Heart block

This is an example of ventricular pacing at different rates in a patient with complete heart block. Initially the pacemaker is set to 80/min. At a quick glance this produces an effect similar to ventilator-induced systolic pressure variation, but since it is nothing of the sort it could be called 'masquerading systolic pressure variation' !

When the pacing rate is increased to 90/min the variation in blood pressure (and stroke volume and cardiac output) disappears. When the pacing rate is reduced to 80/min, the variation in blood pressure is seen again, but this time it is cycling at 10.5/min whereas at the start of the display the cycling rate was 7.5/min.

The explanation is that the atrial rate was about 90/min.