Heart of Scale: Why Bigger ECG Models Don’t Always Beat Better Biases A hospital does not buy an ECG model because it enjoys leaderboard furniture. It buys one because somebody wants a cheap, reliable signal from a noisy waveform: rhythm abnormality, structural heart disease, ICU risk, mortality risk, maybe a demographic or physiological clue that was not explicitly labeled during pre-training. ...
Cost is not always about size. That is an inconvenient sentence for anyone trying to sell a larger medical foundation model by waving parameter counts like a hospital procurement trophy. In ECG modeling, the expensive question is not simply whether one can pretrain on more recordings. The harder question is whether the model architecture and pretraining task actually match the structure of the signal. ...
ECG models have a deceptively simple job: read a heartbeat and infer what might be wrong. The real problem is that a heartbeat is not a single line of data. A standard 12-lead ECG is a coordinated view of cardiac electrical activity from multiple spatial angles. Meanwhile, the associated clinical report is not a clean label. It is a human-written summary: useful, compressed, inconsistent, and occasionally full of stylistic residue. Medicine, regrettably, still contains humans. ...