Ecg Interpretation Paediatrics
Eleanora Parrot
MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner
In utero, blood is shunted away from the pulmonary vasculature leading to higher pulmonary pressures and a relatively larger and thicker right ventricle. Right axis deviation is thus a normal finding at birth, and usually resolves by 6 months of age.
The presence of ECG features of left ventricular hypertrophy in a paediatric patient should prompt the clinician to look for other ECG and clinical features of hypertrophic cardiomyopathy and investigate as appropriate.
Abnormal T waves: Upright T waves in V1 and V4R in children 3 days to 6 years (provided that T waves are normal elsewhere, i.e. upright in V6). This is evidence alone of significant RVH.
This guideline aims to help with the interpretation of CSF results for the purpose of diagnosing or excluding meningitis. The use of CSF for other purposes (including the diagnosis of specific neurological conditions, subarachnoid haemorrhage or malignancy) is outside its scope.
Pediatric echocardiography is ultrasonography used to evaluate the anatomical structure and function of the heart. This activity reviews pediatric echocardiography's utility and highlights the role the interprofessional team has in evaluating patients for congenital heart disease.
Objectives:
- Outline the basics of echocardiography.Identify indications for pediatric echocardiography.Describe differences amongst pediatric and adult echocardiography.Summarize how interprofessional team strategies can improve diagnostic results when employing echocardiography in both children and adults.
Echocardiography is the first-line, non-invasive approach to management in evaluating anatomical, physiological, and hemodynamic abnormalities of the heart.[1] It is one of many imaging modalities utilized by cardiologists around the world. Before beginning this discussion, we must first address the nomenclature. Echocardiography is an all-encompassing term for cardiac ultrasound. It includes many invasive and non-invasive modalities such as transthoracic echocardiography (TTE), stress echocardiography, transesophageal echocardiography, fetal echocardiography, three-dimensional echocardiography, intracardiac echocardiography, Intra-valvular echocardiography, and Intra-operative echocardiography.
This article will discuss pediatric TTEs, a reliable diagnostic approach that has shown to yield as little as 87 diagnostic errors out of 50,660 total TTEs in a previously published study.[2] Both comprehensive transthoracic echocardiography (cTTE) and functional transthoracic echocardiography (fTTE) will be covered. This discussion will be done with an emphasis on highlighting how Pediatric TTEs differ from general adult TTEs. Lastly, given an incidence of 4 to 12 per every 1000 live births, congenital heart disease (CHD) will undoubtedly be a predominant topic covered below.[3]
Pediatric TTEs typically resemble Adult TTEs in regards to cardiac structure morphology and to obtaining the basic views. However, one can imagine the added anatomical difficulty of interpreting a pediatric TTE in a patient with a complex CHD malformation. Such atypical anatomical appearances place significance on identifying morphological characteristics, especially in pediatric populations. For this same reason, pediatric TTEs require further in-depth evaluation of the suprasternal notch, right parasternal, and subxiphoid views. Views that are of less significance compared to adult TTEs.
All Ultrasound (US) devices used for cTTEs should include software to perform the basics of 2D imaging, M-mode, color flow Doppler, and spectral Doppler.[6] The details of each modality are discussed below as well as in the Clinical Significance section.
US probes are used to transmit mechanical longitudinal electrical waves through a medium. This is done by transmitting an electrical current via alternating potential differences amongst electrodes encompassing piezoelectrical crystals. Once electrically stimulated, these crystals will produce sound waves. The sound waves will propagate through the medium at velocities dependent on the material's density. Waves will return to the crystals, at which point the waves will be converted back into an electrical signal and converted into images. Such images are the basis of two-dimensional echocardiography.[7]
US probes are utilized in the same methodology as above to produce doppler images. A color Doppler image varies by color depending on the direction of a moving medium. If an object moves away from the probe, it will produce a longer wavelength, interpreted as a blue color. If an object is moving toward the probe, it will produce a smaller wavelength, interpreted as a red color. A spectral doppler encompasses a pulse and continuous wave Doppler, which varies from color doppler by calculating the mean and peak gradients. This is illustrated along with a graph for the simplicity of comparison. A tissue Doppler can be done via pulse or color mode. It is used to produce peak myocardial velocities.
