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Zones of atrial vulnerability. Relationships to basic cycle length.

Publication ,  Journal Article
Friedman, HS; Sinha, B; Tun, A; Pasha, R; Sharafkhaneh, A; Bharadwaj, A
Published in: Circulation
September 15, 1996

BACKGROUND: Bradycardia is commonly found in individuals at risk for paroxysmal atrial fibrillation (AF). However, a clear relationship between lengthening of basic cyclic length (BCL) and AF has not been demonstrated. METHODS AND RESULTS: In 20 open-chest dogs, atrial refractoriness, AF vulnerability, and atrial activation times (ACTs) were determined in sinus rhythm and at BCLs of 400, 300, and 200 ms, and the findings at the same coupling intervals and stimulus strengths were compared. As BCL increased, AFV zone lengthened, and its outer limit occurred later in diastole. The outer limit of the AF vulnerability zone for a BCL was its relative refractory period; the inner limit, however, was not its effective refractory period. A border zone, defined by the inner limit of the AF vulnerability zone and the effective refractory period for a BCL, decreased as BCL lengthened, offsetting the increase in the AF vulnerability zone. The border zone was characterized by paradoxical stimulus current strength propagation relations and features suggesting supernormal conduction. ACT also increased with BCL lengthening. When AF induced by rapid atrial burst pacing was contrasted with AF induced by an extrastimulus, it tended to have a more disorganized pattern and lasted longer. CONCLUSIONS: Lengthening of BCL increases the AF vulnerability zone, extending its outer limit later in diastole and comprising an increasing component of the total duration of the relative refractory period. Very short BCLs create conditions that also favor AF vulnerability.

Duke Scholars

Published In

Circulation

DOI

ISSN

0009-7322

Publication Date

September 15, 1996

Volume

94

Issue

6

Start / End Page

1456 / 1464

Location

United States

Related Subject Headings

  • Refractory Period, Electrophysiological
  • Heart Conduction System
  • Electrocardiography
  • Dogs
  • Cardiovascular System & Hematology
  • Cardiac Pacing, Artificial
  • Cardiac Complexes, Premature
  • Bradycardia
  • Atrial Fibrillation
  • Animals
 

Citation

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Friedman, H. S., Sinha, B., Tun, A., Pasha, R., Sharafkhaneh, A., & Bharadwaj, A. (1996). Zones of atrial vulnerability. Relationships to basic cycle length. Circulation, 94(6), 1456–1464. https://doi.org/10.1161/01.cir.94.6.1456
Friedman, H. S., B. Sinha, A. Tun, R. Pasha, A. Sharafkhaneh, and A. Bharadwaj. “Zones of atrial vulnerability. Relationships to basic cycle length.Circulation 94, no. 6 (September 15, 1996): 1456–64. https://doi.org/10.1161/01.cir.94.6.1456.
Friedman HS, Sinha B, Tun A, Pasha R, Sharafkhaneh A, Bharadwaj A. Zones of atrial vulnerability. Relationships to basic cycle length. Circulation. 1996 Sep 15;94(6):1456–64.
Friedman, H. S., et al. “Zones of atrial vulnerability. Relationships to basic cycle length.Circulation, vol. 94, no. 6, Sept. 1996, pp. 1456–64. Pubmed, doi:10.1161/01.cir.94.6.1456.
Friedman HS, Sinha B, Tun A, Pasha R, Sharafkhaneh A, Bharadwaj A. Zones of atrial vulnerability. Relationships to basic cycle length. Circulation. 1996 Sep 15;94(6):1456–1464.

Published In

Circulation

DOI

ISSN

0009-7322

Publication Date

September 15, 1996

Volume

94

Issue

6

Start / End Page

1456 / 1464

Location

United States

Related Subject Headings

  • Refractory Period, Electrophysiological
  • Heart Conduction System
  • Electrocardiography
  • Dogs
  • Cardiovascular System & Hematology
  • Cardiac Pacing, Artificial
  • Cardiac Complexes, Premature
  • Bradycardia
  • Atrial Fibrillation
  • Animals