Curative treatment of atrial fibrillation with intraoperative radiofrequency ablation: short-term and midterm results

Characterization of the Optical and Thermal Properties of Cardiac Tissue as a Function of Temperature

In this work, we devised the first characterization of the optical and thermal properties of ex vivo cardiac tissue as a function of different selected temperatures, ranging from room temperature to hyperthermic and ablative temperatures. The broadband (i.e., from 650 nm to 1100 nm) estimation of the optical properties, i.e., absorption coefficient (μa) and reduced scattering coefficient $({\mu ^{\prime}}_s)$, was performed by means of time-domain diffuse optics. Besides, the measurement of the thermal properties was based on the transient hot-wire technique, employing a dual-needle probe to estimate the tissue thermal conductivity (k), thermal diffusivity (α), and volumetric heat capacity (Cv). Increasing the tissue temperature led to variations in the spectral characteristics of μa (e.g., the redshift of the 780 nm peak, the rise of a new peak at 840 nm, and the formation of a valley at 900 nm). Moreover, an increase in the values of ${\mu ^{\prime}}_s$ was assessed as tissue temperature raised (e.g., for 800 nm, at 25 °C ${\mu ^{\prime}}_s = 9.8{\text{ c}}{{\text{m}}^{{\text{ - 1}}}}$, while at 77 °C ${\mu ^{\prime}}_s = 29.1{\text{ c}}{{\text{m}}^{{\text{ - 1}}}}$). Concerning the thermal properties characterization, k was almost constant in the selected temperature interval. Conversely, α and Cv were subjected to an increase and a decrease with temperature, respectively; thus, they registered values of 0.190 mm2/s and 3.03 MJ/(m3•K) at the maximum investigated temperature (79 °C), accordingly.Clinical Relevance- The experimentally obtained optical and thermal properties of cardiac tissue are useful to improve the accuracy of simulation-based tools for thermal therapy planning. Furthermore, the measured properties can serve as a reference for the realization of tissue-mimicking phantoms for medical training and testing of medical instruments.

Minimally-invasive cardiac surgery: a bibliometric analysis of impact and force to identify key and facilitating advanced training

Background

The number of citations an article receives is a marker of its scientific influence within a particular specialty. This bibliometric analysis intended to recognise the top 100 cited articles in minimally-invasive cardiac surgery, to determine the fundamental subject areas that have borne considerable influence upon clinical practice and academic knowledge whilst also considering bibliometric scope. This is increasingly relevant in a continually advancing specialty and one where minimally-invasive cardiac procedures have the potential for huge benefits to patient outcomes.

Methods

The Web of Science (Clarivate Analytics) data citation index database was searched with the following terms: [Minimal* AND Invasive* AND Card* AND Surg*]. Results were limited to full text English language manuscripts and ranked by citation number. Further analysis of the top 100 cited articles was carried out according to subject, author, publication year, journal, institution and country of origin.

Results

A total of 4716 eligible manuscripts were retrieved. Of the top 100 papers, the median (range) citation number was 101 (51–414). The most cited paper by Lichtenstein et al. (Circulation 114(6):591–596, 2006) published in Circulation with 414 citations focused on transapical transcatheter aortic valve implantation as a viable alternative to aortic valve replacement with cardiopulmonary bypass in selected patients with aortic stenosis. The Annals of Thoracic Surgery published the most papers and received the most citations (n = 35; 3036 citations). The United States of America had the most publications and citations (n = 52; 5303 citations), followed by Germany (n = 27; 2598 citations). Harvard Medical School, Boston, Massachusetts, published the most papers of all institutions. Minimally-invasive cardiac surgery pertaining to valve surgery (n = 42) and coronary artery bypass surgery (n = 30) were the two most frequent topics by a large margin.

Conclusions

This work establishes a comprehensive and informative analysis of the most influential publications in minimally-invasive cardiac surgery and outlines what constitutes a citable article. Undertaking a quantitative evaluation of the top 100 papers aids in recognising the contributions of key authors and institutions as well as guiding future efforts in this field to continually improve the quality of care offered to complex cardiac patients.

