IABP: Late Deflation

This shows the arterial tracing of Late Deflation of an IABP

Late Deflation - the IABP not deflating until after onset of systole - is another very dangerous failure mode. As with early inflation, the acute increase in afterload can result in cardiac arrest due to an abrupt and great increase in myocardial wall stress. Less direly, it may simply result in a marked decrease in cardiac output.

Late Deflation may also increase the possibility of left to right shunting in the event of an existing defect, such as a PFO (present in up to 33%), or other physical wall defect.

Note here the widening of the diastolic balloon augmentation wave. You recall that with a normally assisted beat, the end-diastolic pressure is less than with a native, unassisted diastole. Here you see a rise in EDP, which may even be higher than the EDP of a native, unassisted beat.

A normal IABP pressure trace is shown in the inset to the right.