Myocardial Bridging

Acute myocardial infarction or Takotsubo syndrome in a patient with stunned myocardium due to myocardial bridging? A case report of diagnostic dilemma clarified after serial workup

BACKGROUND

Myocardial bridging is a cardiac anomaly where a segment of epicardial coronary arteries runs through the myocardium and can rarely cause MI. Takotsubo syndrome is a stress-induced cardiomyopathy that can mimic MI. Catecholamine surge during stress can contribute to Takotsubo syndrome, but whether this surge can trigger an inconspicuous myocardial bridging to manifest symptomatically remains unclear, and alternately, whether a myocardial bridge might cause worsening of Takotsubo syndrome is also a matter that needs further research.

CASE PRESENTATION

We report the case of a patient who initially presented with features of acute exacerbation of bronchiectasis and subsequently developed symptoms and ECG features suggestive of acute myocardial infarction. Echocardiography revealed features of takotsubo syndrome, and complete myocardial bridging was revealed via coronary angiography. The patient was managed conservatively with pharmacological treatment, and after a few days, echocardiographic features were reversed. As such, the diagnosis shifted toward Takotsubo syndrome with myocardial stunning due to co-existent myocardial bridging.

CONCLUSION

We report a rare case of a patient with acute bronchiectasis exacerbation with features suggestive of acute myocardial infarction who had findings of Takotsubo syndrome and complete myocardial bridging. In the beginning, it was difficult to determine whether the symptoms arose due to acute MI resulting from myocardial bridging or were solely due to takotsubo syndrome because of stress from bronchiectasis. Although myocardial bridging is often overlooked as an etiology for acute MI, this case highlights the importance of expanding the differential diagnosis to myocardial bridging in the work-up for the cause of acute MI and how Takotsubo syndrome can mimic acute MI and pose a diagnostic challenge.

Mid-ventricular Takotsubo Cardiomyopathy With Coexisting Myocardial Bridge

Typical takotsubo cardiomyopathy (TCM) is a reversible form of myocardial injury that presents with a characteristic ballooning abnormality of the left ventricular apex. Typical TCM has been associated with myocardial bridging; however, mid-ventricular variant TCM has not. We describe a rare case of mid-ventricular variant TCM with a coexisting left anterior descending artery myocardial bridge and discuss management strategies. Furthermore, we propose potential pathophysiological mechanisms that may contribute to the symptomatic presentation of both conditions as a manifestation of common etiological factors.

Acute Myocardial Infarction Due to Myocardial Bridge Treated With Surgery: a Case Report

Myocardial bridging is congenital anomaly characterized by segment of epicardial coronary arteries passing through the myocardium. Various ischemic conditions are related with this pathology. We report a case of myocardial bridging that was complicated with acute anterior myocardial infarction and a review of the literature. The patient was treated successfully with coronary bypass graft surgery after unsuccessful percutaneous intervention.

A Morphological Study of Myocardial Bridges in the Fetal Heart

Introduction:Myocardial bridges (MB) are congenital anomalies of hearts observed as muscle fibers covering epicardial branches of the coronary artery. The left anterior descending artery (LAD) was found to be commonly showing myocardial bridges (MBs). Clinically, MBs were claimed to cause varied symptomatology. The data on the morphology and prevalence of MBs in fetuses was limited, despite the commonly accepted congenital origin. Material and methods:Fetal hearts obtained from 37 fetuses from the donation program were used. The hearts were dissected out from the thorax by standard dissection procedure. The pericardium and epicardium were dissected. The coronary arteries were delineated, and MBs were observed and noted. The coronary artery segment having MBs, its distance from the ostium as well as the direction and length of the MBs were studied. Results:The MBs were observed in 20 out of 37 fetal hearts studied over the left anterior descending, right coronary, posterior interventricular and circumflex arteries. The mid or distal part of the coronary arteries frequently exhibited MBs. The mean length of the MB was 4.2 mm, with MBs being situated about 1.5 cm away from the coronary ostium. The oblique pattern of MB was more frequently noted. Conclusion:The morphology and prevalence of fetal MBs showed common occurrence in the LAD artery, with a predominant oblique morphological pattern.

Comprehensive functional and anatomic assessment of myocardial bridging: Unlocking the Gordian Knot

Myocardial bridging (MB) is the most frequent congenital coronary anomaly in which a segment of an epicardial coronary artery takes a tunneled course under a bridge of the myocardium. This segment is compressed during systole, resulting in the so-called "milking effect" at coronary angiography. As coronary blood flow occurs primarily during diastole, the clinical relevance of MB is heterogeneous, being usually considered an asymptomatic bystander. However, many studies have suggested its association with myocardial ischemia, anginal symptoms, and adverse cardiac events. The advent of contemporary non-invasive and invasive imaging modalities and the standardization of intracoronary functional assessment tools have remarkably improved our understanding of MB-related ischemia, suggesting the role of atherosclerotic lesions proximal to MB, vasomotor disorders and microvascular dysfunction as possible pathophysiological substrates. The aim of this review is to provide a contemporary overview of the pathophysiology and of the non-invasive and invasive assessment of MB, in the attempt to implement a case-by-case therapeutic approach according to the specific endotype of MB-related ischemia.

