Key result
Coronary sinus pacing for 20 minutes significantly shortened high right atrial monophasic action potential duration compared to baseline (220 vs 229 ms, P=0.003).
Why the study?
Does an altered activation sequence via coronary sinus pacing induce short-term memory (measured by MAPd shortening) in the human atrium?
Does an altered activation sequence via coronary sinus pacing induce short-term memory (measured by MAPd shortening) in the human atrium?
This study demonstrates that short-term memory exists in the human atrium, expressed as a shortening of the monophasic action potential duration following an altered activation sequence.
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.
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Nam et al. (2005) studied this question. Coronary sinus pacing vs. Baseline high right atrium pacing was evaluated on Change in high right atrium monophasic action potential duration (MAPd) (p=0.003). Coronary sinus pacing for 20 minutes significantly shortened high right atrial monophasic action potential duration compared to baseline (220 vs 229 ms, P=0.003).
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