Intracellular Calcium Dynamics and Acceleration of Sinus Rhythm by β-Adrenergic Stimulation
Key result
Isoproterenol infusion shifted the pacemaking site to the superior SAN, where Ca(i) transient relaxation time was shorter (124±34 ms) than in the inferior SAN (138±24 ms; P=0.01).
Population
25 isolated canine right atrium preparations
Comparison
Isoproterenol infusion (1 micromol/L) vs Baseline (before isoproterenol)
Design
Preclinical
Authors
Discussion
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Member takes
Implication
Supports Ca-voltage clock synergy in SAN acceleration; leaves open translation to human sinus node therapies.
Structured PICO
P
Population
25 isolated canine right atrium preparations used to map intracellular calcium and membrane potential.
I
Intervention
Isoproterenol infusion (1 micromol/L)
C
Comparator
Baseline (before isoproterenol)
O
Outcome
Intracellular calcium (Cai) dynamics and membrane potential, including pacemaking site and late diastolic Cai elevation (LDCAE)surrogate
Beta-adrenergic stimulation accelerates sinus rhythm through synergistic interactions between the Ca2+ clock in the superior sinoatrial node and the voltage clock.
Cite This Study
Joung et al. (2009) studied Sinoatrial node automaticity (n=25). Isoproterenol vs. Baseline was evaluated on Sinus rate acceleration and late diastolic Ca(i) elevation. Isoproterenol infusion shifted the pacemaking site to the superior SAN, where Ca(i) transient relaxation time was shorter (124±34 ms) than in the inferior SAN (138±24 ms; P=0.01).