Sequence and dispersion of repolarization of the right atrium: Implications of repolarization disturbance in atrial fibrillation

Research output: ThesisDoctoral Thesis (compilation)

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.

Details

Authors
  • Zhen Li
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Cardiac and Cardiovascular Systems

Keywords

  • Kardiovaskulära systemet, Cardiovascular system, electroanatomical mapping, monophasic action potential, atrial fibrillation, repolarization, dispersion
Original languageEnglish
QualificationDoctor
Awarding Institution
Supervisors/Assistant supervisor
  • [unknown], [unknown], Supervisor, External person
Award date2004 Jan 1
Publisher
  • Yunlong Xia. Nerkuriusgatan 4, Lund. 22457,
Print ISBNs91-628-6292-8
Publication statusPublished - 2004
Publication categoryResearch

Bibliographic note

Defence details Date: 2004-01-01 Time: 10:15 Place: Sölvegatan 17, Universitetssjukhuset i Lund External reviewer(s) Name: Nils Edvardsson, Nils Edvardsson Title: [unknown] Affiliation: [unknown] --- Article: I. Z. Li, E. Hertervig, O. Kongstad, M. Holm, E. Grins, S. B. Olsson, S. Yuan. Global repolarization sequence of the right atrium: Monophasic action potential mapping in healthy pigs. PACE 2003;26:1803-8.II. Z. Li, E. Hertervig, S. Yuan, Y. Yang, Z. Lin, S. B. Olsson. Dispersion of atrial repolarization in patients with paroxysmal atrial fibrillation. Europace 2001;3:285-291.III. Z. Li, E. Hertervig, J. Carlson, C. Johansson, S. B. Olsson, S. Yuan. Dispersion of refractoriness in patients with paroxysmal atrial fibrillation: Evaluation with simultaneous endocardial recordings from both atria. J Electrocardiol 2002;35:227-234.IV. E. Hertervig, Z. Li, O. Kongstad, M. Holm, S. B. Olsson, S. Yuan. Global dispersion of right atrial repolarization in healthy pigs and patients. Scand Cardiovasc J 2003;37:239-233.V. Z. Li, E. Hertervig, O. Kongstad, M. Holm, S. B. Olsson, S. Yuan. Regional heterogeneity of right atrial repolarization in healthy swine: an in vivo study of monophasic action potential mapping using electroanatomical mapping system. 2004; in submission.