What is the role of pacemakers and implantable cardioverter-defibrillators (ICDs) in the treatment of long QT syndrome (LQTS)?

Updated: Nov 29, 2017
  • Author: Ali A Sovari, MD, FACP, FACC; Chief Editor: Mikhael F El-Chami, MD  more...
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Answer

The implantable cardioverter-defibrillator (ICD) has been shown to be highly effective in preventing sudden cardiac death in high-risk patients. During a mean 8-year follow-up study of 125 patients with long QT syndrome (LQTS) who received an ICD, there was a 1.3% death rate in high-risk ICD patients, compared to 16% in non-ICD patients. [29] High-risk patients are defined as those with aborted cardiac arrest or recurrent cardiac events (eg, syncope or torsade de pointes) despite conventional therapy (ie, beta-blocker alone) and those with very prolonged QT interval (>500 ms).

An alternative treatment is beta blockade in combination with pacemaker implantation and/or stellectomy in some patients.

The use of an ICD may be considered as primary therapy if the patient has a strong family history of sudden cardiac death. However, because some studies showed that a family history of sudden cardiac death is not an independent risk factor, [30] some experts do not recommend ICD therapy based only on a family history of sudden cardiac death. [31]

Early ICD therapy should be considered in high-risk patients with Jervell and Lang-Nielsen (JLN) syndrome, because the efficacy of beta-blockers has been found to be more limited in these patients. [32]

The usefulness of implanted cardiac pacemakers is based on the premise that pacing eliminates arrhythmogenic bradycardia, decreases heart-rate irregularities (eliminating short-long-short sequences), and decreases repolarization heterogeneity, thereby diminishing the risk of torsade de pointes ventricular tachycardia. Pacemakers are particularly helpful in patients with documented pause-bradycardia–induced torsade de pointes and in patients with LQT3.

However, data indicate that cardiac events continue to occur in high-risk patients with cardiac pacing. Because newer models of ICDs include a cardiac pacing function, cardiac pacing (without defibrillators) is unlikely to be used in patients with LQTS. Pacing alone may be used in low-risk patients with LQT3.


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