Diagnostic ultrasounds produce low-frequency currents ranging from 2.5 to 14 MHz. Thus, producing a radiation-free modality safe to use in children, infants, and fetuses. Multiple probes are available, which vary by frequency. To grasp the significance of high vs. low-frequency probes, one must recall the inverse relationship between wavelength and frequency. The higher frequency probes are ideal for small infants, providing the clinician with a smaller wavelength allowing one to obtain a higher resolution image of superficial structures.
Prior to the exam, the child could be asked to hold parental oral intake for 6 to 8 hours, as light sedation is required at times for younger children. The patient will be asked to lay supine on the exam table or bed, with the head of the bed at roughly a 30-degree angle. If possible, the lateral decubitus position can provide optimal images given the gravitational pull of the heart towards the surface. In infants, the parent may wish to hold the patient for simplicity. Distractors are provided when needed. A few electrodes will be placed on the child to allow ECG gated images. The gown will be lowered to expose the patient's left breast. A towel is provided to adolescents for privacy purposes. US jelly will then be placed on the tip of the probe, and the exam will start.
Each cTTE should be done in a step-wise fashion. The exam steps are typically defined by the institution, providing the interpreter with a stream-lined systematic approach to all cTTE reads. Such a defined systematic approach provides simplicity to interpreting each individual cTTE. Specifically for pediatric cTTEs, importance is placed on the initial recognition of basic anatomy to rule out or rule any CHD. This is done by starting with the subcostal view to identify the apex, ventricles, and great vessels. Once cardiac orientation is established, the sonographer should transition through windows in a sequential clockwise approach.
An fTTE, also known as a bedside TTE, has no specific technique. It is done strictly for rapid evaluation of structural-functional characteristics. Many fTTE machines do not even possess doppler or ECG gating capabilities. The apical and subcostal acoustic windows are most utilized.
The diagnostic ability of TTEs is well known, widely accepted, and has been documented in a multitude of publications.[8][9][10][11][12][13][14] Here we will breakdown the clinical application/diagnostic ability of TTEs into four groups. First, we will discuss the utility of each specific modality included in a pediatric cTTE. Second, we will discuss the predominant pathologies viewed broken down by imaging window. Third, we will provide observed parameters specifically for each structure. Lastly, we will address the utility of an fTTE in the ICU setting.
Multiple structural, functional, and hemodynamic values are required to perform a cTTE. With the most variation from typical Adult TTEs, the former require adjustment according to body surface area.[15][16][17] This structural adjustment is then reported as a Z-score, allowing normalization of the data.[18][19] More information regarding the most up-to-date z-score calculators is available here.[20]
Listed below are the recommended measurements according to a report from the Task Force of the Pediatric Council of the American Society of Echocardiography and a report from the Task Force of a Standardized Echocardiography of the American Society of Echocardiography.[21][22]
The combination of determining an indication, obtaining and interpreting a cTTE certainly requires interprofessional collaboration. For starters, a pediatrician must obtain a good history to clearly offer an appropriate indication. Once the cTTE is ordered, a certified ultrasound technician must perform the cTTE. This task can be difficult, especially in the setting of a young child. Nurses are needed to help distract the patient, and at times, a pharmacist may be consulted to provide mild sedation as the image quality is key for interpretation. Lastly, a cardiologist is needed to actually read and interpret the images.
The need for such an interprofessional team approach has been demonstrated inadvertently. A recent study demonstrated the significance of sedation via comparison of sedated vs. non-sedated pediatric cTTEs regarding providing optimal images. The conclusion was that sedated cTTEs provide a significant improvement in image quality. Without a multidisciplinary approach, obtaining optimal images in pediatric patients would not be possible.[26] [Level 4]
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