Influence of Phase Duration of Biphasic Waveforms on Defibrillation Energy Requirements With a 70-μF Capacitance

Schauerte, Patrick; Schöndube, Friedrich A.; Grossmann, Marius; Dörge, Hilmar; Stein, Frank; Dohmen, Bernhard M.; Moumen, Abdel; Erena, Konstantin; Messmer, Bruno J.; Hanrath, Peter; Stellbrink, Christoph

doi:10.1161/01.cir.97.20.2073

Cited by 19 publications

(16 citation statements)

References 43 publications

(39 reference statements)

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“…Yet, the optimal shock duration or phase 1 tilt with the lowest DFT may vary considerably, depending on electrode impedance or capacitance size. 2,5,15 The present study underscores the value of using ULV to predict the optimal TSD for internal defibrillation. A similar correlation between ULV and DFT over different shock durations has recently been reported for monophasic shocks and biphasic shocks of varying phase 2 duration.…”

Section: Discussionmentioning

confidence: 60%

“…DFTs and ULVs were determined for 10 TSDs (2,4,6,8,10,12,14,16,18, and 20 ms), with a relation of phase 1 to phase 2 duration of 50%:50%. The order of testing of the different TSDs was randomized within each animal.…”

Section: Waveform Durationsmentioning

confidence: 99%

“…1,2 Depending on factors such as applied capacitance 3,4 and electrode impedance, 5 the optimal total shock duration (TSD) may vary from patient to patient. Testing of the defibrillation threshold (DFT) of different TSDs in individual patients would require the induction of multiple episodes of ventricular fibrillation (VF), which may lead to intolerable hemodynamic impairment.…”

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confidence: 99%

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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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Section: Discussionmentioning

confidence: 60%

Section: Waveform Durationsmentioning

confidence: 99%

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

et al. 1999

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“…The term ‘burping’ came from the analogy to the removal of excess gas from a baby [86]. All major predictions of the burping theory have been verified in animal studies [87–91].…”

Section: Optimal Pulse Widthsmentioning

confidence: 99%

Achieving low defibrillation thresholds at implant: pharmacological influences, RV coil polarity and position, SVC coil usage and positioning, pulse width settings, and the azygous vein

Kroll

Schwab

2010

Fundamemntal Clinical Pharma

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Approximately 30% of implantable cardioverter defibrillator (ICD) patients still die of sudden death. A major cause of these sudden deaths is the failure to defibrillate because of failure to achieve a low defibrillation threshold (DFT). Anti‐arrhythmic drugs can have a profound positive or negative effect on the DFT. Unfortunately, present clinical practice continues to feature many procedures and tactics that have minimal to negative DFT benefit. In addition, many demonstrated helpful tactics are not understood or followed. This review covers the optimal RV (right ventricular) coil position and polarity, superior vena cava (SVC) coil positioning and usage, pulse width settings, and azygous vein coil implants. Specifically, the RV coil should be set to an anodal polarity and never ‘reversed’. The optimal RV coil position appears to be along the mid‐septum. The SVC coil should be kept out of the right atrium and placed in the innominate vein junction. The SVC coil should be always on for high impedance patients. For low impedance patients, the SVC coil should be set on or off depending on which setting gives the lowest DFT. Pulse widths should be set to correspond to optimally charging and discharging a cardiac membrane time constant of between 3.5 and 4.5 ms. For the highest DFT patients, a separate coil should be placed in the azygous vein and connected to the ICD ‘SVC’ port. Anachronistic approaches such as the use of polarity reversal, apical RV coil tip forcing, and subcutaneous arrays are also discussed.

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“…Temperaturmessungen mit einem Thermistor an der Außenseite der stimulierten Gefäße, gegenüber der Stimulationselektrode, zeigten keine signifikante Temperaturerhöhung am Gefäß während hochfrequenter Stimulation mit 30 V an. Es ist denkbar, dass wie in der Elektrostimulation und Defibrillation des Myokards Parameter wie Impulsdauer, Impulsform oder Impulspolarität die notwendige parasympathische Stimulationsspannung weiter reduzieren können (7,14,15).…”

Section: Limitationenunclassified

Die Behandlung des tachykarden Vorhofflimmerns durch kathetergestützte elektrische Stimulation des kardialen parasympathischen Nervensystems

Schauerte¹,

Scherlag

2000

Z Kardiol

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Influence of Phase Duration of Biphasic Waveforms on Defibrillation Energy Requirements With a 70-μF Capacitance

Cited by 19 publications

References 43 publications

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

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

Achieving low defibrillation thresholds at implant: pharmacological influences, RV coil polarity and position, SVC coil usage and positioning, pulse width settings, and the azygous vein

Die Behandlung des tachykarden Vorhofflimmerns durch kathetergestützte elektrische Stimulation des kardialen parasympathischen Nervensystems

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