Pls HELP!! Confused, Am I understanding this right?

Skips, MSN, RN · Jan 31, 2013

Yes, you are right. A-fib is a problem with the SA node being dysfunctional, so the electrical impulse doesn't begin there...it begins somewhere else, causing the atria to contract. The AV node is still functioning, so the ventricles think they need to keep up with the workload. Sometimes the heart rate is normal, though. Sometimes it's not.

Morganalefey · Jan 31, 2013

See if this helps :)

dah doh, BSN, RN · Jan 31, 2013

Loved the heartbeat dance! Made me laugh!

nurseprnRN, BSN, RN · Feb 1, 2013

The atria aren't so much contracting as quivering, and the ventricle actually fills more or less passively. Therefore because the ventricular rate is irregularly irregular, by definition, each beat has an irregular amount of blood to pump out, so the pulse quality varies beat-to-beat too. If the ventricles contract irregularly, for example, two beats are close together, then a pause, a beat, another beat, then three fast ones, all eight of those beats will have different amounts of time for filling and thus different amounts of blood to pump out, resulting in a different systolic pressure for each one. This is, in part, why automatic BP cuffs are useless in afib. You need practiced human ears to see what the real BP is.

Ventricular rate in afib is never regular. The impulses getting through the AV node are not always effective and they sure as heck aren't regular.

scrlet · Feb 2, 2013

The atria aren't so much contracting as quivering, and the ventricle actually fills more or less passively. Therefore because the ventricular rate is irregularly irregular, by definition, each beat has an irregular amount of blood to pump out, so the pulse quality varies beat-to-beat too. If the ventricles contract irregularly, for example, two beats are close together, then a pause, a beat, another beat, then three fast ones, all eight of those beats will have different amounts of time for filling and thus different amounts of blood to pump out, resulting in a different systolic pressure for each one. This is, in part, why automatic BP cuffs are useless in afib. You need practiced human ears to see what the real BP is.

Ventricular rate in afib is never regular. The impulses getting through the AV node are not always effective and they sure as heck aren't regular.

Last semester I had a pt with A-fib and and we did a apical/radial rate and it was off of course by a bit, but it was interesting to listen to it. I will say, yesterday was a doozy of a day and a bit scary i might add!!! i made it through though. I was having trouble listening to heart sounds and I was disappointed I didn't get the help I asked for from my instructor in differentiating between sounds, so I would know. I was listening to the Apical HR but I was hearing popping sounds too? idk I had another student listen, she heard the same thing! Anyways thank you everyone for your help :)

nurseprnRN, BSN, RN · Feb 2, 2013

Popping sounds might have been from the lungs. Or was it with every ventricular contraction? Does the patient have a really old valve replacement (they click)? Or a calcified valve? See if you can find a hint in the physician's admitting physical.

scrlet · Feb 3, 2013

I combed page by page through my pt chart, all it has is the admitting dx of a-fib and the coexisting dx are CVA, HTN, coronary artery disease, CHF, hypothyroidism oh and previous MI! But nowhere in the chart is there anything about surgeries. It could of been lung sounds. The pt was moaning a lot and the breath sounds were loud. I'm just use to hearing "effective" sounds and I can usually seperate the heart from the lungs, but it was hard this time. I just don't feel like my clinical instructor is willing to help me, she is new to teaching and I just have a HUGE vib she doesn't like me.

twinmommy+2, ADN, BSN, MSN · Feb 4, 2013

If you pass a cup under water for 10 seconds, will you get more water than if you pass the same cup under the faucet for 5 seconds? Yes. Your filling time will determine your stroke volume. So if your heart is beating faster, the time the cup (ventricle) is under the faucet (tricuspid or bicuspid valve) is shortened, making the amount of blood in the ventricle significantly less.

Don't forget about the quivering of the atrium, the patient is at risk of stroke because of not moving the blood efficiently, and should be placed on blood thinners.

HouTx, BSN, MSN, EdD · Feb 4, 2013

Congrats on digging deep to make sure you have a clearer understanding of this important concept. Remember how cardiac valves actually operate. AV valves are passive.... the automatically open when the ventricles are relaxed, and close when the ventricles begin to contract and pull on papillary muscles to hold them shut. Keep this image in mind.

I re-read the PPs comments to make sure that I am not repeating this - In a perfectly synched heart, the AV valves open passively (higher pressure from Atria pushes them open & ventricle is relaxed) as the atria begin to 'tighten up'... the atrial blood drains into the ventricles (which are relaxed at that point). Then, the atria actually contract & 'push' the remaining atrial blood into the ventricles just before ventricles begin to contract and pull the valves closed. This is called atrial kick & it adds ~ 30% to the ventricular volume.

So, if the atria are not in synch... due to any one of a number of atrial problems, including afib or PACs, the atrial kick is lost. So, right off the bat, the ventricles are only 70% filled when they begin to contract - so the cardiac output is decreased by at least 30%. Interestingly enough, many patients with atrial arrhythmias don't feel anything different when PACs or a-fib happens.... instead, they feel the next 'normal' beat because that ejection volume is so much bigger... and describe it as a palpitation.

Since the atria are never really able to empty themselves in a-fib and PACs (because they are trying to eject against a closed AV valve) some blood just sits around and this gives rise to the potential formation of clots.

A deeper understanding of the underlying physiology is what separates the expert clinician from his/her peers.....

nurseprnRN, BSN, RN · Feb 4, 2013

Don't forget about the quivering of the atrium, the patient is at risk of stroke because of not moving the blood efficiently, and should be placed on blood thinners.

Many people including, alas, physicians and nurses who know better, refer to anticoagulation medications (both antiplatelet and those acting on other parts of the clotting cascade) as "blood thinners." Unfortunately, and inaccurately, this puts people in mind of paint thinned by solvents or watered-down milk, or maybe thin, inadequate clothing. The problem then becomes that they are not aware of the actual physiological reason their medications are prescribed to reduce risk for embolic events, either stroke or deep vein thrombosis and pulmonary embolus. I have had patients tell me they are "always cold since taking that blood thinner."

The risk of discontinuing the medication because the effects are inaccurately communicated is great, and very real. Anticoagulants do not "thin" the blood. They decrease blood clotting to decrease the chances of a clot in the heart from causing stroke or clot in a vein traveling to the lungs by preventing it from growing larger while the body's natural processes break it down for disposal. Side effects include easier bruising and bleeding. There, is that so hard?

nurseprnRN, BSN, RN · Feb 4, 2013

Want to know whether you have atrial contraction if you don't have an EKG? Look at the jugular vein. There are no valves between the right atrium and the vena cava, and so when the atria contract you might see a little backward pulsation in the jugular (you might need to lie the patient partway down, or more, to see this). This called the "a wave" and your peers will be astonished if you ask if the patient has one and that you know what it is and means. :)