Cardiac resynchronization therapy is associated with a reduction in ICD therapies as it improves ventricular...

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• Repeated implantable cardioverter-defibrillator (ICD) therapies can cause myocardial damage, increasing arrhythmia and mortality risks.
• Left ventricular dysfunction, defined by ejection fraction (LVEF) <50%, is a common indication for device therapy.

Purpose of the Study:

• To evaluate if cardiac resynchronization therapy-defibrillator (CRT-D) reduces appropriate therapies compared to ICD alone in patients with reduced LVEF.
• To identify predictors of first appropriate therapy in patients receiving ICD or CRT-D.

Main Methods:

• Retrospective study of 175 patients with reduced LVEF (<50%) treated with ICD or CRT-D between 2009-2014.
• Patients received devices for primary or secondary prevention of sudden cardiac death.
• Cox regression analysis was used to assess predictors of first appropriate therapy.

Main Results:

• 25.1% of patients received at least one appropriate therapy.
• CRT-D patients had lower baseline LVEF and worse NYHA class but experienced a significantly lower risk of first appropriate therapy (aHR: 0.24) if LVEF improved >35%.
• No significant difference in mortality was observed between ICD and CRT-D groups.

Conclusions:

• Despite a worse baseline clinical profile, CRT-D patients received fewer device therapies compared to ICD patients.
• The reduction in therapies for CRT-D recipients is significantly associated with improved LVEF.