Question

A 12-lead calibration that is 2 vertical large boxes is referred to as?

This term refers to the fact there can be only ONE dominant pacemaker?

What is the R to R HR if you have 5 large boxes and 3 small boxes?

This word means a depolarization NOT originating from SA node?

Answer 1

Sub part 1:

A 12 lead calibration that is 2 vertical large boxes is known as standard ECG calibration. Here 1 vertical large box represent amplitude of 0.5 mV. So 2 vertical large boxes will give amplitude of 1 mV.

Sub part 2:

Pacemaker potential frequency defines that there exist only one dominant pacemaker which is having maximum depolarisation frequency.

Sub part 3:

HR= 1500/ no of small boxes

1 large box = 5 small box

So 5 large box = 25 small box

Total small box = 28

HR= 1500/28

=53.57 = 54 heartbeat per minute

Sub part 4:

Stokes Adam syndrome is a clinical term which says depolarisation does not occur from SA node as it ceases. So next pacemaker AV node will cause depolarisation.