ALCAPA syndrome: a rare cause of sudden cardiac arrest in adulthood?—a case report

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare coronary artery anomaly occurring in approximately 1 in 300,000 live births. Typically diagnosed in infancy, ALCAPA can lead to significant cardiovascular complications, including myocardial ischemia, heart failure, and sudden cardiac death if untreated. The adult form of ALCAPA is less common and often identified incidentally through modern cardiac imaging techniques. We describe the case of a 30-year-old white German woman who suffered an out-of-hospital cardiac arrest. Immediate resuscitation was performed, and after successful defibrillation, she was stabilized. Initial hospital assessments, including electrocardiogram (ECG) and echocardiography, showed no abnormalities. However, coronary computed tomography (CT) angiography revealed that the left anterior descending coronary artery (LAD) originated from the pulmonary artery, confirming a diagnosis of ALCAPA. Additionally, an anomaly in the circumflex artery (CX) was discovered, which originated from the right coronary artery (RCA) and ran retroaortically to the lateral wall of the left ventricle. A persistent foramen ovale (PFO) was suspected. Cardiac magnetic resonance imaging (MRI) showed no signs of myocardial scarring. Therefore, additional genetic testing was recommended to evaluate potential non-ischemic causes of the cardiac arrest. The patient underwent successful surgical revascularization of the LAD using the left internal thoracic artery (LIMA) and closure of PFO. Post-surgery, the patient commenced rehabilitation and an implantable cardioverter-defibrillator (ICD) was implanted. This case highlights the complexities in diagnosing and managing ALCAPA in adults. While most patients with ALCAPA present during infancy with heart failure or myocardial ischemia, survival into adulthood without symptoms is rare and depends on the development of extensive collateral circulation. Adult presentation with sudden cardiac arrest in a previously healthy individual is particularly uncommon and poses significant diagnostic challenges. Treatment is typically surgical but must be tailored to the individual, especially in older adults who may benefit from conservative management. This case underscores the importance of interdisciplinary decision-making in the management of ALCAPA to ensure optimal patient outcomes and the importance of advanced cardiac imaging in unexplained cardiac arrest in young adults.