Lifestyle changes are recommended for all individuals with long QT syndrome (LQTS) regardless of whether they have a clinical and / or molecular diagnosis of LQTS and it is a Class I ACC / AHA / ESC recommendation. All patients with LQTS should avoid competitive sports. In LQT1 patients, swimming should be specifically limited or performed only under supervision. Individuals with LQT2 have to avoid sudden acoustic stimuli especially during sleep like telephone bells and alarm clock. All patients with LQTS should avoid drugs known to prolong the QT interval and those that deplete potassium / magnesium.

Beta blockers in LQTS

Beta blockers are recommended for patients with a clinical diagnosis of LQTS i.e., in the presence of prolonged QT interval. Symptomatic LQTS cases benefit with beta blockers. Beta blockers are strongly indicated especially if there is a family history of early sudden cardiac death and in those with QTc longer than 500 msec and complex ventricular arrhythmias. Beta blockers are are Class IIa indication in those with only a molecular diagnosis of LQTS. Beta blockers can be effective in reducing sudden cardiac death (SCD) in patients with a molecular diagnosis of LQTS and normal QT interval.

Predictors of failure of beta blockers in LQTS

Following are the situations which predict beta blocker failure: LQT2, LQT3, QTc > 500ms and first syncopial spell before 7 years of age. In these situations, use of an implantable cardioverter defibrillator (ICD) for primary prevention may be considered.

Mexiletine with beta blockers in LQTS

Mexiletine along with beta blockers may be used in LQTS 3.

ICD along with beta blockers in LQTS

ICD implantation along with beta blocker therapy is recommended in those with a previous cardiac arrest and having a reasonable expectation of survival more than 1 year with a good functional status. ICD along with beta blockers can be effective in reducing SCD in LQTS patients with with syncope and / or ventricular tachycardia (VT) while on beta blockers.

Role of permanent pacemaker implantation in LQTS

There is a role for permanent pacemaker implantation in selected cases of LQTS with A-V block. They may also be indicated as an adjuvant to beta blockers in those with pause-dependent tachyarrhythmias, after consideration for an ICD.

Genetic Analysis in LQTS

Silent carriers of LQTS genetic defects can be detected and treated with beta blockers for prophylaxis of life-threatening arrhythmias. All individuals with LQTS should receive genetic counseling about the risk of transmitting LQTS to offspring. In patients affected by LQTS, genetic analysis is useful for risk stratification and for making therapeutic decisions.

Acquired LQTS

The most important aspect in acquired LQTIS is to avoid drugs prolonging the QT interval. Correction of hypokalemia and hypomagnesemia are essential. Class 1B anti-arrhythmics or isoproterenol may be used cautiously. Atrial or ventricular overdrive pacing may be useful by reducing the QT interval and the propensity for tachyarrhythmias.