Sun10October1036AM 2

The arterial pressure waveform can provide information regarding the performance of the heart and the clinical state of the patient.

Which one of the following waveform characteristics provides the most information regarding myocardial contractility?

(Please select 1 option)

Integration of the area under the curve.

Calculation of mean arterial pressure.

Slope of the upstroke of the curve. Correct

Slope of diastolic decay of the curve.

Position of the dicrotic notch on the downstroke.

Explanation

The slope of the upstroke of the wave reflects myocardial contractility represented by the derivative: dP/dt. Change of pressure with regard to change in time.

Information derived from the arterial pressure waveform:

Heart rate

Systolic, diastolic and mean arterial pressure: MAP can be determined by integrating a pressure signal over the duration of one cycle. The mean pressure is then given by the value of this integral divided by time.

Stroke volume can be calculated by integrating the area under the curve from the beginning of the upstroke to the dicrotic notch. If this is multiplied by the heart rate, then cardiac output can be estimated.

Position of the dicrotic notch on the down stroke. A low dicrotic notch is seen in hypovolaemic patients.

Slope of the diastolic decay indicates resistance to outflow. A slow fall is seen in vasoconstriction.

Answer Statistics

1

24%

2

2%

3

72%

4

2%

5

3%

Times answered: 238