The Jugulars in Atrial Fibrillation AF

1. Why will AF attenuate the X' descent and cause a dominant Y descent?

ANS: In AF the RV contraction is decreased due to a lack of a booster pump effect of atrial contraction at the end of diastole.

2. Why will a patient in AF with congestive heart failure often have no X' descent at all, i.e., only a Y descent may be seen?

ANS: a. The decrease in RV contraction due to the decreased venous return causes a decreased descent of the base.

The wave before the X' cannot be an A wave since it is not due to atrial contraction. Note the good X' descent, despite the dominant Y descent, in this patient with moderate rheumatic MR.

The wave before the X' cannot be an A wave since it is not due to atrial contraction. Note the good X' descent, despite the dominant Y descent, in this patient with moderate rheumatic MR.

b. The right atrium in a patient with heart failure is under increased tension from excess sympathetic stimulation and from the high pressure in the atrioventricle when the AV valve is open. Thus the atrium is less compliant than normal. Therefore, there will be a steeper rise in atrial pressure as it receives its blood from the venae cavae to build up a V wave during ventricular systole.

3. What is the name of the wave preceding the X' in AF?

4. How can you quickly tell that the major descent that you are seeing is a Y descent in the presence of rapid AF?

ANS: Auscultation is the best method for rapid rates. At rapid rates a Y descent falls onto the Sl. With rapid rates you may also make use of peaks as well as descents because with an X' descent, the peak of the jugular movements occur with the Sl. With AF the peak is reached at the time of the S2.

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Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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