A child's ECG changes continuously with age: the heart rate, the electrical axis and the waveform in the newborn differ markedly from adult reference values and normalise gradually through childhood. The interpretation is made in the same systematic way as in adults, but against the age-specific reference values below.
Method of interpretation
- Heart rate
- Heart rhythm
- The P wave
- The PR interval
- The QRS complex
- The ST segment
- The T wave
- The U wave
- The QT interval (QTc)
Neonatal reference values
Davignon et al. The ranges are 98 % confidence intervals, with the mean given in parentheses.
| Age | < 1 day | 1–3 days | 3–7 days | 7–30 days | 1–3 months | 3–6 months | 6–12 months | 1–3 years | 3–5 years | 5–8 years | 8–12 years | 12–16 years | > 16 years |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Heart rate (beats/min) | 93–155 (122) | 91–158 (124) | 90–166 (128) | 106–182 (148) | 120–179 (149) | 105–185 (142) | 107–168 (132) | 90–151 (119) | 73–137 (108) | 65–133 (100) | 63–129 (92) | 66–120 (86) | 50 – 120 |
| Electrical axis (degrees) | 58–168 (>135) | 65–171 (>134) | 76–168 (>133) | 65–159 (110) | 31–115 (75) | 7–105 (60) | 7–98 (54) | 8–100 (55) | 7–104 (55) | 10–140 (66) | 9–115 (61) | 11–133 (58) | -15 – 110 |
| QRS duration | 21–76 | 22–67 | 21–68 | 22–79 | 23–75 | 22–79 | 23–76 | 27–75 | 30–72 | 32–79 | 32–85 | 34–88 | 0.05 – 0.10 |
| PR interval | 79–160 (107) | 81–139 (108) | 75–137 (104) | 73–138 (101) | 73–130 (98) | 74–145 (106) | 73–156 (156) | 82–148 (114) | 85–161 (118) | 90–164 (124) | 87–171 (128) | 92–175 (135) | 0.12 – 0.20 |
| Q in III (mm) | 0.1–5 | 0.1–5 | 0.1–5 | 0.1–5 | 0.1–5 | <6.6 | <6.3 | <5.3 | <4.2 | <3.2 | <2.7 | <3.0 | <3 |
| R in V1 (mm) | 5–27 (14) | 5–27 (15) | 3–25 (13) | 3–22 (11) | 3–19 (10) | 3–20 (10) | 2–20 (9) | 3–18 (9) | 2–18 (8) | 1–13 (7) | 0.5–10 (6) | 0.5–10 (5) | 0.5 – 14 |
| S in V1 (mm) | 0.5–23 (9) | 0.5–21 (10) | 0.5–17 (7) | 0.5–12 (4) | 0.5–13 (5) | 0.5–17 (6) | 0.5–18 (7) | 1–21 (9) | 2–22 (10) | 3–24 (12) | 3–26 (12) | 3–22 (11) | 0.5 – 23 |
| R/S ratio in V1 | 0.2–9.8 (2.3) | 0.2–6.0 (2.0) | 0.2–9.8 (2.8) | 1.0–7.0 (2.9) | 0.3–7.5 (2.3) | 0.2–6.0 (2.4) | 0.1–3.9 (1.8) | 0.1–4.2 (1.4) | 0–2.8 (0.9) | 0–2.0 (0.8) | 0–1.9 (0.6) | 0–1.8 (0.5) | |
| R in V6 (mm) | 0–12 (5) | 0.1–12 (5) | 0.5–12 (5) | 3–17 (8) | 5–22 (12) | 6–23 (14) | 6–23 (13) | 6–23 (14) | 9–25 (15) | 9–27 (17) | 10–26 (17) | 7–23 (15) | 4 – 21 |
| S in V6 (mm) | 0.2–10 (4) | 0.2–10 (3) | 0.4–10 (4) | 0.2–10 (3) | 0.3–7 (3) | 0.2–10 (3) | 0.2–8 (2) | 0.1–7 (2) | 0.1–6 (2) | 0.1–4 (1) | 0.0–4 (1) | 0–4 (1) | 0 – 4 |
| R/S ratio in V6 | 0.5–9 (2.5) | 0.5–11 (3) | 0.5–10 (2.5) | 0.5–12 (4) | 0.5–12 (4.5) | 0.5–18 (6.5) | 0.5–22 (8) | 0.5–28 (9.5) | 0.8–30 (11) | 1–30 (12) | 2–33 (14) | 2–39 (15) |
Children, overview
Rijnbeek et al. Median values with the 2nd and 98th percentiles.
