RT-188
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Prediction of early atrial
fibrillation relapse after endocavitary electrical cardioversion by frequency analysis of
signal averaged P wave
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Antonio Michelucci, Luigi
Padeletti, Maria Cristina Porciani, Paolo Pieragnoli, Marco Frati, Silvio Vena, Andrea
Colella, Gian Franco Gensini.
Istituto di Clinica Medica Generale e Cardiologia, Universita di Firenze, Italy
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Abstract
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Background. The risk of recurrence of
atrial fibrillation is high in the first days after electrical cardioversion and
predictors of recurrences, with an acceptable positive or negative predictive value, are
not clearly established so far. Thus we decided to test P wave signal-averaging as a
predictor of arrhythmia susceptibility in a prospective study on patients who undergo
endocavitary electrical cardioversion.
Material and methods. We studied 22 patients with chronic atrial
fibrillation who underwent endocavitary electrical cardioversion (EEC: low energy DC
shocks delivered via all poles of 2 decapolar catheters positioned in the right atrium and
coronary sinus). Ten pts (8 males, 59 ± 5 yrs) presented relapse (AFR) within 15 days and
12 pts (7 males, 64 ± 12 yrs) did not (noAFR). The two groups were age-matched. All pts
were under various antiarrhythmic drugs. P wave signal-averaging (trigger on P wave,
template comparing method, at least 400 beats, ELP device by Cardiomedica, Rome),
performed immediately after EEC, allowed evaluation of filtered (40-250 Hz) P wave
duration (FPW) and of P wave frequency content (Fast Fourier method, 0.05-130 and 10-130
Hz) as sum of the 3 orthogonal leads. Arrhythmia duration (ArD) and defibrillation
threshold (DT) were also evaluated.
Results. Mean value of FPW did not differ significantly between AFR
(132 ± 11 msec) and noAFR (136 ± 14 msec). Instead frequency content between 0.05 and
130 Hz was found to be significantly (p < 0.001) higher in AFR (26.72 ± 2.48 µV2)
than in noAFR (22.50 ± 3.02 µV2). Even frequency content between 10 and 130
Hz proved to be significantly (p < 0.0085) higher in AFR (11.27 ± 2.97 µV2)
than in noAFR (7.43 ± 3.81 µV2). Mean values of ArD (AFR: 7.4 ± 6.4 months,
noAFR: 4.3 ± 4.8 months) and of DT (AFR: 5.6 ± 2.1 joules, noAFR: 6.2 ± 2.6 joules) did
not differ significantly between the two groups.
Conclusions. P wave frequency content appears able to predict early
atrial fibrillation relapse after EEC probably because reflects abnormalities degree of
atrial electrophysiologic substrate. This could be very useful to select therapy after
cardioversion.
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Key Words
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Atrial fibrillation – transvenous internal
cardioversion
low energy atrial cardioversion, P wave signal averaging, time domain analysis, frequency
domain ananlysis, prediction of early AF relaps, OA
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