Real-Time Internal Steam Pop Detection during Radiofrequency Ablation with a Radiofrequency Ablation Needle Integrated with a Temperature and Pressure Sensor: Preclinical and Clinical Pilot Tests

A radiofrequency ablation (RFA) needle integrated with a temperature sensor (T-sensor) and pressure sensor (P-sensor) is designed and utilized for real-time internal steam pop monitoring during RFA. The characteristics of the sensor-integrated RFA needle (sRFA-needle) are investigated quantitatively using a pressure chamber system, and the feasibility and usability of the needle in preclinical and clinical trials is demonstrated. The sharp changes in the temperature and normalized pressure sensor signals induced by the abrupt release of hot and high-pressure steam can be clearly monitored during the steam pop phenomena. The basic mechanism of the preliminary steam pop is hypothesized and verified using in situ ultrasound imaging data and computational analysis data of the RFA procedure. Moreover, the usability of the system in clinical trials is investigated, and the steam pop phenomena during the RFA procedure are detected using T-sensor and P-sensor. The results confirm that the sensor integration on the medical needle can provide critical data for safer and more effective medical practices.

Left Atrial Appendage Exclusion in Atrial Fibrillation Radiofrequency Ablation during Mitral Valve Surgery: A Single-Center Experience

Background

Atrial fibrillation surgical radiofrequency ablation (AFSA) during mitral valve surgery (MVS) has almost completely superseded the Cox-Maze procedure for the treatment of atrial fibrillation.

Methods

We retrospectively analyzed 100 patients who underwent MVS + AFSA in our institution from January 2008 to June 2017. We compared the effectiveness of AFSA in patients who underwent LAA exclusion to those who did not. Moreover, we analyzed the role of preoperative AF duration (≤ or >1 year) and medial-lateral left atrial dimensions (ML-LAD) (≤ or >6 cm). The efficacy endpoint was freedom from AF at discharge and at 2-year follow-up. The safety endpoints were need of a permanent pacemaker (PMK), surgical re-exploration, occurrence of stroke, and left circumflex artery or esophageal lesions.

Results

Overall, the rate of AF freedom was 69% at discharge and 80% at 2-year follow-up. LAA exclusion did not influence AF freedom at 2-year follow-up, and 84.6% of patients who underwent LAA exclusion were in the sinus rythm (SR) at 2 year compared to 75% of those who did not receive LAA exclusion free from AF as well (p=0.230). AF duration ≤1 or >1 year did not influence sinus rhythm (SR) maintenance (85.7% vs. 75.8%; p=0.224), and in these two groups, LAA exclusion did not change the efficacy of AFSA. ML-LAD ≤ 6 cm was associated with better results in terms of SR maintenance. A statistically significant association between LAA exclusion and SR maintenance at 2-year follow-up (p=0.017) was found among patients with ML-LAD ≤ 6 cm. Complications included 7 cases of PMK implantation, 2 cases of surgical re-exploration, and 1 case of stroke. No circumflex artery or esophageal lesions occurred after surgical procedures.

Conclusions

In our experience, AFSA during isolated MVS resulted in good outcomes in terms of SR maintenance and incidence of complications. AF duration ≤ 1 year did not influence results, while patients with ML-LAD ≤ 6 cm had significantly better results regarding SR at follow-up. In patients with ML-LAD ≤ 6 cm, LAA exclusion significantly increased the success rate of SR maintenance at 2-year follow-up.

Detection of oesophageal course during left atrial catheter ablation

BACKGROUND

Oesophageal changes and injuries were recorded after atrial fibrillation(AF) ablation procedures. The reduction of power in the posterior left atrial(LA) wall(closest to the oesophagus) and the monitoring of temperature in the oesophagus(OE) reduced oesophageal injuries. The intracardiac-echocardiography(ICE) with a Cartosound module provides two-dimensional imaging (2D) to assess detailed cardiac anatomy and its relationship with the OE. The aim of this study was to highlight the safety and feasibility of 3D-reconstruction of the oesophageal course in left atrial catheter ablation(CA) procedures without OE temperature probe or quadripolar catheter to guide ICE OE reconstruction.

