Predicting Successful Transthoracic Cardioversion by Dominant Atrial Fibrillatory Frequency Analysis: The Effects of Bisoprolol
The most common strategies in the management of atrial fibrillation (AF) involve electrical cardioversion and pharmacological agents. Bisoprolol is a high selective β1 adrenoceptor blocker used for ventricular rate control and to help maintain sinus rhythm. In a retrospective study we com pared ECG frequency domain variables between patients who underwent a successful electrical cardioversion and those that were unsuccessful. As well as this we assessed whether there was a difference in these variables for patients who underwent electrical cardioversion while on bisoprolol. Signal processing was performed on 51 patients undergoing electrical cardioversion: bandpass filtering (0.5-50Hz), QRST cancellation and frequency analysis. An incremental defibrillation energy pro tocol was delivered until cardioversion or up to a maximum level of 200 [J]. The study indicated a significant difference in the dominant AF frequency for long segments (DAFF_L) be tween cardioverted and non-cardioverted subgroups, employ ing an energy less or equal to 100 Joules respectively: (5.5391 ± 1.0396) [Hz] vs. (6.0859 ±0.8071) [Hz] (n=48, p = 0.048), and in patients on bisoprolol: (5.5250 ±1.0302) [Hz] vs. (6.4489 ±0.5828) [Hz] (n=26, p = 0.008). Also, the energy required for successful cardioversion was significantly lower for patients on bisoprolol: (110.00 ± 27.77) [J] vs. (129.41 ±30.92) [J], p=0.046. Also, there was a positive correlation between the DAFF_L and the minimal energy necessary for successful cardioversion (ρ =0.434, p=0.007); a better correlation was obtained for patients on bisoprolol (ρ =0.575, p=0.005). Therefore, analysis of DAFF_L on Lead II can be a useful indicator for predicting defibrillation success in AF patients undergoing transthoracic electric cardioversion, and there is a positive incidence of Bisoprolol upon the values of DAFF_L and electrical cardioversion success at minimal shock energy.
KeywordsAtrial fibrillation cardioversion atrial fibrillatory frequency Bisoprolol effects QRS complex cancellation
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