BACKGROUND: Holt-Oram syndrome (HOS) is a rare but significant syndrome consisting of structural heart defects, conduction abnormalities, and upper extremity anomalies. It was first described in the British Heart Journal in 1960 by Mary Holt and Samuel Oram as a report of atrial septal defect, conduction disturbances, and hand malformations occurring in family members. Patients can present with heart blocks or symptoms of underlying congenital heart defects.

CASE REPORT: A 41-year-old man with Holt-Oram syndrome presented with seizure-like activity and was found to have an underlying conduction disturbance. Physical exam showed bilateral atrophic upper extremities with anatomic disfiguration, and weakness of the intrinsic hand muscles. Cardiovascular exam revealed a slow heart rate with irregular rhythm. EKG showed sinus arrest with junctional escape rhythm. Cardiac catheterization revealed coronary anomalies, including absent left main coronary artery and separate ostia of the left anterior ascending and left circumflex coronary artery. Coronary arteries were patent. Following electrophysiology study, sick sinus syndrome and AV block were diagnosed, and the patient received implantation of a permanent pacemaker.

CONCLUSIONS: This patient presented with a seizure-like episode attributed to hypoxia during asystole from an underlying cardiac conduction defect associated with Holt-Oram syndrome. Arrhythmias and heart blocks are seen in these patients, and conduction defects are highly associated with congenital heart defects. Holt-Oram syndrome rarely presents with coronary artery anomalies. There is no reported case of separate coronary ostia and absent left main coronary artery. Prompt diagnosis is important since anomalies in coronary and upper extremity vasculature might be challenging for invasive procedures.

Keywords: Atrioventricular Block - diagnosis, Abnormalities, Multiple, Coronary Angiography, Coronary Vessel Anomalies - diagnosis, Heart Defects, Congenital - complications, Heart Septal Defects, Atrial - complications, Lower Extremity Deformities, Congenital - complications, Sick Sinus Syndrome - diagnosis, Upper Extremity Deformities, Congenital - complications