Ventricular fibrillation frequency from implanted cardioverter defibrillator devices

Area of Science:

• Cardiology
• Biomedical Engineering
• Electrophysiology

Background:

• Ventricular fibrillation (VF) dominant frequency (DF) offers insights into arrhythmia complexity and mechanisms.
• DF analysis using electrograms (EGMs) from implantable cardioverter-defibrillators (ICDs) may guide VF therapies.
• Reproducibility of DF during separate VF events is crucial for clinical application.

Purpose of the Study:

• To assess the reproducibility of dominant frequency (DF) during induced ventricular fibrillation (VF) in patients with ICDs.
• To determine if DF analysis can provide insights into VF mechanisms and guide therapies.
• To evaluate the sensitivity of DF to pharmacological interventions.

Main Methods:

• Identified 82 patients with Medtronic ICDs experiencing two induced VF episodes during testing.
• Extracted and analyzed EGMs using fast Fourier transform to determine DF.
• Correlated DF values between the first and second VF episodes.

Main Results:

• Mean DF was 4.7 ± 0.6 Hz (cycle length 213 ms).
• DF demonstrated high reproducibility between VF episodes (interclass correlation = 0.87, P < 0.01).
• Class III antiarrhythmic agents significantly lowered DF (4.4 ± 0.4 Hz vs. 4.8 ± 0.6 Hz, P < 0.01).

Conclusions:

• Dominant frequency (DF) of induced ventricular fibrillation (VF) is highly reproducible.
• DF analysis is sensitive to pharmacological interventions affecting the refractory period.
• DF estimates from ICDs may have clinical utility for investigating VF initiation and early phases.