One-stage Approach for Hybrid Atrial Fibrillation Treatment

Login or register to view PDF.
Abstract

The one-stage approach for hybrid atrial fibrillation involves the simultaneous and close cooperation of different medical specialties. This review attempts to describe its challenging issues, exposing a plan to balance thrombotic risk and bleeding risk. It describes the combined surgical-electrophysiological procedure. Specific topics, involving hemodynamic, fluid and respiratory management during surgery are considered, and problems related to postoperative pain are surveyed.

Disclosure
Mark La Meir might have a financial interest in this publication. He also consults for AtriCure.
Correspondence
Vincent Umbrain, Department of Anaesthesiology and Perioperative Medicine, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium. E: Vincent.umbrain@uzbrussel.be
Received date
19 September 2017
Accepted date
16 November 2017
Citation
Arrhythmia & Electrophysiology Review 2017;6(4):210–6.
DOI
https://doi.org/10.15420/2017.36.2

The current option for refractory treatment for atrial fibrillation (AF) includes hybrid AF-surgery.1–2 The hybrid approach was originally a combination of mini-invasive surgical epicardial evaluation and ablation, as well as endocardial electrophysiologist (EP) catheter ablation with the intention of creating a lesion set to cure AF.3 In the search for greater efficacy with less patient invalidation, different surgical and EP approaches have been developed. Variable timing between the epicardial approach and EP endocardial procedure has also emerged. Potential risks (Table 1) and claimed conversion rates to sinus rhythm after hybrid AF treatment vary from 27 to 94 %.4–13 The large variation in success rate is probably due to differences in patient selection between centres, staging and surgical technical approaches, lesion sets, periprocedural care and endpoints, energy sources, and choice of endpoints used after the procedure. Experience and technical improvements, as well as a search for greater value-based healthcare treatment of AF has led us to develop a one-stage hybrid method described in this manuscript.

For refractory AF, our team recommends a combination of minimal invasive epicardial evaluation and ablation, together with EP mapping and ablation on the beating heart in a single procedure. The suggested epicardial technique involves mostly surgical unilateral left thoracoscopic evaluation and ablation approach, while the EP maps and ablates throughout the endocard after a percutaneous femoral approach during the procedure. Sometimes, depending on the patient’s antecedents, the epicard is approached with either a sequential, bilateral or unilateral right thoracoscopy.4 We believe that a one-stage approach provides unique and important advantages for patients compared to a two-stage procedure (Table 2).

The approach for hybrid AF surgery involves some particularities and challenging issues that require specific attention from the medical specialities involved. The purpose of this review is to describe our standard approach as follows: determine optimum timing of the last anticoagulant administration during the preoperative visit to minimise thrombus risk in the left atrial appendix and bleeding risk during surgery; expose respiratory management of prolonged sequential bilateral or unilateral thoracoscopy, hereby optimising oxygen delivery but reducing the risk of atelectasis; interpret haemodynamic control problems related to thoracoscopy, diastolic dysfunction with loss of atrial kick and decreased venous return by ablation on the pulmonary veins; show optimal positioning for surgery to facilitate access of the epicardial radio-ablation procedure; point out specific problems related to postoperative pain, its localization and treatment options; touch on the potential consequences of left atrial appendix clipping on fluid administration during and after surgery; and comment on early feeding problems after surgery.

Hybrid Method

Team

In practice, hybrid AF-surgery may be considered a joint venture of different medical specialities requiring close cooperation and immediate presence of a cardiologist, electrophysiologist, cardiac surgeon, anaesthesiologist, immediate care holders (nurses of the ward, operating room, high care or intensive care team, acute pain team), respiratory care specialists and pain doctors. The cardiopulmonary bypass department is also informed and on standby due to a <1.6 % risk of conversion to sternotomy with eventual repair under cardiopulmonary bypass.11

