The importance of two arrhythmogenic mechanisms, ventricular reentry and automaticity, was assessed after coronary ligation in 35 cats. Automaticity was estimated by the frequency of ventricular escape beats after intravenous acetylcholine, and reentry was estimated by the number of repetitive beats induced by premature ventricular stimuli. Increased automaticity only was present after coronary...

The effects of intravenous procainamide infusion of 10-14 mg/kg body weight (i.e., 750 mg) of procainamide (PA) on reentry within the His-Purkinje system (HPS) were studied in 13 patients using His bundle electrograms and ventricular extrastimulus method. PA abolished reentry in eight patients (group 1) and decreased the width of reentry zone in the remaining five (group 2). At comparable S,S2 ...

let $m$ be a right module over a ring $r$, $tau_m$ a preradical on $sigma[m]$, and$ninsigma[m]$. in this note we show that if $n_1, n_2in sigma[m]$ are two$tau_m$-lifting modules such that $n_i$ is $n_j$-projective ($i,j=1,2$), then $n=n_1oplusn_2$ is $tau_m$-lifting. we investigate when homomorphic image of a $tau_m$-lifting moduleis $tau_m$-lifting.

Paroxysmal supraventricular tachycardia (SVT) is commonly produced by two mechanisms: atrial reentry via an A-V nodal pathway or a rapid firing ectopic focus. Studies in the experimental animal and in human beings with sustained SVT have sbown that the site for reentry appears to be the upper A-V junction. This report documents an unusual site d reentry in a patient with recurrent SVT. Progress...

The effects of intravenous procainamide infusion of 10-14 mg/kg body weight (i.e., 750 mg) of procainamide (PA) on reentry within the His-Purkinje system (HPS) were studied in 13 patients using His bundle electrograms and ventricular extrastimulus method. PA abolished reentry in eight patients (group 1) and decreased the width of reentry zone in the remaining five (group 2). At comparable S,S2 ...

BACKGROUND Initiation of reentrant ventricular tachycardia (VT) involves complex interactions between front and tail of the activation wave. Recent experimental work has identified the time interval between S2 repolarization proximal to a line of functional block and S2 activation at the adjacent distal side as a critical determinant of reentry. OBJECTIVES We hypothesized that (1) an algorith...

BACKGROUND In canine hearts with inducible reentry, the isthmus tends to form along an axis from the area of last to first activity during sinus rhythm. It was hypothesized that this phenomenon could be quantified to predict reentry and the isthmus location. METHODS AND RESULTS An in situ canine model of reentrant ventricular tachycardia occurring in the epicardial border zone was used in 54 ...

The role of dynamic instabilities in the initiation of reentry in diseased (remodeled) hearts remains poorly explored. Using computer simulations, we studied the effects of altered Na(+) channel and cell coupling properties on the vulnerable window (VW) for reentry in simulated two-dimensional cardiac tissue with and without dynamic instabilities. We related the VW for reentry to effects on con...

BACKGROUND Functional reentry in the heart takes the form of spiral waves. Drifting spiral waves can become pinned to anatomic obstacles and thus attain stability and persistence. Lidocaine is an antiarrhythmic agent commonly used to treat ventricular tachycardia clinically. We examined the ability of small obstacles to anchor spiral waves and the effect of lidocaine on their attachment. METH...