AFIB RVR ON ECG
Management of Atrial fibrillation
William Kelly, MSN, FNP-C
Author | Nurse Practitioner
Atrial Fibrillation (AFIB) and AFIB RVR are common conditions that you’ll see as a nurse within both inpatient and outpatient settings. These patients are often asymptomatic, but may have severe symptoms and even be unstable, especially with AFIB RVR.
Recognizing AFIB on the monitor/EKG and knowing how to treat it is important as the nurse, as you’ll be on the front line with these patients!
What is Atrial Fibrillation (AFIB)?
Atrial Fibrillation (AF or AFIB) is an “irregularly irregular” arrhythmia that usually occurs in a structurally diseased heart.
AFIB occurs when too many atrial impulses are usually coming from the pulmonary veins, causing rapid fibrillation or “quivering” of both the left and right atria.
Remember, the heart has four chambers: left and right atria on the top and left and right ventricle on the bottom. With AFIB, the top chambers are in a constant state of fibrillation.
During a normal heartbeat, the atria first contract, pushing blood into the ventricles, and the ventricles then pump the blood to the rest of the body. In AFIB, the atria lose this “atrial kick,” leading to ineffective atrial filling and decreased cardiac output, especially at rapid rates.
Cardiac Conduction Review
It is helpful to remember how the cardiac conductions system works to understand what is going on with AFIB.
Remember, the heart has specific electrical conduction tissue, which creates and moves the electrical signal throughout the heart to produce an organized rhythm. This organization lets the heart fill and pump effectively.
The heart’s pacemaker is the sinus node located in the right atrium. This region of cells creates the “normal” impulse and sends it throughout the atria and then through the AV node. This AV node normally slows the conduction to allow for ventricular filling. The PR interval on the EKG denotes this slowing of the conduction.
Once traveling through the AV node, the impulse goes through the Bundle of His. It splits down the left and right bundle branches towards each ventricle, then through the Purkinje fibers and eventually the ventricles, causing a heartbeat.
In AFIB, rapid-firing comes from the atria, usually where the pulmonary veins meet the left atria. This leads to the quivering of both atria and ineffective atrial filling and atrial kick.
While the AV node does slow down conduction, it can only do so much on its own. With such rapid firing from the atria, many of these impulses want to make it down to the ventricles and cause heartbeats.
As you can imagine, this can lead to very fast heart rates – what we call AFIB RVR or rapid ventricular response.
What is AFIB RVR?
AFIB RVR (Rapid Ventricular Response) occurs due to the frequent electrical impulses from the atria.
The AV node is only able to slow the frequent electrical impulses down so much, so many of the impulses are conducted through to the ventricles, leading to a rapid ventricular response or a fast heart rate >100bpm and often much faster.
Patients with these fast rates are often symptomatic and may become hypotensive. These patients will usually require IV medications to slow down their rate, and possibly even electrical cardioversion (more on that later!).
What causes AFIB?
AFIB usually occurs in predisposed hearts and is often set off by reversible triggers.
Chronic diseases which predispose the heart to AFIB include:
Anything causing atrial enlargement such as CHF, Cardiomyopathy, COPD, OSA, obesity
Valvular Heart Disease
Rheumatic Fever, aortic stenosis, valve repelacements, etc
Ischemic Heart Disease
Coronary artery disease, past or current myocardial infarctions (heart attacks!)
Usually, some reversible trigger throws the patient into AFIB. These reversible triggers include:
CABG or heart transplants, usually within the first 2 weeks postop
PEs can cause right atrial heart strain and Increased pulmonary vascular resistance
Alcoholics and binge-drinking can cause Holiday Heart syndrome, which can occur in 60% of binge drinkers
Cocaine and amphetamines can increase sympathetic tone and leave the heart predisposed to arrhythmias such as AFIB
Hyperthyroidism (low TSH) can cause increased sympathetic tone and lead to arrhythmias
Low magnesium levels can lead to AFIB, generally levels < 1.5 (check this).
Certain medications can trigger AFIB including Theophylline and adenosine.
Although caffeine is often thought of as contributory to ectopy and AFIB, there is no direct evidence it does trigger AF. However, it is something to consider.
Nursing Assessment of AFIB RVR
Symptoms of AFIB
Up to 44% of patients with Afib are asymptomatic. Patients with faster rates are more likely to develop symptoms, and those with CHF are more likely to experience hemodynamic instability and severe symptoms (aka low BP and possible code situation).
