<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Davidenko, J M</style></author><author><style face="normal" font="default" size="100%">Pertsov, A V</style></author><author><style face="normal" font="default" size="100%">Salomonsz, R</style></author><author><style face="normal" font="default" size="100%">Baxter, Bill</style></author><author><style face="normal" font="default" size="100%">Jalife, J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Spatiotemporal irregularities of spiral wave activity in isolated ventricular muscle.</style></title><secondary-title><style face="normal" font="default" size="100%">J Electrocardiol</style></secondary-title><alt-title><style face="normal" font="default" size="100%">J Electrocardiol</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Cardiac Pacing, Artificial</style></keyword><keyword><style  face="normal" font="default" size="100%">Fluorescent Dyes</style></keyword><keyword><style  face="normal" font="default" size="100%">Heart Conduction System</style></keyword><keyword><style  face="normal" font="default" size="100%">Membrane Potentials</style></keyword><keyword><style  face="normal" font="default" size="100%">Optics and Photonics</style></keyword><keyword><style  face="normal" font="default" size="100%">Pericardium</style></keyword><keyword><style  face="normal" font="default" size="100%">Signal Processing, Computer-Assisted</style></keyword><keyword><style  face="normal" font="default" size="100%">Tachycardia</style></keyword><keyword><style  face="normal" font="default" size="100%">Ventricular Function</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1992</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1992</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/1552240</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">24 Suppl</style></volume><pages><style face="normal" font="default" size="100%">113-22</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;&lt;span style=&quot;font-family: arial, helvetica, clean, sans-serif; font-size: 13px; line-height: 17px;&quot;&gt;Voltage-sensitive dyes and high resolution optical mapping were used to analyze the characteristics of spiral waves of excitation in isolated ventricular myocardium. In addition, analytical techniques, which have been previously used in the study of the characteristics of spiral waves in chemical reactions, were applied to determine the voltage structure of the center of the rotating activity (ie, the core). During stable spiral wave activity local activation occurs in a periodic fashion (ie, 1:1 stimulus: response activation ratio) throughout the preparation, except at the core, which is a small elongated area where the activity is of low voltage and the activation ratio is 1:0. The voltage amplitude increases gradually from the center of the core to the periphery. In some cases, however, regular activation patterns at the periphery may coexist with irregular local activation patterns near the core. Such a spatiotemporal irregularity is attended by variations in the core size and shape and results from changes in the core position. The authors conclude that functionally determined reentrant activity in the heart may be the result of spiral waves of propagation and that local spatiotemporal irregularities in the activation pattern are the result of changes in the core position.&lt;/span&gt;&lt;/p&gt;</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Davidenko, J M</style></author><author><style face="normal" font="default" size="100%">Pertsov, A V</style></author><author><style face="normal" font="default" size="100%">Salomonsz, R</style></author><author><style face="normal" font="default" size="100%">Baxter, Bill</style></author><author><style face="normal" font="default" size="100%">Jalife, J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Stationary and drifting spiral waves of excitation in isolated cardiac muscle.</style></title><secondary-title><style face="normal" font="default" size="100%">Nature</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Nature</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Dogs</style></keyword><keyword><style  face="normal" font="default" size="100%">Heart</style></keyword><keyword><style  face="normal" font="default" size="100%">Mathematics</style></keyword><keyword><style  face="normal" font="default" size="100%">Membrane Potentials</style></keyword><keyword><style  face="normal" font="default" size="100%">Models, Biological</style></keyword><keyword><style  face="normal" font="default" size="100%">Myocardial Contraction</style></keyword><keyword><style  face="normal" font="default" size="100%">Sheep</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1992</style></year><pub-dates><date><style  face="normal" font="default" size="100%">01/1992</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/1731248</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">355</style></volume><pages><style face="normal" font="default" size="100%">349-51</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;&lt;span style=&quot;font-family: arial, helvetica, clean, sans-serif; font-size: 13px; line-height: 17px;&quot;&gt;Excitable media can support spiral waves rotating around an organizing centre. Spiral waves have been discovered in different types of autocatalytic chemical reactions and in biological systems. The so-called 're-entrant excitation' of myocardial cells, causing the most dangerous cardiac arrhythmias, including ventricular tachycardia and fibrillation, could be the result of spiral waves. Here we use a potentiometric dye in combination with CCD (charge-coupled device) imaging technology to demonstrate spiral waves in the heart muscle. The spirals were elongated and the rotation period, Ts, was about 180 ms (3-5 times faster than normal heart rate). In most episodes, the spiral was anchored to small arteries or bands of connective tissue, and gave rise to stationary rotations. In some cases, the core drifted away from its site of origin and dissipated at a tissue border. Drift was associated with a Doppler shift in the local excitation period, T, with T ahead of the core being about 20% shorter than T behind the core.&lt;/span&gt;&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">6358</style></issue></record></records></xml>