June 8, 2001Circulation Research
Potential Ionic Mechanism for Repolarization Differences Between Canine Right and Left Atrium
Key result
Left atrial myocytes demonstrated significantly greater rapid delayed rectifier current density than right atrial myocytes (1.83 vs 1.15 pA/pF; P<0.01), explaining their shorter repolarization.
Population
Isolated canine atrial myocytes, multicellular preparations, and in vivo canine models
Comparison
Evaluation of left atrial ionic currents, action… vs Right atrial (RA) myocytes and tissue
Design
Preclinical
Authors
Discussion
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Implication
May inform LA-specific AF mechanisms in models; leaves open human translation and therapeutic targeting.
Structured PICO
P
Population
Isolated canine atrial myocytes (n=16 cells per group for patch clamp), multicellular preparations, and in vivo canine models
I
Intervention
Evaluation of left atrial (LA) ionic currents, action potentials, and response to dofetilide
C
Comparator
Right atrial (RA) myocytes and tissue
O
Outcome
Density of the rapid delayed rectifier current (I(Kr)) and action potential duration (APD)surrogate
Main Result
Absolute Event Rate: 1.83% vs 1.15%
p-value: p=<0.01
Left atrial myocytes have a larger rapid delayed rectifier current (I(Kr)) than right atrial myocytes, explaining the shorter action potential duration and effective refractory period in the left atrium, which may contribute to its role as a driver region for atrial fibrillation.
Cite This Study
Li et al. (2001) studied Atrial fibrillation. Left atrium myocytes vs. Right atrium myocytes was evaluated on Rapid delayed rectifier current (I(Kr)) density at +20 mV (p=<0.01). Left atrial myocytes demonstrated significantly greater rapid delayed rectifier current density than right atrial myocytes (1.83 vs 1.15 pA/pF; P<0.01), explaining their shorter repolarization.