Muscle overlying the intramyocardial segment of an epicardial coronary artery, first mentioned by Reyman1 in 1737, is termed a myocardial bridge, and the artery coursing within the myocardium is called a tunneled artery (Figure 1). It is characterized by systolic compression of the tunneled segment, which remains clinically silent in the vast majority of cases. An in-depth analysis of autopsy samples was first presented by Geiringer et al2 in 1951, but clinical interest and systematic research was triggered by an observed association of myocardial bridging with myocardial ischemia.2–5 



Figure 1. Typical systolic compression (arrows) of the mid LAD at two sites in series. Diastolic lumen dimensions are normal. The coronary tree shows no angiographic signs of coronary atherosclerosis.



New imaging techniques have led to improved identification and functional quantitation of myocardial bridging in vivo, which is crucial for establishing a link between systolic compression and the clinical presentation, and hence for commencing appropriate therapy. In the present article, we summarize clinically relevant aspects of myocardial bridging with an emphasis on morphological and hemodynamic alterations and their representation in imaging techniques.

The prevalence varies substantially among studies with a much higher rate at autopsy versus angiography (Table).2,4–28 Variation at autopsy may in part be attributable to the care taken at preparation and the selection of hearts. Polacek, who included myocardial loops, reports the highest rate with bridges or loops in 86% of cases.29 On average, myocardial bridges are present in about one third of adults. 

View this table:

Prevalence of Myocardial Bridging at Autopsy and Angiography 



The rate of angiographic bridging is <5%, attributable to thin bridges causing little compression. In subjects with angiographically normal coronary arteries, the use of provocation tests may enhance systolic myocardial compression and thereby reveal myocardial bridges in ≤40% of cases.26,30

A …

Update on Myocardial Bridging

Effects of gender and race on prognosis after myocardial infarction: adverse prognosis for women, particularly black women.

Myocardial bridges: A review

Time for primary review 22 days. 

While it is recognised that gender differences exist in cardiovascular disease, it has only recently been appreciated that significant gender differences also exist in cardiovascular function. Ageing is associated with a different spectrum of cardiac and vascular maladaptations in women compared to men. These differences may contribute to poorer outcome in women affected by ischaemic disease compared to men as well as the higher prevalence of symptomatic cardiac failure seen in women. The most obvious gender-related difference in physiological ageing is the menopause in women. The relation of this ‘event’ to cardiovascular disease has generated much controversy, especially with respect to hormone replacement therapy in the management of cardiac patients. Controversy also exists in the role of declining androgen levels in men with age and the advisability of testosterone supplementation in men. This review will examine gender differences which become apparent due to ageing, as well as the specific effect of the menopause and hormone replacement on cardiac and vascular structure and function. It will also summarise the impact of these physiological and epidemiological differences on the expression of cardiovascular disease in men and women. Studies examining the role of gender and hormone withdrawal and administration in animal studies will also be summarised. Limitations in current research and recommendations for future areas of research are put forward.

Because of the higher cardiac mortality in men compared to women until late in life [1], most early studies focused exclusively on that gender. Women have been excluded from research protocols during childbearing years and in old age because of co-morbidities [2]. Recently research emphasis has shifted in line with the recognition that cardiovascular disease remains the most prevalent illness affecting women and remains the most frequent cause of female death in most Western nations … 

* Corresponding author. Tel.: +44-171-351-8112; fax: +44-171-823-3392 peter.collins{at}ic.ac.uk

/pdf/the-roles-of-gender-the-menopause-and-hormone-replacement-on-uxkn8cs739.pdf

The roles of gender, the menopause and hormone replacement on cardiovascular function

BACKGROUNDIn autopsy, myocardial bridging is a common finding. With coronary angiography, a systolic compression, mainly of the left anterior descending coronary artery, is observed in 1% to 3% of the patients. Controversy exists concerning the functional importance of this finding. To obtain a functional insight into the myocardial bridging, intravascular ultrasound and intracoronary Doppler were performed.METHODS AND RESULTSIntracoronary ultrasound and Doppler were performed in 14 patients with angiographic evidence of systolic vessel compression ("milking effect") in the left anterior descending coronary artery. The 4.8F, 20-MHz ultrasound catheter could not be advanced through the entire myocardial bridge segment in 6 of the 14 patients studied because the lumen was < 1.6 mm. In these patients, only the proximal parts of the bridge segment were scanned. The changes in cross-sectional shape during the cardiac cycle were determined for both the normal proximal segment and the bridge segment by use of a ...

Comparison of intravascular ultrasound and angiography in the assessment of myocardial bridging.

The clinical, electrocardiographs and angiocardiographic data are reported of 37 patients with myocardial bridges, in the absence of coronary atherosclerosis. An intramyocardial course of the left anterior descending coronary artery was present in all cases: myocardial bridges on the posterior descending and first diagonal branch were associated in one patient.

The clinical presentation was that of ischemic heart disease in all cases, with stable angina in nine, unstable angina in 19, the intermediate syndrome in five, and a history or evidence of previous myocardial infarction in four.

In 20 cases, left ventricular wall motion appeared to be abnormal on the antero-lateral or apical profile.

One patient died suddenly the day following hospital discharge; of 27 patients followed over a 3–36 month interval, only four (15%) were free of symptoms on medical treatment.

The frequent association of myocardial bridges with a clinical picture of ischemic heart disease which is sometimes severe, is emphasized together with the disappointing results of medical treatment.

Myocardial bridges and ischemic heart disease

In a group of 70 patients, 29 women and 41 men, with atypical chest pain and normal findings at coronary arteriography, some hemodynamic and angiographic parameters of left ventricular function were measured, for the purpose of determining the values of normality and to document possible differences between sexes.

Of the diastolic parameters, the left ventricular end-diastolic pressure and volume was lower in women than in men, the LVEDP being 11.9 ± 3.4 against 13.7 ± 3.6 mm Hg ( P < 0.025), and ED V of 76.1 ± 15 against 89.5 ± 23 ml/m2 ( P < 0.005).

Of the systolic parameters, the ejection fraction of 74 ± 7% in women was significantly higher than that of 67 ± 7% in men ( P < 0.0005), and so was the mean velocity of volume reduction of 2.59 ± 0.58 of women against that of 2.26 ± 0.35 of men ( P < 0.01).

The physiological diversity between the sexes, with women showing a constant hyperdynamic condition in comparison to men, with smaller ventricular volumes and increased contraction, seems to offer a possible explanation for some intriguing aspects of the diagnosis of ischemic heart disease in the female sex.

B. Dander

Papers

Myocardial bridges and ischemic heart disease

Left ventricular function in men and women. Another difference between sexes