Fact or Fiction: Heart Failure and Atrial Fibrillation are Intertwined?
Written by W. Michael Kutayli, MD
September is Atrial Fibrillation (AF) Awareness Month and with at least 2.7 million Americans living with AF, it is easy to understand why awareness is needed.
Most practitioners know the basics behind AF – an irregular heart rhythm that can lead to:
- Blood clots
- Heart failure
- Other heart-related complications
But are as many aware that AF and Congestive Heart Failure (CHF) are so intertwined?
Both AF and CHF are common and carry significant morbidity and mortality. The presence of one increases the likelihood of the other.
AF and CHF frequently share:
- Common risk factors
Hypertension, diabetes mellitus, coronary artery disease and/or valvular disease
- Tend to occur in patients of advanced age
Framingham Heart Study (FHS) data suggests the two conditions follow each other at similar rates, however direct causality has yet to be proven definitively. In heart failure (HF) patients, there is evidence to support structural, neuro-hormonal, and electrical atrial remodeling, each of which may contribute to the development of AF. In AF patients, electrical and hemodynamic deterioration can lead to tachycardia-mediated cardiomyopathy (TMC).
How Heart Failure Can Cause Atrial Fibrillation
- HF-induced AF has a more direct structural basis rather than an electrophysiological one
- HF-induced atrial remodeling often results from poor left ventricle (LV) performance, increased left atrium (LA) pressure/size and functional mitral regurgitation (MR)
- Vulnerability to AF thus occurs with LA stretch and subsequent dilatation, causing interstitial fibrosis
- Interatrial alterations result in local heterogeneous conduction, slowed conduction, and local block, creating a substrate for arrhythmogenesis
How Atrial Fibrillation Can Cause Heart Failure
Several mechanisms causing deterioration in cardiac transport function in AF patients
- Irregular respiratory rate (RR) intervals leading to decreased ventricular filling
- Increased LV end diastolic pressure
- Reduction in cardiac output and function
- Loss of atrial systole (i.e. “atrial kick”)
- Tachycardia mediated cardiomyopathy
Potentially reversible, rate control is key
Treatment options for patients with AF and CHF include anticoagulation, rate control, rhythm control, antiarrhythmic drugs (AADs), non-antiarrhythmic medical therapy, ablations and implanted devices such as pacemakers.
But where do you start?
Atrial Fibrillation and Congestive Heart Failure: Management of Atrial Fibrillation in the Decompensated Heart Failure Patient
All reversible causes of AF and HF should be identified and corrected whenever possible. The initial strategy should be to treat the HF with diuretics, vasodilators and other agents, while also slowing the ventricular response to AF. In patients with congestion or hypotension, IV digoxin or IV amiodarone are recommended to acutely control the HR. Beta-blockers should be started only following stabilization of patients with decompensated HF; however beta-blockers are first choice of treatment in systolic HF. Generally, non-dihydropyridine Ca-channel blockers should be avoided due to their negative inotropic side effects. It is rarely necessary to acutely cardiovert a patient back to sinus rhythm, unless they have hemodynamic instability. Early recurrence of AF is common in acute HF.
Atrial Fibrillation and Congestive Heart Failure: Anticoagulation
Anticoagulation must be considered in all HF patients presenting with AF, as the presence of heart failure automatically increases the risk of stroke in AF patients based on the commonly used CHADS2-VASc scoring system.
- AF is a powerful risk factor for stroke and thromboembolism
- HF carried a four-fold risk of thromboembolic events per year, whereas HTN and CAD implied three times and twice the risk, respectively
- Despite this, commonly used risk stratification schemes such as CHADS2-VASc assign similar risk to each “point” and may underestimate the true risk
- Concern most relevant in intermediate risk patients with isolated HF (score of 1); reasonable to offer anticoagulation to these patients as long as no significant bleeding risk
- There are a variety of anticoagulant options today, including warfarin and the direct oral anticoagulants (dabigatran, rivaroxaban, apixaban and edoxaban)
- Left atrial appendage occlusion devices (i.e. WATCHMAN) are reasonable in patients with high risk of bleeding or intolerance to medical anticoagulation
Atrial Fibrillation and Congestive Heart Failure: Rate vs Rhythm Control
A decision will ultimately need to be made regarding long term management strategies, namely the options of rate control vs. rhythm control. Generally, this decision is based on each individual patient’s symptoms and clinical profile.
A rate control strategy may be reasonable in patients with asymptomatic, persistent, well-tolerated AF. AV nodal blocking agents can be used to slow the ventricular response rate down. Pacemaker implantation and AV node ablation (“Ablate and Pace”) is the ultimate rate control method, to be used in rapid, uncontrolled AF, in patients refractory or intolerant of medical therapy. Biventricular devices should be considered in HF patient with LVEF <50% if AV node ablation is considered.
A rhythm control strategy should be utilized in patients with newly diagnosed AF, or AF that is symptomatic and poorly tolerated. Rhythm control can be achieved with medical therapy or invasively with catheter based or surgical procedures.
Invasive rhythm control management includes surgical and catheter ablation of AF. The cornerstone of ablative therapy for AF is pulmonary vein isolation. This can be achieved in the OR, generally at the time of concomitant heart surgery, or in the EP lab. Catheter based therapies include radiofrequency and cryoablation. Catheter ablation has been shown to significantly lower rate of composite end point of death from any cause or hospitalization for worsening HF compared with medical therapy in the recent CASTLE AF trial.
Atrial Fibrillation and Congestive Heart Failure: Summary
- AF often present in CHF can worsen symptoms, and is associated with poorer prognosis
- Most AF patients with HF meet criteria for long term anticoagulation
- For patients with AF and compensated HF, rhythm control reasonable as initial strategy
- Rate control preferable in elderly with fewer symptoms
- AAD Dofetilide is a good first choice; Amiodarone reasonable in the elderly
- Catheter ablation is a therapeutic option in drug refractory rhythm control patients
- Beta blockers first line for rate control; consider AVN RFA/Pacer if other options fail
Bryan Heart Offers a Specialized Clinic for Atrial Fibrillation Patients
Our Bryan Atrial Fibrillation Center of Excellence (BrACE) team of physicians and nurses provide personalized care, attention and expertise your patients need to treat and manage their condition. For more information or to refer a patient to the BrACE Clinic, please visit or call 402-483-3346.