The mean age at the time of the first (ECG 1) and last (ECG 2) available ECG recordings and the respective median PR intervals and QRS complex durations in ECG
| Mean age | SD | Median PR (ms) | Median QRS (ms) | |
| ECG 1 | 39.4 (n=57) | 12.3 | 200 (IQR=107) (n=43) | 96 (IQR=17) (n=37) |
| ECG 2 | 45.7 (n=37) | 12.3 | 226 (IQR=120) (n=31) | 100 (IQR=25) (n=32) |
PR, PR interval in ECG; QRS, QRS complex duration in ECG.