Patient Preoperative Visit

An in-depth preoperative visit focusing on the patient’s rhythm history and their cardiovascular risk factors often allows estimation of probability of conversion to sinus rhythm and duration of surgery. The factors affecting success rate are prior duration of AF, size of left atrial dilatation11 and prior treatment of comorbidity factors such as arterial hypertension, valvular heart disease, obesity, chronic obstructive pulmonary disease, chronic kidney disease and obesity before surgery.1

Complications for Hybrid Atrial Fibillation Surgery

Open in new tab
Open ppt

One-stage Hybid Procedure

Open in new tab
Open ppt

As surgery often requires sequential single-lung ventilation, anamnesis of former pulmonary afflictions is recorded. Postoperative choices of enhanced pain treatment after surgery, with consideration of multi-model therapeutic strategy14 (use of diverse analgesic compounds to reduce opiate consumption; see Figure 1) and particular choices should be discussed during the preoperative visit. The benefits and risks of treating postoperative pain using intravenous, epidural or paravertebral approaches are explained.15–20 Local anaesthetics with or without opioids are used for the epidural or paravertebral approach. A morphine or piritramide opiate pump is used for the intravenous route. A choice is made in light of the patient’s history and preferences, and experience of the anaesthetist (Table 3). Of concern in this choice is coagulation status just before surgery. The exact timing of discontinuation of anticoagulants before surgery is discussed in Table 4. Briefly, the aim is to find a window of opportunity between risk of bleeding with existing coagulation guidelines during surgery,21–25 and increased risk of thrombi generation in the left atrial appendix of patients with AF and an enlarged left atrium with decreased blood flow velocities. This is not always an easy task. Most guidelines for stopping anticoagulants apply to general surgery and not specifically to AF patients scheduled for hybrid AF surgery, where the left atrial appendix will be mobilised and ultimately stapled. If there is doubt of coagulation status, an assessment of the patient’s coagulation status just before incision with TEG/ROTEM monitoring, when available, may reduce the risk of epidural or paravertebral bleeding with subsequent medullar compression.26–28 However, the exact value of using this method of monitoring in this context is insufficiently studied and needs to be further investigated.29

Enhanced Postoperative Pain Treatment

Open in new tab
Open ppt

A detailed, yet gentle explanation to patients about the goal and surgical technique is often helpful in reducing preoperative anxiety and sympathetic activity. In most cases, the patient’s preference is a patient-controlled intravenous or thoracic epidural technique. A paravertebral block is eventually used as a postoperative rescue issue for patients with refractory pain after patient-controlled intravenous pain when administration of non-steroidal anti-inflammatory agents is not indicated. Both epidural and paravertebral block with catheter insertion in AF patients under anticoagulant treatment present a threat challenge to the anaesthesiologist as inserting the needle or catheter may lacerate a blood vessel and subsequently create a risk of medullar compression.29 In normal circumstances the risk for neuraxial haematoma is estimated to be between 1 in 220 000 and 1 in 320 000. Short new oral anticoagulant (NOAC) discontinuation times may increase this risk. Multiple neuraxial puncture attempts should, therefore, be avoided in patients with spinal abnormalities or with other underlying hereditary or acquired coagulation disorders.

Patients are informed of the need for radial artery catheter for beat-to-beat blood pressure monitoring during surgery and insertion of a jugular venous catheter for eventual continuous administration of inotropic support during or immediately after surgery.

Anaesthetic Approach Before Surgery

Preparation of anaesthesia before surgery (see the preoperative checklist in Table 5) includes radial artery monitoring set, eventual epidural catheter set, patient-controlled intravenous or epidural pump device, intubation equipment for left and/or right-sided thoracoscopy through selective left endobronchial intubation by endotracheal intubation with a bronchial blocker or EZ-blocker under fibrescopic control, central venous catheter set, norepinephrine, and possibly dobutamine pump. All patients receive a bladder catheter. Temperature recording with active patient warming (Bair Hugger or analogue) to maintain core temperature (bladder temperature) above 35.5°C is favoured. External and internal defibrillator pads and a same-day checked defibrillator are needed. The immediate vicinity of a primed cardiopulmonary bypass (CPB) machine is checked for possible repair of pulmonary vein or left atrium laceration under cardiopulmonary bypass.

