Independent component approach to the analysis of epicardial atrial electrograms of electrically induced atrial fibrillation

[[abstract]]Recently, independent component analysis (ICA) has been used to reveal hidden factors that underlie sets of random variables. In order to understand of the mechanism and characteristics of atrial fibrillation (AF), we have used ICA technique to separate the possible independent reentrant wavelets in the atrium during AF. All animal experiments were performed with canines weighed between 10 and 15 kg. The recorded signals included sinus rhythm, during AF, AF after injection of antiarrhythmic drug and before restoration of normal sinus rhythm. In sinus rhythm, only one signal component with regular activation sequence was present. During AF, some wavelets that have higher frequencies and irregular activation sequences were separated. After antiarrhythmic drug injection, both the number of wavelets and the frequencies of wavelets were decreased. Before restoration of normal sinus rhythm, wavelet reduced to one or two and the rhythm can be re-controlled by the sinoatrial node. According to our results, we proposed a hypothesis that before the termination of AF, reentrant wavelets were reduced to a single component with frequency close to the upper limit of sinus rhythm. The location of this signal component was close to the area around SA node