Table 2 Action potential characteristics of single isolated firing human SANCs.

Data were from 11 single SANCs isolated from two hearts (one female, one male). *P < 0.05, compared to baseline by two-tailed paired t test. AP CL, action potential cycle length; MDP, maximum diastolic potential; TIP, time to ignition phase.

nArrested
potential
AP CL (ms)MDP (mV)TIP (ms)
BaselineBaselineβ-AR
stimulation
Baselineβ-AR
stimulation
Baselineβ-AR
stimulation
Firing SANCs4NA1698 ± 4821211 ± 374*−50.1 ± 2.3−55.3 ± 5.41582 ± 483958 ± 357*
Arrested SANCs
(responder)
4−39.7 ± 3.3NA2936 ± 608NA−56.2 ± 4.2NA2302 ± 616
Arrested SANCs
(nonresponder)
3−31.3 ± 8.8NANANANANANA