| 0–1 month | 1–3 months | 3–6 months | 6–12 months | 1–3 years | 3–5 years | 5–8 years | 8–12 years | 12–16 years | ||
|---|---|---|---|---|---|---|---|---|---|---|
| Heart rate (beats/min) | Boys | 160 (129, 192) | 152 (126, 187) | 134 (112, 165) | 128 (106, 194) | 119 (97, 155) | 98 (73, 123) | 88 (62, 113) | 78 (55, 101) | 73 (48, 99) |
| Girls | 155 (136, 216) | 154 (126, 200) | 139 (122, 191) | 134 (106, 187) | 128 (95, 178) | 101 (78, 124) | 89 (68, 115) | 80 (58, 110) | 76 (54, 107) | |
| P wave axis | Boys | 56 (13, 99) | 52 (10, 73) | 49 (–5, 70) | 49 (9, 87) | 48 (–12, 78) | 43 (–13, 69) | 41 (–54, 72) | 39 (–17, 76) | 40 (–24, 76) |
| Girls | 52 (24, 80) | 48 (20, 77) | 51 (16, 80) | 50 (14, 69) | 47 (1, 90) | 44 (–6, 90) | 42 (–13, 77) | 42 (–15, 82) | 45 (–18, 77) | |
| P wave duration | Boys | 78 (64, 85) | 79 (65, 98) | 81 (64, 103) | 80 (66, 96) | 80 (63, 113) | 87 (67, 102) | 92 (73, 108) | 98 (78, 117) | 100 (82, 118) |
| Girls | 79 (69, 106) | 78 (62, 105) | 78 (63, 106) | 80 (64, 07) | 83 (62, 104) | 84 (66, 101) | 89 (71, 107) | 94 (75, 114) | 98 (78, 122) | |
| PR interval (ms) | Boys | 99 (77, 120) | 98 (85, 120) | 106 (87, 134) | 114 (82, 141) | 118 (86, 151) | 121 (98, 152) | 129 (99, 160) | 134 (105, 174) | 139 (107, 178) |
| Girls | 101 (91, 121) | 99 (78, 133) | 106 (84, 127) | 109 (88, 133) | 113 (78, 147) | 123 (99, 153) | 124 (92, 156) | 129 (103, 163) | 135 (106, 176) | |
| Electrical axis (QRS axis, degrees) | Boys | 97 (75, 140) | 87 (37, 138) | 66 (–6, 107) | 68 (14, 122) | 64 (–4, 118) | 70 (7, 112) | 70 (–10, 112) | 70 (–21, 114) | 65 (–9, 112) |
| Girls | 110 (63, 155) | 80 (39, 121) | 70 (17, 108) | 67 (1, 102) | 69 (2, 121) | 69 (3, 106) | 74 (27, 117) | 66 (5, 117) | 66 (5, 101) | |
| QRS duration (ms) | Boys | 67 (50, 85) | 64 (52, 77) | 66 (54, 85) | 69 (52, 86) | 71 (54, 88) | 75 (58, 92) | 80 (63, 98) | 85 (67, 103) | 91 (78, 111) |
| Girls | 67 (54, 79) | 63 (48, 77) | 64 (50, 78) | 64 (52, 80) | 68 (54, 85) | 71 (58, 88) | 77 (59, 95) | 82 (66, 99) | 87 (72, 106) | |
| QTc interval (ms, by Bazett's formula) | Boys | 413 (378, 448) | 419 (396, 458) | 422 (391, 453) | 411 (379, 449) | 412 (383, 455) | 412 (377, 448) | 411 (371, 443) | 411 (373, 440) | 407 (362, 449) |
Children, the P wave
Rijnbeek et al. Median value with the 98th percentile (the upper limit of normal) in parentheses, given in millivolts (mV). Multiply by 10 for millimetres at standard calibration.
| Lead | 0–1 month | 1–3 months | 3–6 months | 6–12 months | 1–3 years | 3–5 years | 5–8 years | 8–12 years | 12–16 years | |
|---|---|---|---|---|---|---|---|---|---|---|
| II | Boys | 0.15 (0.23) | 0.16 (0.25) | 0.15 (0.22) | 0.16 (0.26) | 0.15 (0.25) | 0.13 (0.23) | 0.12 (0.22) | 0.12 (0.22) | 0.13 (0.24) |
| Girls | 0.16 (0.25) | 0.16 (0.23) | 0.16 (0.23) | 0.16 (0.24) | 0.16 (0.25) | 0.13 (0.23) | 0.12 (0.24) | 0.14 (0.24) | 0.15 (0.26) | |
| V1 | Boys | 0.12 (0.22) | 0.10 (0.19) | 0.09 (0.17) | 0.10 (0.17) | 0.13 (0.20) | 0.12 (0.19) | 0.12 (0.20) | 0.11 (0.19) | 0.11 (0.18) |
| Girls | 0.10 (0.19) | 0.10 (0.16) | 0.10 (0.16) | 0.11 (0.21) | 0.12 (0.20) | 0.12 (0.20) | 0.11 (0.18) | 0.11 (0.19) | 0.10 (0.17) |
Children, the Q wave
Rijnbeek et al. Median value with the 98th percentile (the upper limit of normal) in parentheses, given in millivolts (mV).
