Data distribution impacts the performance and generalisability of contrastive learning-based foundation models of electrocardiograms. - Gul Rukh Khattak; Konstantinos Patlatzoglou; Joseph Barker; Libor Pastika; Boroumand Zeidaabadi; Ahmed El-Medany; Hesham Aggour; Yixiu Liang; Antônio H. Ribeiro; Jeffrey Annis; Antônio Luiz Pinho Ribeiro; Junbo Ge; et al. (CoRR, 2025)