Dr. Naima Maqsood, Dr. Kelly Arps, and Dr. Jake Roberts discuss the acute management of atrial fibrillation with guest expert Dr. Jonathan Chrispin. Episode audio was edited by CardioNerds Intern Dr. Bhavya Shah.
This episode reviews acute management strategies for atrial fibrillation. Atrial fibrillation is the most common chronic arrhythmia worldwide and is associated with increasingly prevalent comorbidities, including advanced age, obesity, and hypertension. Atrial fibrillation is a frequent indication for hospitalization and a complicating factor during hospital stays for other conditions. Here, we discuss considerations for the acute management of atrial fibrillation, including indications for rate versus rhythm control strategies, treatment targets for these approaches, considerations including pharmacologic versus electrical cardioversion, and management in the post-operative setting.
A key component to the management of acute atrial fibrillation involves addressing the underlying cause of the acute presentation. For example, if a patient presents with rapid atrial fibrillation and signs of infection, treatment of the underlying infection will help improve the elevated heart rate.
Selecting a rate control versus rhythm control strategy in the acute setting involves considerations of comorbid conditions such as heart failure and competing risk factors such as critical illness that may favor one strategy over another. Recent data strongly supports the use of rhythm control in heart failure patients. Patients should be initiated on anticoagulation prior to pursuing a rhythm control strategy.
There are several strategies for rate control medications with therapies including beta-blockers, non-dihydropyridine calcium channel blockers, and digoxin. The selection of which agent to use depends on additional comorbidities and the overall clinical assessment. For example, a patient with severely decompensated low-output heart failure may not tolerate a beta-blocker or calcium channel blocker in the acute phase due to hypotension risks but may benefit from the use of digoxin to provide rate control and some inotropic support.
Thromboembolic prevention remains a cornerstone of atrial fibrillation management, and considerations must always be made in terms of the duration of atrial fibrillation, thromboembolic risk, and risks of anticoagulation.
While postoperative atrial fibrillation is more common after cardiac surgeries, there is no major difference in management between patients who undergo cardiac versus non-cardiac procedures. Considerations involve whether the patient has a prior history of atrial fibrillation, surgery-specific bleeding risks related to anticoagulation, and monitoring in the post-operative period to assess for recurrence.
Notes
1. Our first patient is a 65-year-old man with obesity, hypertension, obstructive sleep apnea, and pre-diabetes presenting for evaluation of worsening shortness of breath and palpitations. The patient has no known history of heart disease. Telemetry shows atrial fibrillation with ventricular rates elevated to 130-140 bpm. What would be the initial approach to addressing the acute management of atrial fibrillation in this patient? What are some of the primary considerations in the initial history and chart review?
An important first step involves taking a careful history to understand the timing of symptom onset and potential underlying causes contributing to a patient’s acute presentation with rapid atrial fibrillation.
Understanding the episode trigger determines management by targeting reversible causes of the acute presentation and elucidating whether the episode is triggered by a cardiac or non-cardiac condition. For example, if a patient presents with a few days of infectious symptoms, treating the infection is likely to lead to improvements in heart rate.
Determining the tempo of symptoms has further importance for assessing the risk of thromboembolism and anticoagulation consideration.
2. How would the initial evaluation be different for patients who have a new diagnosis of atrial fibrillation compared to those who have a known prior history of this arrhythmia?
The acuity of symptom onset plays an essential role in these considerations. For example, a patient may describe symptoms that have been ongoing for several months, which indicate a diagnosis beyond the acute phase of their presentation and would involve different considerations than for a patient who first noticed symptoms within the past few hours.
One way to view RVR rates in a patient with longstanding or permanent atrial fibrillation is to consider this vital sign as that patient’s version of sinus tachycardia in response to another physiologic process. In that setting, you would not try an approach to directly lower their heart rate but would instead attempt to determine and address the underlying cause of their presentation.
An additional consideration for patients without known prior atrial fibrillation is that they have likely never been on any rate-controlling agents and may have variable initial responses to these interventions.
3.In cases for which acute rate control of atrial fibrillation is indicated, what is the recommended heart rate target and how quickly should we aim to reach that target?
The initial first step in management should focus on addressing the underlying cause of the patient’s elevated heart rate while in atrial fibrillation. Once those factors are addressed and elevated heart rates persist, a rate-controlling agent can be considered.
Often, a primary reason for rate control is for symptom relief since patients can be very symptomatic from an elevated heart rate alone.
A reasonable goal for the intermediate setting is to achieve a heart rate of less than 100-110 bpm. One study compared lenient (resting heart rate <110 bpm) versus strict (resting heart rate <80 bpm and heart rate during moderate exercise <110 bpm) rate control in patients with atrial fibrillation and found no difference in outcomes related to mortality, hospitalization for heart failure, stroke, embolism, bleeding, or life-threatening arrhythmic events but that lenient control was easier to achieve.1 For this reason, aggressive rate control in the acute setting may not have a significant impact apart from symptom relief. There are not often clear indications to rapidly lower a patient’s heart rate, for example, from 140 to 90 bpm. Conversely, lowering a patient’s heart rate too rapidly can be detrimental by causing bradycardia or hypotension with excessive use of nodal blocking agents.
4.What are some of the considerations for the selection of rate-controlling agents?
Beta-blockers and non-dihydropyridine calcium channel blockers remain the mainstay of therapies used for rate control. The choice between these agents often depends on the comorbidities present. For example, if a patient has a known reduced LVEF, you may often avoid calcium channel blockers and opt for careful titration of beta-blockers. Often, the use of beta-blockers also allows for the management of additional comorbidities, including heart failure and coronary disease.
