Abnormalities of carotid waveform

Parts of a normal carotid waveform:

It has 4 parts:

1. Percussion wave: Pressure transmission to carotids before blood reaches carotids
2. Tidal wave: Blood reaching the carotids: Indicates cardiac output
3. Dicrotic notch: Closure of semilunar valve
4. Dicrotic wave: Due to back pressure from small vessels: Indicates peripheral vascular resistance (PVR).

Normal waveform:

Abnormalities:

Parvus et tardus:

• Parvus = Low amplitude
• et tardus = Late peak
• Seen in severe AS.

Pulsus bisferiens:

• 2 systolic peaks of equal amplitude
• Seen in severe AR.

HOCM:

• 2 systolic peaks
• The second peak has lower amplitude than first one.

Dicrotic pulse:

• 2 peaks: one at systole and the other at diastole
• May occur in shock or severe sepsis.

Pulsus alternans:

• The systolic pressure varies from beat-to-beat independently of the respiratory cycle
• Sinus rhythm is maintained
• Seen in severe LV systolic dysfunction.