Repeated exposure to transient obstructive sleep apnea-related conditions causes an atrial fibrillation substrate in a chronic rat model

Benedikt Linz, Mathias Hohl, Lisa Lang, Dickson W. L. Wong, Alexander G. Nickel, Carolina De La Torre, Carsten Sticht, Klaus Wirth, Peter Boor, Christoph Maack, Thimoteus Speer, Thomas Jespersen, Ulrich Schotten, Prashanthan Sanders, Michael Bohm, Dominik Linz*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

BACKGROUND High night-to-night variability in obstructive sleep apnea (OSA) is associated with atrial fibrillation (AF). Obstructive apneas are characterized by intermittent deoxygenation-reoxygenation and intrathoracic pressure swings during ineffective inspiration against occluded upper airways.

OBJECTIVE We elucidated the effect of repeated exposure to transient OSA conditions simulated by intermittent negative upper airway pressure (INAP) on the development of an AF substrate.

METHODS INAP (48 events/4 h; apnea-hypopnea index 12 events/h) was applied in sedated spontaneously breathing rats (2% isoflurane) to simulate mild-to-moderate OSA. Rats without INAP served as a control group (CTR). In an acute test series (ATS), rats were either killed immediately (n = 9 per group) or after 24 hours of recovery (ATS-REC: n = 5 per group). To simulate high night-to-night variability in OSA, INAP applications (n = 10; 24 events/4 h; apneahypopnea index 6/h) were repeated every second day for 3 weeks in a chronic test series (CTS).

RESULTS INAP increased atrial oxidative stress acutely, represented in decreases of reduced to oxidized glutathione ratio (ATS: INAP: 0.33 +/- 0.05 vs CTR: 1 +/- 0.26; P = .016), which was reversible after 24 hours (ATS-REC: INAP vs CTR; P = .274). Although atrial oxidative stress did not accumulate in the CTS, atrial histological analysis revealed increased cardiomyocyte diameters, reduced connexin 43 expression, and increased interstitial fibrosis formation (CTS: INAP 7.0% +/- 0.5 % vs CTR 5.1% +/- 0.3 %; P = .013), which were associated with longer inducible AF episodes (CTS: INAP: 11.65 +/- 4.43 seconds vs CTR: 0.7 +/- 0.33 seconds; P = .033).

CONCLUSION Acute simulation of OSA was associated with reversible atrial oxidative stress. Cumulative exposure to these transient OSA-related conditions resulted in AF substrates and was associated with increased AF susceptibility. Mild-to-moderate OSA with high night-to-night variability may deserve intensive management to prevent atrial substrate development.

Original languageEnglish
Pages (from-to)455-464
Number of pages10
JournalHeart Rhythm
Volume18
Issue number3
DOIs
Publication statusPublished - Mar 2021

Keywords

  • Atrial fibrillation
  • Night-to-night variability
  • Obstructive sleep apnea
  • Rats
  • Substrate
  • HEART-FAILURE
  • RECURRENCE
  • SEVERITY
  • PRESSURE
  • IMPACT

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