The aim of this study was to evaluate the relation between atrial fibrillatory frequency (AFF) and the probability of successful internal cardioversion of atrial fibrillation (AF). Thirty consecutive patients suggested for DC cardioversion at the Royal Victoria Hospital in Belfast, were included in the study. Two catheters were positioned in the right atrial appendage (RAA) and the coronary sinus (CS), for delivering a biphasic shock waveform, 6/6 msec, synchronized with the R-wave on the ECG signal. The atrial fibrillatory activity was derived from 60 seconds of surface ECG from the defibrillator pads, prior to shock delivery, by bandpass filtering and ventricular activity (QRST) cancellation. QRST complexes subtraction was implemented by means of a template matching and signal averaging algorithm. FFT was applied to the residual atrial fibrillatory signal. Atrial fibrillatory frequency was estimated from the dominant frequency in the 3-12Hz band of the power spectrum. Eighteen patients were successfully cardioverted using a voltage step up protocol beginning from 50V up to 300V (biphasic pulse amplitude). Twelve of the cases were not successfully cardioverted to sinus rhythm. The AFF was 5.42 +/- 1.03 Hz (within the range of 3.69 - 7.38 Hz) in patients successfully cardioverted vs. 6.5 +/- 0.68 Hz (within the range of 5.38-7.56 Hz) in patients which failed cardioversion, P < 0.004. AFF was < 6.26 Hz in 15 of the 18 patients with successful cardioversion. AF cardioversion was predicted with a specificity of 83.33% in the best cases, and with an acceptable sensitivity of 75%. Also, there was a positive correlation (rho = 0.624 and P < 0.01) between the minimal defibrillation energy and the fibrillatory frequency in cardioverted patients. In conclusion, calculated AFF from the surface ECG, may predict the success of internal low energy cardioversion of patients with atrial fibrillation.
|Conference||WORLD CONGRESS ON MEDICAL PHYSICS AND BIOMEDICAL ENGINEERING 2006, VOL 14, PTS 1-6|
|Period||1/01/07 → …|
- Atrial Fibrillation
- Fibrillation Frequency
- QRS Cancellation.