RV electrical activation in heart failure during right, left, and biventricular pacing.

Objectives: To compare right ventricular (RV) activation during intrinsic conduction or pacing in heart failure (HF) patients.

Background: RV activation during intrinsic conduction or pacing in patients with left ventricular (LV) dysfunction is unclear but may affect the prognosis. In cardiac resynchronization therapy (CRT), timed LV pacing (CRT-LV) may be superior to biventricular pacing (CRT-BiV), and is hypothesized to be due to the merging of LV-paced and right bundle branch-mediated wavefronts, thus avoiding perturbation of RV electrical activation.

Activation and repolarization of the normal human heart under complete physiological conditions.

Knowledge of normal human cardiac excitation stems from isolated heart or intraoperative mapping studies under nonphysiological conditions. Here, we use a noninvasive imaging modality (electrocardiographic imaging) to study normal activation and repolarization in intact unanesthetized healthy adults under complete physiological conditions. Epicardial potentials, electrograms, and isochrones were noninvasively reconstructed.

Electrocardiographic imaging of cardiac resynchronization therapy in heart failure: observation of variable electrophysiologic responses.

Background: Cardiac resynchronization therapy (CRT) for congestive heart failure patients with delayed left ventricular (LV) conduction is clinically beneficial in approximately 70% of patients. Unresolved issues include patient selection, lead placement, and efficacy of LV pacing alone. Being an electrical approach, detailed electrical information during CRT is critical to resolving these issues.

Electrocardiographic imaging (ECGI), a novel diagnostic modality used for mapping of focal left ventricular tachycardia in a young athlete.

We report the first clinical application of electrocardiographic imaging (ECGI), a new, noninvasive imaging modality for arrhythmias, in an athlete with focal ventricular tachycardia (VT) originating from a left ventricular (LV) diverticulum. A reconstructed map of the epicardial activation sequence during a single premature ventricular complex (PVC) of an identical QRS morphology to the clinical VT, generated from 224-electrode body surface ECGs and a chest CT (ECGI), localized the PVC to the site of the diverticulum. This correlated with subsequent maps obtained using standard techniques.

Noninvasive electrocardiographic imaging (ECGI): comparison to intraoperative mapping in patients.

Objectives/background: Cardiac arrhythmias are a leading cause of death and disability. Electrocardiographic imaging (ECGI) is a noninvasive imaging modality that reconstructs potentials, electrograms, and isochrones on the epicardial surface from body surface measurements. We previously demonstrated in animal experiments through comparison with simultaneously measured epicardial data the high accuracy of ECGI in imaging cardiac electrical events.

Noninvasive electrocardiographic imaging for cardiac electrophysiology and arrhythmia.

Over 7 million people worldwide die annually from erratic heart rhythms (cardiac arrhythmias), and many more are disabled. Yet there is no imaging modality to identify patients at risk, provide accurate diagnosis and guide therapy. Standard diagnostic techniques such as the electrocardiogram (ECG) provide only low-resolution projections of cardiac electrical activity on the body surface.

Heart-surface reconstruction and ECG electrodes localization using fluoroscopy, epipolar geometry and stereovision: application to noninvasive imaging of cardiac electrical activity.

To date there is no imaging modality for cardiac arrhythmias which remain the leading cause of sudden death in the United States (> 300000/yr.). Electrocardiographic imaging (ECGI), a noninvasive modality that images cardiac arrhythmias from body surface potentials, requires the geometrical relationship between the heart surface and the positions of body surface ECG electrodes.

Noninvasive electrocardiographic imaging (ECGI): application of the generalized minimal residual (GMRes) method.

Electrocardiographic imaging (ECGI) is a developing imaging modality for cardiac electrophysiology and arrhythmias. It reconstructs epicardial potentials, electrograms, and isochrones from electrocardiographic body-surface potentials noninvasively. Current ECGI methodology employs Tikhonov regularization, which imposes constraints on the reconstructed potentials or their derivatives.