesion on coronary angiography (CAG). It is known to be harmless but may cause several cardiac events and recurrent hospitalization, so in the present study the long-term clinical course of patients with isolated MB and predictors of readmission were investigated.

METHODS AND RESULTS

Total 684 patients (343 males, 60.5+/-11.2 years) with persistent chest pain without critical stenosis on CAG were enrolled. The patients were divided into 2 groups according to the presence of MB. Clinical follow-up was performed with respect to readmission after baseline 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%). There was a significant higher incidence of readmission in the MB group (P=0.038). In multivariate analysis, long MB (hazard ratio (HR) 2.780; 95% confidence interval (CI) 1.070-7.218, P=0.036) and spontaneous vasospasm in CAG (HR 2.335; 95%CI 1.055-5.171, P=0.037) were the predictors of readmission. Moreover, additional use of aspirin or statin decreased the readmission rate.

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. Especially, patients with a long MB and vasospasm on CAG need intensive medical therapy, including antiplatelet treatment.

A haemodynamic model for heart-mural coronary artery-myocardial bridge

An experimental model for heart-mural coronary artery-myocardial bridge was established based on the theory of haemodynamics. The application of the model demonstrated that it can repeat to great extent the phenomenon of the myocardial bridge compressing the mural coronary artery, which results in abnormal haemodynamic characteristics. The results of simulation experiments are mostly consistent with clinical research.

Myocardial bridging in Taiwan: depiction by multidetector computed tomography coronary angiography

BACKGROUND/PURPOSE

Myocardial bridging (MB) is a condition in which a segment of the major epicardial coronary artery is tunneled within and surrounded by the myocardium. This condition has been linked to severe complications. The aim of this study was to evaluate the incidence of MB in Taiwanese subjects examined with electrocardiogram-gated, 16-slice, multidetector computed tomography (MDCT) coronary angiography, as well as to determine the location, depth, and length of the bridged segments and the concomitant atherosclerosis of MB.

METHODS

From August 2004 to May 2005, 276 consecutive subjects referred to our department for MDCT coronary angiography were enrolled in the study after written informed consent was obtained from each participant.

RESULTS

Twenty-four subjects (8.7%) had at least one coronary segment that was completely surrounded by myocardium. Patients ranged in age from 27 to 76 years, with an average of 54 +/- 12 years. Thirty coronary segments were found to have MB. The most common location of MB was in segment 7, which accounted for 14 coronary segments (46.7%) of the total number of bridged segments; left anterior descending artery (LAD) segments accounted for 23 (76.7%); and right coronary artery and left circumflex artery segments accounted for three (10%) and two (6.7%), respectively. The length of bridged segments ranged from 5.2 to 50.6 mm, with an average length of 24.6 +/- 11.8 mm, and the depth of the bridged segments ranged from 0.5 to 9.1 mm, with an average depth of 3.65 +/- 1.89 mm. Two bridged segments (6.7%) had concomitant atherosclerosis; these were located in segment 7 (24.0 mm long and 6.10 mm deep) and segment 8 (27.1 mm long and 7.0 mm deep). Bridged segments with concomitant atherosclerosis were deeper, but not longer, compared with bridged segments without concomitant atherosclerosis (p < 0.05).

CONCLUSION

Electrocardiogram-gated MDCT is an effective noninvasive tool for evaluating MB in a clinical setting. The most common location of MB was in the LAD, especially in segment 7. Bridged segments with concomitant atherosclerosis were deeper, but not longer, compared with bridged segments without concomitant atherosclerosis.

Prevalence of myocardial bridging and correlation with coronary atherosclerosis studied with 64-slice CT coronary angiography

PURPOSE

This study aimed to assess the prevalence and characteristics of myocardial bridging in patients who underwent multislice computed tomography coronary angiography (MSCT-CA) and to evaluate the correlation between bridged coronary segments and atherosclerosis.

MATERIALS AND METHODS

A total of 277 patients (mean age 60+/-11 years) we consecutively examined with 64-slice MSCT-CA for suspected or known coronary atherosclerosis were retrospectively reviewed for myocardial bridging. Segments proximal and distal to the bridging were evaluated for atherosclerotic plaque, as were the remaining coronary segments.

RESULTS

Myocardial bridging was present in 82 patients (30%, mean age 59+/-12). Bridges were of variable length (<1 cm 58%; 1-2 cm 32%; >2 cm 10%) and depth (superficial 69%, intramyocardial 31%) and frequently localised in the mid-distal segment of the left anterior descending artery (95%). Myocardial bridging cannot be considered a significant risk factor for coronary atherosclerosis (odds ratio 0.49) compared with traditional cardiovascular risk factors. Coronary segments proximal to the bridge showed no atherosclerotic disease (33%), positive remodelling (27%), <50% stenosis (20%) or >50% stenosis (20%). We identified 12 noncalcified, 32 mixed and 17 calcified plaques. The distal segments were significantly less affected (p<0.0001).

CONCLUSIONS

MSCT-CA is a reliable, noninvasive method that is able to depict myocardial bridging and associated atherosclerotic plaque in the proximal segments.

Heart pump system in "heart-mural coronary artery-myocardial bridge" simulative device

The myocardial tissue covering the artery is termed a myocardial bridge. But so far many researches on the myocardial bridge have been involved with clinical patients or animals, which have some limitations (e.g. lack of systematicness, difficulties in measuring the flow in the mural coronary artery and so on). Designing a "Heart-Mural coronary artery-Myocardial Bridge" Simulative Device provides a good approach to solve above problems; however, documents on this subject have seldom been reported until now. The heart pump as the key part of the whole simulative device should be able to simulate the waveform of blood pressure, adjust blood flow and regulate heart rate. Our experimental results basically met above requirements. The heart pump proposed in the paper presented an alternative experimental method to go further into other issues about the cardiovascular circulation system.

Pericardial adhesions simulating myocardial bridging

A 48-year-old man with aortic valve disease was diagnosed to have myocardial bridging on preoperative coronary angiography. During surgical exploration, only pericardial adhesions were found, with a normal epicardial coronary course.