00781nas a2200289 4500008004100000022001400041245004000055210003900095260001200134300003200146490000800178653001200186653002400198653002400222653002100246653002700267653001200294653002900306100001400335700001400349700001600363700001700379700001200396700001900408700001700427856004700444 1995 eng d a0036-807500aMechanisms of cardiac fibrillation.0 aMechanisms of cardiac fibrillation c11/1995 a1222-3; author reply 1224-50 v27010aAnimals10aComputer Simulation10aElectrocardiography10aHeart Ventricles10aModels, Cardiovascular10aRabbits10aVentricular Fibrillation1 aGray, R A1 aJalife, J1 aPanfilov, A1 aBaxter, Bill1 aCabo, C1 aDavidenko, J M1 aPertsov, A V uhttp://www.ncbi.nlm.nih.gov/pubmed/750205504137nas a2200313 4500008004100000022001400041245013200055210006900187260001300256300001200269490000700281520321100288653001203499653002403511653001003535653004003545653002703585653001403612653001203626653002903638100001403667700001403681700001603695700001703711700001203728700001903740700001703759856004703776 1995 eng d a0009-732200aNonstationary vortexlike reentrant activity as a mechanism of polymorphic ventricular tachycardia in the isolated rabbit heart.0 aNonstationary vortexlike reentrant activity as a mechanism of po c05/1995  a2454-690 v913 a

BACKGROUND: 

Ventricular tachycardia may result from vortexlike reentrant excitation of the myocardium. Our general hypothesis is that in the structurally normal heart, these arrhythmias are the result of one or two nonstationary three-dimensional electrical scroll waves activating the heart muscle at very high frequencies.

METHODS AND RESULTS: 

We used a combination of high-resolution video imaging, electrocardiography, and image processing in the isolated rabbit heart, together with mathematical modeling. We characterized the dynamics of changes in transmembrane potential patterns on the epicardial surface of the ventricles using optical mapping. Image processing techniques were used to identify the surface manifestation of the reentrant organizing centers, and the location of these centers was used to determine the movement of the reentrant pathway. We also used numerical simulations incorporating Fitzhugh-Nagumo kinetics and realistic heart geometry to study how stationary and nonstationary scroll waves are manifest on the epicardial surface and in the simulated ECG. We present epicardial surface manifestations (reentrant spiral waves) and ECG patterns of nonstationary reentrant activity that are consistent with those generated by scroll waves established at the right and left ventricles. We identified the organizing centers of the reentrant circuits on the epicardial surface during polymorphic tachycardia, and these centers moved during the episodes. In addition, the arrhythmias that showed the greatest movement of the reentrant centers displayed the largest changes in QRS morphology. The numerical simulations showed that stationary scroll waves give rise to monomorphic ECG signals, but nonstationary meandering scroll waves give rise to undulating ECGs characteristic of torsade de pointes.

CONCLUSIONS: 

Polymorphic ventricular tachycardia in the healthy, isolated rabbit heart is the result of either a single or paired ("figure-of-eight") nonstationary scroll waves. The extent of the scroll wave movement corresponds to the degree of polymorphism in the ECG. These results are consistent with our numerical simulations that showed monomorphic ECG patterns of activity for stationary scroll waves but polymorphic patterns for scroll waves that were nonstationary.

10aAnimals10aElectrocardiography10aHeart10aImage Processing, Computer-Assisted10aModels, Cardiovascular10aPerfusion10aRabbits10aTachycardia, Ventricular1 aGray, R A1 aJalife, J1 aPanfilov, A1 aBaxter, Bill1 aCabo, C1 aDavidenko, J M1 aPertsov, A V uhttp://www.ncbi.nlm.nih.gov/pubmed/7729033