Abstract Body (Do not enter title and authors here): Introduction: Superficial myocardial bridging (MB) and intracavitary course (IC) of the left anterior descending artery (LAD) are considered benign conditions. Small segment bridging is common at the proximal and distal ends of the IC where the artery enters and exits the right ventricular cavity. However, a longer course of MB before IC and presentation as angina-like pain are rarely described, making the case unique.

Case Summary: A female in her 30s presented with left-sided chest pain radiating to the left upper limb. ECG, echocardiography, and chest x-ray were normal. Given her age, non-smoking status, and angina-like presentation, she was referred for CT coronary angiography to look for any structural cardiac or coronary anomaly. CT showed no hemodynamically significant plaque. However, a variant course of LAD was noted, with 12 mm long and 1-2 mm deep MB affecting the mid-segment of LAD. MB continued as IC for 17 mm length along the mid-to-distal course of LAD in the right ventricular cavity between the free and septal walls of the chamber. Long-segment mild-to-moderate stenosis was noted in the affected segments (MB and IC) on diastolic reconstruction with mild pre- and post-stenotic dilatation of LAD.

IC is difficult to recognize in conventional angiography. We noticed two important imaging features in this case that can act as clues for the identification of this variant on conventional angiography. One was a subtle secondary curve noted at the level of IC. The other was a relatively posterior position of LAD with respect to the great cerebral vein and a demonstrable increased distance between them. The patient was managed medically and counseled in cardiology.

Discussion: MB and IC are often labeled as benign conditions.MB is an important differential in young, non-smoking patients who are at low risk of developing atherosclerosis. It can present with angina-like chest pain, acute coronary syndromes, arrhythmias, or sudden cardiac death. Medical management of the condition includes beta-blockers and calcium channel blockers. Percutaneous intervention with drug-eluting stents or surgical myotomy of the bridge is advised in refractory cases. IC poses a risk of injury during cardiac procedures. If not correctly identified, It can lead to myocardial ischemia or coronary fistula causing volume overload and heart failure. Imaging clues, mentioned above on CT of the current case, can help identify IC in non-suspecting cases during cardiac procedures.