METHODS

180 patients(PT) underwent left atrial ablation. AF ablation were 125(69.5%); incisional left atrial tachycardias(IAFL) were 37(20.6%); left atrial tachycardias(LAT) were 19(10.6%). The LA and pulmonary vein anatomies were rendered by traditional electroanatomic mapping(EAM) and merged with an ICE anatomic map. In 109 PT ICE imaging was used to create a geometry of the OE(group A). A quadripolar catheter was used in 71 PT to show OE course associated to ICE(group B).

RESULTS

Ablation energy delivery was performed outside the broadest OE anatomy borders. The duration of procedures was longer in group B vs group A Fluoroscopy time was lower in Group A than Group B(Group A 7 ± 3.2 vs 19.2 ± 2.4 min; p < 0.01).

CONCLUSIONS

OE monitoring with ICE is safe and feasible. Oesophageal anatomy is complex and variable. Many PT will have a broad oesophageal boundary, which increases the risk of untoward thermal injury during posterior LA ablation. ICE with 3D construction of the OE enhances border detection of the OE, and as such, should decrease the risk of oesophageal injury by improving avoidance strategies without intra-oesophageal catheter visualization.

Management of Atrio-Esophageal Fistula Following Left Atrial Ablation

Currently, no guidelines have been established for the treatment of atrio-esophageal fistula (AEF) secondary to left atrial ablation therapy. After comprehensive literature review, we aim to make suggestions on the management of this complex complication and also present a case series. We performed a review of the existing literature on AEF in the setting of atrial ablation. Using keywords atrial fibrillation, atrial ablation, fistula formation, atrio-esophageal fistula, complications, interventions, and prognosis, a search was made using the medical databases PUBMED and MEDLINE for reports in English from 2000 to April 2015. A statistical analysis was performed to compare the three different intervention arms: medical management, stent placement and surgical intervention. The results of our systematic review confirm the high mortality rate associated with AEF following left atrial ablation and the necessity to diagnose atrio-esophageal injury in a timely manner. The mortality rates of this complication are 96% with medical management alone, 100% with stent placement, and 33 % with surgical intervention. Atrio-esophageal injury and subsequent AEF is an infrequent but potentially fatal complication of atrial ablation. Early, prompt, and definitive surgical intervention is the treatment of choice.

Atrioesophageal fistula following ablation procedures for atrial fibrillation: systematic review of case reports

BACKGROUND

Atrioesophageal fistula (AEF) is a rare but serious adverse event of atrial fibrillation (AF) ablation.

OBJECTIVE

To identify the clinical characteristics of AEF following ablation procedures for AF and determine the associated mortality.

METHODS

A systematic review of observational cases of AEF following ablation procedures for AF was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement protocol.

RESULTS

53 cases were identified. Mean age was 54±13 years; 73% (39/53) of cases occurred in males. Mean interval between procedure and presentation was 20±12 days, ranging from 2 to 60 days. AEF was observed in 12 patients who underwent surgical radiofrequency ablation (RFA) and in 41 patients with percutaneous RFA. Fever was the most common presenting symptom (n=44) followed by neurological deficits (n=27) and haematemesis (n=19). CT of the chest (n=27) was the preferred diagnostic test. Patients who did not receive a primary esophageal repair were more likely to have a deadly outcome (34% vs 83%; p<0.05). No difference in mortality rate was found between patients who underwent surgical RFA when compared with percutaneous RFA (58% vs 56%; p=0.579). No association was found between onset of symptoms and mortality (19±10 vs 23±14 days; p=0.355).

