Do ICD diagnostics predict failure of ventricular tachycardia response to antitachycardia pacing and need for shock?

Area of Science:

• Cardiology
• Electrophysiology
• Heart Failure Management

Background:

• Monomorphic ventricular tachycardia (MMVT) in heart failure patients with implantable cardioverter defibrillators (ICDs) that fails antitachycardia pacing (ATP) and requires shock is associated with higher mortality.
• The underlying reason for this increased mortality, specifically whether it relates to decompensated heart failure, remains unclear.

Purpose of the Study:

• To investigate if heart failure diagnostics from ICDs can predict ATP failure and the subsequent need for shock to terminate MMVT.
• To explore the association between specific heart failure indicators and the efficacy of ATP in terminating MMVT.

Main Methods:

• A retrospective review of 103 heart failure patients with Medtronic ICDs experiencing MMVT.
• Analysis of 452 MMVT events, examining pre-event heart failure diagnostics including atrial fibrillation burden, patient activity, night heart rate, heart rate variability, OptiVol fluid index, and MMVT heart rate.

Main Results:

• MMVT events requiring shock after ATP failure exhibited significantly faster heart rates and higher atrial fibrillation burden compared to those successfully terminated by ATP.
• Patient activity, night heart rate, heart rate variability, and OptiVol fluid index did not significantly differ between ATP-responsive and ATP-failing MMVT events.
• Multivariate analysis revealed that higher atrial fibrillation burden and lower patient activity were independently associated with ATP failure and the need for shock termination.

Conclusions:

• Device-based heart failure diagnostics are associated with MMVT events that fail ATP and necessitate shock.
• These findings suggest that indicators of decompensated heart failure can predict ATP failure in patients with ICDs, highlighting a potential mechanism for increased mortality.