Theory 04/Cardiac cycle/Onset phase
Onset Is Pacemaker Drift
The claim
Heart rate is set by the rate of spontaneous depolarisation in the pacemaker, not by autonomic tone alone.
01Mechanism
The cell drifts to threshold at a rate set by its funny current; the rate determines the interval.
02Prediction
Rate should track depolarisation rate.
03Refutation
Rate tracking autonomic input would remove the drift.