CONCLUSIONS

AEF following ablation procedures for AF is a serious complication with high mortality rates. Presenting symptoms most often include a triad of fever, neurological deficit and/or haematemesis within 60 days of procedure. The preferred diagnostic test is CT of the chest. The treatments of choice is surgical repair.

Atrio-oesophageal fistula after transcatheter radiofrequency ablation

A 68-year-old woman presented 3 weeks following unsuccessful transcatheter radiofrequency ablation (TcRFA) for treatment of her chronic atrial fibrillation. Neurological signs manifested on day 2 of admission with generalised tonic-clonic seizures and reduced Glasgow Coma Score. She was treated for presumed central nervous system (CNS) infection, intubated and transferred to the intensive care unit. CT of the head showed bilateral oedema secondary to acute embolic stroke. Blood cultures grew Streptococcus viridans, and lumbar puncture findings were consistent with CNS infection. Echocardiography showed only a septostomy puncture from the atrial fibrillation ablation procedure. Thoracic CT demonstrated air in the left atrium, consistent with the diagnosis of atrio-oesophageal fistula, a rarely reported iatrogenic complication of TcRFA. MRI of the head showed significant neurological injury with innumerable embolic infarcts. After discussion with her family regarding the significant neurological insult, and with no signs of any clinical improvement, the patient died on day 8 of admission.

Left-sided mini-maze procedure via the left atrial appendage

This study presents a novel way to perform the mini-maze procedure through the left atrial appendage. By this way, the usual additional incision of the intra-atrial groove is avoided, especially in patients receiving coronary artery bypass grafting (CABG) or aortic valve replacement without mitral valve disease. We retrospectively analysed 23 consecutive patients who received this novel mini-maze procedure between 2009 and 2011. In recognition of a learning curve, we divided the patients into two groups (Group 1: Patients 1-11 versus Group 2: Patients 12-23), according to the date of operation. In Group 2, 7 patients (58.33%) were completely free of atrial fibrillation at the time of the follow-up. In Group 1, only 2 (18.18%) patients were successfully treated resulting in a stable sinus rhythm at the time of the follow-up. The mini-maze procedure performed through the left atrial appendage is a safe and feasible technique; however, it seems to be less effective than the Cox-maze III procedure and is associated with a learning curve.

Cardioscopic Trans-septal Cryoablation of Left Atrium in Nonmitral Cases

BACKGROUND

: A modified maze procedure in which trans-septal cardioscopy was used for cryoablation in the left atrium is described.

METHODS

: The technique was used in 11 consecutive patients (9 men and 2 women, 56.5 ± 19.8 years) with permanent atrial fibrillation (Af) and concomitant nonmitral cardiac or aortic disease: aortic valvular disease in 4 patients, atrial septal defect (ASD) in 2 patients, tricuspid regurgitation in 2 patients, acute aortic dissection in 1 patient, arch aneurysm in 1 patient, and coronary artery disease in 1 patient. The mean Af duration detected in 7 cases was 18.5 ± 10.1 months. Partial sternotomy was used in aortic valve replacement, ASD closure, and tricuspid valve plasty, and fullsternotomy was used in aortic graft replacement and coronary artery bypass. Cardiopulmonary bypass was established, aortic cross-clamp was performed, a right atriotomy was created, a cryoablation probe and cardioscope (3 mm) were introduced into the left atrium through a 1-cm cut at the fossa ovalis or ASD, and cardioscopic left-atrial endocardial cryoablation was performed. The right-side maze procedure was conducted directly. The atrial appendages were excised in each case.

RESULTS

: Left-atrial cardioscopic cryoablation required 25.0 ± 5.5 minutes, and no deaths or procedure-related morbidities occurred. The mean follow-up period was 12 ± 8.5 months. One patient with tricuspid regurgitation died of liver failure. With the exception of coronary and acute dissection cases, all patients have maintained a sinus rhythm.

CONCLUSION

: Although experience is limited, videocardioscopic trans-septal left-atrial cryoablation is a viable method for nonmitral Af cases, and the partial sternotomy approach can be performed.

