จากรูป เป็น ปกติข อง CVP
A wave - occurs after the P wave of the ECG complex during
the PR interval. It reflects the increased atrial pressure that
occurs with atrial contraction. Note that the A wave will be
absent in patients who do not have a distinct atrial contraction,
such as those with atrial fibrillation. Since the CVP value
should be a reflection of the Right Ventricular End-Diastolic
Pressure, the CVP reading is taken at the last half of the A
wave at the midpoint of the X descent. Calculate the CVP by
averaging the pressure measured at the peak
of the A wave and at the subsequent trough. due to atrial
contraction. Absent in atrial fibrillation. Enlarged in tricuspid
stenosis, pulmonary stenosis and pulmonary hypertension.
The C wave - occurs at the end of the QRS complex at the
beginning of the ST segment on the ECG tracing. It reflects
closure of the tricuspid valve between the right atrium and right
ventricle and the slight bulging of the tricuspid valve during
ventricular contraction. The C wave is not always visualized.
X descent - due to atrial relaxation.
The V wave occurs at the end of the T wave on the ECG
tracing. It reflects the increased
pressure during passive atrial filling.
The Y descent occurs prior to the P wave on the ECG tracing. It
reflects the opening of the
tricuspid valve and the passive flow of blood from the right
atrium into the right ventricle
prior to atrial contraction.
Canon waves - large waves not corresponding to a, v or c
waves. Due to complete heart block or junctional arrhythmias.
ตัว อย่า ง 1
Measure CVP here