"Two for One", Novel Dual Left Anterior Descending Artery (LAD) Variant: Type XIII.

Dual left anterior descending artery (LAD) is a rare phenomenon that occurs in less than one percent of the population. To date, 12 variants have been identified. Proper identification of coronary vessels is crucial in emergent situations that require prompt action, such as percutaneous coronary intervention (PCI). We propose that our case highlights a novel 13th (type XIII) variant. We present the case of a 57-year-old African American woman with a past medical history of hypertension, glaucoma, cerebral vascular accident, dyslipidemia who presented to the ED complaining of atypical chest pain for one day duration. Electrocardiography showed normal sinus rhythm at 60 beats per minute (bpm), normal axis, normal intervals, no acute ischemic changes, and an isolated T wave inversion in DIII. Cardiac markers were within normal limits. The patient was started on aspirin 81mg, atorvastatin 40mg, and restarted on amlodipine 5mg. Echocardiography showed a left ventricular ejection fraction (LVEF): 65%, normal right ventricular size and systolic function, mild mitral valve regurgitation, and mild aortic regurgitation. Computed tomographic (CT) angiography showed a novel subtype of dual LAD, the left circumflex and right coronary arteries were patent. The patient was discharged once stabilized and advised to follow up with cardiology. Dual LAD describes a rare anatomic variant in which two coronary branches, known as short and long LAD arteries, supply the territory normally supplied by the solitary LAD artery. To date, 12 variants of dual LAD, classified by origin and course of the short and long LAD arteries, have been described in the literature. To the best of our knowledge, the current case describes a novel subtype of dual LAD, variant XIII. The LAD originates as usual from the left main coronary artery (LMCA) and initially runs in the anterior interventricular groove for a short course before bifurcating into two long LADs which both leave the interventricular groove and course out to the apex. One of the vessels courses laterally and the other courses medially of the interventricular groove. It is pertinent to identify the coronary vessels accurately before certain interventions are taken. Acknowledgement of this phenomenon can help guide accurate management in the future for patients with this condition.