A DECREASED RATE OF DEPOLARIZATION Membrane -20 2004006008001001200 requires more Time time to reach msec threshold. B NEGATIVE SHIFT IN MAXIMUM DIASTOLIC POTENTIAL Three ways the Sa 20 Membrane node slow the firing potenta-20 (mv) Threshold rate of its pacemaker saring froma more 40 IMaximum dias requires more time toreach threshold._80 potential 020040060080010001200 Time C POSITIVE SHIFT IN THRESHOLD Reaching a more 八八 A. The positive threshold re time. 020040060080010001200Three ways the SA node slow the firing rate of its pacemaker 27