What is Pulsus Paradoxus?
Rahul's Noteblog
Notes on Cardiology
What is Pulsus Paradoxus?
Definition of Pulsus Paradoxus:
Pulsus paradoxus is defined as a decrease in systolic blood pressure of greater than 10 mm Hg with inspiration. It is detected by inflating a blood pressure cuff above systolic pressure and then slowly deflating it. Pulsus paradoxus is caused by conditions which tighten the space around the beating heart, e.g., constrictive pericarditis, acute cardiac tamponade, obstructive lung disease, or restrictive cardiomyopathy.
What happens when a normal person inspires?
Now, in a normal person, the heart is surrounded by plenty of free space around it. So when a healthy person inhales, the right ventricle expands due to increased venous return, and this right-ventricular expansion has no effect on the functionality of the left side of the heart.
What happens when a person with a constrictive cardiac disease inspires?
However, in any pathologic condition like constrictive pericarditis, this free space surrounding the heart is reduced. So when a person with constrictive pericarditis inhales, the right ventricle pushes into the left ventricle compressing it and decreasing the ejection fraction causing transient hypotension. This means that if you're measuring the blood pressure in a patient with pulsus paradoxus, the Korotkoff sounds will be heard only when the patient is expiring and not while inspiring because the blood pressure drops while inspiring.
Conclusion:
So whenever there is transient hypotension with inhalation, the person is suffering from a constrictive cardiac pathology.
Additional Reading:
Basic Cardiology
1. Electrical Activity of the Heart
2. Heart Muscle Mechanics
3. Heart Sounds and Murmurs
4. Additional FAQ on Heart Sounds and Murmurs
5. Cardiac Conduction Diagram
6. Blood Pressures in Cardiac Chambers
7. What is Pulsus Paradoxus?
8. FAQ on Heart Murmurs and Mechanisms of Turbulent Flow
9. Notes on Fetal Circulation
10. FAQ on Ischemic Myocardial Infarction
11. FAQ on Electrocardiograms / ECG / EKG
12. FAQ on Cardiac Conduction
Cardiology Videos
1. Video of Cardiology Examination in a Clinical Setting
Medical Images
Useful Medical Images & Diagrams (link opens in a new window)
Related Topics
1. Thorax Anatomy
2. Vascular Disorders
3. Heart Disorders
4. Histology of the Cardiovascular System
5. Jugular Venous Distention Workup
6. ER Chest Pain Workup
7. Cardiac Examination for Internal Medicine
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