Assessing myocardial bridging and left ventricular configuration by 64-slice computed tomography in patients with apical hypertrophic cardiomyopathy presenting with chest pain. J Comput Assist Tomogr. 2010;34:70-74. [PMID: 20118725 DOI: 10.1097/rct.0b013e3181b66d31]

Myocardial bridges: A meta-analysis

Myocardial bridges are anatomical entities characterized by myocardium covering segments of coronary arteries. In some patients, the presence of a myocardial bridge is benign and is only incidentally found on autopsy. In other patients, however, myocardial bridges can lead to compression of the coronary artery during systolic contraction and delayed diastolic relaxation, resulting in myocardial ischemia. This ischemia in turn can lead to myocardial infarction, ventricular arrhythmias and sudden cardiac death. Myocardial bridges have also been linked to an increased incidence of atherosclerosis, which has been attributed to increased shear stress and the presence of vasoactive factors. Other studies however, demonstrated the protective roles of myocardial bridges. In this study, using systematic review and a meta-analytical approach we investigate the prevalence and morphology of myocardial bridges in both clinical imaging and cadaveric dissections. We also discuss the pathophysiology, clinical significance, and management of these anatomical entities.

Multimodality imaging in apical hypertrophic cardiomyopathy

Apical hypertrophic cardiomyopathy (AHCM) is a relatively rare morphologic variant of HCM in which the hypertrophy of myocardium is localized to the left ventricular apex. Symptoms of AHCM might vary from none to others mimic coronary artery disease including acute coronary syndrome, thus resulting in inappropriate hospitalization. Transthoracic echocardiography is the first-line imaging technique for the diagnosis of hypertrophic cardiomyopathies. However, when the hypertrophy of the myocardium is localized in the ventricular apex might results in missed diagnosis. Aim of this paper is to review the different imaging techniques used for the diagnosis of AHCM and their role in the detection and comprehension of this uncommon disease.

Evaluation of coronary artery disease and cardiac morphology and function in patients with hypertrophic cardiomyopathy, using cardiac computed tomography

Coronary artery disease and cardiac morphology and function were evaluated in 51 patients with hypertrophic cardiomyopathy (HCM), without typical chest pain, using cardiac computed tomography (CT). This study investigated the prevalence of coronary artery disease, the indicators of obstructive coronary stenosis, and the magnitude of left ventricular (LV) hypertrophy. The patients' mean coronary artery calcium score was 198.8 ± 312.0 and was positively correlated with the number of coronary risk factors (r = 0.32; P < 0.05). Of the 51 patients with HCM, 42 (82.4 %) had some degree of stenosis and 8 (15.7 %) had obstructive stenosis. Noncalcified and mixed plaques were detected in 14 (27.5 %) and 11 (21.6 %) patients, respectively. Multivariate logistic regression revealed that diabetes was an independent indicator of the presence of obstructive stenosis in HCM patients. Multivariate linear regression revealed that low estimated glomerular filtration rates and high triglyceride concentrations were independent indicators of higher LV mass indexes. In conclusion, cardiac CT revealed that coronary artery disease was common among patients with HCM. The presence of obstructive coronary stenosis and the magnitude of LV hypertrophy were related to the presence of diabetes, triglyceride levels, and estimated glomerular filtration rate.

Myocardial bridging analysis by coronary computed tomographic angiography in a Saudi population

AIM: To assess the incidence, location, morphology and clinical association of myocardial bridging in a Saudi population using coronary computed tomographic angiography (CCTA).

METHODS: A total of 350 CCTA of Saudi patients were included in this study (236 men, 114 women) with a mean age of 56.3 years. All patients were examined for appropriateness criteria of CCTA indications (typical chest pain, recent onset cardiomyopathy, left bundle branch block, etc.). The scans were retrospectively reviewed for the presence of myocardial bridging and any other pathological association.

RESULTS: Myocardial bridging was found in 89 of 350 (22.5%) patients. Most of the intramuscular segments were of the superficial type and found in the mid left anterior descending (LAD) (24.6%), followed by distal LAD (3.7%), diagonal branches (2%), ramus intermedius artery (1.4%) and obtuse marginal artery (0.8%). No myocardial bridging was detected in the right coronary or circumflex arteries. No significant differences were found between males and females (P = 0.14). Coronary artery atherosclerosis was found in 51 of 89 (57.3%) patients with MB. Atherosclerotic plaques were not detected in the intramuscular or distal segment of bridging arteries. Dynamic compression was observed in 35 (94.5%) patients with full encasement. No evidence of myocardial hypoperfusion was found in the territories supplied by the bridging arteries.

CONCLUSION: CCTA is excellent in analyzing myocardial bridging in a Saudi population and the results are comparable to other populations. However, finding the real incidence may need a large multicenter study.

Apical hypertrophic cardiomyopathy: correlations between echocardiographic parameters, angiographic left ventricular morphology, and clinical outcomes

BACKGROUND

Echocardiographic parameters could be implicated in the development of apical asynergy (characterized by apical sequestration or apical aneurysm) and worse cardiovascular outcome in patients with apical hypertrophic cardiomyopathy (ApHCM).

HYPOTHESIS

Echocardiographic parameters and morphological patterns of left ventriculograms are associated with cardiovascular morbidity and mortality in patients with ApHCM.

METHODS

We followed 47 cases with echocardiographically documented ApHCM. Echocardiographic findings of the extent and degree of hypertrophy, sustained cavity obliteration, and paradoxical diastolic jet flow were measured. All patients underwent a cardiac catheterization except for the cases whose informed consent was not acquired. The clinical manifestations were assessed and recorded by the attending physicians during 35.4 ± 23.7 months follow-up.

RESULTS

Among the 47 patients with ApHCM, 30 patients presented as the "pure" form and 17 patients present as the "mixed" form. Seventeen of 28 patients with sustained cavity obliteration showed paradoxical flow by echocardiography. Thirty-one underwent left ventriculograms and showed morphological abnormalities, including "ace-of-spades" configuration (15/31), apical sequestration (12/31), and apical aneurysm (4/31). The results demonstrated that cardiovascular morbidities occurred in 21 of 47 patients and were closely related to the presence of mixed form ApHCM, cavity obliteration, and paradoxical flow by univariate and multivariate Cox analysis. During the period of follow-up, 4 patients (9.5%) died, and among them 3 had concomitant apical aneurysm.

CONCLUSIONS

We concluded that detection of cavity obliteration and paradoxical flow and discrimination of pure form from mixed form by echocardiography, as well apical sequestration from apical aneurysm in ApHCM patients, is warranted.