Variation of carotid venous wave shape: high protruding a wave

2021-03-18 12:00 AM

A protruding wave occurs before systole, with no larger carotid artery pulsation and before T1 sound. The cannon a-wave occurs during systole, right when the carotid artery beats and after T1.

Description

The carotid veins suddenly burst rapidly and sharply, immediately before the first sound of the heart. Large waves preceded ventricular systolic and carotid artery pulsation.

Causes

Right ventricular enlargement.

Pulmonary valve stenosis.

Pulmonary hypertension.

Tricuspid valve stenosis.

Mechanism

Right atrial hypertension resists right ventricular filling pressure is a common mechanism. In pulmonary valve stenosis and pulmonary hypertension, due to an increase in right ventricular afterload, reduces the volume of the stroke and increases the end-diastolic pressure in the right ventricle, thereby increasing right atrial pressure. This can induce (or be motivated by) RV enlargement, thus increasing filling resistance and end-diastolic pressure.

In tricuspid stenosis, less blood flows into the ventricles, resulting in large stasis of blood volume and pressure in the right atrium. The right atrium then contracts against a background of high pressure, thus further highlighting the wave.

Explain what is confusing - large waves and cannon a-waves:

The protruding wave and the cannon wave are difficult to see and difficult to distinguish.

Two useful tips to remember when examining the carotid veins:

A protruding wave occurs before systole, with no larger carotid artery pulsation, and before T1 sound.

The cannon a-wave occurs during systole, right when the carotid artery beats and after T1.