When Ebstein Meets Fallot: A Right-Sided ECG Puzzle.

CASE SUMMARY: A 14-year-old boy was admitted after resuscitated ventricular fibrillation. He had tetralogy of Fallot associated with Ebstein's anomaly, surgically repaired at age 7 without tricuspid intervention. His ECG demonstrates overlapping features of both conditions: high-amplitude right bundle branch block and right ventricular hypertrophy consistent with repaired tetralogy of Fallot, along with broad "Himalayan" P waves, first-degree atrioventricular block, and fragmented QRS complexes reflecting Ebstein-related conduction abnormalities. This electrocardiographic coexistence illustrates how dual congenital substrates may converge into a single electrical phenotype.

TAKE-HOME MESSAGES: An atypical ECG pattern in congenital heart disease may unmask an associated anomaly. Fragmented QRS in Ebstein's anomaly is a potential marker of increased arrhythmic risk.