Hybrid Therapy for Atrial Fibrillation: where the Knife meets the Catheter

During the past decades there has been a consistent evolution of both surgical and catheter-based techniques for the treatment of stand-alone atrial fibrillation, as alternatives or in combination with anti-arrhythmic drugs. Transcatheter ablation has significantly improved outcomes, despite often requiring multiple procedures and with limited success rates especially in presence of persistent atrial fibrillation. Surgical procedures have dramatically evolved from the original cut-and-sew Maze operation, allowing nowadays for closed-chest epicardial ablations on the beating heart. Recently, the concept of a close collaboration between the cardiac surgeon and the electrophysiologist has emerged as an intriguing option in order to overcome the drawbacks and suboptimal results of both techniques; therefore, the hybrid approach has been proposed as a potentially more successful strategy, allowing for a patient-tailored therapeutical approach. We reviewed the recent advancements either from the transcatheter and surgical standpoint, with a peculiar focus on the current option to merge both techniques along with an up-to-date review of the preliminary clinical experiences with the hybrid, surgical-transcatheter treatment of stand-alone atrial fibrillation.

Right atrial lesions do not improve the efficacy of a complete left atrial lesion set in the surgical treatment of atrial fibrillation, but they do increase procedural morbidity

OBJECTIVE

Some have suggested the superiority of biatrial versus left atrial lesions. We sought to analyze our experience.

METHODS

We retrospectively reviewed 305 consecutive patients from 2007 to 2011. Rhythm success was defined as freedom from atrial fibrillation (AF) or flutter determined by 12-lead electrocardiograms at 3-month intervals. Lesions sets were pulmonary vein isolation (PVI), left-extended (PVI + mitral valve annulus [MV] lesion ± left atrial appendage lesion [LAA]) or biatrial-extended (right atrial ablation + PVI + MV ± LAA).

RESULTS

The success rates of PVI, left-extended, and biatrial-extended lesions were as follows: at 3 months, 56.7%, 74.7%, and 79.4% (P = .003); at 6 months, 56.9%, 72.9%, and 74.6% (P = .02); at 9 months, 54.6%, 72.5%, and 83.3% (P < .001); and at 12 months, 52.6%, 76.1%, and 80.0% (P < .001). Biatrial lesions had a higher rate of pacemaker placement than did left atrial lesions (16.5% vs 7.5%; P = .02). When we grouped patients by left lesion (PVI, PVI + MV, PVI + MV + LAA) irrespective of right atrial ablation, success was as follows: 3 months, 57.9%, 71.1%, and 87.8% (P < .01); 6 months, 58.1%, 71.6%, and 77.6% (P = .03); 9 months, 55.9%, 71.3%, and 89.6% (P < .01); and 12 months, 54.1%, 74.7%, and 83.7% (P < .01).

CONCLUSIONS

PVI is associated with lower rhythm success than an extended left atrial lesion set. The addition of a right atrial lesion to an extended left atrial lesion set does not improve efficacy, but it does increase the rate of pacemaker placement for sinus dysfunction. Adding an LAA lesion may confer additional efficacy when added to a lesion set that includes PVI + MV.

A minimally invasive cox-maze procedure: operative technique and results

OBJECTIVE

The Cox-Maze procedure (CMP) for the surgical treatment of atrial fibrillation (AF) traditionally has required a median sternotomy and cardiopulmonary bypass. This study describes a method using ablation technologies to create the full Cox-Maze lesion set through a 5- to 6-cm right minithoracotomy.

METHODS

Twenty-two consecutive patients underwent a CMP through a right mini-thoracotomy and cardiopulmonary bypass. All patients were followed prospectively with electrocardiogram and 24-hour Holter monitoring at 3, 6, and 12 months. The CMP lesion set was created using bipolar radiofrequency energy and cryotherapy.