Sudden Death without a Clear Cause after Comprehensive Investigation: An Example of Forensic Approach to Atypical/Uncertain Findings

Sudden death (SD) is defined as the unexpected natural death occurred within an hour after the onset of symptoms or from the last moment the subject has been seen in a healthy condition. Brugada syndrome (BrS) is one of the most remarkable cardiac causes of SD among young people. We report the case of a 20-year-old man who suddenly died after reportedly having smoked cannabis. Autopsy, toxicology, and genetic testing were performed. Autopsy found a long and thick myocardial bridging (MB) at 2 cm from the beginning of the left anterior descending coronary artery. Furthermore, at the histopathological examination, fibrosis and disarray in myocardial area above the MB, fatty tissue in the right ventricle and fibrosis of the sino-atrial node area were found. Toxicology testing was inconclusive, while genetic testing found a rare missense variant of the TTN gene, classified as likely benign, and a variant of unknown significance in the SLMAP gene (a gene that can be associated with BrS). Hence, despite several atypical features were found, no inference on the cause of the death could be made under current evidence.

Update on the Diagnostic Pitfalls of Autopsy and Post-Mortem Genetic Testing in Cardiomyopathies

Inherited cardiomyopathies are frequent causes of sudden cardiac death (SCD), especially in young patients. Despite at the autopsy they usually have distinctive microscopic and/or macroscopic diagnostic features, their phenotypes may be mild or ambiguous, possibly leading to misdiagnoses or missed diagnoses. In this review, the main differential diagnoses of hypertrophic cardiomyopathy (e.g., athlete's heart, idiopathic left ventricular hypertrophy), arrhythmogenic cardiomyopathy (e.g., adipositas cordis, myocarditis) and dilated cardiomyopathy (e.g., acquired forms of dilated cardiomyopathy, left ventricular noncompaction) are discussed. Moreover, the diagnostic issues in SCD victims affected by phenotype-negative hypertrophic cardiomyopathy and the relationship between myocardial bridging and hypertrophic cardiomyopathy are analyzed. Finally, the applications/limits of virtopsy and post-mortem genetic testing in this field are discussed, with particular attention to the issues related to the assessment of the significance of the genetic variants.

Challenges in Evaluation and Management of Children with Myocardial Bridging

Myocardial bridging (MB) is a congenital anomaly where a coronary artery branch or group of branches extends inside a tunnel consisting of myocardium. Although it is mostly considered "benign," it is reported that MB may lead to significant cardiac problems and sudden cardiac deaths. While it is a congenital anomaly, its symptoms usually arise at further ages rather than childhood. The literature on MB in children is in the form of case reports or small case series. This is why pediatric cases are assessed in the light of information obtained from adults. This review compiled the literature on MB in adults and children and compared it, as well as discussing questions arising regarding the clinic, diagnosis, and treatment of MB.

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.

Myocardial bridging: non-invasive diagnostics and management

The article discusses a case of episodes of asymptomatic ST-T depression during exercise in a 37-year-old patient with complaints of irregular heartbeat, tachycardia up to 100 bpm, not related to exercise. According to contrast-enhanced multislice computed tomography, in the middle third, a muscle bridge with stenosis of up to 30% was found. The diagnosis was made: Congenital coronary artery anomaly: transmyocardial muscular bridge of the middle third of left anterior descending artery with stenosis up to 30%. Class 1 silent myocardial ischemia. Stage 0, class 0 chronic heart failure. Using non-invasive coronary imaging, it was possible to identify the cause of transient ST-T depression and to choose the appropriate therapy.

Plaque herniation after stenting the culprit lesion with myocardial bridging in ST elevation myocardial infarction: A case report

BACKGROUND

Myocardial bridging (MB) is increasingly recognized to stimulate atherogenesis, which may contribute to an acute coronary syndrome. Stenting the coronary segment with MB has been recognized to have an increased risk of in-stent restenosis, stent fracture and coronary perforation. The safety and efficacy of stenting the culprit lesion with overlaying MB in ST elevation myocardial infarction (STEMI) as primary reperfusion therapy has not been established.

CASE SUMMARY

We reported a patient who presented with inferior STEMI with a culprit lesion of an acute thrombotic occlusion in the right coronary artery and thrombolysis and thrombin inhibition in myocardial infarction 0 flow. After the stent placement during primary percutaneous coronary intervention, intravascular ultrasound revealed MB overlying the stented segment where heavy atherosclerotic plaque were present. Likely due to the combination of plaque herniation or prolapse caused by MB, as well as local increased inflammation and thrombogenicity, acute stent thrombosis occurred at this region, which led to acute stent failure. The patient required an emergent repeated cardiac catheterization and placing a second layer of stent to enhance the radial strength and reduce the inter-strut space.

CONCLUSION

Plaque herniation or prolapse after stenting a MB segment in STEMI is a potential etiology for acute stent failure.