Some symptoms of AFIB can include:
Most common complaint
Shortness of breath
Dizziness or lightheadedness
Fluttering or skipping in their chest, or possibly just feeling their heart pounding
Chest pressure, pain, or discomfort
Loss of consciousness
The Physical Exam
- Pallor or flushed
- May appear tachypneic
- BP: May be low at fast rates and with poor cardiac output
- Pulse/HR: Often >100 (RVR)
- Respirations: Normal or increased
- SPO2: Usually normal
- Usually Normal
- May have crackles if CHF
- Rapid and irregular rate
Identifying AFIB RVR on the ECG
AFIB will NOT have visible P waves. Instead, there will be a fibrillatory baseline. There is no depolarization wave throughout the atria, but rather rapid twitching and many “small” depolarizations, firing at rates 350-600 times per minute.
The QRS complex should be narrow unless an underlying intraventricular conduction delay is present, such as a bundle branch block.
The T waves may be difficult to decipher between the F-wave baseline completely. T wave abnormalities are common, including T wave flattening.
AFIB is irregularly irregular. This means that the R-R interval is continuously changing, and there is no pattern.
AFIB can be at any rate, but faster than 100 is considered AFIB RVR. Without medications to slow it down, rates are usually between 90-170 bpm.
Initial Nursing Interventions
Any patient with cardiac symptoms should get an EKG.
Patients with new AFIB should have a 12-lead EKG to confirm the diagnosis.
If the patient is at significant fast rates, keep them hooked up to grab another one once the rate improves or the patient converts.
Patients with any cardiac symptoms should be placed on the cardiac monitor.
Those patients with a history of AFIB with normal rates does not necessarily need a cardiac monitor.
If the patient is significantly hypoxic or tachypneic, apply 2-4 L/min NC to maintain SPO2 >90%.
Start two peripheral IVs at least 22g, but preferably one at least 20g. If they are in AFIB RVR, they will likely need an IV Cardizem drip and IV heparin in separate lines.
If there is a concern for pulmonary embolism or embolic stroke, make sure to place an 18-20g in the AC.
While drawing blood, make sure to draw a blue top as PT/INR, PTT, and a D-dimer may be ordered.
Remember that any unstable tachyarrhythmia should follow ACLS guidelines. This means the patient may need electrically cardioverted. If they are unstable (Low BP, impending arrest), then place the defibrillation pads on the patient and hook them up to the defibrillator.
Workup for AFIB RVR
The workup will depend if the patient is in new-onset AF or already has chronic AF and if they are in RVR or not.
Patients with a known history of AFIB who have controlled rates don’t need any specific testing. They are usually on chronic medications to control their heart rates and anticoagulants to prevent blood clots.
Patients with new AFIB or AFIB RVR require more extensive testing, and the workup may depend on their symptoms.
General workup for new AFIB includes:
AFIB can be diagnosed with this, as well as to look for any other abnormalities such as a STEMI
CBC, CMP, and magnesium will often be checked
Coag studies such as PT/INR and PTT, BNP if s/s of heart failure, digoxin level if patient is taking, and a D-dimer may be ordered as well
If they have any cardiac or pulmonary complaints this should be obtained
If there is suspicion of a PE. It May also detect atrial thrombi but is not very sensitive
If any altered mental status or stroke-like s/s
Complications of AFIB
So why do we even care about AFIB? Well, there can be disastrous consequences if we do not treat it appropriately.
Patients with AFIB have an inadequate atrial filling of blood, as well a loss of the atrial kick which pushes blood from the atria to the ventricles. This decreases cardiac output. When the ventricles have a rapid response, these insufficiencies worsen and can lead to hemodynamic compromise – hypotension, hypoxemia, and eventually cardiac arrest.
Patients with Left ventricular dysfunction (aka CHF with a low EF) already have a weak heart. This drop in cardiac output will be more significant, often leading to severe symptoms and an unstable patient!
With the atria quivering – stasis of blood occurs. Remember, stasis of blood is one of the 3 factors that can lead to blood clots (Virchow’s triad). This increases the likelihood of thrombus formation.
Both of these are very serious conditions which can lead to disability and death, so prevention of this complication is important.
Treatment of AFIB RVR
Treatment of AFIB differs and depends on the patient’s symptoms and quality of life. This will involve at least one, but possibly all three of the following:
- Rate control: Control the heart rate with AFIB (preventing RVR)
- Rhythm Control: Convert and maintain the patient in a normal sinus rhythm
- Anticoagulation: Giving blood thinners to prevent blood clot formation within the atria
Which the Provider team and Cardiology will ultimately choose treatment options. We’ll dive a little deeper into each of these treatment options.