RESULTS

There was no operative mortality or major complications.Two patients required a permanent pacemaker. Five patients (23%) had early atrial tachyarrhythmias. At last follow-up(mean, 18 ± 12 months), all the patients (n=22) were free from atrial dysrhythmias. At 3 months (n=19), 84% of patients were off antiarrhythmic drugs. At 6 months (n=18), 94% of patients were free from AF and off antiarrhythmic medications. At 12 months (n=16), 81% of patients were free from AF and off antiarrhythmic drugs and three patients remained on warfarin for a mechanical mitral valve.

CONCLUSIONS

A full CMP can be performed through a right mini-thoracotomy with outstanding short-term results. This less invasive procedure can be offered to patients without compromising efficacy.

2012 HRS/EHRA/ECAS expert consensus statement on catheter and surgical ablation of atrial fibrillation: recommendations for patient selection, procedural techniques, patient management and follow-up, definitions, endpoints, and research trial design

This is a report of the Heart Rhythm Society (HRS) Task Force on Catheter and Surgical Ablation of Atrial Fibrillation, developed in partnership with the European Heart Rhythm Association (EHRA), a registered branch of the European Society of Cardiology and the European Cardiac Arrhythmia Society (ECAS), and in collaboration with the American College of Cardiology (ACC), American Heart Association (AHA), the Asia Pacific Heart Rhythm Society (APHRS), and the Society of Thoracic Surgeons (STS). This is endorsed by the governing bodies of the ACC Foundation, the AHA, the ECAS, the EHRA, the STS, the APHRS, and the HRS.

Surgical therapy of atrial fibrillation

Atrial fibrillation (AF) can be found in an increasing number of cardiac surgical patients due to a higher patient's age and comorbidities. Atrial fibrillation is known, however, to be a risk factor for a greater mortality, and one aim of intraoperative AF treatment is to approximate early and long-term survival of AF patients to survival of patients with preoperative sinus rhythm. Today, surgeons are more and more able to perform less complex, that is, minimally invasive cardiac surgical procedures. The evolution of alternative ablation technologies using different energy sources has revolutionized the surgical therapy of atrial fibrillation and allows adding the ablation therapy without adding significant risk. Thus, the surgical treatment of atrial fibrillation in combination with the cardiac surgery procedure allows to improve the postoperative long-term survival and to reduce permanent anticoagulation in these patients. This paper focuses on the variety of incisions, lesion sets, and surgical techniques, as well as energy modalities and results of AF ablation and also summarizes future trends and current devices in use.

Incidence and predictors of pacemaker placement after surgical ablation for atrial fibrillation

BACKGROUND

Bradyarrhythmia requiring pacemaker placement is a relatively common complication after surgical ablation for atrial fibrillation (AF). We report our experience with surgical ablation procedures using various energy modalities and lesion sets in an attempt to identify the risk factors associated with postoperative pacemaker requirement.

METHODS

Intraoperative data were collected prospectively, and preoperative and postoperative data were collected retrospectively. Energy modality and lesion sets used were dependent on availability on the date of the procedure and surgeon preference.

RESULTS

From October 1999 to October 2009, 701 patients underwent surgical ablation for AF at our institution. Forty-five patients (7.6%) required early postoperative pacemaker placement. There were no significant differences in baseline characteristics or associated procedures between patients who required pacemaker placement and those who did not. Ninety-day mortality was greater in patients requiring pacemaker placement (15.6% versus 6.6%; p = 0.025). In multivariable analysis, a pacemaker requirement was more likely with the use of microwave energy (odds ratio [OR] 2.87; confidence interval [CI], 1.41 to 5.84; p = 0.004) and a right atrial lesion set (OR, 2.82; CI, 1.07 to 7.45; p = 0.036).

CONCLUSIONS

In conclusion, over our 10-year experience with surgical AF ablations, the incidence of pacemaker requirement was much lower than that reported in series of classic "cut and sew" Maze procedures, even among patients undergoing full biatrial ablations. Although biatrial ablation is currently our favored approach to patients with long-standing or persistent AF, right atrial lesion sets increase the risk of this complication and should be used judiciously.

