Abstract Background Coronary artery anomalies are uncommon but clinically important causes of arrhythmia and ischemia. Anomalous origin of the left circumflex artery from the right pulmonary artery is rare, requiring advanced imaging for diagnosis. Case A 48-year-old male with a history of ventricular bigeminy and obstructive sleep apnea presented for evaluation of symptomatic premature ventricular contractions (PVCs). Initial ambulatory Holter monitoring demonstrated a high PVC burden (34%), rare atrial ectopy, and non-sustained supraventricular tachycardia. Transthoracic echocardiography revealed mildly reduced left ventricular systolic function (EF 45-50%). Following beta blocker initiation, the patient developed progressive dyspnea, palpitations, and functional impairment, prompting therapy discontinuation. Coronary angiography, pursued for abnormal stress testing and ischemic evaluation, revealed an inability to engage the Left Circumflex Artery (LCx), raising suspicion for a congenital coronary anomaly. Cardiovascular computed tomography (CCT) was subsequently performed, which delineated an anomalous origin of the LCx from the right pulmonary artery (RPA), with collateral retrograde perfusion from a dominant right coronary artery (RCA). Discussion Congenital coronary anomalies represent a heterogeneous group of rare but clinically significant malformations, with an overall prevalence below 2% in the general population. Among these, anomalous origin of the LCx from RPA is exceedingly rare, with only isolated cases described in the literature. Although often asymptomatic, anomalous coronary origins can precipitate arrhythmias, myocardial ischemia, or even sudden cardiac death, particularly when myocardial territories rely on collateral perfusion. In this case, the patient’s high PVC burden, coupled with the inability to engage the LCx during invasive coronary angiography, raised suspicion of an anomalous coronary course. While invasive angiography remains the reference standard for coronary evaluation, it may be limited in visualizing anomalous vessels originating from non-aortic structures. In such scenarios, CCT provides unparalleled anatomic detail, offering high spatial resolution and three-dimensional reconstructions critical for delineating anomalous coronary pathways. In our patient, CCT was pivotal not only in confirming the anomalous origin of the LCx from the RPA but also in identifying a dominant RCA providing retrograde collateral perfusion to the LCx territory.Recognition of such anomalies has important implications for risk stratification, procedural planning, and long-term management. Furthermore, cases like this reinforce the indispensable role of multimodality imaging in contemporary cardiovascular diagnostics, particularly when conventional techniques are inconclusive or misleading. Thus, CCT imaging served as the definitive modality in characterizing a rare congenital anomaly in a patient evaluated for arrhythmia, emphasizing the transformative impact of noninvasive imaging technologies. This abstract is funded by: None
Hassan et al. (Fri,) studied this question.