Defining the Defibrillation Dosage

Kroll, Mark W.; Lehmann, Michael H.; Tchou, Patrick

doi:10.1007/978-1-4615-6345-7_4

Cited by 8 publications

(4 citation statements)

References 36 publications

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“…Further details on the topic of ICD waveform response to impedance variation,—with tilt and energy constancy as dose controllers,—are critically reviewed by Kroll et al 19 …”

Section: Discussionmentioning

confidence: 99%

Voltage gradients in transvenous and subcutaneous defibrillation and their risk of myocardial damage

Belalcazar¹,

Stahl

Friedman

et al. 2023

Cardiovasc electrophysiol

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Introduction: Transvenous implantable cardioverter-defibrillator (ICD) shocks have been associated with cardiac biomarker elevations and are thought in some cases to contribute to adverse clinical outcomes and mortality, possibly from myocardium exposed to excessive shock voltage gradients. Currently, there are only limited data for comparison with subcutaneous ICDs. We sought to compare ventricular myocardium voltage gradients resulting from transvenous (TV) and subcutaneous defibrillator (S-ICD) shocks to assess their risk of myocardial damage.Methods: A finite element model was derived from thoracic magnetic resonance imaging (MRI). Voltage gradients were modeled for an S-ICD with a left-sided parasternal coil and a left-sided TV-ICD with a mid-cavity, a septal right ventricle (RV) coil, or a dual coil lead (TV mid, TV septal, TV septal + superior vena cava [SVC]). High gradients were defined as > 100 V/cm. Results:The volumes of ventricular myocardium with high gradients > 100 V/cm were 0.02, 2.4, 7.7, and 0 cc for TV mid, TV septal, TV septal + SVC, and S-ICD, respectively. Conclusion:Our models suggest that S-ICD shocks produce more uniform gradients in the myocardium, with less exposure to potentially damaging electrical fields, compared to TV-ICDs. Dual coil TV leads yield higher gradients, as does closer proximity of the shock coil to the myocardium.

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“…Further details on the topic of ICD waveform response to impedance variation,—with tilt and energy constancy as dose controllers,—are critically reviewed by Kroll et al 19 …”

Section: Discussionmentioning

confidence: 99%

Voltage gradients in transvenous and subcutaneous defibrillation and their risk of myocardial damage

Belalcazar¹,

Stahl

Friedman

et al. 2023

Cardiovasc electrophysiol

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“…The presence of large amounts of foreign material may predispose the patient to infection. These electrodes may damage the underlying cardiac structures and decrease the ability to transthoracically defibrillate because of their insulating nature 29 . Furthermore, the metal sheet‐type electrodes form fibrous connective tissue around them that substantially increases the DFT.…”

Section: Discussionmentioning

confidence: 99%

“…These electrodes may damage the underlying cardiac structures and decrease the ability to transthoracically defibrillate because of their insulating nature. 29 Furthermore, the metal sheet-type electrodes form fibrous connective tissue around them that substantially increases the DFT. Recently, a Heart correction net that is attached to the outside of the heart has been proposed as a device for treating heart failure, 30,31 and the manufacturing technologies for tailor-made cardiac devices that fit the shape of individual hearts has been already established.…”

Section: Translational Perspectivementioning

confidence: 99%

Low‐energy defibrillation using a base–apex epicardial electrode

Okada,

Washio,

Sugiura

et al. 2023

Pacing Clinical Electrophis

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BackgroundCurrent implantable cardioverter defibrillators (ICDs) require electric conduction with high voltage and high energy, which can impair cardiac function and induce another malignant arrhythmia. As a result, there has been a demand for an ICD that can effectively operate with lower energy to mitigate the risks of a strong electric shock.MethodsA pair of sheet‐shaped electrodes covering the heart were analyzed in three configurations (top–bottom, left–right, and front–back) using a heart simulator. We also varied the distance between the two electrodes (clearance) to identify the electrode shape with the lowest defibrillation threshold (DFT). We also investigated the ICD shock waveform, shock direction, and the effect of the backside insulator of the electrode.ResultsThe DFT was high when the clearance was too small and the DFT was high even when the clearance was too large, suggesting that an optimal value clearance. The top–bottom electrodes with optimal clearance showed the lowest DFT when the biphasic shocks set the top electrode to a high potential first and then the bottom electrode was set to a high potential. An interval between a first shock waveform and a second shock waveform should be provided for low‐energy defibrillation. Because the insulator prevents unnecessary current flow to the backside, the DFT of the electrodes with insulators is less than those without insulators.ConclusionPainless defibrillation using sheet‐shaped electrodes on the epicardium is predicated on the basis of results using a heart simulator.

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“…Thus, implantable defibrillators have incorporated truncated exponentials for both phases. The exponential is truncated when a preset time has elapsed or when a given tilt (the percent change from the leading edge to the trailing edge of the exponential) has been achieved (52). Therefore, the exact shape of the waveform can be dependent on the impedance of the load, including contributions from the electrode/tissue interface and the biological resistance of the tissue.…”

mentioning

confidence: 99%

Automatic Implantable Cardioverter-defibrillators

Smith

Ideker²

1999

Annu. Rev. Biomed. Eng.

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Ventricular fibrillation, a loss of synchronous electrical activity in the heart which leads to hemodynamic collapse, is a leading cause of death. Because of the devastating personal and societal effects of this phenomenon, the automatic cardioverter-defibrillator has been developed for automatic detection and termination of the arrhythmia and is in widespread clinical use. Advances in circuits, leads, waveforms, and signal processing along with increased knowledge of the mechanisms of fibrillation have led to continuing improvements in this device, extending its use to many patients. A device has also been developed for the automatic or semiautomatic treatment of atrial fibrillation, an arrhythmia less life-threatening than ventricular fibrillation, but still a serious health problem. Continued improvement of these devices and the development of qualitatively new approaches hold great promise for exciting therapeutic advances in this area.

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Defining the Defibrillation Dosage

Cited by 8 publications

References 36 publications

Voltage gradients in transvenous and subcutaneous defibrillation and their risk of myocardial damage

Voltage gradients in transvenous and subcutaneous defibrillation and their risk of myocardial damage

Low‐energy defibrillation using a base–apex epicardial electrode

Automatic Implantable Cardioverter-defibrillators

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