When to consider AV node ablation

CardioNerds (Dr. Kelly Arps, Dr. Naima Maqsood, and Dr. Elizabeth Davis) discuss chronic AF management with Dr. Edmond Cronin. This episode seeks to explore the chronic management of atrial fibrillation (AF) as described by the 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. The discussion covers the different AF classifications, symptomatology, and management including medications and invasive therapies. Importantly, the episode explores current gaps in knowledge and where there is indecision regarding proper treatment course, as in those with heart failure and AF. Our expert, Dr. Cronin, helps elucidate these gaps and apply guideline knowledge to patient scenarios. Audio editing for this episode was performed by CardioNerds intern Dr. Bhavya Shah. CardioNerds Atrial Fibrillation PageCardioNerds Episode PageCardioNerds AcademyCardionerds Healy Honor Roll CardioNerds Journal ClubSubscribe to The Heartbeat Newsletter!Check out CardioNerds SWAG!Become a CardioNerds Patron! Pearls Review the guidelines- Catheter ablation is a Class I recommendation for select patient groups  Appropriately recognize AF stages- preAF conditions, symptomatology, classification system (paroxysmal, persistent, long-standing persistent, permanent)  Be familiar with the EAST-AFNET4 trial, as it changed the approach of rate vs rhythm control  Understand treatment approaches- lifestyle modifications, management of comorbidities, rate vs rhythm control medications, cardioversion, ablation, pulmonary vein isolation, surgical MAZE  Sympathize with patients- understand their treatment goals  Notes Notes: Notes drafted by Dr. Davis.    What are the stages of atrial fibrillation?   The stages of AF were redefined in the 2023 guidelines to better recognize AF as a progressive disease that requires different strategies at the different therapies  Stage 1 At Risk for AF: presence of modifiable (obesity, lack of fitness, HTN, sleep apnea, alcohol, diabetes) and nonmodifiable (genetics, male sex, age) risk factors associated with AF  Stage 2 Pre-AF: presence of structural (atrial enlargement) or electrical (frequent atrial ectopy, short bursts of atrial tachycardia, atrial flutter) findings further pre-disposing a patient to AF  Stage 3 AF: patient may transition between these stages  Paroxysmal AF (3A): intermittent and terminates within ≤ 7 days of onset  Persistent AF (3B): continuous and sustained for > 7 days and requires intervention  Long-standing persistent AF (3C): continuous for > 12 months   Successful AF ablation (3D): freedom from AF after percutaneous or surgical intervention  Stage 4 Permanent AF: no further attempts at rhythm control after discussion between patient and clinician   The term chronic AF is considered obsolete and such terminology should be abandoned   What are common symptoms of AF?   Symptoms vary with ventricular rate, functional status, duration, and patient perception  May present as an embolic complication or heart failure exacerbation  Most commonly patients report palpitations, chest pain, dyspnea, fatigue, or lightheadedness. Vague exertional intolerance is common  Some patients also have polyuria due to increased production of atrial natriuretic peptide  Less commonly can present as tachycardia-associated cardiomyopathy or syncope  Cardioversion into sinus rhythm may be diagnostic to help determine if a given set of symptoms are from atrial fibrillation to help guide the expected utility of more aggressive rhythm control strategies.   What are the current guidelines regarding rhythm control and available options?  COR-LOE 1B: In patients with reduced LV function and persistent (or high burden) AF, a trial of rhythm control should be recommended to evaluate whether AF is contributing to the reduced LV function   COR-LOE 2a-B: In patients with reduced LV function and persistent (or high burden) AF, a trial of rhythm control should be recommended to evaluate whether AF is contributing to the reduced LV function. In patients with a recent diagnosis of AF (<1 year), rhythm control can be useful to reduce hospitalizations, stroke, and mortality. In patients with AF and HF, rhythm control can be useful for improving symptoms and improving outcomes, such as mortality and hospitalizations for HF and ischemia. In patients with AF, rhythm-control strategies can be useful to reduce the likelihood of AF progression.  COR-LOE 2b-C: In patients with AF where symptoms associated with AF are uncertain, a trial of rhythm control (eg, cardioversion or pharmacological therapy) may be useful to determine what if any symptoms are attributable to AF.  COR-LOE 2b-B: In patients with AF, rhythm-control strategies may be useful to reduce the likelihood of development of dementia or worsening cardiac structural abnormalities.  