AFIB causes stroke, DVT causes PE?

loving2024, BSN, RN · Dec 31, 2014

Blood clot sometimes breaks and travels through the blood to the lungs and cause PE.

Dvt cant cause stroke because stroke deals with lack of blood to the brain (remember artery takes blood to the rest of the body and brain and veins takes blood back to the heart).

So in order for blood clot to cause a stroke, it has to be a clot from an arteries not vein.

jj224 · Dec 31, 2014

A DVT is in your venous system, which if mobilized goes through superior or inferior vena cava to R atrium, R ventricle and up the pulmonary artery to the lungs. It can't pass through your pulmonary circulation to L atrium, L ventricle, up the aorta then up either carotid to the brain causing a stroke.

AFIB, on the other hand, can cause a clot to form in either atria - caused by incomplete emptying. If clot formed in R atrium, it can cause a PE. If in L atrium, it can cause a CVA OR an MI since the coronary arteries branch off the aorta.

KelRN215, BSN, RN · Dec 31, 2014

Because venous blood returns to the right side of the heart and then goes to the lungs, a DVT won't cause a stroke because it won't get past the lungs to do that. That's why it causes a PE, venous blood (with DVT) enters the right atrium-left atrium-pulmonary artery-lungs and causes a PE. AFib could cause a PE if a clot forms in the right atrium, it causes a stroke when a clot forms in the left atrium, travels to the aorta and then occludes the carotid artery.

Lev, MSN, RN, NP · Dec 31, 2014

What happens in afib? The atria are vibrating. What collects in the atria? Blood. What happens when a container vibrates? Its content also vibrates. What can happen when you shake blood around? It can clot. And if that clot is large enough it can travel to the brain causing a stroke OR it can travel to the lungs, which is a PE. A DVT is a clot that forms in veins of the arms and legs (more commonly the legs). If a clot becomes detached or shoots up through the heart and into the lungs you get a PE.

icuRNmaggie, BSN, RN · Dec 31, 2014

A DVT can cause a stroke if the patient has a patent foramen ovale.

loving2024, BSN, RN · Dec 31, 2014

A DVT can cause a stroke if the patient has a patent foramen ovale.

Thanks for sharing. I didnt even know this type of birth defect exist.

There is always something to learn in nursing.

nurseprnRN, BSN, RN · Dec 31, 2014

As a refresher, please take a look at normal vascular anatomy.

Body > Veins > Vena Cava > Right Atrium > tricuspid valve > Right Ventricle > pulmonic valve > Pulmonary Artery

> LUNGS

>Pulmonary Vein > Left Atrium > mitral valve > Left ventricle > aortic valve > Arteries > Body

Given normal anatomy, i.e., no intracardiac malformations, there is simply no way for a floating object in the venous side to get to the left heart at all; it gets strained out in the pulmonary capillary bed. As a matter of fact, that's why you have a pulmonary capillary bed, to act as a strainer for all the microemboli you have in the course of an active life. This should also reassure you about little clots and small amounts of air in IVs-- they all go to the pulmonary capillary bed and lyse (the clots) or get absorbed and exhaled (the bubbles).

The only way a deep VEIN thrombosis can get to the cerebral arterial circulation is if there is a direct connection between the venous side and the arterial side in the heart AND the venous pressure is HIGHER than the arterial pressure.

Anyone with an atrial or ventricular septal defect AND a right-to-left shunt would be at risk for arterial embolus of venous origin, and this would be bad. However, since in most people, the left heart pressures are significantly higher than right heart pressures (by a factor of five to ten, more or less), any air or clot in the right heart keeps going right on out the pulmonary artery to the capillary bed. Unsuspected ASDs are a known cause of stroke in younger people who lack other risk factors-- think of the much-beloved erstwhile heart and soul of the Patriots' line, Tedy Bruschi, whose stroke fortunately resolved and whose ASD was repaired endoscopically; he went back to football for the rest of that season and the next one (although he has since retired and now does commercials for MRI centers and life insurance). As a matter of fact, most ASDs are found by accident or on post for unrelated issues, since the left-to-right shunt doesn't do much harm unless it's so huge that you get bad pulmonary hypertension and capillary bed damage (seen in single ventricle, for example).

Now, as to the idea of AF putting people at risk for (not necessarily causing) cerebral embolic stroke (or other arterial emboli with infarct, come to that), you should be able to see that if the atria aren't contracting briskly, then blood pooling in there can develop clot. The clot in the LA can then zip through the mitral valve into the left ventricle (LV) and then go out the aorta to wherever it goes. If it goes to the brain, stroke. If it goes to the kidney, renal infarct. If it goes to the mesenteric artery, gut infarct (very, very bad thing). If it goes down the femoral artery, leg turns blue. If the clot is in the RA and goes to the RV, you can have a PE. However, many small PEs are never detected (see, usefulness of pulmonary capillary bed); a clot that would cause a stroke in the arterial cerebral circulation might (and probably did) go completely unnoticed in the lungs.

I hope this helps. It doesn't answer your question, but it should clear up your misconceptions. It's a common misconception even among nurses, who should know better-- so many people think they can't irrigate a little clot out of an IV because they'll cause a stroke, or that air bubbles in the IV tubing will be lethal. No intracardiac abnormality, not gonna happen.

Nursing2102 · Dec 31, 2014

Thanks everyone! This made it much clearer.

icuRNmaggie, BSN, RN · Jan 1, 2015

In the patient has been in rapid afib for less than 48 hours, the physician may attempt cardioversion in an emergency situation.

If the duration of the afib is unknown, a TEE will be done first to rule out clots.

If the pt is being electively cardioverted, he will receive anticoagulation for a couple of weeks to reduce the risk of a stroke.