Evaluation of intracoronary function after reduction of ventricular rate by esmolol in severe stenotic myocardial bridge: A case report.

Background: Severe stenotic myocardial bridges (MBs) have been reported to lead to intracoronary ischaemia, but the physiological evaluation of MBs using intracoronary function evaluation indicators after intraoperative drug treatment has not been fully established.

Case Summary: We performed through snuff fossa for coronary angiography in a patient with chest tightness after repeated exercise, and the results showed that the middle part of the anterior descending branch was a MB with 100% systolic compression. The intracoronary function evaluation (defined as the ratio of distal coronary pressure to aortic pressure with zero microcirculation resistance) was instantaneous wave-free ratio (IFR) without drug and fractional flow reserve (FFR) with adenosine. The IFR was 0.73, and the FFR was 0.66. Then esmolol 0.02 µg/kg/min was intravenously injected. The IFR and FFR were measured again when the heart rate dropped to 60 beats/min. The IFR was 0.83, and the FFR 0.65.

Conclusion: This case report is a case of isolated MB with severe stenosis. After intraoperative drug treatment decreased the ventricular rate, an increase in the coronary function evaluation index was immediately observed to confirm the effective improvement of coronary blood flow.