Related Experiment Video
Updated: Aug 14, 2026

Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
Published on: July 3, 2013
Correlation of electrotonic monophasic action potential shortening with short-term memory in human atrium
Gi-Byoung Nam1, Kee-Joon Choi, Jun Kim
1Department of Internal Medicine, University of Ulsan College of Medicine, Seoul, Korea.
Abstract:
To determine the presence of memory in human atria, we recorded monophasic action potential (MAP) at the high right atrium (HRA) in 21 patients. After reaching a steady state at 600 ms, HRA pacing was switched to the coronary sinus (CS) pacing to alter the activation sequence. After 20 minutes of CS pacing, pacing was continued at HRA to record the memory effect of CS pacing. Atrial memory was defined as the change in HRA MAP duration (MAPd) after 20 minutes of altered activation sequence. Baseline MAPd was 229 +/- 31 ms, which was shortened to 226 +/- 24 ms immediately after CS pacing. After 20 minutes of CS pacing, HRA MAPd during HRA pacing was 220 +/- 28 ms, which was significantly shorter than the baseline MAPd (P = 0.003). The degree of atrial memory was associated with the degree of initial electrotonic MAPd changes caused by the altered activation sequence. These results suggest that memory phenomenon exists in human atria, and it can be expressed as a change in MAPd.
Related Concept Videos
Cardiac Action Potential
The cardiac action potential process involves a series of phases characterized by the movement of ions across the cardiac cell membranes, leading to the depolarization and repolarization of the cardiac myocytes.
Ionic Basis of Cardiac Action Potentials
Correlation between ECG and Cardiac Cycle
A cardiac action potential originates in the SA node and spreads throughout the atria and the AV node in approximately 0.03 seconds. This results in the P wave in an ECG and triggers atrial contraction. The action potential is then briefly slowed at the AV node, allowing the atria to contract and fill the ventricles with blood before...
Electrophysiology of Normal Cardiac Rhythm
Action Potential: Phases of Stimulation
Resting Phase:
In this phase, the cell's membrane is at its resting potential, typically around -70 millivolts (mV) for neurons. Inside the cell, there is a higher concentration of potassium ions (K+) and a lower concentration of sodium ions (Na+). Voltage-gated sodium channels are closed, and...
Action Potentials
Action Potential
Membrane potential in neurons
Neurons typically have a resting membrane potential of about -70 millivolts (mV). When they receive...