Enhanced Postoperative Analgesia Approaches

Open in new tab
Open ppt

Surgery

Anaesthetic drugs are determined by the patient’s antecedents and anaesthetist’s habits or preferences and include opioids, propofol/etomidate, non-depolarizing muscle relaxants (rocuronium, cisatracurium) and inhalational anaesthetics (isoflurane, sevoflurane). All patients receive antibiotic prophylaxis before incision. A repeat dose is given for surgeries lasting for more than 4 h.

Anaesthetic specificities for hybrid surgery involve control of perioperative haemodynamic and ventilatory stability and postoperative pain control.

The ventilation settings are adapted to single-lung ventilation request during surgery. For single-lung ventilation tidal volumes are decreased (from 7–8 ml/kg to 5–6 ml/kg ideal bodyweight), respiratory frequency increased (from 14 to 20/min or more depending on initial basal respiratory rate). High versus low positive end-expiratory pressure (PEEP)-levels, when needed, are prudently increased depending on their impact on blood pressure and pulse oxygen saturation. Often, a permissive attitude to hypercapnia with arterial carbon dioxide levels of 50 mmHg is accepted. Alveolar recruitment is performed depending on patient blood pressure, pulse saturation and surgical consent. Particular attention should be given to alveolar recruitment when changing sides if a two-stage sequential thoracoscopy is performed.

An enhanced incidence of hypotension due to diastolic dysfunction, loss of atrial kick, carbon dioxide insufflation in the thoracic, mediastinal and pericardial cavities, and effect of surgery during ablation on pulmonary venous return is frequently observed after onset of single-lung ventilation. Carbon dioxide insufflation pressure during thoracoscopy should be adapted to blood pressure and limited to 8 mmHg or less to avoid a tamponade effect. Judicious titration of phenylephrine, noradrenaline or dobutamine is often requested. Impaired or restrictive diastolic function, sequential one-lung ventilation with clipping of the left atrial appendage and consequent altered postoperative atrial natriuretic hormone levels justifies reasoned and restricted fluid administration.

Fluid administration is adapted to current guidelines30–32 and eventual surgical blood loss. As in most cases, blood loss is minimal and blood products can be avoided. Fluid administration starts with a balanced crystalloid solution set at 2 ml/kg per h and is further adapted in function of transoesophageal echocardiography imaging. However, a tendency to restrain fluids is observed in later stapling of the left atrial appendage. In general, total fluid administration given during surgery ranges from 500 to 1000 ml.

Patient Positioning

Patient positioning for surgery involves opening the space on the front axillary line to provide optimal access to the fourth and fifth intercostal space with an inflatable balloon placed below the patient’s back. The balloon is inflated for improved access and widening of the intercostal opening with consideration to the pressure exerted on the cervical lordosis and the possible hyperextension in the lumbar area. Both arms are flexed and placed sideways to the operation table to widen the operative area. A radial artery catheter is preferred as a brachial artery catheter often leads to greater kinking or obstruction in patients positioned with flexed elbows (Figure 2). The area surrounding the sternum is kept electrode-free for a worst-case scenario with unforeseen bleeding leading to sternotomy (Figure 3).

Epicardial Approach

Hybrid AF-surgery consists of a combined thoracoscopic epicardial and endovascular endocardial approach. The epicardial approach consists of left and possibly right thoracoscopy. Briefly, a 6 mm camera port is placed in the fifth intercostal space at the mid-axillary line and in the sixth or seventh intercostal space anterior axillary line. A 5 mm working port is placed in the third intercostal space anterior axillary line. The pericardium is opened anterior to the phrenic nerve and transverse and oblique sinuses, and is bluntly dissected. A bipolar RF-clamp is used for antral isolation of both pairs of pulmonary veins with four to six applications. Afterwards, a bipolar RF pen or linear pen device is used to perform a roof line and inferior line connecting, respectively, on both superior and inferior pulmonary veins to create the box lesion for posterior left atrial wall isolation. Box lesion ablation is completed when the right atrium is dilated with two additional ablation lines: one line with the use of the clamp encircling the vena cava superior and a bicaval line using the pen and connecting both caval veins. In most patients, the left atrial appendix appendage is also clipped. Communication between the surgeon and anaesthetist is important as pulmonary venous return is sometimes hindered during ablation. Subsequent hypotension and lowered oxygen saturation levels are treated with norepinephrine titration, higher inspired oxygen levels as indicated, and surgical repositioning.

