Pacemaker-Based Cardiac Neuromodulation Therapy in Patients With Hypertension: A Pilot Study.

Background In prior unblinded studies, cardiac neuromodulation therapy (CNT) employing a sequence of variably timed short and longer atrioventricular intervals yielded sustained reductions of systolic blood pressure (SBP) in patients with hypertension. The effects of CNT on SBP were investigated in this double-blind randomized pilot study. Methods and Results Eligible patients had daytime ambulatory SBP (aSBP) ≥130 mm Hg and office SBP ≥140 mm Hg despite taking ≥1 antihypertensive medication, and an indication for a dual-chamber pacemaker.

Rationale and evidence for the development of a durable device-based cardiac neuromodulation therapy for hypertension.

We assessed the feasibility of achieving acute, sustained blood pressure reductions through the use of cardiac pacing algorithms delivered via standard dual-chamber pacing based on introducing short atrio-ventricular (AV) delays (SAVD). Eighteen hypertensive subjects (57.3 ± 9.

Basis for the Induction of Tissue-Level Phase-2 Reentry as a Repolarization Disorder in the Brugada Syndrome.

Aims: Human action potentials in the Brugada syndrome have been characterized by delayed or even complete loss of dome formation, especially in the right ventricular epicardial layers. Such a repolarization pattern is believed to trigger phase-2 reentry (P2R); however, little is known about the conditions necessary for its initiation. This study aims to determine the specific mechanisms that facilitate P2R induction in Brugada-affected cardiac tissue in humans.

Properties of two human atrial cell models in tissue: restitution, memory, propagation, and reentry.

To date, two detailed ionic models of human atrial cell electrophysiology have been developed, the Nygren et al. model (NM) and the Courtemanche et al. model (CM).

Dynamics of human atrial cell models: restitution, memory, and intracellular calcium dynamics in single cells.

Mathematical models of cardiac cells have become important tools for investigating the electrophysiological properties and behavior of the heart. As the number of published models increases, it becomes more difficult to choose a model appropriate for the conditions to be studied, especially when multiple models describing the species and region of the heart of interest are available. In this paper, we will review and compare two detailed ionic models of human atrial myocytes, the Nygren et al.

Triggers of sustained monomorphic ventricular tachycardia differ among patients with varying etiologies of left ventricular dysfunction.

Background: The mechanisms underlying the initiation of sustained ventricular tachycardia (VT) have not been fully elucidated. The extent to which reentry, abnormal automaticity, and triggered activity play a role in VT differs depending on the etiology of left ventricular dysfunction. By analyzing electrograms from implantable cardioverter defibrillator (ICD), we sought to determine whether there were differences in VT initiation patterns between patients with ischemic and nonischemic cardiomyopathy.

Multiple mechanisms of spiral wave breakup in a model of cardiac electrical activity.

It has become widely accepted that the most dangerous cardiac arrhythmias are due to reentrant waves, i.e., electrical wave(s) that recirculate repeatedly throughout the tissue at a higher frequency than the waves produced by the heart's natural pacemaker (sinoatrial node).

Real-time computer simulations of excitable media: JAVA as a scientific language and as a wrapper for C and FORTRAN programs.

We describe a useful setting for interactive, real-time study of mathematical models of cardiac electrical activity, using implicit and explicit integration schemes implemented in JAVA. These programs are intended as a teaching aid for the study and understanding of general excitable media. Particularly for cardiac cell models and the ionic currents underlying their basic electrical dynamics.