cardiovascular disorders
Long QT Interval Syndromes
Treatment of Long QT Interval Syndromes
Treatment of any VT/VF Alleviation of predisposing causes and triggers, especially electrolyte abnormalities and use of certain medications Usually beta blockade Sometimes an ICD Rarely, left cardiac sympathetic denervation Details of Treatment are discussed elsewhere but include cardioversion and magnesium sulfate IV. Patients with frequent or long runs of torsades de pointes ventricular tachycardia may benefit from treatment to shorten the QT interval by increasing the heart rate using temporary pacing, IV Long-term treatment to prevent sudden death includes avoidance of specific triggers (including strenuous exercise in LQTS1 and LQTS2) and QTc-prolonging conditions. When possible, clinicians should stop any predisposing medications and prescribe alternatives (seeCredibleMedsfor up-to-date information). Patients, particularly those who will not accept exercise restrictions, should be counseled on the need for appropriate cautions (eg, availability of an automated external defibrillator during training and competition). Beta-blocker drug therapy is recommended for patients with LQTS1 or LQTS2, those who have had syncope, cardiac arrest, or those who have demonstrated VF or sustained VT. Patients with LQTS3 may benefit frommexiletine. When a beta-blocker is used, a long-acting beta-blocker without intrinsic sympathomimetic activity (eg,nadolol, slow-releasepropranolol) is preferred. Permanent pacing to increase the basal ventricular rate and to prevent post-extrasystolic pauses may reduce the probability of recurrent TdeP VT. An Implantable Cardioverter-Defibrillators (ICD) (ICD) is indicated in patients who have been resuscitated after cardiac arrest and in those who have cardiac syncope despite therapy with a beta-blocker (see table 