Assessment of local atrial repolarization in a porcine acetylcholine model of atrial flutter and fibrillation

Aidonidis, Isaac; Poyatzi, Aphrodite; Stamatiou, Georgia; Lymberi, Maria; Molyvdas, Paschalis-Adam

doi:10.2143/ac.64.1.2034363

Cited by 6 publications

(3 citation statements)

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“…The inefficacy of RAN to completely suppress the inducibility of sAT could be associated with the relatively slower rates of tachycardia relative to atrial flutter or fibrillation. 9 This may point out the importance of the diastolic interval duration for RAN's efficiency in abolishing this arrhythmia. RAN needs high activation rates to depress atrial INa and, thus, to block areas of delayed conduction.…”

Section: Discussionmentioning

confidence: 99%

Effects of Ranolazine and its Combination with Amiodarone on Rapid Pacing-induced Reentrant Atrial Tachycardia in Rabbits

Aidonidis

Simopoulos

Δίπλα

et al. 2021

J Innov Cardiac Rhythm Manage.

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Ranolazine (RAN) has previously been shown to lower the onset of cholinergic atrial fibrillation in intact animals; however, its efficacy in the setting of atrial tachycardia (AT) is unknown. The purpose of this study was to investigate the effects of RAN alone or in combination with amiodarone (AMIO) on rapid pacing-evoked right AT in rabbit hearts. Right atrial monophasic action potentials (MAPs) were recorded in 11 anesthetized rabbits, using combination MAP pacing catheters. Vulnerability to AT was tested by employing consecutive trains of rapid burst pacing prior to and after 2.4 mg/kg of RAN alone delivered intravenously and then in combination with 3 mg/kg of AMIO as a 15-minute infusion. Primary endpoints were postdrug AT reproducibility as well as cycle length (CL) and tachycardia duration. MAP duration at 75% repolarization and the effective refractory period (ERP) were assessed during programmed pacing to calculate the atrial postrepolarization refractoriness (aPRR = ERP-MAPD 75%). AT was elicited in eight out of 11 rabbits; only these animals were included for further investigation. RAN did not abolish the inducibility of AT in any experiment; however, it prolonged its CL (baseline vs. RAN: 120 ± 16 ms vs. 138 ± 18 ms; p = 0.053). Supplemental AMIO further increased the AT CL (baseline vs. RAN + AMIO: 120 ± 16 ms vs. 152 ± 23 ms; p = 0.006), without affecting arrhythmia reinducibility. Slowing of the tachycardia after RAN or RAN + AMIO was associated with spontaneous termination of the arrhythmia. RAN prolonged the aPRR significantly, while AMIO in addition to RAN potentiated this effect. Neither RAN alone nor its combination with AMIO abolished the elicitation of AT in this model. However, both agents synergistically prolonged the aPRR, resulting in the slowing of AT and promoting spontaneous termination of the arrhythmia.

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Section: Discussionmentioning

confidence: 99%

Effects of Ranolazine and its Combination with Amiodarone on Rapid Pacing-induced Reentrant Atrial Tachycardia in Rabbits

Aidonidis

Simopoulos

Δίπλα

et al. 2021

J Innov Cardiac Rhythm Manage.

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“…MAP signals were characterized by determining relative occurrences and associated waveform properties relative to the tip location of a given catheter. Thus these signals enabled a more detailed anatomic/physiologic study of smaller areas of underlying myocardial substrate [16] , [19] – [21] . MAP detection required achieving a threshold of activation as well as the application of proper contact forces ( Fig.…”

Section: Methodsmentioning

confidence: 99%

“…It should be noted that there have been previous attempts to design mapping/ablation catheters with the ability to specifically record monophasic action potentials (MAPs), but none remain in clinical practice today [14] , [15] . In 2009, utilizing a porcine model, Aidonidis et al [16] hypothesized that the patterns of local repolarization in the high and low right atrium would allow determination of the optimal sites with pronounced propensity for eliciting disorganization during atrial flutter and AF; to do so they used focal catheters that were capable of continuously recording MAPs. More specifically, they noted that by monitoring high atrial MAPs, they could identify discordant repolarizations during atrial flutter or AF, whereas the low atrial MAPs maintained their baseline regular morphologies.…”

Section: Introductionmentioning

confidence: 99%

Assessing the Relative Integrity of Formed Cardiac Linear Lesions by Recording Both Focal Monophasic Action Potentials and Contact Forces: A Technical Brief

Benscoter

Iaizzo

2015

IEEE J. Transl. Eng. Health Med.

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The use of therapeutic ablation in patients with atrial fibrillation has become a mainstay in the treatment of this disease, yet often these individuals require multiple procedures. In other words, successful first time treatments are impacted by challenges, including the generation of linear lesions in certain anatomies like the mitral isthmus of the left atrium. Hence, there is a need to find ways to address the presence of unwanted conduction gaps at the time of lesion creation. In this paper, we describe a novel approach to examine conduction gaps, by using a proof of concept device to examine local electrical activation within the cardiac areas of an applied lesion, i.e., to locate gaps in the lesion set. To accomplish this, both epicardial and endocardial linear ablation lines composed of spot lesions with conduction gaps were created in a porcine model. The forces necessary to elicit monophasic action potentials (MAP) were collected from >200 measurements on the epicardium of the right ventricle. Ablations were then performed on the ventricular epicardium and left atrial mitral isthmus endocardially, while recording MAPs. We were able to successfully demonstrate the use of a proof of concept device to identify conduction gaps in linear lesion sets; furthermore, we were able to determine required contact forces to appropriately determine focal electrical changes of the underlying tissues. New catheter designs that incorporate capabilities to record focal MAPs could be employed clinically to better assess a given lesion quality and/or to determine the existence of an undesired conduction gap.

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Animal models of arrhythmia: classic electrophysiology to genetically modified large animals

et al. 2019

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Assessment of local atrial repolarization in a porcine acetylcholine model of atrial flutter and fibrillation

Cited by 6 publications

References 0 publications

Effects of Ranolazine and its Combination with Amiodarone on Rapid Pacing-induced Reentrant Atrial Tachycardia in Rabbits

Effects of Ranolazine and its Combination with Amiodarone on Rapid Pacing-induced Reentrant Atrial Tachycardia in Rabbits

Assessing the Relative Integrity of Formed Cardiac Linear Lesions by Recording Both Focal Monophasic Action Potentials and Contact Forces: A Technical Brief

Animal models of arrhythmia: classic electrophysiology to genetically modified large animals

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