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- Li, Zhen, et al.
(författare)
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Dispersion of refractoriness in patients with paroxysmal atrial fibrillation: Evaluation with simultaneous endocardial recordings from both atria.
- 2002
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Ingår i: Journal of Electrocardiology. - : Elsevier BV. - 1532-8430 .- 0022-0736. ; 35:3, s. 227-234
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Tidskriftsartikel (refereegranskat)abstract
- This article studies the role of dispersion of atrial refractoriness (DAR) in the genesis of atrial fibrillation (AF). A 20-polar Halo catheter or a 40-polar basket catheter was placed in the right atrium and a 10-polar catheter in the coronary sinus in 21 patients with paroxysmal AF. Bipolar electrograms during AF were recorded from 7 to 16 sites in both atria. As control, electrograms during AF induced by extra-stimulation or burst pacing were also recorded from 4 to 14 sites in both atria in 12 patients with supraventricular tachycardias but without history of AF. The local atrial fibrillation intervals (AFI) during a period of 10 s or 20 s were measured and the mean, median and the 5th, 10th and 15th percentile AFIs at each site were calculated as estimates of the local effective refractory period (AERP). The maximum dispersion and variance of the estimated AERP among the 7-16/4-14 sites were used as measures of the DAR. The maximum dispersion and variance of the 5th and 10th percentile AFIs were significantly greater in the AF group than those in the control group, which were mainly due to the shortening of the minimum 5th and 10th percentile AFIs. No significant differences in dispersion and variance of the mean and median AFIs were shown between the 2 groups. The dispersion and variance of atrial refractoriness during AF estimated from the measurement of short AFIs were significantly greater in patients with paroxysmal AF than in those without clinical AF. The increased dispersion of refractoriness in patients with AF was mainly due to the shortening of the minimum AFIs. These findings suggest the involvement of an increased dispersion of atrial refractoriness in the genesis of paroxysmal AF.
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| 3. |
- Li, Zhen
(författare)
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Sequence and dispersion of repolarization of the right atrium: Implications of repolarization disturbance in atrial fibrillation
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- To explore the global sequence and dispersion of repolarization of the right atrium, monophasic action potentials (MAPs) were sequentially recorded from the right atrium using an electroanatomical mapping (CARTO) system in 10 healthy pigs and in 10 patients with (n=6) and without (n=4) paroxysmal atrial fibrillation (PAF) during sinus rhythm, or using two MAP recording catheters in 30 patients with or without PAF (n=15 each) during sinus rhythm, pacing, and programmed stimulation. The dispersion of activation time (AT), repolarization time (RT) and MAP duration (MAPd) were analyzed. During induced atrial fibrillation (AF), bipolar electrograms were recorded at 4, 10 or 20 right atrial sites and 5 coronary sinus sites in 21 patients with and 12 patients without clinical PAF. The local atrial fibrillation intervals (AFIs) were measured as estimates of the local effective refractory period (ERP). Results: Satisfactory MAPs were obtained from 51 ±14 sites in the 10 pigs and 33±21 sites in the 10 patients using the CARTO system and from 6.6±1.9 sites in the 30 patients using two MAP recording catheters. Bipolar electrograms were obtained from 11±1 sites in the 33 patients. Color-coded, 3-dimensional maps of activation and repolarization sequences were reconstructed using the CARTO system. Gradients of RT were recognizable on all maps, and the sequence of repolarization was mainly following that of activation. A significant correlation was found in all pigs between the RT and AT, but not between the MAPd and AT. The global dispersions of AT, MAPd and RT among all sites were significantly greater than those among 10, 20 or 30 randomly selected sites. The global dispersions were also significantly greater than those calculated from seven different regional areas. No significant regional differences in MAPd or RT were observed. The dispersions of AT, MAPd and RT during sinus rhythm and programmed stimulation, and the estimated dispersions of ERP during AF were significantly greater in patients with PAF than in those without clinical AF. Conclusions: Repolarization gradients exist over the right atrial endocardium in healthy pigs and the temporospatial pattern of activation is an important determinant of the repolarization sequence. MAP mapping using the CARTO system is feasible in evaluating the global repolarization in experimental and clinical settings. The number of recordings could significantly affect the measurement results of the atrial repolarization. The global repolarization could not be estimated by mapping of local areas. Regional heterogeneity of the repolarization is not significant in the in situ right atrium in pigs. Increased dispersion of atrial repolarization contributes to the genesis and/or perpetuation of AF in our patients.
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