Ventricular Fibrillation Due to Single, Localized Induction and Condenser Shocks Applied During the Vulnerable Phase of Ventricular Systole

Wiggers, Carl J.; Wégria, René

doi:10.1152/ajplegacy.1940.128.3.500

Cited by 390 publications

(80 citation statements)

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“…25 26 A constant-current stimulator driven by a specially designed computer program delivered a train of 10 S, stimuli at twice diastolic threshold with a basic cycle length of 350 msec. A premature stimulus, the S2 was then introduced 200 msec after the final S, paced beat.…”

Section: Methodsmentioning

confidence: 99%

The effect of chemical ablation of the endocardium on ventricular fibrillation threshold.

Damiano¹,

Smith²,

Tripp³

et al. 1986

Circulation

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The purpose of this study was to examine the effects of ablation of the superficial endocardium and Purkinje network on left ventricular fibrillation threshold. Lugol's solution was applied through small ventriculotomies to the left and right ventricular endocardium of 10 dogs on cardiopulmonary bypass. Two control groups of five animals each underwent either endocardial application of saline or epicardial application of Lugol's solution. perimentally to be an important substrate in ventricular tachycardia, its role in ventricular fibrillation is less clear.'2-' Nevertheless, transmural recordings during ventricular fibrillation have documented endocardial to epicardial spread of activation with variable block, implying an endocardial origin of many of the activation fronts that maintain the arrhythmia.'9The purpose of this study was to examine the effect of ablation of the superficial endocardium and Purkinje fiber network on the ability to initiate ventricular fibrillation. Lugol's solution, a concentrated iodine solution, has an affinity for glycogen. It has been demonstrated to stain and ablate both Purkinje fibers and endocardial tissue.2>22 In this study, the electrophysiologic effects of the endocardial application of Lugol's solution on ventricular fibrillation threshold were examined. In addition, the rheologic and histologic changes induced by this procedure were also investigated. MethodsTwenty adult mongrel dogs weighing 25 to 35 kg were anesthetized with intravenous sodium pentobarbitol (30 mg/kg) and maintained on a constant-drip infusion of 2 mg/min throughout the study.

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Section: Methodsmentioning

confidence: 99%

The effect of chemical ablation of the endocardium on ventricular fibrillation threshold.

Damiano¹,

Smith²,

Tripp³

et al. 1986

Circulation

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“…It is commonly thought that the success or failure of FFP is determined by a well-known phenomenon called vulnerability (Mines 1914;Wiggers & Wégria 1940). Indeed, we can explain the success of the unpinning mechanism sketched in figure 1 by looking first at a one-dimensional cable.…”

Section: Vulnerable Window and Unpinning Windowmentioning

confidence: 99%

Phase-resolved analysis of the susceptibility of pinned spiral waves to far-field pacing in a two-dimensional model of excitable media

Bittihn

Squires

Luther

et al. 2010

Phil. Trans. R. Soc. A.

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Life-threatening cardiac arrhythmias are associated with the existence of stable and unstable spiral waves. Termination of such complex spatio-temporal patterns by local control is substantially limited by anchoring of spiral waves at natural heterogeneities. Far-field pacing (FFP) is a new local control strategy that has been shown to be capable of unpinning waves from obstacles. In this article, we investigate in detail the FFP unpinning mechanism for a single rotating wave pinned to a heterogeneity. We identify qualitatively different phase regimes of the rotating wave showing that the concept of vulnerability is important but not sufficient to explain the failure of unpinning in all cases. Specifically, we find that a reduced excitation threshold can lead to the failure of unpinning, even inside the vulnerable window. The critical value of the excitation threshold (below which no unpinning is possible) decreases for higher electric field strengths and larger obstacles. In contrast, for a high excitation threshold, the success of unpinning is determined solely by vulnerability, allowing for a convenient estimation of the unpinning success rate. In some cases, we also observe phase resetting in discontinuous phase intervals of the spiral wave. This effect is important for the application of multiple stimuli in experiments.

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“…13 If a critical shock strength (ULV) is exceeded, these shocks no longer induce VF. 14 Linear correlation between ULV and DFT has been demonstrated in several human and animal studies.…”

Section: Discussionmentioning

confidence: 99%

Effect of Biphasic Shock Duration on Defibrillation Threshold With Different Electrode Configurations and Phase 2 Capacitances

et al. 1999

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Background-The defibrillation threshold (DFT) may be affected by biphasic shock duration (BSD), electrode configuration, and capacitance. The upper limit of vulnerability (ULV) may be used to estimate the DFT. For different lead configurations and phase 2 capacitances, we investigated in 18 pigs whether the use of ULV may predict waveforms with lowest DFT. Methods and Results-DFT and ULV were determined by up-down protocols for 10 BSDs. ULVs were measured by T-wave scanning during ventricular pacing (cycle length 500 ms). In protocol 1 (nϭ6), a pectoral "active can" was combined with an electrode in the superior vena cava as common cathode and a right ventricle electrode as anode (ACϩSVC). In protocol 2 and protocol 3 (nϭ6 each), only the "active can" was used as proximal electrode (AC). Capacitance was 150 F during both phases in protocol 1 and protocol 3 but 150 F (phase 1) and 300 F (phase 2) in protocol 2. ULV and DFT demonstrated a linear correlation in each protocol (rϭ0.78 to 0.84). Lowest DFTs were found at 10 ms for ACϩSVC and at 14 ms for AC (PϽ0.001). At optimal BSDs, voltage DFTs did not differ significantly between AC (527Ϯ57 V) and ACϩSVC (520Ϯ70 V). Switching capacitors for phase 2 in a way that reduced leading-edge voltage by 50% while doubling capacity did not change BSD for optimal voltage DFT but increased minimum DFT from 527Ϯ57 V to 653Ϯ133 V (Pϭ0.04). Conclusions-The BSD with lowest DFT is shorter for ACϩSVC than for AC. There is no significant difference in voltage DFT between both at optimal BSD. A lower phase 2 capacitance reduces DFTs irrespective of BSD. Because strength-duration curves for DFT and ULV correlate for different BSDs, lead systems, and phase 2 capacitances, ULV determination may allow the prediction of waveforms with lowest DFT. (Circulation. 1999;99:1516-1522.)

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Ventricular Fibrillation Due to Single, Localized Induction and Condenser Shocks Applied During the Vulnerable Phase of Ventricular Systole

Cited by 390 publications

References 0 publications

The effect of chemical ablation of the endocardium on ventricular fibrillation threshold.

The effect of chemical ablation of the endocardium on ventricular fibrillation threshold.

Phase-resolved analysis of the susceptibility of pinned spiral waves to far-field pacing in a two-dimensional model of excitable media

Effect of Biphasic Shock Duration on Defibrillation Threshold With Different Electrode Configurations and Phase 2 Capacitances

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