| Age | HR (bpm) | QRS axis (degrees) | PR interval (sec) | QRS interval (sec) | R in V1 (mm) | S in V1 (mm) | R in V6 (mm) | S in V6 (mm) |
| 1st wk | 90-160 | 60-180 | 0.08-0.15 | 0.03-0.08 | 5-26 | 0-23 | 0-12 | 0-10 |
| 1-3 wk | 100-180 | 45-160 | 0.08-0.15 | 0.03-0.08 | 3-21 | 0-16 | 2-16 | 0-10 |
| 1-2 mo | 120-180 | 30-135 | 0.08-0.15 | 0.03-0.08 | 3-18 | 0-15 | 5-21 | 0-10 |
| 3-5 mo | 105-185 | 0-135 | 0.08-0.15 | 0.03-0.08 | 3-20 | 0-15 | 6-22 | 0-10 |
| 6-11 mo | 110-170 | 0-135 | 0.07-0.16 | 0.03-0.08 | 2-20 | 0.5-20 | 6-23 | 0-7 |
| 1-2 yr | 90-165 | 0-110 | 0.08-0.16 | 0.03-0.08 | 2-18 | 0.5-21 | 6-23 | 0-7 |
| 3-4 yr | 70-140 | 0-110 | 0.09-0.17 | 0.04-0.08 | 1-18 | 0.5-21 | 4-24 | 0-5 |
| 5-7 yr | 65-140 | 0-110 | 0.09-0.17 | 0.04-0.08 | 0.5-14 | 0.5-24 | 4-26 | 0-4 |
| 8-11 yr | 60-130 | -15-110 | 0.09-0.17 | 0.04-0.09 | 0-14 | 0.5-25 | 4-25 | 0-4 |
| 12-15 yr | 65-130 | -15-110 | 0.09-0.18 | 0.04-0.09 | 0-14 | 0.5-21 | 4-25 | 0-4 |
| >16 yr | 50-120 | -15-110 | 0.12-0.20 | 0.05-0.10 | 0-14 | 0.5-23 | 4-21 | 0-4 |
References
Abdulla R, Bonney W, Khalid O, Awad S. Pediatric Electrocardiography Cham. Springer International Publishing; 2016. [book]