Amplitude-duration relation for direct ventricular defibrillation with rectangular current pulses

Koning, Giel G.; Schneider, H.; Hoelen, Adriaan J.; Reneman, Robert S.

doi:10.1007/bf02477110

Cited by 58 publications

(11 citation statements)

References 20 publications

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“…Based on valuable considerations by Irnich, 8 we used the average amplitude during the pulse (∫ U(t)/t) rather than the charging (leading edge) amplitude or pulse energy. In comparison, authors that recorded strength‐duration curves for defibrillation used rectangular or nearly rectangular (tilt < 15%) pulses, or they calculated average amplitudes 17–27 …”

Section: Methodsmentioning

confidence: 99%

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A Comparison of Chronaxies for Ventricular Fibrillation Induction, Defibrillation, and Cardiac Stimulation: Unexpected Findings and Their Implications

Lawo

Deneke

Schrader

et al. 2009

Cardiovasc electrophysiol

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It may be reasonable to study whether LEC pulses from 0.25 ms to 0.30 ms in duration and up to 250 V in amplitude would increase therapeutic yield in VT termination without VF induction in humans. Contrary to the current belief, the discrepancy between defibrillation and stimulation chronaxie is not caused by different electrode size. We postulate that the time constant of the fast sodium channel reactivation may be the underlying reason.

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Section: Methodsmentioning

confidence: 99%

“…In comparison, authors that recorded strengthduration curves for defibrillation used rectangular or nearly rectangular (tilt < 15%) pulses, or they calculated average amplitudes. [17][18][19][20][21][22][23][24][25][26][27]…”

Section: Strength-duration Curvesmentioning

confidence: 99%

A Comparison of Chronaxies for Ventricular Fibrillation Induction, Defibrillation, and Cardiac Stimulation: Unexpected Findings and Their Implications

Lawo

Deneke

Schrader

et al. 2009

Cardiovasc electrophysiol

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“…Using Eq. [7] for calculation of the minimal flux density and assuming r = 0.25 m and c = 1, the minimal thresholds for magnetostimulation can be estimated for myelinated nerves: …”

Section: Nerves and Cardiac Musclesmentioning

confidence: 99%

Magnetostimulation in MRI

Irnich

Schmitt

1995

Magnetic Resonance in Med

106

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In national and international bodies, there is active discussion of appropriate safety regulations of levels of magnetic field strength in MRI. Present limits are usually expressed in terms of the switching rate dB/dt, but the validity of this is open to debate. Application of the fundamental law of electrostimulation is well-established, both on theoretical and experimental grounds. Application of this law, in combination with Maxwell's law, yields a very simple equation that we call the fundamental law of magnetostimulation. This law has the hyperbolic form of a strength-duration curve and allows an estimation of the lowest possible value of the magnetic flux density capable of stimulating nerves and muscles. Calculations prove that the threshold for heart excitation is much higher than those for nerve and muscle stimulations. Experimental results from us and other authors confirm the correctness of the derived laws for magnetostimulation. In light of these findings, proposed safety limits should be reconsidered.

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“…Also, the safety factors of these three 10 ms waveforms are not significantly different (p = 0.05) than the 5 ms single pulse. The higher defibrillation threshold current density for the 5 ms single pulse is expected because of the well known strength/duration relationship for tissue stimulation and defibrillation (GEDDES et al, 1970;KONING et al, 1975;BOURLAND et al, 1978a). Hence, if the total pulse duration is held constant, there is no physiological advantage to the reciprocal pulse waveform.…”

Section: Discussionmentioning

confidence: 99%

Efficacy and safety of the reciprocal pulse defibrillator current waveform

Niebauer

Babbs

Geddes

et al. 1984

Med. Biol. Eng. Comput.

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The efficacy and safety of a new defibrillating current waveform, consisting of a low-tilt 5 ms trapezoidal pulse followed closely by a second identical pulse of opposite polarity, was tested m seven isolated, perfused, working canine hearts suspended in an isoresistive, isosmotic shock bath at 37 o C. The efficacy and safety of the reciprocal pulse was compared with a single 5 ms pulse, a single 10 ms pulse, and a dual (unidirectional) 5 ms pulse waveform. The mean threshold average current densities for the 5 ms single pulse, 10 ms single pulse, dual 5 ms pulse, and reciprocal pulse (absolute values) were 50, 38, 36, and 37 mA/cm 2 , respectively. The corresponding mean threshold energy densities in the shock bath were 2.8, 2.9, 2.9, and 3.1 mJ/cm 3 . Despite the differences in threshold current density among the waveforms, no differences in safety factor (shock strength for 50 per cent post-shock depression, divided by threshold shock strength) were found among the waveforms. The current safety factors were 5.4, 5.4, 5.6, and 5.5 for the 5 ms single pulse, 10 ms single pulse, dual unidirectional pulse and reciprocal pulse, respectively. The corresponding energy density safety factors were 25, 27, 29, and 27. Thus the use of this reciprocal pulse waveform provides no advantage in efficacy or safety over waveforms of the same total duration.

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Amplitude-duration relation for direct ventricular defibrillation with rectangular current pulses

Cited by 58 publications

References 20 publications

A Comparison of Chronaxies for Ventricular Fibrillation Induction, Defibrillation, and Cardiac Stimulation: Unexpected Findings and Their Implications

A Comparison of Chronaxies for Ventricular Fibrillation Induction, Defibrillation, and Cardiac Stimulation: Unexpected Findings and Their Implications

Magnetostimulation in MRI

Efficacy and safety of the reciprocal pulse defibrillator current waveform

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