I also remember the time between Christmas and New Year being very busy - I thought for a similar reason - people understandably just don't want to be in hospital for Christmas.
E.g., using sensors that are cheap, and are less invasive than EKG electrodes. Kinda like the way Apple watches can now continuously monitor stuff
The problem obviously with heart attacks is the implications of false negatives and positives are huge, and the tracing from a watch would be less reliable than the gold-standard ECG / EKG.