Electrophysiology

Percutaneous femoral electrophysiological examination and ablation includes the insertion of a decapolar coronary sinus catheter under fluoroscopy and a trans-septal puncture for placing a long 8-Fr sheath under combined guidance of TEE and fluoroscopy. The patient is heparinised after the trans-septal puncture with a heparin dose of 1,000 IU/10 kg bodyweight to obtain a target activated clotting time >300s. Eventual heparin increments are given to maintain ACT values. A circular mapping catheter and a radiofrequency (RF) ablation catheter are used with an open, irrigated 3.5 mm tip to create a detailed electro-anatomic map of the left atrium. The ‘epicardial box lesion’ ablation block is controlled endocardially by checking the entry and exit block of the pulmonary veins alongside the posterior wall of the left atrium. The circular mapping catheter is used to evaluate the entry block of the pulmonary veins and the posterior left atrial box, and is defined as the absence of atrial bipolar signs. The exit block checks the pulmonary veins or the posterior wall during pacing with an output of 10 mA and a pulse width of 2 ms without conduction to the left atrium. If either block is not present, additional endocardial ablation is performed to close the conduction gaps. A radiofrequency power-controlled mode with a power limit of 35 W with maximal temperature of 48°C is used until block achievement.

A cavo-tricuspid isthmus endocardial or a mitral line ablation is added in the presence of a flutter or a mitral isthmus dependent flutter, respectively, during the procedure. If despite these epicardial and endocardial ablations AF persists, left and right continuous fractionated atrial electrogram mapping/ablation is performed. Target sites are defined as the fastest local repetitive electrical activity, multicomponent fragmented signals or as activation delay between the distal and proximal bipolar electrodes covering most the cycle length. The endpoint of ablation coincides with a regular or disappeared local signal, conversion to sinus rhythm or the presence of stable atrial flutter. Patients who do not convert to sinus rhythm during hybrid AF ablation are cardioverted. In sinus rhythm, all ablation lines are then revisited to confirm bidirectional conduction using the standard criteria. The pericardium is approximated with a stitch, and a chest tube is placed in one or both pleural cavities depending on the approach.

Discoutinuation times of Oral Anticoagulants & Medications

Open in new tab
Open ppt

Preoperative Anaesthesia Checklist

Open in new tab
Open ppt

Perioperative Management

Pain Triggers

Postoperative pain treatment after hybrid surgery for AF presents interesting challenges with a fluctuating variability of localisation and intensity. This is explained by nerve sensitisation induced at several places by the surgical approach combined with the endocardial and pericardial radiofrequency-ablation procedure (Figure 1).

The first potential cause of postoperative pain, and often the first reported, is related to neural activation in the pleural cavities. This is caused by the insertion of intercostal ports, insufflation of carbon dioxide (which cannot always be totally removed at the end of surgery) or the presence of thoracic drains in one or both pleural cavities. Pain symptoms are specifically respiratory (inspiratory) and drain-related. In case of shoulder pain, inadequate CO2 removal with secondary phrenic nerve irritation should be considered. Of importance for the long term, the intercostal nerves may be pressurised by the 5-mm ports in patients with narrow intercostal distances and rarely progress to intercostal nerve neuropathic pain.

