Atrial fibrillation is a medical condition that affects roughly 33.5 million people worldwide [1]. Underlying cardiac conditions such as hypertension and coronary heart disease, which are common in developed countries, are risk factors for this condition. In lower income countries, rheumatic heart disease is associated with a higher incidence of atrial fibrillation, though rates are decreasing worldwide due to access to antibiotics. A later stage treatment approach for atrial fibrillation is ablation, with the assistance of anesthesia.
The pathophysiology of atrial fibrillation involves rapid firing from a single focus in the atria that triggers a change in heart rate and rhythm. The most common location is from the pulmonary veins, which can be targeted with catheter ablation. Treatment is focused on prevention of future episodes in addition to prevention of thromboembolism. First line treatment for atrial fibrillation is rate or rhythm control with oral medications such as beta-blockers or amiodarone. Thromboembolism risk is reduced with a direct oral anticoagulant.
If patients continue to remain symptomatic with recurrent episodes of atrial fibrillation despite medication, ablation is a highly effective procedural technique that can be considered. It is associated with 70-75% of patients being symptom-free after 1 year with 4% risk of major complications like stroke, cardiac perforation, or damage to the surrounding structures, such as the esophagus and phrenic nerve [2]. Electrophysiology evaluation is used to determine the location of myocardial tissue which is most responsible for the repetitive firing. An electroanatomical map is made, creating a 3-D representation of the patient’s heart to determine where the physician will use radiofrequency energy, cryothermal energy, or laser balloon to ablate myocardial tissue [2].
Cardiac ablation is a technique that is highly dependent on the practicing physician, with variability in duration of the procedure and the type of ablative energy used. The anesthesia used for atrial fibrillation ablation is highly important as this procedure is associated with significant risks. Conscious sedation with fentanyl and midazolam used to be the most common technique until studies comparing conscious sedation against general anesthesia found lower rates of recurrence and pulmonary vein reconnection with general anesthesia [3]. New retrospective cohort studies comparing monitored anesthetic care (MAC) vs. general anesthesia (GA) demonstrated MAC was independently associated with shorter total laboratory time due to reducing non-procedure time with no significant changes in freedom from documented atrial fibrillation, atrial flutter, atrial tachycardia and no significant difference in complication rates [4,6].
Despite this evidence, in a 2021 retrospective review, researchers demonstrated GA was still the most common mode of sedation for 54,231 patients who underwent cardiac ablation in the U.S., with 94% of patients receiving general anesthesia and only 6% receiving monitored anesthetic care (MAC) [5]. Patients who received MAC were more likely to be >80 years old, female, and have American Society of Anesthesiologist physical status > III. MAC cases were mostly done in Northeast urban hospital centers.
Current literature demonstrates that MAC is a safe anesthetic option for atrial fibrillation ablation that is not currently used widely in the United States. Due to its benefits, including shorter time in the laboratory with equitable outcomes to general anesthesia, more anesthesiologists may choose to use MAC over GA in the future.
References
- Lip GYH, Brechin CM, Lane DA. The global burden of atrial fibrillation and stroke: a systematic review of the epidemiology of atrial fibrillation in regions outside North America and Europe. Chest. 2012 Dec;142(6):1489-1498. doi: 10.1378/chest.11-2888. PMID: 22459778.
- Oral H, Knight BP, Ozaydin M, Tada H, Chugh A, Hassan S, Scharf C, Lai SW, Greenstein R, Pelosi F Jr, Strickberger SA, Morady F. Clinical significance of early recurrences of atrial fibrillation after pulmonary vein isolation. J Am Coll Cardiol. 2002 Jul 3;40(1):100-4. doi: 10.1016/s0735-1097(02)01939-3. PMID: 12103262.
- Price A, Santucci P. Electrophysiology procedures: weighing the factors affecting choice of anesthesia. Semin Cardiothorac Vasc Anesth. 2013 Sep;17(3):203-11. doi: 10.1177/1089253213494023. Epub 2013 Jul 3. PMID: 23827944.
- Dada RS, Hayanga JWA, Woods K, Schwartzman D, Thibault D, Ellison M, Schmidt S, Siddoway D, Badhwar V, Hayanga HK. Anesthetic Choice for Atrial Fibrillation Ablation: A National Anesthesia Clinical Outcomes Registry Analysis. J Cardiothorac Vasc Anesth. 2021 Jan 5:S1053-0770(20)31393-8. doi: 10.1053/j.jvca.2020.12.046. Epub ahead of print. PMID: 33518460.
- Wasserlauf J, Knight BP, Li Z, et al. Moderate Sedation Reduces Lab Time Compared to General Anesthesia during Cryoballoon Ablation for AF Without Compromising Safety or Long-Term Efficacy. Pacing Clin Electrophysiol 2016; 39:1359. doi: 10.1111/pace.12961. Epub 2016 Nov 10. PMID: 27747896.
- Kuck KH, Brugada J, Fürnkranz A, et al. Cryoballoon or Radiofrequency Ablation for Paroxysmal Atrial Fibrillation. N Engl J Med 2016; 374:2235. doi: 10.1056/NEJMoa1602014. Epub 2016 Apr 4. PMID: 27042964.
