Can I feel pulsus paradoxus myself?

Usually not. The change is too small to feel. It normally takes a measurement, such as a blood-pressure cuff or a device that reads the pulse signal, to notice it.

Is pulsus paradoxus always a sign of something serious?

Not always. A small drop in the pulse when you breathe in is normal. A large drop can be a warning sign, especially after heart surgery, and is worth checking with your care team.

← Patient & family guide Plain-language guide

What is pulsus paradoxus?

It's a long name for a simple idea: a bigger-than-normal drop in the strength of your pulse each time you breathe in. Here's what it means, especially after heart surgery, and when to get help.

The short version: a small drop in your pulse when you breathe in is normal. A large drop can be a warning sign that the heart is under pressure, for example from fluid building up around it. Doctors take it seriously, especially after heart surgery.

What happens in your body

Every time you breathe in, the pressure inside your chest changes a little, and your pulse normally dips just slightly. If there is too much fluid pressing on the heart, that dip gets much bigger. You usually can't feel this yourself, it takes a measurement to spot it.

Pulsus paradoxus

A bigger-than-normal drop in your pulse each time you breathe in. Doctors treat it as a warning sign.

Why it matters after heart surgery

In the first few weeks after heart surgery, a small number of people build up fluid around the heart. This is more common after valve surgery and in people on blood thinners, and it often appears in the second or third week, after you're home. A larger drop in your pulse when you breathe in can be one early clue that the heart is under pressure.

How is it checked?

Traditionally, a doctor measures it with a blood-pressure cuff. Newer tools, like the investigational software PulSentry, look for this same pattern in the pulse signal from a fingertip oxygen clip, the kind you've probably seen at the doctor's office.

PulSentry is still being studied and is not FDA-cleared. It supports your care team; it does not replace them, and it does not diagnose or treat anything.

When should I call my doctor or 911?

Call 911 or go to the emergency room right away if you have:

Severe shortness of breath
Fainting, or feeling like you might pass out
Chest pressure or chest pain

Call your care team if you feel newly short of breath, very tired, dizzy, or your heartbeat feels fast. When in doubt, ask.

Medically reviewed by Gregory R. Mason, MD

Pulmonary & Critical Care Medicine · Last reviewed June 2026

Where this information comes from

MedlinePlus (U.S. National Library of Medicine). Pulse oximetry; pericardial effusion.
Mayo Clinic. Cardiac tamponade, patient information.
For clinicians: What is pulsus paradoxus? A clinician's guide.

New here? Start with the patient & family guide. Are you a clinician? See the clinical version of this article.