Laser photoablation of experimental post-infarction ventricular tachycardia guided by three dimensional activation mapping.

Background And Objective: The purpose of this study was to evaluate the efficacy of epicardially delivered laser energy to ablate induced ventricular tachycardia in a post-infarction canine model.

Study Design/materials And Methods: In 13 canines, the left anterior wall myocardial infarction was created. Five days later, 240 plunged electrodes were inserted into the heart.

Myocardial temperatures during in vivo endocardial Nd:YAG laser irradiation.

To determine safety and efficacy of neodymium:YAG laser irradiation of the endocardium, temperatures at both the epicardium and the endocardium were recorded for thermal damage evaluation. A total of 48 coagulation lesions were created at power settings of 20 and 30 W in 20 open chest dogs by transcatheter endocardial laser irradiation. Tissue temperatures were monitored by epicardial thermography (Tepi), and by endocardial thermocouples at the catheter tip (Tprox) and 4 mm below the endocardial surface (Tdist).

Computerized three-dimensional activation mapping study of spontaneous ventricular arrhythmias during acute myocardial ischemia in dogs. Evidence against macroreentrant mechanism.

This study was undertaken to investigate the activation patterns of spontaneous ventricular arrhythmias during acute myocardial ischemia in dogs. In 14 open-chest dogs, the left anterior descending coronary artery was occluded for 2 hours. Three-dimensional activation maps were derived from 240 bipolar sites by insertion of 60 plunge needle electrodes into both ventricles and the septum.

Myocardial temperature distribution under cw Nd:YAG laser irradiation in in vitro and in vivo situations: theory and experiment.

Tissue samples ranging from 2 to 16 mm in thickness were irradiated at 1064 nm with energies ranging from 40 to 2400 J. Coagulation lesions of in vitro and in vivo experiments were subjected to temperature profiling and submitted for histology. Irreversible damage was calculated with the damage integral formalism, following the bioheat equation solved with Monte Carlo computer light-distribution simulations.

The validity of children's self-reports of physical activity: a preliminary study.

Ninety-two healthy children provided self-reports of their physical activity. Self-reports were based upon posters depicting children performing typical childhood activities and were validated by measured oxygen uptake during maximal cycle ergometry. Results indicated that when children were classified as sedentary or active by their poster selection, active children had significantly greater oxygen uptake than sedentary children.

Self-reports of salt intake by 10- to 18-year-olds: relationship to urinary sodium excretion.

Our data indicated that self-reports of consumption of salty foods by children and adolescents were associated with 24-hour urinary sodium excretion. Specifically, youths 10 to 18 years of age who selected a poster depicting high-sodium foods excreted significantly more sodium than youths who selected a poster depicting low-sodium foods. Future research is needed to refine simplified self-report measures, to corroborate the validity of the measures, and to extend the studies to other samples, e.