Parts of a normal carotid waveform:
It has 4 parts:
- Percussion wave: Pressure transmission to carotids before blood reaches carotids
- Tidal wave: Blood reaching the carotids: Indicates cardiac output
- Dicrotic notch: Closure of semilunar valve
- Dicrotic wave: Due to back pressure from small vessels: Indicates peripheral vascular resistance (PVR).
Parvus et tardus:
- Parvus = Low amplitude
- et tardus = Late peak
- Seen in severe AS.
- 2 systolic peaks of equal amplitude
- Seen in severe AR.
- 2 systolic peaks
- The second peak has lower amplitude than first one.
- 2 peaks: one at systole and the other at diastole
- May occur in shock or severe sepsis.
- The systolic pressure varies from beat-to-beat independently of the respiratory cycle
- Sinus rhythm is maintained
- Seen in severe LV systolic dysfunction.