Onset dynamics of ventricular tachyarrhythmias as measured by dominant frequency.

BACKGROUND

Differences in dominant frequency (DF), a measure of electrical activation rate, were used to characterize and classify ventricular tachyarrhythmias (VTA) at onset.

METHOD

In canine 3- to 5-day-old infarct border zone, monomorphic re-entrant ventricular tachycardia (MVT) was repeatedly induced by programmed electrical stimulation (14 experiments, total of 23 instances used for analysis). Ventricular fibrillation (VF) and polymorphic ventricular tachycardia (PVT) occasionally occurred (total of 23 and 4 episodes, respectively, for all experiments). For each of 196 to 312 border zone bipolar electrode recordings, the DF and DF spatial derivative (DFD) were calculated to assess electrical activity organization and were used to classify VTAs at onset. For classification, measurements were made at 1.5 and 3 seconds from last stimulus for all recording sites, and at 2.25 and 3 seconds for 3- to 7-site subsets as a test with limited data.

RESULTS

At 1.5 seconds after stimulus end, the DF/DFD magnitudes were ordered: MVT < PVT < VF (P < .001). DF/DFD trended upward in VF, downward in MVT, and lacked trend in PVT (P < .001). Based on DF/DFD magnitudes/trends, the MVT/VF classifier accuracy was 94.6% (all sites/1.5 s), 97.9% (all sites/3 s), 82.6% (subset sites/2.25 s), and 86.3% (subset sites/3 s).

CONCLUSION

VTAs are distinguishable at early onset by degree and trend in organization of electrical activity as estimated by DF and DFD. VF becomes increasingly disorganized, MVT becomes increasingly organized, and PVT remains intermediate. It may be possible to apply this technique for analysis and classification in a clinical setting using currently available special mapping catheters.