Immediate countershock versus cardiopulmonary resuscitation before countershock in a 5-minute swine model of ventricular fibrillation arrest

Niemann, James T.; Cruz, Brian; Garner, Daniel; Lewis, Roger J.

doi:10.1067/mem.2000.109441

Cited by 50 publications

(22 citation statements)

References 7 publications

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“…We did not observe an added benefit to preceding the first shock with CPR when VF was of moderate duration. This finding is consistent with previous findings in swine 21 and humans. 14,15 The ScE may be useful in differentiating which patients may be best treated with IC from those who would benefit from having some CPR first, ie, an ScE of Յ1.20 would indicate immediate shock.…”

Section: Discussionsupporting

confidence: 83%

Ventricular Fibrillation Scaling Exponent Can Guide Timing of Defibrillation and Other Therapies

et al. 2004

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Background— The scaling exponent (ScE) of the ventricular fibrillation (VF) waveform correlates with duration of VF and predicts defibrillation outcome. We compared 4 therapeutic approaches to the treatment of VF of various durations. Methods and Results— Seventy-two swine (19.5 to 25.7 kg) were randomly assigned to 1 of 9 groups (n=8 each). VF was induced and left untreated until the ScE reached 1.10, 1.20, 1.30, or 1.40. Animals were treated with either immediate countershock (IC); 3 minutes of CPR before the first countershock (CPR); CPR for 2 minutes, then drugs given with 3 more minutes of CPR before the first shock (CPR-D); or drugs given at the start of CPR with 3 minutes of CPR before the first shock (Drugs+CPR). Return of spontaneous circulation (ROSC) and 1-hour survival were analyzed with χ 2 and Kaplan-Meier survival curves. IC was effective when the ScE was low but had decreasing success as the ScE increased. No animals in the 1.30 or 1.40 groups had ROSC from IC (0 of 16). CPR did not improve first shock outcome in the 1.20 CPR group (3 of 8 ROSC). Kaplan-Meier survival analyses indicated that IC significantly delayed time to ROSC in both the 1.3 ( P =0.0006) and the 1.4 ( P =0.005) groups. Conclusions— VF of brief to moderate duration is effectively treated by IC. When VF is prolonged, as indicated by an ScE of 1.3 or greater, IC was not effective and delayed time to ROSC. The ScE can help in choosing the first intervention in the treatment of VF.

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Section: Discussionsupporting

confidence: 83%

Ventricular Fibrillation Scaling Exponent Can Guide Timing of Defibrillation and Other Therapies

et al. 2004

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“…Unfortunately, pigs are susceptible to developing hemodynamically unstable ventricular arrhythmias and the success rate of resuscitation of a pig after prolonged unstable ventricular tachycardia is known to be disappointing. [23][24][25] Visual inspection of the epicardium clearly revealed epicardial lesions, ≈22 mm in diameter despite a only 12-mm circular ablation catheter. This raises the question how fast the effect of electroporation ablation takes in.…”

Section: Acute Outcomementioning

confidence: 99%

Safety and Feasibility of Closed Chest Epicardial Catheter Ablation Using Electroporation

Neven

Driel

Wessel

et al. 2014

Circ: Arrhythmia and Electrophysiology

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Background-Permanent coronary artery damage is a hazardous complication of epicardial radiofrequency ablation.Irreversible electroporation (IRE) is a promising nonthermal ablation modality able to create deep myocardial lesions. We investigated the effects of epicardial IRE on luminal coronary artery diameter and lesion depth. Methods and Results-In 5 pigs (60-75 kg), the pericardium was exposed using surgical subxiphoidal epicardial access. A custom deflectable octopolar 12-mm circular catheter with 2-mm ring electrodes was introduced in the pericardium via a steerable sheath. After coronary angiography (CAG), the proximal, mid, and distal left anterior descending, and circumflex coronary arteries were targeted with a single, cathodal 200 J application. CAG was repeated after IRE and after 3 months follow-up. Using quantitative CAG, the minimal luminal diameter at the lesion site was compared with the average of the diameters just proximal and distal to that lesion. Study ProtocolThe study was performed in 6 pigs (weight 60-75 kg). Amiodarone therapy was started 1 week before the index procedure (400 mg once daily) to prevent procedure-related arrhythmias. Carbasalate calcium (80 mg once daily) and clopidogrel (75 mg once daily) therapy was started 3 days before the index procedure and continued until euthanasia. The animals were sedated, intubated, and anesthetized according to standard procedures. Using a surgical subxiphoidal pericardial approach, a custom deflectable octopolar 12-mm circular catheter with 2-mm ring electrodes was introduced in the pericardial space via a 40-cm 8.5F deflectable sheath (Agilis EPI Steerable Introducer; St Jude Medical, St Paul, MN; Figure 1). After left anterior descending artery (LAD) and circumflex coronary artery (RCx) angiography, the mid and distal LAD and RCx were targeted with electroporation catheter ablation ( Figure 2). A single, cathodal 200 J application was delivered. This was repeated at 2 or 3 different locations over the LAD and RCx while avoiding overlap. The energy was generated by a monophasic external defibrillator (Lifepak 9; Physio-Control, Inc, Redmond, WA). A large skin patch (7506; Valleylab Inc, Boulder, CO) on the lower back served as indifferent electrode. A cathodal polarity was chosen because that has the highest threshold for arcing in a blood environment. 13 Coronary angiography (CAG) was repeated after the last application.After 3-month survival, CAG of the LAD and RCx was repeated, the thorax was opened by sternotomy, and the animal was euthanized by exsanguination. After the heart was removed, the pericardium was peeled off and the areas with ablation lesions were excised and fixated in formalin. Measurement of Coronary DiametersLuminal diameters of the coronary artery, proximal and distal to the application site, and the minimal diameter at the application site were measured using quantitative CAG. The latter value was then compared with the average value of the diameters proximal and distal to the application site. Histological Evaluation...

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“…Nevertheless, 25-to 35-kg swine are the animal model of choice for cardiac arrest and CPR studies because of their similarity to adults in terms of chest wall size and configuration and coronary artery anatomy. 11,14,20,21,[27][28][29] In conclusion, this study demonstrates that both RV and LV volumes increase substantially during the first minutes of untreated VF in swine with closed chest and closed pericardium. The implications of these findings for resuscitation from VF deserve further investigation.…”

Section: Discussionmentioning

confidence: 87%

“…7,8,20 In contrast, defibrillation from prolonged VF (5 to 15 minutes) results in asystole or pulseless electrical activity with poor outcomes unless prompt preshock and/or postshock CPR is provided. 3,4,9,10,21 Although it has been postulated that these pulseless rhythms may be due to RV overdistention and inadequate LV preload, our data argue strongly against this mechanism.…”

Section: Discussionmentioning

confidence: 99%

Magnetic Resonance Imaging During Untreated Ventricular Fibrillation Reveals Prompt Right Ventricular Overdistention Without Left Ventricular Volume Loss

et al. 2005

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Immediate countershock versus cardiopulmonary resuscitation before countershock in a 5-minute swine model of ventricular fibrillation arrest

Cited by 50 publications

References 7 publications

Ventricular Fibrillation Scaling Exponent Can Guide Timing of Defibrillation and Other Therapies

Ventricular Fibrillation Scaling Exponent Can Guide Timing of Defibrillation and Other Therapies

Safety and Feasibility of Closed Chest Epicardial Catheter Ablation Using Electroporation

Magnetic Resonance Imaging During Untreated Ventricular Fibrillation Reveals Prompt Right Ventricular Overdistention Without Left Ventricular Volume Loss

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