Cardiac Ablation – Atrial Fibrillation

Anesthesia Implications

Position: Supine, arms at side on armboards
Time: 4+ hours (very long)
Blood Loss: Very Low (5-10 ml)
Post-op Pain: Minimal (1-3)
Maintenance Paralytic: Ask surgeon
Lead: Yes

Cancellation – These cases may be cancelled if the TEE at the beginning of the procedure shows a thrombus in the atrium (these are usually found in the left atrial appendage).

Arterial Line – standard for these cases to monitor for tamponade/hemodynamic instability. Hemodynamics can be very labile due to intermittent pacing and the general condition of the typical afib patient. Art lines can be difficult to place. If proving to be impossible, the surgeon may place an arterial line in the femoral artery. ACTs will be routinely taken via the arterial line.

Bite block – A strong suggestion is to place a soft bite block after induction to protect against tongue/lip/tooth injuries during cardio versions.

Esophageal temperature monitor – these are standard for these cases. Because the esophagus can be very close to where ablation will be taking place, the doctor is going to want to know if there are sudden changes in the esophageal temperature.

Isoproterenol – frequently used, especially in cases where the patient is bradycardic.

Cardioversion – There may be multiple cardioversions during the case. Typically this doesn’t warrant any particular action but to closely watch vitals.

Heparin – given at regular intervals based on the ACT value

Vascular perforation – high risk in these cases. If this is suspected, an emergency thoracotomy may be indicated. Most of these procedures are done in a hybrid procedure room/cath lab. This is to facilitate an emergency thoracotomy without delay.

Paralytics – Some surgeons do not allow paralytics after intubation. This allows phrenic nerve mapping. In other cases, surgeons are ok with maintenance paralytics – so ask!

Low tidal volumes with high respiration rate – This makes the procedure easier for the surgeon.

Devices – multiple new devices (eg. EsoSure, ensoETM, circa S-cath) are being employed to reduce the risk of atrial-esophageal fistula. If you’re dealing with a new surgeon, make sure to ask for the preference.

If tamponade occurs – avoid the use of phenylephrine to correct pressures. Use ephedrine or epinephrine. If absolutely necessary, the venous introducers at the groin can be utilized to give fluids. Protamine will be used to reverse the heparin (1 mg/100 u of Heparin previously administered. Give SLOWLY). Blood removed via pericardiocentesis will be reinjected via the femoral line. If bleeding persists (doesn’t clot) an emergency repair of the perforated atrium will have to be performed.

Long procedure (general considerations): Procedures anticipated to last longer than 2 hours generally require a urinary catheter. Also consider checking lines and positioning regularly as the risks of infiltration and nerve damage are increased with procedure time. Consider an IV fluid warmer and a forced air warmer to keep the patient euthermic.

Fluoroscopy / Xray (general considerations): Have lead aprons and thyroid shields available. Alternatively, distancing yourself 3 to 6 feet will reduce scatter radiation to 0.1% to 0.025% respectively. Occupational maximum exposure to radiation should be limited to a maximum average of 20 Sv (joules per kilogram – otherwise known as the Sievert/Sv) per year over a 5 year period. Limits should never exceed 50 Sv in a single year.

Arterial line (general considerations): Preoperatively check pulses to gauge the best side to attempt the A-line. Perform an Allen test to ensure adequate blood flow. Have the A-line equipment set up and ready in the room.

This surgery is performed typically after the patient has already unsuccessfully attempted medical/pharmaceutical management of atrial fibrillation.

A bipolar radiofrequency ablator is inserted into the femoral vein. The femoral vein is utilized as a track to run the ablator to the chambers of the heart. Once there, access to the left atrium may be accessed through the foramen ovale