Classification of "Athlete's Heart" using machine learning of conventional 12-lead ECG: male elite 3,000-m runner data in the CHIEF study. - Fan, Chia-Hao; Chen, Chin-Fen; Huang, Wei-Chun; Kwon, Younghoon; Sui, Xuemei; Lavie, Carl J.; Lin, Gen-Min (Frontiers in Sports & Active Living, 2026)