Two-dimensional analysis of ventricular fibrillation in the guinea pig.

Cardiac arrhythmias are undesirable electrical activity in the heart. Ventricular fibrillation (VF) is a fatal cardiac arrhythmia and is characterized by the breakdown of organized electrical activity in the ventricular myocardium. However, little is known about VF, partially because it is difficult to study and understand an apparently disorganized activity. One method for discovering the nature of VF is processing the epicardial electrical signals by using cardiac mapping techniques. These techniques involve the study of propagation patterns seen in VF. In this project, we used guinea pigs to study the spatial organization of the epicardial electrical activity during VF. VF was induced in 9 open chest guinea pigs and epicardial electrode data were acquired by using a square array of 192 electrodes for 4 seconds every minute. The mean correlation length and dominant frequency were measured in each recorded segment. Correlation length is a measure of the spatial order in a system and dominant frequency is the frequency corresponding to the spectral maximum. The mean correlation length was found to vary between 1-7 mm and the dominant frequency was in the range of 1-14 Hz. This study suggests that guinea pig VF exhibits a level of organization equivalent to or greater than that seen in previous studies.