Intracardiac catheter ablation for the treatment of arrhythmia

Ablation is a procedure to treat atrial fibrillation. It uses small burns or freezes to cause some scarring on the inside of the heart to help break up the electrical signals that cause irregular heartbeats.

In adults, atrial fibrillation is the most commonly encountered cardiac arrythmia, overall around 1% (much increase in adults > 65 years of age). Morbidity associated with heart failure and stroke. Thrombus formation promoted in left atria due to incomplete ejection from abnormal rhythm. Atrial rates up to 300-600 beats per minute, although AV node blocks most (resulting in around 90-170 beats per minute). ECG shows irregular R-R intervals (in absence of complete AV nodal blockade), absence of P waves, variable atrial cycle length (usually < 200 ms) (Malladi).

Risk factors for atrial fibrillation (Malladi):

• Hypertension
• Congestive heart failure
• Diabetes mellitus
• Men > women
• Caucasians > African Americans
• Heavy alcohol consumption
• Coronary artery disease/acute myocardial infarction
• Valvular heart disease
• Obesity
• Thyroid dysfunction
• Cardiac surgery
• Electrolyte abnormalities
• Family history

Intracardiac catheter ablation for the treatment of arrhythmia

Anesthesia type	General (sometimes MAC/sedation)
Airway	ETT
Lines and access	2 PIVs (Usually one larger gauge 16/18). +/- arterial line
Monitors	Standard, Esophageal Temperature Probe
Primary anesthetic considerations
Preoperative	These patients are usually already on anticoagulants. If they are not, expect a TEE to be performed before the start of the procedure to rule out any thrombus in the LAA.
Intraoperative	Before ablation, the proceduralist will often ask you to reposition the esophageal temperature probe to ensure that the esophagus is not damaged during ablation. Monitor closely and frequently inform proceduralists of esophageal temperature. Serial ACTs will be drawn throughout the procedure. Patients will receive IV heparin throughout the case as instructed by proceduralists. Paralytic is often contraindicated during maintenance as the proceduralist will pace the phrenic nerve during the ablation to ensure it remains intact. An excellent alternative is to run a remifentanil infusion during the case.
Postoperative	PACU then usually home (or short stay), patient to remain flat for several hours, watch for late complications of procedure
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Preoperative management

Patient evaluation

System	Considerations
Airway
Neurologic
Cardiovascular	Paroxysmal or chronic atrial fibrillation, CHADS2 scoring, history (cardiac history, risk factors for atrial fibrillation), review if patient has valvular abnormalities
Pulmonary
Gastrointestinal
Hematologic	Review anticoagulation status
Renal
Endocrine
Other

Labs and studies

• CBC, metabolic panel (electrolytes, renal function), ECG

Operating room setup

• Usually in cath lab or hybrid room
• Standard setup
• Arterial line transducer
• Esophageal temperature probe (may have specific one supplied by procedural team)
• Defib/cardioversion pads
• Lead/radiation shielding for providers

Intraoperative management

Monitoring and access

Standard Monitors. Establish two PIVs (one large bore in case of myocardial perforation). +/- arterial line (consider EF). +/- OG tube.

Induction and airway management

Standard GETA, occasionally performed under MAC (Kottkamp) (although general preferred to help keep patient immobile for arrhythmia mapping, additionally procedure may take many hours, and general anesthesia associated with higher cure rate with single procedure compared to conscious sedation (Di Biase)).

Positioning

Supine. Arms will be tucked. Ensure all lines are neatly tucked and off of the floor to ensure they are not caught by the swinging C-arm.