Rate-control is achieved via medications to slow down the ventricular response to the AFIB. Common medications include Metoprolol, Diltiazem, Digoxin, Esmolol, Amiodarone, and even magnesium sulfate.
For AFIB RVR, we often give the following medications to control the rate:
Also called Cardizem, this is more commonly given for AFIB RVR. The dose is 0.25mg/kg bolus, which is usually around 20mg. This should be pushed over 2 minutes. A repeat bolus of 0.35mg/kg can be given in 15 minutes if rate control is insufficient, and then a patient should be started on a titratable Cardizem drip.
Also called Lopressor, this is especially helpful if the patient is on a Beta-blocker at home and maybe has missed some doses. The dose is 2.5-5mg IV q5m x 3. Administer the IV push over 2 minutes, and monitor rhythm and blood pressure closely. Use with caution with asthma/COPD exacerbations.
Low BP & RVR
One thing to point out is that those patients with significant left ventricular heart failure and AF RVR may paradoxically improve their blood pressure with rate control, so it still may be wise to administer a low dose of metoprolol or cardizem in these select patients if borderline hypotension is present. Always verify with the Physician/APP.
Rhythm-control is achieved via medications or electrical cardioversion. If the patient is unstable, they will be electrically cardioverted. Otherwise, the cardiologist may choose to start the patient on an antiarrhythmic such as amiodarone, Flecainide, multaq, etc.
Many elderly patients who do not have significant symptoms will not undergo rhythm control. This is ultimately up to the cardiologist.
IV amiodarone can be used, or the cardiologist may choose to start an oral antiarrhythmic such as Amiodarone, Sotalol, Dofetilide, etc
Unstable patients should undergo synchronized cardioversion with the defibrillator
Patients with frequent symptoms (often younger patients) may undergo an ablation to burn off the area of the heart that is triggering AFIB
Anticoagulation is almost always used in patients with AFIB, unless there is acute bleeding or a significant risk of bleeding.
Anticoagulation is used to prevent thrombus formation which can cause PEs and Strokes as explained above. Within the hospital, anticoagulation will include either:
The Provider will order a titratable heparin drip per facility protocol. This usually will have an initial bolus ordered as well. The patient’s PTT will occasionally be checked and the drip will be adjusted accordingly. Heparin drips offer quickly-reversible anticoagulation in case the patient starts bleeding.
SubQ lovenox at a dose of 1mg/kg BID can be given alternatively.
Before being discharged, the patient is then transitioned onto an oral anticoagulant such as coumadin, Eliquis, Xarelto, Pradaxa, or ASA/Plavix.
Coumadin is much less commonly prescribed than it used to be because it requires frequent blood checks of INR, as well as dietary changes and medications, can significantly impact its therapeutic levels
The CHADSVASC score is used to gauge risk for thrombus formation, which factors in age, sex, h/o CHF, HTN, Stroke/TIA/DVT/PE, Vascular disease, or Diabetes. If the patient does not have a high risk of bleeding such as intracranial bleeding, GIB, or frequent falls, then they are usually started on an anticoagulant.
The workup and treatment will depend on the patient’s symptoms and overall clinical picture. With AFIB, there is no one-size-fits-all approach!
Focus on rate control and anticoagulation! Become familiar with IV Cardizem and titrating a Cardizem drip, as well as IV Lopressor!
Unstable = Shock
Patients who are unstable should be electrically cardioverted with a synchronized shock. Remember to press SYNC, and the dose is 50-100J. These patients will require sedation and pain control (i.e. IV fentanyl).
Want to learn more?
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Kumar, K. (2022). Overview of atrial fibrillation. In T. W. Post (Ed.), UpToDate. Retrieved from https://www.uptodate.com/contents/overview-of-atrial-fibrillation
Olshansky, B. (2022). The electrocardiogram in atrial fibrillation. In T. W. Post (Ed.), UpToDate. Retrieved from https://www.uptodate.com/contents/the-electrocardiogram-inatrial-fibrillation
Phang, R., Prutkin, J. M., Ganz, L. I. (2022). Overview of atrial flutter. In T. W. Post (Ed.), UpToDate. Retrieved from https://www.uptodate.com/contents/overview-of-atrial-flutter
Prutkins, J. M. (2022). Electrocardiographic and electrophysiologic features of atrial flutter. In T. W. Post (Ed.), UpToDate. Retrieved from https://www.uptodate.com/contents/electrocardiographic-and-electrophysiologic-features-of-atrial-flutter