ECG for the General Pediatricians: Practical Approach to Children with Apparently Normal Physical Exam and Normal ECGs

Noh, Chung Il

Abstract

Most general pediatricians usually think that cardiac diseases are entirely outside their field and never try to take care of the patients with cardiac disease. Sometimes, however, most pediatricians cannot help avoiding the patients with cardiac disease wherever they are engaged in. To them, one of most important issue is to identify whether the patients have cardiac disease or not, especially which can cause medico-legal problems if they miss the diagnosis. Whether they can diagnose the disease correctly is not the issue in real practice. In this sense, ECG is one of the useful tools to screen many important cardiac diseases among patients with apparently normal physical exam (PE). ECG can be a marker of sudden death and/or inapparent cardiac disease. Indicators of impending arrhythmic events and sudden cardiac death in intensive care unit (ICU: and/or outpatient setting) are abnormal QTU complex (duration, morphology, dispersion, beat-to-beat variability of QT, T alternans), ST segment fluctuation, and heart rate variability. In outpatient setting, important cardiac diseases to be ruled out among apparently normal PE include primary arrhythmia syndrome (long QT syndrome, Brugada syndrome, catecholaminergic polymorphic vetricular tachycardia(VT), and short QT syndrome), cardiomyopathies (hypertrophic, restrictive, and arrhythmogenic RV cardiomyopathy) and congenital anomaly in coronary arteries. The common ECG characteristics of above diseases include abnormalities in ST segment and TU complexes. This indicates that defining the repolarization abnormalities in ECG is the most important in screening cardiac diseases. Most cardiomyopathy (CMP), and coronary artery anomaly show non-specific TU change, atrial/ventricular hypertrophy, and ST segment change. The representative diseases which have abnormal ST segment-TU complex are long or short QT syndrome, Brugada syndrome, arrhythmogenic RV dysplasia-CMP, hypertrophic CMP, restrictive CMP, several pericardial diseases, myocarditis, and abnormal coronary arteries. The juvenile pattern of T-wave inversion in V1-V3 should not persist beyond childhood. Inverted T-wave in V4-V6 are observed in hypertrophic CMP, dilated CMP, left-sided arrhythmogenic RV dysplasia-CMP and long QT syndrome. Although prolongation of corrected QT interval is characteristic feature of long QT syndrome, abnormalities in T-wave morphology are also common. Short QT syndrome is characterized by a QT interval of <320 ms and tall, narrow T waves. Right precordial ST segment elevation is the ECG signature of Brugada syndrome. Other important issue in general pediatricians is "Can general pediatricians interpret ECGs well?" Or do they get adequate, even though not enough, information from ECGs? The study shows that automatic ECG reading is a reliable method in screening cardiac diseases. Conclusively, general pediatricians have to pay much more attention to ST segment-TU complex in apparently normal ECGs. Automatic ECG reading is a reasonable method of screening because of high sensitivity, although specificity is poor.