It is equivalent to a series of atrial or junctional premature beats. Because the T wave and P wave often overlap and are difficult to distinguish, it is called supraventricular tachycardia. The episode can last from a few seconds to several hours or even days. It is commonly seen in children without organic heart disease. Some children have congenital heart abnormalities such as Wolff-Parkinson-White syndrome, Ebstein's anomaly, corrected transposition of the great arteries, cardiomyopathy, endocardial fibroelastosis, or myocarditis. Additionally, digitalis toxicity, electrolyte imbalances, cardiac catheterization, and post-cardiac surgery can also trigger this condition. It is a pediatric cardiac emergency, and improper management can easily lead to heart failure or cardiogenic shock, endangering the patient's life.

bubble_chart Clinical Manifestations

1. Sudden onset and termination, with a rapid and regular heart rate during episodes: 200-300 beats per minute in infants, 150-200 beats per minute in children. 2. The child exhibits dysphoria, restlessness, refusal to eat, vomiting, shortness of breath, night sweats, pallor, cold limbs, and cyanosis. 3. Children may complain of palpitations, chest discomfort, dysphoria or weakness, dizziness, nausea, vomiting, and abdominal pain. 4. Episodes lasting more than 48 hours can lead to heart failure or cardiogenic shock.

bubble_chart Diagnosis

1. The child suddenly experiences dysphoria, shortness of breath, excessive sweating, and pallor. The limbs are cold, with refusal to eat, cyanosis. Older children may complain of chest discomfort, dizziness, lack of strength, nausea, and vomiting, which may suddenly cease. 2. The heart rate increases and becomes regular, possibly accompanied by heart failure or signs of cardiogenic shock. 3. Electrocardiogram findings: Heart rate ranges from 150 to 300 beats per minute, with more than three consecutive premature beats. The rhythm is absolutely regular, with T waves and P waves often overlapping, making P waves difficult to identify. If P waves can be detected, their morphology is altered, and the P-R interval is >0.1 seconds.

Principles of Treatment

1. Cardioversion (including medication, vagal nerve stimulation, and electrical cardioversion). 2. Symptomatic treatment (oxygen inhalation, sedation, and treatment of heart failure and cardiogenic shock). Principles of Medication:

For pediatric VST, propafenone intravenous injection is the first choice, followed by oral digoxin maintenance dose after conversion. Alternatively, a rapid loading dose of cedilanid can be used initially. If cardioversion is unsuccessful, propafenone or verapamil intravenous injection is safer, as cedilanid is a positive inotropic agent, particularly safer for patients with heart failure or hypotension. Auxiliary Examinations: Surface electrocardiogram can confirm the diagnosis, while other examinations are only for disease cause diagnosis.

bubble_chart Cure Criteria

1. Recovery: Restoration of sinus rhythm, symptoms and signs disappear. 2. Improvement: Heart failure and cardiogenic shock are controlled, but sinus rhythm is not restored. 3. No recovery: Symptoms and signs show no improvement, sinus rhythm is not restored, or symptoms and signs continue to worsen until death.

Expert Tip

If a child suddenly experiences dysphoria, restlessness, shortness of breath, excessive sweating, pallor, cold limbs, refusal to eat, cyanosis, vomiting, or if an older child suddenly feels discomfort, dizziness, lack of strength, or palpitations that come and go repeatedly, seek medical attention promptly to avoid delaying treatment and risking life-threatening consequences.