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Abstract
The cardiac impulse originates within the SA node and is conducted through the two atria via working atrial myocytes after activating the right atrium, the impulse enters the approaches to the AV node and is delayed within the compact AV node. After transversing the AV node, the impulse is rapidly delivered to the endocardium through the bundle branches and their Purkinje fibers. The ventricular myocardium is then activated -#102;-#114;-#111;-#109; endocardium to epicardium the right and left ventricles are activated simultaneously. br The ECG is a graphic representation of the summation of all the voltage potentials of the heart for a given point of view at a given time. The ECG remains a quick, noninvasive method for evaluation of arrhythmias, conduction abnormalities, and to an extent, anatomic or myocardial abnormalities. br Arrhythmias means disturbances of rate and rhythm of the heart, arrhythmias are a major cause of morbidity and mortality in children. They may present as a primary dis-#111;-#114;-#100;-#101;-#114; or a secondary dis-#111;-#114;-#100;-#101;-#114; associated with congenital heart disease. There are two major types of arrhythmias tachyarrhythmias and bradyarrhythmias. br Tachyarrhythmias comprises supraventricular tachycardia ”Which arises above the bifurcation of the bundle of His” and ventricular tacycardia ”Which arises below the bifurcation of bundle of His” SVT is the most common abnormal tachyarrhythmias in children. Tachyarrhythmias represented in neonates and infant with signs of acute congestive heart failure while in school aged children and adolescents, palpitations are the leading symptom.