While both rate and rhythm control can improve AF symptoms, several studies (such as AF-CHF) show improved quality of life with rhythm control  EAST-AFNET 4 was significant in that it showed rhythm control was associated with a 25% reduction in the combined endpoint of mortality rate, stroke, and hospitalizations due to HF or ACS  Acute rhythm control can be achieved with electrical or pharmacological cardioversion. Electrical is more effective and faster than pharmacological and is preferred for patients with hemodynamic instability attributable to AF. However, both approaches involved considerations for anticoagulation and thromboembolic risk. Pharmacologic options for cardioversion include ibutilide, amiodarone, flecainide, propafenone, procainamide, dofetilide, and sotalol.   COR-LOE 1-A: In patients with symptomatic AF in whom antiarrhythmic drugs have been ineffective, contraindicated, not tolerated or not preferred, and continued rhythm control is desired, catheter ablation is useful to improve symptoms.  AF ablation is also a suitable first-line option in some patients with paroxysmal AF to reduce recurrence and burden. Patient selection is important. Younger patients, those with minimal atrial enlargement, less myocardial fibrosis, and less persistent forms are more likely to have successful ablations, meaning less likely to have recurrence of AF after ablation.   HFrEF patients derive greater benefit than others from AF ablation in terms of improved functional status, LV function, and cardiovascular outcomes  Surgical ablation can be considered in those undergoing cardiac surgery for some other etiology such as valve surgery or CABG and is associated with increased survival, but some risk of pacemaker placement and renal dysfunction  How would you monitor for AF recurrence in post-ablation or cardioversion? Is there a role for monitoring in every patient?  Cardiac monitoring may be advised to AF patients for various reasons, such as for detecting recurrences, screening, or response to therapy  Long-term surveillance to detect recurrent AF can be beneficial and can be accomplished by various modalities, including wearable devices, smart watches, random monitoring (Holter, event, mobile telemetry), and implantable loop recorders. This is especially helpful in those who had AF-induced cardiomyopathy, especially if their LVEF recovered after rate/rhythm control. This is a population in whom recurrence of AF would want to be promptly noted and addressed.   Loop recorders can also be helpful in detecting subclinical AF or in patients with stroke or TIA of undetermined cause (COR-LOE 2a-B)  What AF burden warrants intervention?  It is important to recognize that AF is a chronic condition and tends to recur, so treatment often is focused on reducing risk of recurrence   Patient-clinician shared decision making is important when deciding when/how to intervene, as there is no cut-off for “significant” burden (COR-LOE 1-B)  What are some options for antiarrhythmic drugs and their characteristics?  Antiarrhythmic drugs are reasonable for long-term maintenance of sinus rhythm for patients with AF who are not candidates for, or decline, catheter ablation, or who prefer antiarrhythmic therapy  Amiodarone can be used in patients with or without HFrEF, as opposed to many other anti-arrhythmics that are (relatively) contraindicated in HFrEF or should be used with caution in such patients, such as flecainide, propafenone, dronedarone, and sotalol. However, due to its adverse effects and multiple drug interactions, is should be used only in patients in which other antiarrhythmic drugs are contraindications, ineffective, or not preferred. Dofetilide can also be used in patients with HFrEF.   In patients on amiodarone, labs should be checked regularly for thyroid, liver and kidney functions. There is also a role for pulmonary function testing and chest x-rays to monitor for pulmonary fibrosis, but frequency is not clearly established. It should be noted that amiodarone-induced lung toxicity occurs between 6 months and 2 years of use.   Flecainide is well tolerated, but is contraindicated in patients with significant coronary artery disease and possibly structural heart disease in general. It can also lead to the development of atrial flutter.   Dofetilide and sotalol require regular renal function monitoring and QTC monitoring  When should AV node ablation (AVNA) be considered?  In patients with AF and uncontrolled rapid ventricular response refractory to rate-control medications (who are not candidates for or in whom rhythm control has been unsuccessful), AVNA can be useful to improve symptoms and QOL (COR-LOE 2a-B)  AVNA is effective for rate control and does not require continuation of medications; however,