Background and aims Anomalous origin of a coronary artery (AOCA) from the inappropriate sinus of Valsalva or from the pulmonary artery is increasingly diagnosed with current imaging techniques. Although most AOCA subtypes are benign, they can rarely cause sudden cardiac death (SCD). The aim of the study was to describe the clinical and pathological features of AOCA in SCD victims.

Methods We reviewed a database of 5100 consecutive cases of SCDs referred to our specialist cardiac pathology centre between 1994 and March 2017 and identified a subgroup of 30 (0.6%) cases with AOCA. All cases underwent detailed post-mortem evaluation including histological analysis by an expert cardiac pathologist. Clinical information was obtained from referring coroners.

Results The mean age was 28±16 years and 23 individuals were males (77%). In 8 (27%) cases SCD occurred before 18 years of age. Cardiac symptoms were present in 11 (37%) individuals and syncope was the most common (n=6, 20%). The mean heart weight was 367±115 g. The most common anomalies were anomalous left coronary artery arising from the right sinus of Valsalva (ALCA) with inter-arterial course (n=11) and anomalous right coronary artery arising from the left sinus of Valsalva (ARCA) with inter-arterial course (n=11). Anomalous left coronary artery arising from pulmonary artery (ALCAPA) was present in 7 cases, while in 1 case the LCA arose from the non-coronaric cusp. Death occurred during exercise in 14 (47%) cases. The AOCA variant where death occurred more frequently during physical activity was ALCA (7/11, 64%), followed by ALCAPA (4/7, 57%) and ARCA (2/11, 18%).

Conclusions AOCA is a rare cause of SCD. Anomalous left or right coronary artery arising from the wrong sinus of Valsalva with inter-arterial course is the most common anatomical variant recognised at the post-mortem of SCD victims. While in ALCA death is commonly associated with exercise, in ARCA death occurs usually during rest or sleep.