High-resolution, real-time, and nonfluoroscopic 3-dimensional cardiac imaging and catheter navigation in humans using a novel dielectric-based system.

Background: Catheter navigation and 3-dimensional (3D) cardiac mapping are essential components of minimally invasive electrophysiological procedures.

Objective: The purpose of this study was to develop a novel 3D mapping system (KODEX - EPD, EPD Solutions, Best, The Netherlands) that measures changing electric field gradients induced on intracardiac electrodes to enable catheter localization and real-time 3D cardiac mapping.

Methods: We first validated the accuracy of the system's measurement and localization capabilities by comparing known and KODEX - EPD-measured distances and locations at 12 anatomical landmarks in both the atria and ventricles of 4 swine.

Cardiac contractility modulation by non-excitatory currents: studies in isolated cardiac muscle.

Background: Myocardial contractility can be altered using voltage clamp techniques by modulating amplitude and duration of the action potential resulting in enhanced calcium entry in the cell of isolated muscle strips (Non-Excitatory Currents; NEC). Extracellular electrical stimuli delivered during the absolute refractory period (Cardiac Contractility Modulation; CCM) have recently been shown to produce inotropic effects in-vivo.

Aim: Understanding the cellular mechanism, underlying the CCM effect, is essential for evaluating its clinical potential.

Ventricular mapping during atrial and right ventricular pacing: relation of electrogram parameters to ventricular tachycardia reentry circuits after myocardial infarction.

Introduction: Ventricular tachycardia (VT) late after myocardial infarction is usually due to reentry in the border zone of the infarct area. Identification of critical parts of the VT reentry circuit by catheter mapping without needing to induce VT is a desirable goal for VT ablation. The aim of this study was to develop a model to predict reentry circuit locations based on characteristics of sinus or paced electrograms and pace mapping (PM) recorded from the infarct region.

Use of novel nonfluoroscopic three-dimensional electroanatomic mapping system to monitor and analyze heart surgery in animal models.

Background: The new method of three-dimensional (3D) electroanatomic mapping was presented as an important tool for cardiac imaging and intervention. We present herein the first use of this technology for the monitoring, analysis, and development of cardiac surgery at the preclinical stage.

Methods: The method is based on utilizing a locatable catheter connected to an endocardial mapping and navigating system, to accurately establish the location and orientation of the tip of the mapping catheter and simultaneously record its local electrogram.

First human chronic experience with cardiac contractility modulation by nonexcitatory electrical currents for treating systolic heart failure: mid-term safety and efficacy results from a multicenter study.

Introduction: Conventional electrical therapies for heart failure (HF) encompass defibrillation and ventricular resynchronization for patients at high risk for lethal arrhythmias and/or with inhomogeneous ventricular contraction. Cardiac contractility modulation (CCM) by means of nonexcitatory electrical currents delivered during the action potential plateau has been shown to acutely enhance systolic function in humans with HF. The aim of this multicenter study was to assess the chronic safety and preliminary efficacy of an implantable device delivering this novel form of electrical therapy.

Enhancement of antral contractions and vagal afferent signaling with synchronized electrical stimulation.

Gastric filling activates vagal afferents involved in peripheral signaling to the central nervous system (CNS) for food intake. It is not known whether these afferents linearly encode increasing contractions of the antrum during antral distension (AD). The aim of this study was to investigate effects of AD and electrically enhanced antral contractions on responses of vagal afferents innervating the antrum.

Relationship of slow conduction detected by pace-mapping to ventricular tachycardia re-entry circuit sites after infarction.

Objectives: This study sought to characterize the relationship of conduction delays detected by pace-mapping, evident as a stimulus to QRS interval (S-QRS) delay >or=40 ms, to ventricular tachycardia (VT) re-entry circuit isthmuses defined by entrainment and ablation.

Background: Areas of slow conduction and block in old infarcts cause re-entrant VT.

Methods: In 12 patients with VT after infarction, pace-mapping was performed at 890 sites.

Temporal changes in the endocardial ST segment during the evolution of myocardial infarction in dogs.

Acute coronary occlusion causes ST-segment elevation on the body surface ECG and on the epicardial electrogram in the territory supplied by that artery. The occurrence and significance of endocardial ST changes have not been studied. The NOGA electromechanical mapping was performed on eight anesthetized dogs at baseline, immediately after occlusion of the LAD, and again at 5 hours to assess regional changes in the ST segment.

Cardiac contractility modulation by electric currents applied during the refractory period in patients with heart failure secondary to ischemic or idiopathic dilated cardiomyopathy.

We assessed the feasibility of cardiac contractility modulation (CCM) by electric currents applied during the refractory period in patients with heart failure (HF). Extracellular electric currents modulating action potential and calcium transients have been shown to potentiate myocardial contractility in vitro and in animal models of chronic HF. CCM signals were biphasic square-wave pulses with adjustable amplitude, duration, and time delay from sensing of local electric activity.

Evaluation of inotropic changes in ventricular function by NOGA mapping: comparison with echocardiography.

Assessment of left ventricular (LV) function in the catheterization laboratory is important to optimize treatment decisions and guide catheter-based local therapies. NOGA electromechanical mapping was developed to assess LV contraction during catheterization; however, quantitative analysis of its "local shortening" (LS) algorithm and direct comparison with conventional methods are lacking. We evaluated the accuracy of NOGA-based regional and global function by examining its ability to detect pharmacologically induced changes in contractility compared with echocardiography.