Jonathan D Hoang, Valerie Y H van Weperen, Ki-Woon Kang, Neil R Jani, Mohammed A Swid, Christopher A Chan, Zulfiqar Ali Lokhandwala, Robert L Lux, Marmar Vaseghi
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引用次数: 0
Abstract
Background: Thoracic epidural anesthesia (TEA) has been shown to reduce the burden of ventricular tachycardia in small case series of patients with refractory ventricular tachyarrhythmias and cardiomyopathy. However, its electrophysiological and autonomic effects in diseased hearts remain unclear, and its use after myocardial infarction is limited by concerns for potential right ventricular dysfunction.
Methods: Myocardial infarction was created in Yorkshire pigs (N=22) by left anterior descending coronary artery occlusion. Approximately, six weeks after myocardial infarction, an epidural catheter was placed at the C7-T1 vertebral level for injection of 2% lidocaine. Right and left ventricular hemodynamics were recorded using Millar pressure-conductance catheters, and ventricular activation recovery intervals (ARIs), a surrogate of action potential durations, by a 56-electrode sock and 64-electrode basket catheter. Hemodynamics and ARIs, baroreflex sensitivity and intrinsic cardiac neural activity, and ventricular effective refractory periods and slope of restitution (Smax) were assessed before and after TEA. Ventricular tachyarrhythmia inducibility was assessed by programmed electrical stimulation.
Results: TEA reduced inducibility of ventricular tachyarrhythmias by 70%. TEA did not affect right ventricular-systolic pressure or contractility, although left ventricular-systolic pressure and contractility decreased modestly. Global and regional ventricular ARIs increased, including in scar and border zone regions post-TEA. TEA reduced ARI dispersion specifically in border zone regions. Ventricular effective refractory periods prolonged significantly at critical sites of arrhythmogenesis, and Smax was reduced. Interestingly, TEA significantly improved cardiac vagal function, as measured by both baroreflex sensitivity and intrinsic cardiac neural activity.
Conclusions: TEA does not compromise right ventricular function in infarcted hearts. Its antiarrhythmic mechanisms are mediated by increases in ventricular effective refractory period and ARIs, decreases in Smax, and reductions in border zone electrophysiological heterogeneities. TEA improves parasympathetic function, which may independently underlie some of its observed antiarrhythmic mechanisms. This study provides novel insights into the antiarrhythmic mechanisms of TEA while highlighting its applicability to the clinical setting.
期刊介绍：
Circulation Research is a peer-reviewed journal that serves as a forum for the highest quality research in basic cardiovascular biology. The journal publishes studies that utilize state-of-the-art approaches to investigate mechanisms of human disease, as well as translational and clinical research that provide fundamental insights into the basis of disease and the mechanism of therapies.
Circulation Research has a broad audience that includes clinical and academic cardiologists, basic cardiovascular scientists, physiologists, cellular and molecular biologists, and cardiovascular pharmacologists. The journal aims to advance the understanding of cardiovascular biology and disease by disseminating cutting-edge research to these diverse communities.
In terms of indexing, Circulation Research is included in several prominent scientific databases, including BIOSIS, CAB Abstracts, Chemical Abstracts, Current Contents, EMBASE, and MEDLINE. This ensures that the journal's articles are easily discoverable and accessible to researchers in the field.
Overall, Circulation Research is a reputable publication that attracts high-quality research and provides a platform for the dissemination of important findings in basic cardiovascular biology and its translational and clinical applications.
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