Treatment of Long QT Syndrome After Aborted Cardiac Arrest When ICD Shocks Persist on Beta-Blockers

This protocol addresses congenital long QT syndrome (LQTS) in a patient who survived a cardiac arrest, has an implanted cardioverter-defibrillator (ICD), and continues to experience multiple appropriate ICD shocks despite ongoing beta-blocker therapy.

Clinical situation

Survivors of cardiac arrest with LQTS face a high risk of arrhythmia recurrence. Even on beta-blocker therapy, recurrent ventricular events occur at a significant rate, which supports the use of an ICD in all cardiac arrest survivors. Some ICD-implanted patients continue to receive repeated appropriate shocks despite beta-blockers — identifying a group who require an additional intervention beyond the first-line regimen.

When the first-line regimen is not sufficient

The initial approach for aborted cardiac arrest in LQTS comprises general protective measures (avoiding QT-prolonging drugs, correcting electrolyte abnormalities, avoiding genotype-specific arrhythmia triggers), a non-selective beta-blocker, and ICD implantation. In LQT3 patients, oral mexiletine is added when a QTc shortening of 40 ms is demonstrated on testing before chronic treatment. When this regimen fails to control arrhythmia burden — specifically, when an ICD carrier continues to experience multiple shocks while on beta-blockers — the next protocol step applies.

Next step

A left-sided cardiac sympathetic denervation procedure is among the interventions considered at this stage. The complete protocol — including selection criteria, procedural considerations, and the full clinical algorithm — is available via the link below.

Instant Access to Structured Evidence-Based Regimens

References

DOI: 10.1093/eurheartj/ehac262

ICD implantation in addition to beta-blockers is recommended in LQTS patients with CA.
Survivors of a CA have a high risk of recurrences, even on beta-blockers (14% within 5 years on therapy), supporting the use of ICD in CA survivors.
Left cardiac sympathetic denervation (LCSD) is recommended for symptomatic patients despite beta-blockers when ICD is contraindicated or declined, or for an ICD carrier who experiences multiple shocks while on beta-blockers.

View source ↗