Apparent dual exit pathways during ventricular tachycardia recorded by an ICD

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• Ventricular tachycardia (VT) with dual exit pathways is a recognized phenomenon.
• Investigating the mechanisms of VT is crucial for effective treatment and device management.

Purpose of the Study:

• To evaluate suggestive evidence of dual exit pathway behavior during VT in a patient with an implanted cardioverter-defibrillator.
• To determine the role of the right ventricle (RV) in the VT circuit.

Main Methods:

• Continuous recordings of right ventricular (RV) and left ventricular (LV) electrograms were obtained.
• Analysis focused on the varying delay between LV and RV activation during VT.
• The RV rate was monitored during increases in the LV-RV delay.

Main Results:

• Varying delays between LV and RV activation were documented.
• The RV rate remained unchanged despite increases in the LV-RV delay.
• This indicated no participation of the RV in the VT circuit.

Conclusions:

• The findings ruled out the presence of VT with dual exit pathways in this patient.
• An unusual RV bystander, not participating in the VT circuit, was identified.
• This case highlights the importance of detailed electrogram analysis in understanding VT mechanisms.