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Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
Published on: July 3, 2013
Calcium transients modulate action potential repolarizations in ventricular fibrillation.
Bum-Rak Choi1, Tong Liu, Guy Salama
1University of Pittsburgh, PA 15261, USA. bchoi@tulane.edu
Summary
Intracellular calcium (Cai) anomalies contribute to action potential alternans and ventricular fibrillation (VF). This study reveals Cai influences action potential duration, potentially promoting wave breaks during VF.
Area of Science:
- Cardiovascular Physiology
- Cardiac Electrophysiology
- Computational Biology
Background:
- Action potential alternans is a marker for ischemic heart disease and ventricular fibrillation (VF) risk.
- Alternans mechanisms involve intracellular calcium (Cai) handling abnormalities, affecting action potential duration (APD) and potentially promoting VF wave breaks.
Purpose of the Study:
- To investigate the role of intracellular calcium (Cai) in promoting wave breaks during ventricular fibrillation (VF).
- To analyze the dynamic relationship between transmembrane potential (Vm) and Cai oscillations during VF.
Main Methods:
- Simultaneous measurement of Vm and Cai using voltage-sensitive dye (RH237) and Ca2+ fluorescence probe (Rhod-2).
- Induction of VF via burst stimulation.
- Cross-correlation analysis to assess Vm-Cai relationships during VF.
Main Results:
- A maximum correlation of 12 ms delay between Vm and Cai suggests Vm still triggers Cai release in VF.
- An inverse correlation at -20 ms indicates Cai amplitude modulates action potential recovery during VF.
Conclusions:
- Intracellular calcium (Cai) dynamics significantly influence action potential duration (APD) during ventricular fibrillation (VF).
- These Cai-mediated APD modulations may promote the wave breaks characteristic of VF, highlighting a potential therapeutic target.
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