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Atrial cellular electrophysiological changes in patients with ventricular dysfunction may predispose to AF
Antony J Workman1, Davide Pau, Calum J Redpath
1British Heart Foundation Glasgow Cardiovascular Research Centre, Division of Cardiovascular & Medical Sciences, Faculty of Medicine, University of Glasgow, UK. A.J.Workman@clinmed.gla.ac.uk
Heart Rhythm
|March 28, 2009
Summary
Left ventricular systolic dysfunction (LVSD) shortens the atrial effective refractory period (ERP) in patients with sinus rhythm. This electrophysiological change may increase the risk of developing atrial fibrillation (AF).
Area of Science:
- Cardiovascular Electrophysiology
- Cardiac Cell Biology
- Arrhythmia Mechanisms
Background:
- Left ventricular systolic dysfunction (LVSD) is a known risk factor for atrial fibrillation (AF).
- The specific atrial cellular electrophysiological mechanisms linking LVSD to AF in humans remain incompletely understood.
Purpose of the Study:
- To investigate if LVSD in patients maintaining sinus rhythm (SR) is associated with alterations in atrial cellular electrophysiology.
- To determine if these electrophysiological changes could predispose individuals to developing AF.
Main Methods:
- Myocytes were isolated from the right atria of 214 patients in SR undergoing cardiac surgery.
- Whole-cell patch clamp techniques were employed to measure action potentials and ion currents.
Main Results:
- Moderate to severe LVSD correlated with a significantly shortened atrial cellular effective refractory period (ERP).
- Patients with LVSD exhibited a lower left ventricular ejection fraction (LVEF) compared to those without.
- A decrease in the transient outward potassium ion current and a positive shift in its activation voltage were observed in LVSD patients.
Conclusions:
- LVSD in patients with SR is independently linked to a shortened atrial cellular ERP.
- This electrophysiological alteration is a potential mechanism contributing to the increased predisposition to atrial fibrillation.
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