Ventricular fibrillation frequency from implanted cardioverter defibrillator devices
Panfilov I et al. – The dominant frequency (DF) of short intervals of induced ventricular fibrillation (VF) is highly reproducible and is sensitive to pharmacologic interventions that extend effective refractory period. Such estimates of DF may thus have clinical utility and in pts with implanted cardioverter defibrillator devices (ICDs) provide a means of investigating mechanisms underlying the initiation and early phases of VF. Methods- Study of the reproducibility of the DF during separate VF events on stored electrograms (EGMs) from ICDs
- Assessment of 82 pts with a Medtronic ICD who had 2 induced VF episodes during ICD testing
- Extraction of EGMs recorded during both episodes
- Determination of DF using fast Fourier transform
Results- Mean DF for population: 4.7 ± 0.6 Hz, corresponding to 213-ms cycle length
- First and second VF episodes highly correlated, showing highly reproducible DF
- DF significantly lower for 18 pts on Class III agents vs remaining 63
- DF of ischemic heart disease pts did not differ from that of dilated cardiomyopathy pts
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