By Yasmine S. Ali, MD, MSCI, FACC, FACP
Although I specialize in advanced cardiac imaging and structural heart disease in adults, I've had the privilege of interacting extensively with my colleagues in pediatric cardiology. One of the key differences from adult cardiology, of course, is patient size and developmental stage, and this affects ECG lead placement for accurately obtaining the pediatric ECG, among other things.
Accurate ECG interpretation in pediatric and adolescent populations also requires nuanced expertise as compared with adults. From heart size to ECG lead placement, key anatomic and physiological differences impact ECG readings and their analyses.1 Recent software developments in ECG technology allow for enhanced precision in ECG interpretation. For instance, in pediatric cases, the R wave of the ECG contains high frequencies, making low pass filtration critical for avoiding potential erroneous interpretation.2
Pediatric patients require specialized approaches
As is well recognized in the field of pediatric cardiology, children's hearts evolve rapidly in early life, with size, conduction speed, and waveform amplitudes requiring specialized ECG interpretation. ECG monitoring in pediatric patients also requires knowledge of common arrhythmias in children as compared with adolescents or adults.
The American Heart Association provides guidance on ECG lead placement, continuous ECG monitoring, and ECG interpretation in pediatric patients. For instance, although lead V1 is commonly used for arrhythmia monitoring in adult patients, lead II is usually selected as a primary lead for continuous monitoring in the pediatric population because supraventricular arrhythmias are more common than ventricular arrhythmias in pediatric patients.3
A number of arrhythmias that would be considered pathologic in adults can be considered normal in children. For example, 15% to 25% of healthy children can display sinus arrhythmia, ectopic atrial rhythm, junctional rhythm, and "wandering pacemaker" on ECG.1
Optimal lead placements serve as a foundation for reliable pediatric ECG readings. While the standard precordial V1-V6 positions used in adult patients are appropriate for that population, they often sit too low on smaller chests. This leads to reduced voltages that could fail to meet amplitude criteria for conditions like ventricular hypertrophy. Thus, modifications to the standard placements are required in pediatric patients in accordance with size and anatomy.
Unique considerations for adolescents
Adolescence is a time of both social and biological transition, and in pediatric cardiology, this transition manifests physiologically with slower heart rates, QRS axis rotation, and T-wave inversions. ECG interpretation and software must therefore take these changes into account.
This growth stage also carries higher risks of phenomena like sudden cardiac arrest from underlying genetic conditions or structural heart abnormalities, and much consideration has been given to the topic of ECG screening and interpretation in the adolescent athlete.4,5
Specific variations in adolescent ECG patterns have been observed and described. For instance, anterior T-wave inversion is frequently seen in adolescents, particularly in females. Female adolescent athletes are also more likely to have extended anterior T-wave inversion.6 Additionally, early repolarization, which could be a cause for concern in adult athletes, is in fact compatible with normal cardiac adaptation to athletic training in adolescents.7
Age-related variations found in both pediatric and adolescent ECGs include heart rate, axis, intervals, and ECG voltage criteria.3,4 Age- and sex-based reference ranges allow clinicians to distinguish normal physiological variance from pathological abnormalities.8 Since incorrect ECG lead placement can result in misinterpretations, correct lead placement based on age and level of development also helps to ensure accuracy and precision, as does specialized ECG technology that specifically considers these differences.
Software developments set to transform interpretation
ECG software now allows for ECG filtering up to 300 hertz, which may be useful in specific circumstances even if not universally, since wider bandwidth means more noise. The AHA guidelines indicate that a low pass filter is important for helping clinicians look for different health issues, such as with amplitude errors in pediatric cases.9 This can lead to richer data capture, enhanced precision, and improved patient outcomes. Next-generation functionality can augment tracing quality and ensure greater accuracy among both pediatric and adolescent patients.
Inclusion of age-specific normal values in overreads will allow for more accurate quality assurance, and will strengthen and reinforce the fundamentals for cardiologists in training and early-career cardiologists as well.
Additionally, AI has become critical in conversations about ECG interpretation; as the technology improves, we'll see more and more AI assistance for clinicians reviewing ECGs.
As leading institutions and facilities integrate these capabilities, more dependable and precise ECG diagnostics will become available, bolstering diagnostic capacity, directing therapeutic decisions, and helping to secure optimum outcomes among younger patients. And as pediatric cardiology continues to advance, specialized knowledge coupled with next-generation software will heighten precision and enable pediatric cardiologists to deliver prompt interventions when truly abnormal rhythms or structural heart disease are detected.
Yasmine S. Ali, MD, MSCI, FACC, FACP, is a board-certified cardiologist; founder and editor-in-chief of heart-health media brand Speak for the Heart; CEO of LastSky Writing, LLC; assistant clinical professor of medicine at Vanderbilt University School of Medicine; and a bestselling author.
1. Drago F, Battipaglia I, and Di Mambro C. Neonatal and pediatric arrhythmias: clinical and electrocardiographic aspects. Cardiac Electrophysiology Clinics. 2018. 10 (2): 397–412. https://doi.org/10.1016/j.ccep.2018.02.008
2. Hirokawa, J., Hitosugi, T., Miki, Y., et al. (2022). The influence of electrocardiogram (ECG) filters on the heights of R and T waves in children. Scientific reports, 12(1), 13279. https://doi.org/10.1038/s41598-022-17680-4
3. Sandau KE, Funk M, Auerbach A, et al. Update to practice standards for electrocardiographic monitoring in hospital settings: A scientific statement from the American Heart Association. Circulation. 2017. 136 (19). https://doi.org/10.1161/CIR.0000000000000527
4. Cavarretta E, Sciarra L, Biondi-Zoccai G, et al. Age-related electrocardiographic characteristics of male junior soccer athletes. Frontiers in Cardiovascular Medicine. 2021. 8: 784170. https://doi.org/10.3389/fcvm.2021.784170
5. Pieles GE and Stuart AG. The adolescent athlete's heart; a miniature adult or grown-up child?" Clinical Cardiology. 2020. 43 (8): 852–62. https://doi.org/10.1002/clc.23417
6. Abela M, Yamagata K, Buttigieg L, et al. The juvenile ECG pattern in adolescent athletes and non-athletes in a national cardiac screening program (BEAT-IT). International Journal of Cardiology. January 2023. 371: 508–15. https://doi.org/10.1016/j.ijcard.2022.09.005
7. Vecchiato M, Baioccato V, Adami PE, et al. Early repolarization in adolescent athletes: A gender comparison of ECG and echocardiographic characteristics. Scandinavian Journal of Medicine & Science in Sports. 2022. 32 (11): 1581–91. https://doi.org/10.1111/sms.14232
8. Mikrou P, Shivaram P, and Kanaris C. How to interpret the paediatric 12-lead ECG. Archives of Disease in Childhood - Education and Practice. 2022. 107 (4): 279–87. https://doi.org/10.1136/archdischild-2021-322428
9. Kligfield, Paul, Leonard S. Gettes, James J. Bailey, et al. "Recommendations for the Standardization and Interpretation of the Electrocardiogram." Circulation 115, no. 10 (2007): 1306–24. https://doi.org/10.1161/circulationaha.106.180200