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Estimating Bilateral Atrial Function by Cardiovascular Magnetic Resonance Feature Tracking in Patients with Paroxysmal Atrial Fibrillation
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Estimating Bilateral Atrial Function by Cardiovascular Magnetic Resonance Feature Tracking in Patients with Paroxysmal Atrial Fibrillation

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Diurnal variations of the dominant cycle length of chronic atrial fibrillation

C J Meurling1, J E Waktare, F Holmqvist

  • 1Department of Cardiology, Lund University Hospital, Lund, Sweden.

American Journal of Physiology. Heart and Circulatory Physiology
|December 21, 2000
PubMed

Insights

In chronic atrial fibrillation, dominating atrial cycle length (DACL) varies between day and night. Shorter mean DACL correlates with less diurnal fluctuation, suggesting complex regulatory mechanisms beyond vagal tone.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Medical Technology

Background:

  • Chronic atrial fibrillation (AF) presents complex electrophysiological challenges.
  • Understanding atrial cycle length (ACL) dynamics is crucial for AF management.
  • High-resolution digital Holter monitoring offers detailed electrocardiogram (ECG) analysis.

Purpose of the Study:

  • To investigate the diurnal variation of dominating atrial cycle length (DACL) in patients with chronic AF.
  • To explore the relationship between mean DACL, its diurnal fluctuation, and ventricular cycle length.
  • To assess potential physiological modulators of DACL in AF.

Main Methods:

  • High-resolution digital Holter recordings in 21 patients with chronic AF.
  • Frequency domain analysis of QRST-reduced ECGs to derive DACL.
  • Statistical correlation analyses to examine relationships between DACL, diurnal variation, and ventricular cycle length.

Main Results:

  • Mean daytime DACL was 150 ± 17 ms and nighttime DACL was 157 ± 22 ms (P = 0.0002).
  • Diurnal DACL fluctuation varied significantly among patients, correlating with mean DACL (R = 0.72, P < 0.001).
  • Mean DACL correlated with ventricular cycle length (R = 0.40, P < 0.001), especially at night (r = 0.49).

Conclusions:

  • Daytime shorter DACL suggests sympathetic or other physiological modulation.
  • Parasympathetic influences are unlikely to be the primary driver of DACL changes.
  • Atrial effective refractory period may not solely determine DACL in AF, indicating other factors are involved.

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