J. Mark Erfe, MD, MPH and Andrei Churyla, MD
Northwestern University, Chicago, IL, USA
Essential Operative Steps
- Lines and monitoring
- General anesthesia with double-lumen endotracheal intubation
- Positioning and sterile preparation
- Intraoperative TEE
- Right-sided trocar placements and pleural space insufflation (< 10mmHg)
- Right-sided oblique and transverse sinus dissection and isolation of pulmonary veins
- Testing of pulmonary vein isolation (pre- and post-ablation)
- SVC to IVC lesion
- Partial “roof” (through the transverse sinus) and partial “floor” lesions (through the oblique sinus)
- Right atrial appendage lesion
- Partial pericardium closure on the right side
- Chest tube insertion, instrument removal, and closure of right side
- Left-sided trocar placements and pleural insufflation
- Left dissection and isolation of pulmonary veins
- Completion of the “floor” and “roof” lesions from the left side, creating LA “box”
- “Box” to left atrial appendage lesion
- Posterior “box” testing
- Left atrial appendage epicardial clip application
- Chest tube insertion, instrument removal, and closure of left side
Potential Complications & Pitfalls
- Incomplete lung isolation: double-lumen tube intubation that fails to occlude the mainstem bronchus of each side will not
create complete lung isolation. Semi-inflated lungs will obstruct the working view - Tension carbothorax: high intrapleural pressure may cause hemodynamic instability. Make sure the insufflation pressure
is set to 8mmHg. Decompress pleural space if instability occurs - Phrenic nerve injury: the phrenic nerve should be inferior to the working plane on the right side, and it should be superior
to the working plane on the left side. Make sure the nerve is appropriately always identified. Cautery should be reduced
to 20-30 to avoid thermal injury. On the left side, the phrenic nerve can be attached to fatty tissue of the lung hilum.
Gentle dissection is needed to avoid traction injury - Damage to the heart chambers and great vessels: lift when cutting the pericardium to pull it away from underlying
structures. Careful dissection in the sinuses. Low threshold for sternotomy to control bleeding. Have cardiopulmonary
bypass and perfusionist readily available - Incomplete ablation of the “floor” and the “roof” lines: look for conductance drop on the radiofrequency ablation monitor
to ensure appropriate lesion depth is reached. Also make sure that the floor and roof lines overlap with the pulmonary
vein isolation lesions on both sides - Esophageal thermal damage: when ablating the “roof” and “floor” line be careful to avoid continuous radiofrequency
ablation application as this can cause thermal damage to the underlying esophagus. Also, make sure the TEE probe is
withdrawn to about 25cm at the lips - Failure to close the pericardium after right-sided ablations: an open right-sided pericardium while insufflating CO2 on
the left side will cause cardiac herniation and hemodynamic compromise - High arrhythmia risk: be aware that manipulation of the heart and pericardium and discharge of radiofrequency devices
near the ventricles increases the risk of intraoperative arrhythmias which may require cardioversion. Make sure
defibrillation pads are positioned correctly prior to the procedure - Incomplete occlusion of left atrial appendage: use TEE to confirm complete occlusion during and after epicardial clip
application. Occasionally a second clip is required - Occlusion or kinking of the circumflex artery with LAA epicardial clip: make sure there are no ischemic changes on
multiple lead EKG and no regional wall motion abnormalities of the LV after epicardial clip application. Immediate
epicardial clip removal is warranted if there are ischemic changes noted
Template Dictation
Preoperative Diagnosis: [TYPE – paroxysmal, persistent, long standing persistent] atrial fibrillation
Postoperative Diagnosis: Same (with appropriate adjustments)
Indication for Procedure: Arrhythmia refractory to [PRIOR TREATMENT – medication and/or catheter-guided
ablation]
Procedure(s) Performed:
- Totally Thoracoscopic Modified Maze
- Left atrial appendage closure [DEVICE – Manufacturer & Model]
Attending Surgeon: [BLANK]
Secondary Surgeon: [BLANK]
Assistants: [BLANK]
Anesthesia: [BLANK]
Indication(s) for Procedure:[AGE]-year old [SEX] with [DURATION] history of [TYPE – paroxysmal, persistent, long
standing persistent] atrial fibrillation. Preoperative cardiac catheterization revealed [FINDINGS]. Preoperative cardiac
echocardiography demonstrated [FINDINGS].