| Lead | 0–1 month | 1–3 months | 3–6 months | 6–12 months | 1–3 years | 3–5 years | 5–8 years | 8–12 years | 12–16 years | ||
|---|---|---|---|---|---|---|---|---|---|---|---|
| II | Boys | 0.14 (0.23) | 0.18 (0.32) | 0.14 (0.34) | 0.18 (0.48) | 0.15 (0.44) | 0.11 (0.26) | 0.10 (0.28) | 0.09 (0.24) | 0.08 (0.21) | |
| Girls | 0.09 (0.26) | 0.14 (0.32) | 0.15 (0.43) | 0.16 (0.44) | 0.16 (0.48) | 0.13 (0.27) | 0.08 (0.26) | 0.08 (0.21) | 0.09 (0.20) | ||
| III | Boys | 0.15 (0.26) | 0.29 (0.50) | 0.31 (0.71) | 0.35 (0.79) | 0.30 (0.74) | 0.19 (0.46) | 0.15 (0.36) | 0.10 (0.28) | 0.10 (0.29) | |
| Girls | 0.18 (0.35) | 0.24 (0.50) | 0.28 (0.65) | 0.34 (0.79) | 0.31 (0.73) | 0.18 (0.40) | 0.16 (0.38) | 0.10 (0.27) | 0.10 (0.21) | ||
| aVF | Boys | 0.13 (0.23) | 0.20 (0.35) | 0.20 (0.40) | 0.22 (0.58) | 0.20 (0.54) | 0.14 (0.34) | 0.12 (0.25) | 0.09 (0.25) | 0.08 (0.23) | |
| Girls | 0.10 (0.27) | 0.17 (0.35) | 0.20 (0.44) | 0.23 (0.52) | 0.20 (0.54) | 0.12 (0.31) | 0.11 (0.31) | 0.08 (0.21) | 0.09 (0.18) | ||
| V6 | Boys | 0.11 (0.22) | 0.16 (0.31) | 0.17 (0.35) | 0.20 (0.60) | 0.20 (0.56) | 0.15 (0.42) | 0.12 (0.39) | 0.12 (0.43) | 0.11 (0.43) | |
| Girls | 0.09 (0.17) | 0.15 (0.37) | 0.15 (0.40) | 0.18 (0.39) | 0.17 (0.49) | 0.15 (0.42) | 0.10 (0.41) | 0.11 (0.34) | 0.09 (0.23) |
Children, the R wave
Rijnbeek et al. Median value with the 98th percentile (the upper limit of normal) in parentheses, given in millivolts (mV).
| Lead | 0–1 month | 1–3 months | 3–6 months | 6–12 months | 1–3 years | 3–5 years | 5–8 years | 8–12 years | 12–16 years | ||
|---|---|---|---|---|---|---|---|---|---|---|---|
| I | Boys | 0.25 (0.45) | 0.56 (1.12) | 0.80 (1.52) | 0.82 (1.52) | 0.77 (1.37) | 0.63 (1.09) | 0.62 (1.16) | 0.59 (1.04) | 0.58 (1.09) | |
| Girls | 0.31 (0.62) | 0.55 (1.09) | 0.74 (1.26) | 0.75 (1.38) | 0.68 (1.52) | 0.65 (1.20) | 0.49 (1.00) | 0.54 (1.21) | 0.48 (1.02) | ||
| II | Boys | 0.64 (1.28) | 1.08 (1.76) | 1.27 (1.97) | 1.27 (2.09) | 1.27 (2.47) | 1.36 (2.20) | 1.24 (2.42) | 1.39 (2.23) | 1.31 (2.08) | |
| Girls | 0.70 (1.21) | 1.15 (2.04) | 1.33 (2.24) | 1.35 (2.21) | 1.27 (2.34) | 1.38 (2.24) | 1.33 (2.27) | 1.32 (2.29) | 1.32 (2.03) | ||
| III | Boys | 0.79 (1.44) | 0.76 (1.60) | 0.72 (1.50) | 0.82 (1.65) | 0.80 (1.96) | 0.94 (1.82) | 0.80 (1.92) | 0.89 (1.86) | 0.85 (1.74) | |
