Abstract
BACKGROUND: Despite the electrocardiogram (ECG) being a critical bedside diagnostic tool, evidence suggests suboptimal ECG interpretation competence among doctors worldwide. Limited research exists evaluating the ECG interpretation skills of South African junior doctors. This study addresses an important knowledge gap in the literature which assesses the knowledge of "must-know" ECG conditions of junior South African doctors, previously identified through a Delphi study. METHODS: This cross-sectional survey assessed ECG interpretation competence among 117 junior doctors across four public hospitals in Gauteng Province, South Africa. Data were collected over the period December 2024 to November 2025. Respondents completed a 20-question assessment based on consensus-derived "must-know" ECG diagnoses for medical students adapted from Viljoen's Delphi study, which identified ECG teaching priorities for medical schools using expert consensus performance was analysed according to professional category, training background, and emergency medicine exposure. RESULTS: Overall mean score was 10.3/20 (51.5%), with only 34.2% achieving the predefined pass standard of 75%. Community service doctors outperformed interns (57.1% vs 49.1-49.3%) though not significantly (p = 0.194). Formal ECG training significantly improved performance: 62.1% versus 52.9% self-taught and 39.4% untrained (p < 0.001). Critical diagnostic deficiencies included polymorphic ventricular tachycardia; monomorphic ventricular tachycardia; second and third-degree heart blocks. The lowest-scoring ECGs were right ventricular hypertrophy, pericarditis, sinus arrhythmia, and first-degree AV block. Emergency medicine exposure showed dose-response trend (53.7% vs 42.1% vs 36.3%) without statistical significance (p = 0.109) due to sample imbalance (n = 106, 7, 4). CONCLUSION: Junior doctors in Gauteng demonstrated ECG interpretation deficiencies for life-threatening conditions such as poly and monomorphic ventricular tachycardia, and second and third-degree heart blocks. The lowest-scoring ECGs were those with pericarditis and right ventricular hypertrophy. Despite these findings, this study suggests that formal ECG training improves ECG diagnostic performance which has significant implications for curriculum development.