Pediatric EKG Interpretation
Before you read the EKG, look for:
- Patient age, as many values change with age
- Standardization: Full standard is two large squares (1 mV, 10 mm) and half standard is one large square (0.5mV, 5 mm)
- Paper speed: the standard is 25 mm/sec. The faster the paper speed the slower the HR will look and vice versa
Basic EKG interpretation
- Heart rate: The standard paper speed is 25 mm (5 large squares)/sec. This means that if the distance between two beats (R-R) is 5 large squares, the HR is 60 beat/min. If the distance between two beats is one large square, the HR is 300 beat/min. Two squares →150, 3 squares →100, 4 squares → 75, 5 squares → 60, 6 squares → 50 beat/min. The HR may be counted by simply dividing 300 by the number of the large squares between two heart beats (R-R).
- Axis: Make sure to determine both P wave and QRS axes. Net summation of positive and negative deflection is used. Look for two perpendicular leads (usually lead I and aVF). When QRS is positive in both lead I and aVF, the axis is in the left lower quadrant (0-90 degrees). If it is negative in lead I and positive in aVF, the axis is in the right lower quadrant (90-180 degrees) and so forth.
- Rhythm: The sinus node is located at the SVC/right atrial junction. Sinus rhythm is characterized by:
a) One P wave preceding each QRS complex.
b) All P waves are uniform in shape.
c) Normal P wave axis is in the left lower quadrant (0-90 degrees), i.e. upright in both lead I and aVF (unless there is dextrocardia). - Durations/Intervals:
a) P wave: Normally it is 2.5 mm wide and 2.5 mm high. Tall P waves indicate RA enlargement (RAE), wide P waves indicate LA enlargement (LAE), wide and bi-peaked P waves indicates bi-atrial enlargement (BAE).
b) PR interval varies with age and heart rate and is <0.2 sec at any age
c) QRS duration (2-3 small squares or 0.08-0.12 sec). Wide QRS may indicate bundle branch block or ventricular beats.
d) QT interval (measured from the beginning of Q to the end of T waves). QTc is the QT interval corrected for the heart rate. QTc=QT (in seconds)/square root of preceding RR interval (in seconds). - Chamber Hypertrophy/Enlargement: a) Right ventricular hypertrophy: I- Voltage criteria (tall R in V1 and deep S in V6>95% for age) II- Extreme right axis deviation III- rSR' in V1 with a tall R' IV- qR pattern in V1 V- Upright T wave in V1 > 1 week of age b) Left ventricular hypertrophy: Less well defined than RVH. I- Voltage criteria (tall R in V6 and deep S in V1) II- Left axis deviation III- Strain pattern in left precordial leads (inverted T waves in V5 and V6)
|
Summary of Normal Values |
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|
Age Group |
Heart Rate (beats/min)* |
Frontal Plane QRS Vector (degrees) |
PR Interval (sec) |
QRS Duration V5 |
Q III (mm) †‡ |
Q V6 (mm) † |
RV1 (mm) |
SV1 (mm) |
R/SV1 |
RV6 (mm) |
SV6 (mm) |
R/SV 6 |
SV1+ RV 6 (mm) † |
R + S V 4 (mm) † |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Less than 1 day |
93-154 |
+59 to -163 |
0.08-0.16 (.11) |
.03-0.07 (.05) |
4.5
|
2
|
5-26 (14) |
0-23 (8) |
.1-U (2.2) |
0-11 (4) |
0-9.5 (3) |
.1-U (2.0)
|
28
|
52.5
|
|
1 to 2 days |
90-159 (123) |
+64 to -161 |
0.08-0.14 (.11) |
.03-0.07 (.05) |
6.5 |
2.5 |
5-27 (14) |
0-21 (9) |
.1-U (2.2) |
0-12 (4.5) |
0-9.5 (3) |
.1-U (2.5)
|
29 |
52 |
|
3 to 6 days |
91-166 (129) |
+77 to -163 |
0.07-0.14 (.11) |
.03-0.14 (.05) |
5.5 |
3 |
3-24 (13) |
0-17 (7) |
.1-U (2.2) |
.5-12 (5) |
0-10 (3.5) |
.1-U (2.2)
|
24.5 |
49 |
|
1 to 3 wks |
107-182 (148) |
+65 to +161 |
0.07-0.14 (.10) |
.03-0.08 (.05) |
6 |
3 |
3-12 (11) |
0-11 (4) |
.1-U (2.2) |
2.5-16.5 (7.5) |
0-10 (3.5) |
.1-U (3.3)
|
21 |
49 |
|
1 to 2 mo |
121-179 (14)9 |
+31 to +113 |
0.07-0.13 (.10) |
.03-0.08 (.05) |
7.5 |
3 |
3-8 (10) |
0-12 (5) |
.1-U (2.2) |
5-21.5 (11.5) |
0-6.5 (3) |
.2-U (4.8)
|
29 |
53.5 |
|
3 to 5 mo |
106-186 (141) |
+7 to +104 |
0.07-0.15 (.11) |
.03-0.08 (.05) |
6.5 |
3 |
3-20 (10) |
0-17 (6) |
.1-U (2.2) |
6.5-22.5 (13) |
0-10 (3) |
.2-U (6.2)
|
35 |
61.5 |
|
6 to 11 mo |
109-169 (134) |
+6 to +99 |
0.07-0.16 (.11) |
.03-0.08 (.05) |
8.5 |
3 |
1.5-20 (9.5) |
.5-18 (4) |
.1-U (2.2) |
6-22.5 (12.5) |
0-7 (2) |
.2-U (7.6)
|
37 |
53 |
|
1 to 2 yr |
89-151 (119) |
+7 to +101 |
0.08-0.15 (.11) |
.04-0.08 (.06) |
6 |
3 |
2.5-17 (9) |
.5-21 (8) |
.1-U (2.2) |
6-22.5 (13) |
0-6.5 (2) |
.3-U (9.3)
|
39 |
49.5 |
|
3 to 4 yr |
73-137 (108) |
+6 to +104 |
0.09-0.16 (.12) |
.04-0.08 (.06) |
5 |
9.5 |
1-18 (8) |
.2-21 (10 |
.1-U (2.2) |
8-24.5 (15) |
0-5 (1.5) |
.6-U (10.8)
|
42 |
53.5 |
|
5 to 7 yr |
65-133 (100) |
+11 to +143 |
0.09-0.16 (.12) |
.04-0.08 (.06) |
4 |
4.5 |
.5-14 (4) |
.3-24 (12) |
.1-U (2.2) |
8.5-26.5 (16) |
0-4 (1) |
.9-U (11.5)
|
47 |
54 |
|
8 to 11 yr |
62-130 (91) |
+9 to +114 |
0.08-0.16 (.11) |
.04-0.09 (.06) |
3 |
3 |
0-12 (5.5) |
.3-25 (12) |
.1-U (2.2) |
9-25.5 (16) |
0-4 (1) |
1.5-U (14.3)
|
45.5 |
53 |
|
12 to 15 yr |
60-119 (85) |
+11 to -130 |
0.08-0.16 (.11) |
.04-0.09 (.07) |
3 |
3 |
0-10 (4) |
.3-21 (11) |
.1-U (2.2) |
6.5-23 (14) |
0-4 (1) |
1.4-U (14.7
|
41 |
50 |
|
* 2 to 98% (mean) |
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