Orientation-Independent Catheter-Based Characterization of Myocardial Activation.

Unlabelled: Cardiac electrogram (EGM) signals and electrophysiologic (EP) characteristics derived from them such as amplitude and timing are central to the diagnosis and therapeutic management of arrhythmias. Bipolar EGMs are often used but possess polarity and shape dependence on catheter orientation contributing to uncertainty.

Objective: We describe a novel method to map cardiac activation that resolves signals into meaningful directions and is insensitive to electrode directional effects.

Resolving Myocardial Activation With Novel Omnipolar Electrograms.

Background: With its inherent limitations, determining local activation times has been the basis of cardiac mapping for over a century. Here, we introduce omnipolar electrograms that originate from the natural direction of a travelling wave and from which instantaneous conduction velocity amplitude and direction can be computed at any single location without first determining activation times. We sought to validate omnipole-derived conduction velocities and explore potential application for localization of sources of arrhythmias.

Contribution of saccadic motion to intravitreal drug transport: theoretical analysis.

Purpose: The vitreous humor liquefies with age and readily sloshes during eye motion. The objective was to develop a computational model to determine the effect of sloshing on intravitreal drug transport for transscleral and intra-vitreal drug sources at various locations

Methods: A finite element model based on a telescopic implicit envelope tracking scheme was developed to model drug dispersion. Flow velocities due to saccadic oscillations were solved for and were used to simulate drug dispersion.

Computer modeling of drug delivery to the posterior eye: effect of active transport and loss to choroidal blood flow.

Purpose: The direct penetration route following transscleral drug administration presents several barrier and clearance mechanisms-including loss to choroidal blood flow, active transport by the retinal pigment epithelium (RPE), and loss to the conjunctival lymphatics and episcleral blood vessels. The objective of this research was to quantify the role of choroidal and episcleral losses.

Materials And Methods: A finite element model was created for drug distribution in the posterior human eye.

Sustained transscleral drug delivery.

Transscleral delivery is an emerging, high-potential method for delivering drugs to the posterior eye. If successful, it could offer non-invasiveness comparable to drops and delivery efficiency comparable to intravitreal injection. However, there are numerous challenges to be overcome before transscleral delivery will be a significant treatment option.