Fig. 1: Model development: NYP multicentre cohort derivation.

The deep learning model was trained and tested using data from an eight-hospital system (NYP Hospital). ECG data were accessed using the MUSE system with removal of ECGs with missing age, sex and patient identifier, poor study quality designation by machine recommending repeating of ECG or presence of ventricular pacing. Echocardiogram data were accessed using hospital systems with removal of patients with repaired or replaced heart failures. This yielded 1.2 million ECG–echocardiogram pairs in 230,018 unique patients with data split into train, validation and test sets.