One stage Hybird AF Surgery Installation

Open in new tab
Open ppt

Free Sternum and Possible Access to Bilateral Incision

Open in new tab
Open ppt

The second possible pain course is by neural activation and sensitisation of several (epicardial) heart nerve endings during the radiofrequency ablation approach. Possibly implicated and sensitised nerves are the phrenic nerve(s), pericardiophrenic nerve, epicardial nerve and intrinsic cardiac nerves, which regroup in a ganglionated plexus located in fat pads. At the atrial level three plexi are described: a superior left atrial plexus disposed over the superior veno-atrial junction, a posterolateral plexus laying over the lateral atrial wall and the left inferior veno-atrial junction and a posteromedial plexus overlying the right veno-atrial junctions. Signals from the heart are transmitted by primary sensory neurons. The afferent fibres originating from the heart travel as sympathetic and parasympathetic nerves and transmit information to the central nervous system about the activities of the heart or the occurrence of tissue injury, the latter through nociceptive fibres. These signals also generate autonomic reflexes, which allow regulation of organ function. Some of the signals, for instance pain signals, can be transmitted to cortical centres and become conscious. Nociceptive fibres are mostly associated with sympathetic fibres. Their cell bodies are found in spinal ganglia and likely end in the posterior roots of the spinal cord, where they synapse in second-order nociceptive neurons. Nociceptive visceral fibres are much less numerous than the nociceptive somatic fibres and usually end at more levels in the spinal cord, thus generating less specific and localised pain sensation. Afferent primary sensory fibres associated with parasympathetic nerve fibres are more involved in regulatory reflexes of system/organ activities. These nerve fibres are mainly associated with the vagal nerve, but several visceral cranial afferent fibres travel with the glossopharyngeal nerve or facial nerve and fibres of the pelvic nerves. The cell bodies of these afferent fibres are found in ganglia associated with these parasympathetic nerves. Primary sensory neurons then project onto second-order visceral sensory neurons located in the medulla oblongata, the nucleus of the solitary tract and other nuclei.33–34

Reported pain sensation after radiofrequency ablation can vary. Most often, a persistent dull type of cardiac pain is reported, but severe, sharp, diffuse heart pain is also possible. This type of pain may be associated with altered ST-segment elevations on ECG-recordings and troponin elevations, and is induced by regional pericarditis radiofrequency. This is to be differentiated from coronary embolisation of left atrial thrombus, ablation damage to the left circumflex artery and pericardial blood effusion. Pericarditis pain is treated with aspirin, NSAIDs, or colchicine when appropriate, often in combination with intravenous opioid administration.35 Whether preoperative central sensitisation induced by the presence of a long-standing AF, young age, extent of radiofrequency ablation or ongoing long-lasting anxiety potentiate this postoperative pericarditis pain is still unknown.

A third possible source of pain is of epigastric or oesophageal origin. Its causes are dual. The reported incidence of inflammation of the anterior oesophageal wall secondary to the RF-ablation on the antrum of the pulmonary veins is 47 %.36 This oesophageal inflammation may also be related, albeit to a lower extent, to TEE insertion and manipulation for exclusion of the presence of thrombi in the left atrial appendix just before surgery.37

Whether preoperative central sensitisation induced by the presence of a long-standing AF, young age, extent of radiofrequency ablation or ongoing and long-lasting anxiety, depression or catastrophising behaviour potentiate this severe postoperative pericarditis pain is unknown.

Postoperative Pain after Hybrid AF Surgery

Open in new tab
Open ppt

Establishing the difference between cardiac pain and stomach/oesophageal pain is sometimes difficult as both the posterior wall of the left atrium and the pulmonary veins share some common efferent nociceptive nerves. In our experience, its onset is later than pain reported that is related to pleural or pericardial neural sensitisation. Discrete oesophageal dysphagia or slow oesophageal food descent often mentioned with resumption of solid fluid intake may be part of this nervous sensitisation. A gastroscopy performed after surgery may help exclude pain of oesophageal or gastric origin.

Pain Control

Pain treatment in our institution starts with paracetamol given before incision and continued for 24–48 h. A surgical infiltration of the wound and the intercostal nerves with ropivacaine is accomplished before closure of the laparoscopic incision sites. Pain control is further enhanced with either an intravenous opioid or an epidural pump with local anaesthetics started 30 min before skin closure. The patient-controlled IV pump consists of either a morphine or piritramide pump. Depending on the VAS scales and patient’s complaints, a background continuous infusion is eventually added. Most pain complaints after surgery decrease drastically after thoracic drain removal. In some patients, however, pain persists for another week. Further pain relief is provided when possible or indicated with intravenous NSAIDs, selective COX-2 inhibitors, tramadol, or morphine/oxycodone. When pain treatment is refractory a paravertebral block is eventually performed.