Maintenance and surgical considerations

• Maintenance of anesthesia with inhalation agent at 0.7 - 1 MAC with a remifentanil infusion (0.05 - 0.5 mcg/kg/min). Consider addition of phenylephrine infusion as well. Proceduralists like to know if any vasopressors are added during the case as they monitor for cardiac tamponade/atrial perforation. I have found it helpful to start a low dose phenylephrine infusion at the beginning of case to maintain hemodynamics.
• Use of heparin if crossing into left side of heart, monitoring ACT if on heparin (300 seconds, Anderson)
• Consider avoid redosing NMB to help with phrenic nerve monitoring (if being employed) (Yildiz)
• Procedure team may administer isoproterenol to induce arrhythmias, additionally adenosine may be requested to help with eliciting pathways
• May need to reverse heparin with protamine at the end

Emergence

Standard emergence. Closure of access site in groin often requires pressure to be held for 15- 30 min. Consider timing emergence to include this. Today, a closure device may be used at access site which negates this additional time. Some proceduralists may request antibiotics if closure device is being used.

Postoperative management

Disposition

• PACU, then usually home (or short stay)
• Will likely need to remain flat for a few hours due to vascular access sites

Pain management

• Usually minimal pain, post-op pain for radiofrequency > post-op pain for cryoablation; acetaminophen or NSAIDs (if no contraindications) (Ashley)

Potential complications

• Arrhythmia
• Perforation of aorta or heart
• Phrenic nerve injury, stroke
• Retroperitoneal hemorrhage
• Air embolism (atrial ablation)
• Esophageal injury
• Vascular access-related complications encountered 3-4% of time (Anderson)

Procedure variants

	atrial flutter ablation	VT ablation	SVT ablation
Unique considerations	similar approach as atrial fibrillation ablation	minimal/no sedation during mapping, then can convert to GA for ablation	usually under light/moderate sedation (since GA can suppress arrhythmia)
Position		Supine	Supine
Surgical time		can be > 6 hours
EBL	usually minimal (just losses from access site)	usually minimal (just losses from access site)	usually minimal (just losses from access site)
Postoperative disposition
Pain management		usually minimal pain	usually minimal pain
Potential complications		Higher chance of needing to defibrillate patient during procedure

References

Anderson R, Harukuni I, Sera V. Anesthetic considerations for electrophysiologic procedures. Anesthesiol Clin. 2013 Jun;31(2):479-89. doi: 10.1016/j.anclin.2013.01.005. Epub 2013 Feb 23. PMID: 23711654.

Ashley, Elizabeth MC, BSc MB ChB FRCA FFICM, Anaesthesia for electrophysiology procedures in the cardiac catheter laboratory, Continuing Education in Anaesthesia Critical Care & Pain, Volume 12, Issue 5, October 2012, Pages 230–236, https://doi.org/10.1093/bjaceaccp/mks032

Di Biase L, Conti S, Mohanty P, Bai R, Sanchez J, Walton D, John A, Santangeli P, Elayi CS, Beheiry S, Gallinghouse GJ, Mohanty S, Horton R, Bailey S, Burkhardt JD, Natale A. General anesthesia reduces the prevalence of pulmonary vein reconnection during repeat ablation when compared with conscious sedation: results from a randomized study. Heart Rhythm. 2011 Mar;8(3):368-72. doi: 10.1016/j.hrthm.2010.10.043. Epub 2010 Nov 2. PMID: 21055479.

Kottkamp H, Hindricks G, Eitel C, Müller K, Siedziako A, Koch J, Anastasiou-Nana M, Varounis C, Arya A, Sommer P, Gaspar T, Piorkowski C, Dagres N. Deep sedation for catheter ablation of atrial fibrillation: a prospective study in 650 consecutive patients. J Cardiovasc Electrophysiol. 2011 Dec;22(12):1339-43. doi: 10.1111/j.1540-8167.2011.02120.x. Epub 2011 Jun 21. PMID: 21692895.

Malladi V, Naeini PS, Razavi M, Collard CD, Anton JM, Tolpin DA. Endovascular ablation of atrial fibrillation. Anesthesiology. 2014 Jun;120(6):1513-9. doi: 10.1097/ALN.0000000000000261. PMID: 24714120.

Yildiz M, Yilmaz Ak H, Oksen D, Oral S. Anesthetic Management In Electrophysiology Laboratory: A Multidisciplinary Review. J Atr Fibrillation. 2018 Feb 28;10(5):1775. doi: 10.4022/jafib.1775. PMID: 29988243; PMCID: PMC6006978.