Electrical communication between cardiomyocytes can be perturbed during arrhythmia, but these perturbations are not captured by conventional electrocardiographic metrics. We developed a theoretical framework to quantify electrical communication using information theory metrics in two-dimensional cell lattice models of cardiac excitation propagation. The time series generated by each cell was co...

BACKGROUND Empirical research describes retirement migration to Mexico as a viable option for some older Americans. However, far less research examines this phenomenon among Mexican immigrants in the United States. The literature that does address this topic treats international migration as a singular occurrence and does not examine the possibility of return and subsequent reentry between coun...

Dispersion of action potential repolarization is known to be an important arrhythmogenic factor in cardiopathies such as Brugada syndrome. In this work, we analyze the effect of a variation in sodium current (I(Na)) inactivation and a heterogeneous rise of transient outward current (I(to)) in the probability of reentry in epicardial tissue. We use the Luo-Rudy model of epicardial ventricular ac...

Atrial fibrillation (AF) is the most common supraventricular tachycardia and its incidence increases with age. The pathophysiology of AF has been studied extensively and is a subject of continuing research. The primary pathologic change seen in AF is progressive fibrosis of the atria and hence structural remodeling, is the mainstay in many forms of AF. Dilation of the atria can be due to almost...

It was hypothesized that quantitative sinus rhythm electrogram measurements could be used to predict conduction events that result from premature stimulation and reentrant ventricular tachycardia inducibility. Sinus rhythm activation and electrogram-duration maps were constructed from bipolar electrograms acquired at 196-312 sites in the epicardial border zone of 43 canine hearts (25 with and 1...

The characteristics of reentrant circuits during short duration ventricular fibrillation (SDVF; 20 s in duration) and the role of Ca(++) and rapid-activating delayed rectifier potassium currents during long duration ventricular fibrillation (LDVF; up to 10 min in duration) were investigated using verapamil and sotalol. Activation mapping of the LV epicardium with a 21 × 24 electrode plaque was ...

In a normal heartbeat, electrical activation starts from the SA node and propagates to both atria. It travels successively through the AV node, the His Bundle and finally the Purkinje fibers that distribute the excitation and contract ventricles. The electrical activation is formed by the unequal ionic distribution on both sides of the sarcoplasmic membrane, producing a difference of potential ...

Exit sites associated with scar-related reentrant arrhythmias represent important targets for catheter ablation therapy. However, their accurate location in a safe and robust manner remains a significant clinical challenge. We recently proposed a novel quantitative metric (termed the Reentry Vulnerability Index, RVI) to determine the difference between activation and repolarisation intervals me...

In vitro models of sustained monomorphic ventricular tachycardia (MVT) are rare and do not usually show spiral reentry on the epicardium. We hypothesized that MVT is associated with the spiral wave in the endocardium and that this stable reentrant propagation is supported by a persistently elevated intracellular calcium (Ca(i)) transient at the core of the spiral wave. We performed dual optical...

BACKGROUND Ventricular tachycardia reentry circuits in chronic infarct scars can contain slow conduction zones, which are difficult to distinguish from bystander areas adjacent to the circuit during catheter mapping. This study developed criteria for identifying reentry circuit sites using computer simulations. These criteria then were tested during catheter mapping in humans to predict sites a...