Postoperative Management

Cardiac Management

Patients are monitored for eventual arrhythmia relapses, coronary vasospasm, circumflex coronary artery damage by radiofrequency and coronary thrombus embolisation for 24 h in intensive care.

For patients with suspected RF-induced pericarditis, regular ECGs and troponin measurements are performed. After ICU discharge some patients are placed under continuous telemetric monitoring. Transthoracic echocardiography is requested and performed to exclude post-procedure pericardial effusion. Low molecular weight heparins are started the evening after surgery. NOACs and oral anticoagulants are re-initiated on the third postoperative day and continued for 3 months. The left atrial appendix is stapled to reduce the stroke incidence after hybrid AF surgery.38–39 Closure of the left atrial appendix leads to lower atrial natriuretic peptide levels and consequently higher risk of fluid retention in the immediate postoperative days. Careful postoperative fluid administration with regular patient weighing is therefore indicated in the first weeks after surgery. A one-month diuretic treatment is usually used to bridge the period before the right atrial appendix or the brain compensates with the patient’s personal natriuretic peptide production at our hospital.40

Follow-up

Clinical follow-up by the cardiologist and/or surgeon with a physical examination, electrocardiogram and 24-h Holter monitoring is implemented at 3, 6 and 12 months following hybrid surgery. A gentle cardiac rehabilitation program following the procedure is encouraged.

Conclusion

Hybrid AF-surgery is a promising therapy for patients refractory to AF-treatment. An integrated approach involving different teams may lead to improved success rate and increased patient satisfaction. Differentiation of the several possible pain triggers, whether thoracic, cardiac or gastro-esophageal in origin, can help resolve observed versatile postoperative pain.

