Efficacy of low-energy t wave shocks for induction of ventricular fibrillation in patients with implantable cardioverter defibrillators

Bhandari, Anil K.; Isber, Nidal; Estioko, Manuel R.; Ziccardi, Thomas; Cannom, David S.; Park, Young; Lerman, Robert D.; Prejean, Curtis A.; Sun, Guo-Wen

doi:10.1016/s0022-0736(98)90004-8

Cited by 12 publications

(11 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…An ideal surrogate for VF susceptibility has not been agreed on. Different electrical stimulation techniques and methods have been proposed and tested, such as a restitution protocol,52 single‐pulse stimulation,53, 54, 55, 56, 57 and 60‐Hz alternating current stimulation 55, 56, 58, 59…”

Section: Discussionmentioning

confidence: 99%

Elimination of Purkinje Fibers by Electroporation Reduces Ventricular Fibrillation Vulnerability

Livia

Sugrue

Witt

et al. 2018

JAHA

View full text Add to dashboard Cite

BackgroundThe Purkinje network appears to play a pivotal role in the triggering as well as maintenance of ventricular fibrillation. Irreversible electroporation (IRE) using direct current has shown promise as a nonthermal ablation modality in the heart, but its ability to target and ablate the Purkinje tissue is undefined. Our aim was to investigate the potential for selective ablation of Purkinje/fascicular fibers using IRE.Methods and ResultsIn an ex vivo Langendorff model of canine heart (n=8), direct current was delivered in a unipolar manner at various dosages from 750 to 2500 V, in 10 pulses with a 90‐μs duration at a frequency of 1 Hz. The window of ventricular fibrillation vulnerability was assessed before and after delivery of electroporation energy using a shock on T‐wave method. IRE consistently eradicated all Purkinje potentials at voltages between 750 and 2500 V (minimum field strength of 250–833 V/cm). The ventricular electrogram amplitude was only minimally reduced by ablation: 0.6±2.3 mV (P=0.03). In 4 hearts after IRE delivery, ventricular fibrillation could not be reinduced. At baseline, the lower limit of vulnerability to ventricular fibrillation was 1.8±0.4 J, and the upper limit of vulnerability was 19.5±3.0 J. The window of vulnerability was 17.8±2.9 J. Delivery of electroporation energy significantly reduced the window of vulnerability to 5.7±2.9 J (P=0.0003), with a postablation lower limit of vulnerability=7.3±2.63 J, and the upper limit of vulnerability=18.8±5.2 J.ConclusionsOur study highlights that Purkinje tissue can be ablated with IRE without any evidence of underlying myocardial damage.

show abstract

Section: Discussionmentioning

confidence: 99%

Elimination of Purkinje Fibers by Electroporation Reduces Ventricular Fibrillation Vulnerability

Livia

Sugrue

Witt

et al. 2018

JAHA

View full text Add to dashboard Cite

show abstract

“…It was hypothesized that the T shock method had an approximately 90% 1 success rate. The sample size used in this protocol was based on the one‐tailed McNemar's test.…”

Section: Methodsmentioning

confidence: 99%

“…The most efficient method of induction should reduce the number of induction attempts, increase the likelihood that VF is induced rather than ventricular tachycardia (VT), and be simple to program. In addition, a method with a decreased time to induction of VF would minimize hemodynamic compromise 1–3 . Among several induction methods available, shock on T wave is a commonly used method to induce VF during the ICD implantation.…”

Section: Introductionmentioning

confidence: 99%

“…Among several induction methods available, shock on T wave is a commonly used method to induce VF during the ICD implantation. Current literature indicates that shock on T has a 90–98% rate of effectiveness in inducing VF at implant 1 . Several studies show that alternating current (AC) is also effective, 4 but AC cannot be used noninvasively at follow‐up.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Shock on T Versus Direct Current Voltage for Induction of Ventricular Fibrillation:

Sharma

Fain

O’Neill

et al. 2004

Pacing Clinical Electrophis

View full text Add to dashboard Cite

VF is induced during ICD implantation to determine efficacy of therapy. Establishing the best clinical method of induction of VF would potentially be beneficial in reducing the number of induction attempts and reducing the frequency of inadvertent induction of VT. Commonly used methods to induce VF include shock in the T wave vulnerable period (T shock) and high frequency stimulation. This study compared the efficacy of T shock with a new induction method using a 9-V DC pulse. The study was a randomized, prospective, case crossover trial in patients receiving ICDs. VF was induced by T shock and DC in a randomized sequence during an ICD implant. VF was induced at least four times in each patient (two T shocks and two DC inductions) and with each induction; attempts were continued with modifications until successful. A paired evaluation between the T shock/DC induction was performed in 37 patients (28 men, age 64 +/- 12 years) with a left ventricular ejection fraction of 0.40 +/- 0.20. Arrhythmia indications were VT (n = 23), VF (n = 10), and VT/VF (n = 4). Drug therapy included amiodarone (n = 10), metoprolol (n = 6), digoxin (n = 1), and lidocaine (n = 1). The average T shock voltage was 207.0 +/- 16.1 V. The S1 cycle drive length was consistently 400 ms, and the mean S2 coupling interval was 317.8 +/- 19.6 ms. The length of time DC applied averaged 3.8 +/- 1.4 seconds. A total of 148 episodes of VF were included in the analysis. T shock induced VF with a cycle length of 213.5 +/- 35.1 ms, and DC induced VF with a cycle length of 214.6 +/- 34.5 ms (P = 0.86). Although VF was eventually induced for each randomization, the number of attempts required were dependent on the method of induction. The successful DC first attempt VF induction rate was 96%, with three patients requiring two attempts during one of the DC inductions. T shock had a 68% first attempt success rate with 21 patients requiring multiple T shocks to induce VF. All nine female patients had at least one unsuccessful first attempt T shock, which contributed to an overall unsuccessful first attempt induction rate significantly higher in women then men (36.1% vs 12.5%, P = 0.001). A constant DC voltage induction of VF may be more effective than T shock for induction of VF in a clinical setting because it reduces the number of attempts required to induce VF. By either method, VF appears to be more difficult to induce in women. DC induction has the advantage of simple programming of only duration of stimulation. These findings have implications particularly for ICD implantation with conscious sedation.

show abstract

“…181,182 With the development of new electrical defibrillation waveforms and lead configurations, electrically active can systems, and efficient energy delivery systems, the transvenous approach is now the main technique for ICD implantation. 183 The transvenous lead systems vary in configuration from manufacturer to manufacturer, but venous access is identical, and lead positioning nearly identical, to the techniques previously described for the ventricular Chapter 18: Permanent Pacemaker and Implantable Cardioverter-Defibrillator Implantation pacing electrode. Because of concerns about the subclavian crush syndrome, cephalic cutdown or percutaneous access to the axillary vein is recommended.…”

Section: Endocardial Approachmentioning

confidence: 99%

Permanent Pacemaker and Implantable Cardioverter-Defibrillator Implantation

Belott¹,

Reynolds²

2007

Clinical Cardiac Pacing, Defibrillation, and Resynchronization Therapy

View full text Add to dashboard Cite

Efficacy of low-energy t wave shocks for induction of ventricular fibrillation in patients with implantable cardioverter defibrillators

Cited by 12 publications

References 22 publications

Elimination of Purkinje Fibers by Electroporation Reduces Ventricular Fibrillation Vulnerability

Elimination of Purkinje Fibers by Electroporation Reduces Ventricular Fibrillation Vulnerability

Shock on T Versus Direct Current Voltage for Induction of Ventricular Fibrillation:

Permanent Pacemaker and Implantable Cardioverter-Defibrillator Implantation

Contact Info

Product

Resources

About