Description of the Procedure: After obtaining informed consent, the patient was brought to the operating room on [DATE]
and was placed in supine position. The patient was intubated by the anesthesia team with a double-lumen endotracheal tube.
All appropriate lines were placed, including an arterial line for hemodynamic monitoring and large bore central venous line for
CVP monitoring and infusions. Preoperative antibiotics were administered for surgical infection prophylaxis. Next, the patient
was positioned on the table with both arms tucked by the sides but hanging slightly off the table to expose the lateral portion
of the chest and axilla. After that, the patient was prepped and draped in sterile surgical fashion. A timeout was performed.
Preoperative TEE was then performed to evaluate cardiac and valve function and to ensure absence of a left atrial appendage
clot. The ability of the patient to tolerate single lung ventilation on both sides was confirmed.
Our attention was subsequently brought to the right side. A 5mm trocar was placed at the midsternal level on the anterior
axillary line. A 5mm trocar was placed [NUMBER] fingerbreadths up, aimed slightly anteriorly. Another 12mm another trocar
was placed [NUMBER] fingerbreadths down, aimed slightly anteriorly. Insufflation of the right pleural space was performed
to the pressure of 8mmHg. Upon examination of the right pleural space, it was obvious that there were no adhesions. Next,
the phrenic nerve was identified. The pericardium was opened 3cm anterior to the phrenic nerve longitudinally. [NUMBER]
suspension stitches were placed to retract the pericardium. After that, the oblique sinus was developed between the IVC and
the right inferior pulmonary vein. The transverse sinus was subsequently developed by dissecting between the pulmonary
artery, right superior pulmonary vein, and SVC. A lighted dissector was utilized to place a rubber guide around the right
pulmonary veins.
Next, Waterston’s groove was developed. The right [COMPANY] pulmonary vein isolation radiofrequency ablation clamp
was inserted in the pleural space and placed on the antrum of the left atrium. Multiple lesions were applied. Of note, testing of
the right pulmonary veins before and after ablation was performed and results were as follows: [SIGNALS: rights superior
pulmonary vein, right inferior pulmonary vein]. A lesion extending from the SVC to the IVC was created with
[COMPANY] linear radiofrequency ablation device. After that, the roof and floor lines were performed with a [COMPANY]
linear radiofrequency ablation device. Next, the right atrial lesions were completed with a [COMPANY] linear radiofrequency
ablation device. The SVC-to-IVC lesion was connected with a separate lesion to the apex of the right atrial appendage. At this
point, the red rubber guide was left in the pericardium for better access from the left side. It was passed through the oblique
sinus to the left side of the heart. The plastic portion of the guide was placed through the transverse sinus to the left.
Pericardium edges were approximated with a horizontal mattress suture. All instruments were then withdrawn, and the chest
cavity was explored to stop any potential bleeding [HEMOSTASIS: Description of hemostasis measures taken]. A
[SIZE]Fr Blake tube was placed in the pleural space.
After that our attention was brought to the left side. A 5mm midsternal trocar was placed at the level of the left mid-axillary
line. A 5mm trocar was placed [NUMBER] fingerbreadths, both in the anterior and superior directions. Another 12mm trocar
was placed [NUMBER] fingerbreadths in the inferior and anterior directions. After that the exploration of the pleural cavity
was performed [FINDINGS]. The pericardium on the left was opened posterior to the phrenic nerve. We were able to maintain
the position of the red rubber guides around the left pulmonary veins. The left-sided radiofrequency ablation clamp was placed
around the antrum of the left atrium to isolate left pulmonary veins. Multiple ablation lesions were administered. Before and
after ablation, we documented [FINDINGS: entry or exit block] from both left pulmonary veins. The [COMPANY] linear
radiofrequency ablation pen was used to touch up the roof and floor lesions to connect both pulmonary vein isolation lesions
and create the left atrial “box” lesion. Next a linear lesion was created from the “box” lesion to the left atrial appendage. Next
the posterior box was tested and [FINDINGS: entry or exit block]. The patient was in [RHYTHM: atrial or ventricular
tachycardia/fibrillation; cardioversion was performed].