References
  1. Kirchhof P, Benussi S, Kotecha D, et al. 2016 ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS: The Task Force for the management of atrial fibrillation of the European Society of Cardiology (ESC) Developed with the special contribution of the European Heart Rhythm Association (EHRA) of the ESC Endorsed by the European Stroke Organisation (ESO).Eur J Cardiothorac Surg 2016;50:1–88
    Crossref | PubMed
  2. Lawrance CP, Henn MC, Damiano RJ Jr. Surgical ablation for atrial fibrillation: techniques, indications, and results. Curr Opin Cardiol 2015;30:58–64.
    Crossref | PubMed
  3. Pak HN, Hwang C, Lim HE, Kim JS, Kim YH. Hybrid epicardial and endocardial ablation of persistent or permanent atrial fibrillation: a new approach for difficult cases. J Cardiovasc Electrophysiol 2007;18:917-23.
    Crossref | PubMed
  4. Pison L, La Meir M, van Opstal J, Blaauw Y, Maessen J, Crijns HJ. Hybrid thoracoscopic surgical and transvenous catheter ablation of atrial fibrillation. J Am Coll Cardiol 2012;60: 54–61.
    Crossref | PubMed
  5. Krul SP, Driessen AH, van Boven WJ, et al. Thoracoscopic video-assisted pulmonary vein antrum isolation, ganglionated plexus ablation, and periprocedural confirmation of ablation lesions: first results of a hybrid surgical-electrophysiological approach for atrial fibrillation. Circ Arrhythm Electrophysiol 2011;4:262–70.
    Crossref | PubMed
  6. La Meir M, Gelsomino S, Lorusso R, et al. The hybrid approach for the surgical treatment of lone atrial fibrillation: one-year results employing a monopolar radiofrequency source. J Cardiothorac Surg 2012;7:71.
    Crossref | PubMed
  7. Muneretto C, Bisleri G, Bontempi L, Curnis A. Durable staged hybrid ablation with thoracoscopic and percutaneous approach for treatment of long-standing atrial fibrillation: a 30-month assessment with continuous monitoring. J Thorac Cardiovasc Surg 2012;144:1460–5.
    Crossref | PubMed
  8. Gehi AK, Mounsey JP, Pursell I, et al. Hybrid epicardial-endocardial ablation using a pericardioscopic technique for the treatment of atrial fibrillation. Heart Rhythm 2013;10:22–8.
    Crossref | PubMed
  9. Krul SP, Pison L, La Meir M, et al. Epicardial and endocardial electrophysiological guided thoracoscopic surgery for atrial fibrillation: a multidisciplinary approach of atrial fibrillation ablation in challenging patients. Int J Cardiol 2014;173:229–35.
    Crossref | PubMed
  10. Je HG, Shuman DJ, Ad N. A systematic review of minimally invasive surgical treatment for atrial fibrillation: a comparison of the Cox-Maze procedure, beating-heart epicardial ablation, and the hybrid procedure on safety and efficacy. Eur J Cardiothorac Surg 2015;48:531–40.
    Crossref | PubMed
  11. De Asmundis C, Chierchia GB, Mugnai G, et al. Midterm clinical outcomes of concomitant thoracoscopic epicardial and transcatheter endocardial ablation for persistent and long-standing persistent atrial fibrillation: a single-centre experience. Europace 2016:19:58–65.
    Crossref | PubMed
  12. Hu QM, Li Y, Xu CL, et al. Analysis of risk factors for recurrence after video-assisted pulmonary vein isolation of lone atrial fibrillation results of 5 years of follow-up. J Thorac Cardiovasc Surg 2014;148:2174–80.
    Crossref | PubMed
  13. Vroomen M, Pison L. Hybrid ablation for atrial fibrillation: a systematic review. J Interv Electrophysiol 2016;47:265–74.
    Crossref | PubMed
  14. Buvanendran A, Kroin JS. Multimodal analgesia for controlling acute postoperative pain. Curr Opin Anaesthesiol 2009;22:588–93.
    Crossref | PubMed
  15. Freise H, Van Aken HK. Risks and benefits of thoracic epidural anesthesia. Br J Anaesth 2011;107:859–68.
    Crossref | PubMed
  16. Pöpping DM, Elia N, Van Aken HK, et al. Impact of epidural analgesia on mortality and morbidity after surgery: systematic review and meta-analysis of randomized controlled trials. Ann Surg 2014;259:1056–67.
    Crossref | PubMed
  17. Block BM, Liu SS, Rowlingson AJ, et al. Efficacy of postoperative epidural analgesia: a meta-analysis. JAMA 2003;290:2455–63.
    Crossref | PubMed
  18. Teeter EG, Kumar PA: Pro Thoracic epidural is superior to paravertebral block for open thoracic durgery. J Cardiothorac Vasc Anesth 2015;29:1717–9.
    Crossref | PubMed
  19. Krakowski JC, Arora H. Con: thoracic epidural is not superior to paravertebral block for open thoracic surgery. J Cardiothorac Vasc Anesth. 2015;29:1720–2.
