Have you experienced your first patient in A-fib with RVR (atrial fibrillation with rapid ventricular response) yet??? If you work in critical care, the emergency department, and especially if you ever find yourself taking care of patients after cardiac surgery, it’s going to happen!
For the CVICU gang: did you know that after cardiac surgery there is a 35% that a patient will go into A-fib?? The more invasive the procedure, the higher the risk goes up- in fact, patients who have a valve repair/replacement with a CABG (coronary artery bypass grafting) may have as high as a 60% chance of going into A-fib during their hospital admission!
Experiencing your first time managing a new onset a-fib, especially if the patient has a rapid ventricular response (a-fib with RVR-which is how this usually presents) can be very anxiety inducing, especially if you’re a new grad! The key to keeping cool is preparing yourself with the knowledge of how to manage this adverse outcome.
What is A-Fib
What is a-fib? Atrial fibrillation occurs when atria (the chambers at the top of the heart) do not conduct electrical impulses to the ventricle and depolarize correctly. Instead, they quiver (fibrillate). This results in reduced ventricular filling because 30% of the volume that the ventricles receive happens at the end of ventricular diastole when the atria contract and squeeze their residual blood into the ventricles. Reduced ventricular filling means less blood in the ventricles, and therefore less blood getting ejected into the body, and ultimately less cardiac output.
A-fib with RVR is especially problematic because a very high heart rate means there is even less time for the ventricles to fill. As a result, cardiac output decreases significantly and the patient can experience hypotension very quickly. Many of these patients also happen to have coronary artery disease, carotid artery disease, and vascular disease which requires higher blood pressures to effectively perfuse the heart muscle, brain, and other vital organs, so this can become an urgent situation very quickly.
The key to knowing how urgent the situation is your clinical assessment! Do they have a mental status? Is their skin adequately perfused (warm, dry, not cyanotic or dusky, presence of capillary refill)? How is their blood pressure? If you’re cycling the BP cuff and it’s taking multiple cycles for the reading to appear or it is read MAP only…that’s a clue it is too LOW!!!
Some patients will present with mild hypotension or remain normotensive and appear clinically stable. Either way, remember to take a deep breath and do the steps you know how to do! Keep reading to the end for a review on management…
Causes
Why is a-fib so common?
- Disease processes like certain types of heart failure, heart valve disease, thyroid disease, diabetes, and more put the myocardium at risk for a-fib (more on that in the valves and common surgery lecture in the CCA membership). These patients may experience A-fib spontaneously or in response to acute illness, physiologic stress, electrolyte imbalances, etc…
- Many cardiac surgery patients have underlying disease processes such as those mentioned above. After surgery, there are a lot of inflammatory mediators floating around the pericardial space that irritate the myocardium and can trigger a-fib as well as other arrhyhtmias.
- Altered levels of certain electrolytes such as potassium and magnesium can make the heart more prone to experiencing arrhythmias such as a-fib (more on that in the conduction and arrhythmia lectures in the CCA membership as well). Our cardiac surgery patients are especially prone to electrolyte imbalances due to the nature of the changes that occur during cardiopulmonary bypass, surgical blood loss, blood and fluid administration during resuscitation, and the fluid and electrolyte shifts that occur during the postoperative period.
A-Fib Management.
Every facility has its own protocols, but the first thing you should do is grab an extra set of hands!
1) Ask a neighbor for help and delegate them to get the charge nurse. Your charge nurse can provide assistance and delegate resources to help you through the next steps.
2) Next you want to call the provider. Let the provider know with clear communication that the patient is in a-fib, what the heart rate is, and what the blood pressure is. While this is happening, you can delegate the next two important steps:
3) Getting a 12-lead EKG to confirm the nature of the arrhythmia and…
4) Send off a set of labs (usually a basic metabolic panel at minimum) to check for any electrolyte imbalances that can be corrected.
**If the patient is hypotensive it’s also a good idea to change the timing on the automatic BP cuff to cycle every 1 minute if you don’t have an arterial line in. If they are stable (normotensive, normal clinical exam) I like to cycle it every 2 minutes until the heart rate becomes more stable.
You may be asked to:
-Administer IV magnesium prophylactically (based on unit protocol, provider preference)
-Draw an ABG or VBG to get a potassium level quickly as well as rule out other causes
-Administer a bolus of IV amiodarone or other anti-arrhythmic medication (based on unit protocol and provider preferene)
-Prepare for and assist with cardioversion if the patient is clinically unstable (especially if they have an altered mental status).
*Side note – if you’re in the CVICU, pay attention to your beta blocker administration. Most cardiac patients are not simply on them for blood pressure management…. perioperative beta blocker administration can help prevent arrhythmias. Always talk to your provider before holding cardiac medications!
For a deeper dive managing a-fib and communicating during emergencies (including the time Chrissy got yelled at during her first Afib with RVR patient), check out the A-fib episode on the CCA Podcast, available on all platforms 🙂