Digoxin is another agent to consider when a patient presents with acutely decompensated heart failure with a low LVEF and may not tolerate a beta-blocker or calcium channel blocker due to the risk of hypotension or worsening cardiogenic shock. Digoxin provides rate control while adding some positive inotropy. In terms of chronic management, digoxin use can be more challenging with close follow-up required to monitor levels. In some cases, amiodarone can be used as an acute rate-control agent, but there is a risk of conversion to sinus rhythm and thromboembolism if not on anticoagulation.
5.In what clinical scenarios might it be more optimal to consider an upfront rhythm control strategy?
Recent data support the benefit of an upfront rhythm control approach in heart failure patients, with complications including cardiovascular death, stroke, or hospitalization for worsening of heart failure or for acute coronary syndrome, reduced in heart failure patients managed with any early rhythm control strategy.2,3
In certain patients with known atrial fibrillation and heart failure, cardioversion can be considered as a strategy to help improve their heart failure symptoms. In these patients, initiating an anti-arrhythmic drug (AAD) prior to cardioversion can improve the likelihood of remaining in sinus rhythm after cardioversion.
6.Our second patient is a 58-year-old woman with a history of heart failure with reduced EF presenting to the ED with progressive lower extremity swelling and shortness of breath. She has a prior diagnosis of paroxysmal atrial fibrillation, and her most recent echo demonstrated an LVEF of 35%. She is found to have bilateral lower extremity pitting edema to her knees and elevated jugular venous pressure while requiring 2L of oxygen by nasal cannula. She is in rapid atrial fibrillation on presentation. Interrogation of her primary prevention ICD shows that she has been in atrial fibrillation for the past 3 weeks. In this scenario involving a patient with an acute heart failure exacerbation, are there considerations for a more upfront rhythm control strategy and perhaps electrical cardioversion?
In this scenario, there is an indication for utilizing an early rhythm control strategy. Even if an initial trial of diuresis and beta-blockers is used initially, the fact that this patient has been in atrial fibrillation for several weeks with only prior paroxysmal episodes indicates that her arrhythmia is likely contributing to her decompensation and therefore should be addressed during hospitalization. This patient should be considered for AAD initiation and careful considerations should be made to ensure that this patient is appropriately anticoagulated. Once anticoagulation has been established, interventions including electrical cardioversion can be considered.
For this patient with a reduced LVEF, AAD initiation should be considered prior to cardioversion with options limited to amiodarone or dofetilide. For patients with renal disease and concerns for QT prolongation, amiodarone can be used as a reasonable short-term solution to bridge the patient to more definitive long-term strategies for rhythm control. This patient can be initiated on AAD and, if she does not convert on medication, can be considered for electrical cardioversion. The timing of cardioversion would depend on when the patient is optimized from a heart failure standpoint, including when the patient has become more euvolemic. With dofetilide, electrical cardioversion is typically attempted after the fourth dose is given to ensure that the patient can stay in sinus rhythm after cardioversion.
7. A common scenario in which we often find ourselves managing atrial fibrillation is in the postoperative setting. What are some of the management strategies for postoperative atrial fibrillation and how does this vary between patients who underwent cardiac versus non-cardiac procedures?
Compared to non-cardiac surgery, in cardiac surgery there is an increased risk for developing postoperative atrial fibrillation, with rates of occurrence ranging from 30-60%.4,5 While there are higher rates of post-operative atrial fibrillation in patients undergoing cardiac surgeries, there is no significant difference in the strategies used to treat patients who underwent cardiac versus non-cardiac surgeries.
For patients who have no prior history of atrial fibrillation prior to developing post-operatively, historical teaching endorsed the idea that this arrhythmia developed in response to inflammation occurring during acute recovery and should not have long-term consequences; however, more recent data suggests that if a patient develops atrial fibrillation post-operatively, they are more likely to have recurrence of this arrhythmia in the future.6
Current guidelines support anticoagulation based on the CHADSVASc score for at least 60 days post-operatively while monitoring for persistence of the arrhythmia.7 Further, data suggest that rhythm approaches post-operatively lead to better long-term outcomes in terms of re-hospitalizations and mortality.
In patients who underwent surgeries with high bleeding risk during recovery and have contraindications to anticoagulation, rate-control strategies are most appropriate initially.
If a patient has new atrial fibrillation without a prior diagnosis, they will need monitoring for recurrence for 30-60 days post-operatively.
8.What are some of the considerations for a pill-in-the-pocket strategy for those patients who experience infrequent episodes of symptomatic atrial fibrillation?
In this strategy, the patient takes medication when they are having symptoms with the intention of terminating the atrial fibrillation episode acutely.
When initiating this approach, it is essential to do so in a monitoring setting because of the effects that can result from giving high doses of these medications to treat acute episodes. For example, with flecainide, a dose of 300 mg may be given at one time compared to a dose of 50-150 mg twice daily to reach the maintenance dose. When medications such as flecainide are given in these loading doses, it is important to monitor for any acute toxicity.
Given the potential toxicities and challenges inherent to a pill-in-the-pocket approach, the desire to prevent rather than reactively treat episodes of atrial fibrillation, and improvements in catheter ablation techniques, this strategy is now rarely used in practice, with patients managed either with a maintenance medication or ablation.
<p><strong>Contributor: Aaron Lessen, MD</strong></p> <p><strong>Educational Pearls:</strong></p> <ul> <li style="font-weight: 400;" aria-level="1"><span style= "font-weight: 400;">Atrial fibrillation is an irregular heart rhythm that sometimes requires rate control in setting of ... Show More