    Crossref | PubMed
  20. Zhang X, Shu L, Lin C, et al. comparison between intraoperative two-space injection thoracic paravertebral block and wound infiltration as a component of multimodal analgesia for postoperative pain management after video-assisted thoracoscopic lobectomy: a randomized controlled trial. J Cardiothorac Vasc Anesth 2015;29:1550–6.
    Crossref | PubMed
  21. Horlocker TT, Wedel DJ, Rowlingson JC, et al. Regional anesthesia in the patient receiving antithrombotic or thrombolytic therapy: American Society of Regional Anesthesia and Pain Medicine Evidence Based Guidelines (Third Edition) Reg Anesth Pain Med 2010;35:64–101.
    PubMed
  22. Horlocker TT. Regional Anesthesia in the patient receiving antithrombotic and antiplatelet therapy Br J Anesth 2011;107:i96–i106.
    Crossref | PubMed
  23. Neal JM, Barrington MJ, Brull R, et al. Second ASRA Practice Advisory on Neurologic Complications Associated with Regional Anesthesia and Pain Medicine: Executive Summary 2015 JC. Reg Anesth Pain Med 2015;40:401–30.
    Crossref | PubMed
  24. Weitz JI, Hirsh J, Samama MM. New antithrombotic drugs: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest 2008;133:234S–256S.
    Crossref | PubMed
  25. Eriksson BI, Quinlan DJ, Weitz JI. Comparative pharmacodynamics and pharmacokinetics of oral direct thrombin and factor Xa inhibitors in development. Clin Pharmacokinet 2009;48:1–22.
    Crossref | PubMed
  26. Jakoi A, Kumar N, Vaccaro A, Radcliff K. Perioperative coagulopathy monitoring. Musculoskeletal Surgery 2014;98,1–8.
    Crossref | PubMed
  27. Petricevic M, Konosic S, Biocina B, et al. Bleeding risk assessment in patients undergoing elective cardiac surgery using ROTEM® platelet and multiplate® impedance aggergometry. Anaesthesia. 2016;71: 636–47.
    Crossref | PubMed
  28. Lee GC, Kicza AM, Liu KY et al. Does rotational thromboelastometry (ROTEM) improve prediction of bleeding after cardiac surgery? Anesth Analg 2012;115:499–506.
    Crossref | PubMed
  29. Dubois V, Dincq AS, Douxfils J, et al. Perioperative management of patients on direct oral anticoagulants. Thromb J 2017;15:14.
    Crossref | PubMed
  30. Woodcock TE, Woodcock TM. Revised Starling equation and the glycocalyx model of transvalvular fluid exchange: an improved paradigm for prescribing intravenous fluid therapy. Br J Anaesth 2012;108:384–94.
    Crossref | PubMed
  31. Miller TE,  Raghunathan K,  Gan TJ. State of the art fluid management in the operating room. Best Pract Res Clin Anaesthesiol 2014;28:261–73.
    Crossref | PubMed
  32. Miller TE, Roche AM, Mythen M. Fluid management and goal-directed therapy as an adjunct to Enhanced Recovery After Surgery (ERAS). Can J Anaesth 2015;62:158–68.
    Crossref | PubMed
  33. Battipaglia I and Lanza GA. Autonomic innervation of the heart. In: Slart RHJA, Tio RA, Elsinga PH, Schwaiger M (eds). Role of Molecular Imaging. Berlin: Springer, 2015;2–11" target="_blank">PubMed
  34. Suraj K. Innervation of the heart an invisible grid with a black box. Trends in Cardiovasc Med 2016;26: 245–57.
    Crossref | PubMed
  35. Orme J, Eddin M, Loli A. Regional pericarditis status post cardiac ablation: a case report. North Am J Med Sci 2014;6:481–3.
    Crossref | PubMed
  36. Schmidt M, Nölker G, Marschang H, et al. Incidence of oesophageal wall injury post-pulmonary vein antrum isolation for treatment of patients with atrial fibrillation. Europace 2008;10: 205–9.
    Crossref | PubMed
  37. Purza R, Ghosh SB, Walker C, et al. Transesophageal echocardiography complications in adult cardiac surgery: a retrospective cohort study. Ann Thorac Surg 2017;103:795–802.
    Crossref | PubMed
  38. Di Biase L, Burkhardt JD, Mohanty P, et al. Left atrial appendage: an underrecognized trigger site of atrial fibrillation. Circulation 2010;122:109–18.
    Crossref | PubMed
  39. Emmert MY, Puippe G, Baumüller S, et al. Safe, effective and durable epicardial left atrial appendage clip occlusion in patients with atrial fibrillation undergoing cardiac surgery: first long-term results from a prospective device trial. Eur J Cardiothorac Surg 2014;45:126–31.
    Crossref | PubMed
  40. Majunke N, Sandri M, Adams V, et al. Atrial and brain natriuretic peptide secretion after percutaneous closure of the left atrial appendage with the watchman device. J Invasive Cardiol 2015;27:448–52.
    PubMed