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Heart rhythm disorders
Mechanoelectrical feedback regulates the arrhythmogenic activity of pulmonary veins
  1. S-L Chang1,
  2. Y-C Chen2,
  3. Y-J Chen3,
  4. W Wangcharoen1,
  5. S-H Lee4,
  6. C-I Lin5,
  7. S-A Chen1
  1. 1Division of Cardiology and Cardiovascular Research Center, National Yang-Ming University School of Medicine and Veterans General Hospital, Taipei, Taiwan
  2. 2Department of Biomedical Engineering, National Defense Medical Center, Taiwan
  3. 3Taipei Medical University, School of Medicine; Division of Cardiovascular Medicine, Taipei Medical University-Wan-Fang Hospital, Taipei, Taiwan
  4. 4Shin-Kong Memorial Hospital; Department of Medicine, Fu Jen Catholic University
  5. 5Institute of Physiology, National Defense Medical Center, Taiwan
  1. Correspondence to:
    Dr Yi-Jen Chen
    Division of Cardiovascular Medicine, Taipei Medical University-Wan-Fang Hospital, 111, Hsin-Lung Road, Sec 3, Taipei, Taiwan; yjchen{at}tmu.edu.tw

Abstract

Background: Atrial fibrillation is commonly associated with dilated pulmonary veins. Stretch has been shown to have mechano-electrical effects.

Objective: To investigate whether stretch can increase the arrhythmogenic activity of the pulmonary veins.

Methods: The transmembrane action potentials were recorded from rabbit pulmonary veins before and after stretch (100 and 300 mg). Gadolinium and streptomycin (stretch-activated ion channel blockers) were each perfused into the pulmonary veins under a 300-mg stretch.

Results: Stretch (0, 100 and 300 mg) force dependently increased the incidence of spontaneous activity (22%, 48% and 83%; p<0.05), mean (standard deviation (SD)) firing rates of spontaneous activity (1.7 (0.2), 2.1 (0.3) and 3 (0.2) Hz; p<0.05) and incidence of early post-depolarisations (9%, 26% and 61%; p<0.05) and delayed post-depolarisations (0%, 4% and 30%; p<0.05) in 23 pulmonary veins. In the seven preparations with spontaneous activity after the 300-mg stretch, gadolinium (1, 3 and 10 μmol/l) decreased the incidence of spontaneous activity by 43%, 29% and 14%, respectively (p<0.05), and decreased the firing rate from 2.9 (0.1) Hz to 0.8 (0.4), 0.3 (0.1) and 0.1 (0.1) Hz, respectively (p<0.05). Streptomycin (10 and 40 μmol/l) decreased the incidence of spontaneous activity by 71% and 29%, respectively (p<0.05), and decreased the firing rate from 2.9 (0.1) Hz to 1.6 (0.4) and 0.5 (0.3) Hz, respectively (p<0.05).

Conclusion: Stretch is an important factor in the electrical activity of the pulmonary vein. Stretch-induced arrhythmogenic activity of the pulmonary vein may contribute to the genesis of atrial fibrillation.

  • APA, amplitudes of the action potential
  • APD, action potential duration
  • DAD, delayed afterrepolarisation
  • EAD, early afterrepolarisation
  • MDP, membranous diastolic potential
  • SAC, stretch-activated ion channel

https://doi.org/10.1136/hrt.2006.089359

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