The length of the left atrial appendage base was measured, and a [LENGTH]mm epicardial clip was applied to the base. On
TEE there was satisfactory occlusion of the orifice of the appendage. There were no ischemic changes on EKG and TEE during
a 3-4-minute monitoring period. At this point, the patient remained in sinus rhythm. A [SIZE]Fr Blake chest tube was
placed. Hemostasis was satisfactory. The lung was ventilated. Trocars were withdrawn. All port sites were closed in multiple
layers.
All sponge, instrument, and needle counts were correct at the completion of the case. Dr. [BLANK] was present and scrubbed
for [BLANK] elements of the procedure.
Multiple Choice Question(s)
- After finishing the right-sided procedure, you place trocars and insufflate the left side. Mean arterial pressure drops from
80s to 50mmHg over the next few minutes, and the patient becomes tachycardic. There is no visible bleeding. Which of the
following is most likely responsible?
A. Preexisting heart failure
B. Insufflation to 8mmHg
C. Failure to close pericardium
D. Persistent right-sided bleeding
E. Cardiac arrhythmia induced by electrocautery
Answer: C. Failure to close the pericardium on the right side will increase the risk of cardiac herniation through a
pericardiotomy aperture on the right side when insufflating the left side. Herniation will acutely reduce preload, dropping the
MAP. High insufflation pressure may cause tension carbothorax and create a similar scenario, but 8mmHg is generally well
tolerated. - Which of the following indicates that an ablation line is transmural?
A. Radiofrequency ablation clamp vibration
B. Impedance increase
C. Conductance drop
D. Visual changes in the tissue
E. Reaching the minimum required total thermal energy
Answer: C. The radiofrequency ablation monitor will display both the impedance and conductance of the signal over time.
The impedance will rise with increased tissue resistance and the conductance will fall when the tissue is completely ablated. - Three weeks after a totally thoracoscopic MAZE, a non-responsive patient is brought to the ED by EMS in profound shock
with MAPs in the 30s mmHg and tachycardia to the 150s. Venous access and intubation are attempted but the oropharynx is
filled with bright red blood. Massive transfusion protocol is initiated but the patient goes into PEA arrest and expires soon
after the ACLS protocol is started. What would have prevented this complication?
A. Ensuring hemostasis prior to closing pericardium
B. Avoiding deep lesions at the SVC-IVC line
C. Properly calibrating the radiofrequency ablation machine prior to ablation
D. Avoiding continuous prolonged radiofrequency ablation application on “floor” and “roof” lines.
E. Confirming appropriate LAA placement on postoperative TEE
Answer: D. This patient developed a large atrial-esophageal fistula after ablation. Creation of the “floor” and “roof” lines may
inadvertently cause thermal damage to the underlying esophagus if radiofrequency ablation application is held for too long
without cooling the space with saline instillation. This is a devastating complication which can be avoided by utilizing proper
ablation technique.
Sources
Dunnington GH, Pierce CL, Eisenberg S, Bing LL, Chang-Sing P, Kaiser DW, Burk S, Moulton LC, Kiankhooy A. A heartteam hybrid approach for atrial fibrillation: a single-centre long-term clinical outcome cohort study. Eur J Cardiothorac Surg.
2021 Dec 1;60(6):1343-1350.
Geuzebroek GS, Bentala M, Molhoek SG, Kelder JC, Schaap J, Van Putte BP. Totally thoracoscopic left atrial Maze:
standardized, effective and safe. Interact Cardiovasc Thorac Surg. 2016;22(3):259-264.
The European Association for Cardio-Thoracic Surgery (EACTS). “The totally thoracoscopic left atrial Maze procedure for
the treatment of AF.” The Multimedia Manual of Cardio-Thoracic Surgery. Online video. Accessed March 25, 2022.
https://www.youtube.com/channel/UCJySvW8hBVRnd0a0SGUYRDA
