Long QT syndrome is a congenital disorder characterized by a prolongation of the QT interval on electrocardiograms and a propensity to ventricular tachyarrhythmias, which may lead to syncope, cardiac arrest, or sudden death
symptoms Long QT syndrome is usually diagnosed after a person has a cardiac event (eg, syncope, cardiac arrest). In some situations, this condition is diagnosed after a family member suddenly dies. In some individuals, the diagnosis is made when an electrocardiogram shows QT prolongation.
Treatment All patients with long QT syndrome (LQTS) should avoid drugs that prolong the QT interval or that reduce their serum potassium or magnesium level. Potassium and magnesium deficiency should be corrected. Although treating asymptomatic patients is somewhat controversial, a safe approach is to treat all patients with congenital LQTS because sudden cardiac death can be the first manifestation of LQTS. Beta-blockers are drugs of choice for patients with LQTS. The protective effect of beta-blockers is related to their adrenergic blockade, which diminishes the risk of cardiac arrhythmias. They may also reduce the QT interval in some patients.
All 168 children were in sinus rhythm. One hundred and fifty-eight patients (94%) had no significant preoperative findings. One child with double discordance had an intermittent complete atrioventricular block, and another one had a long QT syndrome. Children with severe ventricular dysfunction had paroxysmal atrioventricular re-entry tachycardia in 3 cases and abnormally frequent premature ventricular complexes in 3 other cases. Children with severe left atrial dilatation had periods of atrial ectopic tachycardia in one case and atrial fibrillation in another case.