Utility of the AngelMed Guardian System in myocardial bridging: a case report

Myocardial bridging (MB) is a known congenital anomaly in which a segment of the coronary artery transverses from the epicardium through the myocardium. MB may clinically manifest as recurrent angina, acute coronary syndrome, ventricular dysrhythmia, and even sudden cardiac death. On electrocardiogram (EKG), MB can present with findings consistent with significant ST-segment changes. The AngelMed Guardian System (the Guardian device) was developed in an effort to optimize the time from the onset of myocardial ischemia to intervention. The device analyzes myocardial electrical changes and alerts the patient to seek emergent medical evaluation if an acute ST-segment deviation is detected. We describe the first documented case of the Guardian device detecting acute ST-segment changes secondary to myocardial bridging.

A 50-year-old male, with a history of percutaneous coronary intervention of the proximal left anterior descending (LAD) artery, presented to his cardiologist's office with reports of recurrent, atypical chest pain. The Guardian device was implanted. One month after implantation, the patient experienced chest pain and was alerted by the Guardian device to seek emergent medical evaluation. Initial EKG and high-sensitivity troponins were negative for acute ischemia. Guardian device interrogation revealed significant ST depressions, encouraging further ischemic evaluation. The exercise myocardial perfusion imaging revealed an apical reversible defect. Left heart catheterization revealed a large segment of mid-LAD MB with the patient's previous LAD stent noted to be widely patent along with no evidence of new obstructive coronary disease. Following the identification of the MB, medication regimen adjusted and the patient denied recurrence of chest pain or Guardian alerts.

We describe the first documented case of the Guardian device detecting acute ST-segment changes that were secondary to myocardial bridging. The Guardian device appropriately documented an ischemic event not appreciated with initial EKG or troponin testing. With the assistance of the Guardian device, we were able to rapidly identify MB as the cause for the ischemic EKG changes and subsequent abnormal stress test, optimize medical management, and prevent recurrent atypical chest pain along with office and hospital visits.