| Girls | 0.85 (1.50) | 0.91 (1.82) | 0.95 (1.85) | 0.90 (1.95) | 0.96 (2.00) | 0.94 (1.96) | 1.03 (2.09) | 0.92 (1.88) | 0.88 (1.66) | ||
| aVL | Boys | 0.16 (0.32) | 0.35 (0.66) | 0.40 (1.09) | 0.44 (1.04) | 0.38 (0.86) | 0.26 (0.58) | 0.22 (0.70) | 0.17 (0.52) | 0.19 (0.69) | |
| Girls | 0.18 (0.45) | 0.25 (0.69) | 0.37 (0.78) | 0.40 (0.92) | 0.38 (1.02) | 0.24 (0.70) | 0.18 (0.55) | 0.17 (0.69) | 0.16 (0.53) | ||
| aVF | Boys | 0.59 (1.36) | 0.88 (1.58) | 0.93 (1.70) | 0.96 (1.81) | 1.00 (2.20) | 1.13 (1.97) | 1.00 (2.19) | 1.16 (2.00) | 1.06 (1.88) | |
| Girls | 0.72 (1.26) | 0.98 (1.91) | 1.07 (1.82) | 1.11 (2.04) | 1.10 (2.08) | 1.14 (2.06) | 1.20 (2.17) | 1.09 (2.06) | 1.10 (1.84) | ||
| V3R | Boys | 0.62 (1.04) | 0.58 (1.24) | 0.57 (1.20) | 0.48 (1.24) | 0.49 (1.06) | 0.41 (0.81) | 0.23 (0.63) | 0.22 (0.51) | 0.19 (0.54) | |
| Girls | 0.68 (1.26) | 0.55 (0.93) | 0.49 (1.11) | 0.42 (0.98) | 0.43 (0.92) | 0.34 (0.64) | 0.21 (0.57) | 0.19 (0.47) | 0.17 (0.49) | ||
| V1 | Boys | 1.10 (2.05) | 1.23 (2.07) | 1.32 (2.20) | 1.12 (2.14) | 1.08 (2.11) | 0.95 (1.78) | 0.63 (1.48) | 0.54 (1.14) | 0.48 (1.18) | |
| Girls | 1.35 (2.22) | 1.17 (1.99) | 1.14 (2.04) | 1.01 (1.92) | 1.01 (1.91) | 0.77 (1.38) | 0.55 (1.24) | 0.49 (1.14) | 0.35 (1.10) | ||
| V2 | Boys | 1.83 (2.67) | 1.82 (2.63) | 2.08 (2.54) | 1.94 (2.51) | 1.82 (2.41) | 1.58 (2.26) | 1.21 (2.22) | 1.02 (1.90) | 0.94 (1.87) | |
| Girls | 1.83 (2.17) | 1.81 (2.45) | 1.88 (2.60) | 1.82 (2.36) | 1.75 (2.38) | 1.41 (2.25) | 1.06 (1.91) | 0.90 (1.86) | 0.69 (1.57) | ||
| V4 | Boys | 1.80 (2.62) | 2.30 (3.05) | 2.32 (3.23) | 2.27 (3.32) | 2.37 (3.38) | 2.42 (3.30) | 2.11 (3.11) | 1.86 (3.16) | 1.87 (3.06) | |
| Girls | 1.68 (2.21) | 2.26 (3.26) | 2.26 (3.31) | 2.23 (3.09) | 2.21 (3.54) | 2.24 (3.38) | 1.84 (3.04) | 1.72 (3.23) | 1.24 (2.55) | ||
| V6 | Boys | 1.00 (1.78) | 1.55 (2.23) | 1.65 (2.73) | 1.70 (2.79) | 1.79 (2.96) | 1.94 (3.14) | 1.97 (2.98) | 2.18 (3.24) | 2.02 (3.05) | |
| Girls | 0.93 (1.64) | 1.51 (2.67) | 1.60 (2.80) | 1.68 (2.74) | 1.68 (2.67) | 1.89 (2.91) | 2.05 (3.25) | 2.00 (3.04) | 1.65 (2.52) |
Sources
- Davignon A, Rautaharju P, Boisselle E, et al. Normal ECG standards for infants and children. Pediatr Cardiol. 1979/1980.
- Rijnbeek PR, Witsenburg M, Schrama E, Hess J, Kors JA. New normal limits for the paediatric electrocardiogram. Eur Heart J. 2001;22(8):702-711.
