Panescu D, Kroll M, Andrews C, Pratt H. Transthoracic ventricular fibrillation charge thresholds.
ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016;
2015:7208-13. [PMID:
26737955 DOI:
10.1109/embc.2015.7320055]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
UNLABELLED
Standards, including IEC 60479-1 and -2, provide current-based ventricular fibrillation thresholds (VFT) for stimuli durations between 0.1 ms and 10 s. It has been established that the amount of electrical charge, not the current calculated by root-mean-square, is most representative of the effects of cardiac stimulation. There are no unified models that present transthoracic charge VFTs for a wide range of stimuli durations. This work proposes a new unified charge model applicable to transthoracic stimuli durations ranging over 1 μs - 300 s. VFTs were compiled from our previous animal work and from other published reports, including from the studies that provided the raw data for IEC 60479-1 and -2. Our study goal was to cover a wide range of stimuli durations, for which reliable data exists. Consistent data were found for stimuli durations covering the range of 1 μs - 300 s where VFTs were expressed as charge. The model predicted a transthoracic charge VFT of 1 mC at 1 μs duration. The charge VFT increased with stimulus duration and reached 10 C at 300 s. Presenting the first charge-based transthoracic VFT model covering stimuli durations over 1 μs - 300 s, we found 3 behavioral regions of charge VFT vs.
DURATION
For short stimuli durations, 1 μs - 10 ms, VFTs followed a classic Weiss charge strength-duration curve. For long stimuli, longer than 5 s, charge VFTs can be approximated using a 38 mArms constant current model. From 10 ms to 5 s, charge VFTs tracked through a transition zone that could be approximated as a constant charge model Q≈100 mC.
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