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Use of endogenous NADH fluorescence for real-time in situ visualization of epicardial radiofrequency ablation lesions and gaps.

ABSTRACT: Radiofrequency ablation (RFA) aims to produce lesions that interrupt reentrant circuits or block the spread of electrical activation from sites of abnormal activity. Today, there are limited means for real-time visualization of cardiac muscle tissue injury during RFA procedures. We hypothesized that the fluorescence of endogenous NADH could be used as a marker of cardiac muscle injury during epicardial RFA procedures. Studies were conducted in blood-free and blood-perfused hearts from healthy adult Sprague-Dawley rats and New Zealand rabbits. Radiofrequency was applied to the epicardial surface of the heart using a 4-mm standard blazer ablation catheter. A dual camera optical mapping system was used to monitor NADH fluorescence upon ultraviolet illumination of the epicardial surface and to record optical action potentials using the voltage-sensitive probe RH237. Epicardial lesions were seen as areas of low NADH fluorescence. The lesions appeared immediately after ablation and remained stable for several hours. Real-time monitoring of NADH fluorescence allowed visualization of viable tissue between the RFA lesions. Dual recordings of NADH and epicardial electrical activity linked the gaps between lesions to postablation reentries. We found that the fluorescence of endogenous NADH aids the visualization of injured epicardial tissue caused by RFA. This was true for both blood-free and blood-perfused preparations. Gaps between NADH-negative regions revealed unablated tissue, which may promote postablation reentry or provide pathways for the conduction of abnormal electrical activity.

SUBMITTER: Mercader M

PROVIDER: S-EPMC3362111 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature

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Use of endogenous NADH fluorescence for real-time in situ visualization of epicardial radiofrequency ablation lesions and gaps.

Mercader Marco M Swift Luther L Sood Sumit S Asfour Huda H Kay Matthew M Sarvazyan Narine N

American journal of physiology. Heart and circulatory physiology 20120309 10

Radiofrequency ablation (RFA) aims to produce lesions that interrupt reentrant circuits or block the spread of electrical activation from sites of abnormal activity. Today, there are limited means for real-time visualization of cardiac muscle tissue injury during RFA procedures. We hypothesized that the fluorescence of endogenous NADH could be used as a marker of cardiac muscle injury during epicardial RFA procedures. Studies were conducted in blood-free and blood-perfused hearts from healthy ad ...[more]

PMID: 22408016

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Project description:OBJECTIVES:This study sought to test the hypothesis that elimination of sites of abnormal repolarization, via epicardial RFA, suppresses the electrocardiographic and arrhythmic manifestations of BrS. BACKGROUND:Brugada syndrome (BrS) is associated with ventricular tachycardia and ventricular fibrillation leading to sudden cardiac death. Nademanee et al. reported that radiofrequency ablation (RFA) of right ventricular outflow tract epicardium significantly reduced the electrocardiogram and arrhythmic manifestations of BrS. These authors concluded that low-voltage fractionated electrogram activity and late potentials are caused by conduction delay within the right ventricular outflow tract and that the ameliorative effect of RFA is caused by elimination of this substrate. Szel et al. recently demonstrated that the abnormal electrogram activity is associated with repolarization defects rather than depolarization or conduction defects. METHODS:Action potentials (AP), electrograms, and pseudoelectrocardiogram were simultaneously recorded from coronary-perfused canine right ventricular wedge preparations. Two pharmacological models were used to mimic BrS genotype: combination of INa blocker ajmaline (1 to 10 ?M) and IK-ATP agonist pinacidil (1 to 5 ?M); or combination of Ito agonist NS5806 (4 to 10 ?M) and ICa blocker verapamil (0.5 to 2 ?M). After stable induction of abnormal electrograms and arrhythmic activity, the preparation was mapped and epicardial RFA was applied. RESULTS:Fractionated low-voltage electrical activity was observed in right ventricular epicardium but not endocardium as a consequence of heterogeneities in the appearance of the second upstroke of the epicardial AP. Discrete late potentials developed as a result of delay of the second upstroke of the AP and of concealed phase 2 re-entry. Epicardial RFA of these abnormalities normalized Brugada pattern and abolished arrhythmic activity, regardless of the pharmacological model used. CONCLUSIONS:Our results suggest that epicardial RFA exerts its ameliorative effect in the setting of BrS by destroying the cells with the most prominent AP notch, thus eliminating sites of abnormal repolarization and the substrate for ventricular tachycardia ventricular fibrillation.

Dataset Information

Use of endogenous NADH fluorescence for real-time in situ visualization of epicardial radiofrequency ablation lesions and gaps.

Publications

Use of endogenous NADH fluorescence for real-time in situ visualization of epicardial radiofrequency ablation lesions and gaps.

Similar Datasets

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