Combined Bipolar/Unipolar Radiofrequency Maze is Superior to Unipolar Maze in Concomitant Surgery

Introduction:

Atrial fibrillation is the most common arrhythmia with significant morbidity and mortality. Radiofrequency (RF) ablation, despite its shortcomings, remain an acceptable and ‘simple’ technique.

Methods:

We reviewed 137 consecutive concomitant irrigated RF modified maze procedures, and compared the outcomes of 65 patients undergoing Unipolar-RF versus 72 patients using the combined Uni/Bipolar-RF approach. All patients were prospectively followed clinically, with serial electrocardiography and selective echocardiography. One hundred and twenty-two patients (89.1%) underwent mitral valve procedures, and eight coronary bypass, and seven adult congenital operations were performed.

Results:

The predominantly male (54.7%) patients had a mean age of 58.3±11.5 years (23–88 years). At median follow-up of 3.21 years (0.01–6.06 years), 15 (10.9%) patients were lost to follow-up. Freedom from AF in the Uni/Bipolar-RF group was higher at six months: 85.1% (57/67) versus 65% (39/60) in the Unipolar-RF group (P=0.012). This superior trend persisted at five years: 100% (5/5) in the Uni/Bipolar-RF group versus 79.5% (31/39) in the Unipolar-RF group, although this is not statistically significantly (P=0.566). Patients with left atrial dilatation beyond 7.6cm were more likely to remain in AF (OR 0.44, 95% CI, 0.19–1.00, P=0.049). Perioperative mortality was 2.9%. There was no collateral damage by the device and procedure. The mean survival for patients AF-free at last follow-up is 5.73 years (95% CI, 5.48–5.98), comparable to 5.58 years (95% CI, 5.07–6.10) in those remaining in AF. Thirty (22.6%) patients were completely off anti-arrhythmic medication while 36 (25.6%) were anticoagulant-free.

Conclusion:

The combined Uni/bipolar-RF modified bi-atrial Maze technique is simple, safe and superior to isolated Unipolar-RF ablation. Midterm results continue to support its use although long-term durability remains to be elucidated.

Luminal Esophageal Temperature Monitoring With a Deflectable Esophageal Temperature Probe and Intracardiac Echocardiography May Reduce Esophageal Injury During Atrial Fibrillation Ablation Procedures

Background—

Luminal esophageal temperature (LET) monitoring is one strategy to minimize esophageal injury during atrial fibrillation ablation procedures. However, esophageal ulceration and fistulas have been reported despite adequate LET monitoring. The objective of this study was to assess a novel approach to LET monitoring with a deflectable LET probe on the rate of esophageal injury in patients undergoing atrial fibrillation ablation.

Methods and Results—

Forty-five consecutive patients undergoing an atrial fibrillation ablation procedure followed by esophageal endoscopy were included in this prospective observational pilot study. LET monitoring was performed with a 7F deflectable ablation catheter that was positioned as close as possible to the site of left atrial ablation using the deflectable component of the catheter guided by visualization of its position on intracardiac echocardiography. Ablation in the posterior left atrial was limited to 25 W and terminated when the LET increased 2°C from baseline. Endoscopy was performed 1 to 2 days after the procedure. All patients had at least 1 LET elevation >2°C necessitating cessation of ablation. Deflection of the LET probe was needed to accurately measure LET in 5% of patients when ablating near the left pulmonary veins, whereas deflection of the LET probe was necessary in 88% of patients when ablating near the right pulmonary veins. The average maximum increase in LET was 2.5±1.5°C. No patients had esophageal thermal injury on follow-up endoscopy.

Conclusions—

A strategy of optimal LET probe placement using a deflectable LET probe and intracardiac echocardiography guidance, combined with cessation of radiofrequency ablation with a 2°C rise in LET, may reduce esophageal thermal injury during left atrial ablation procedures.

Chylothorax and chylopericardium following mitral and tricuspid valve repairs and radiofrequency maze procedure

Surgical radiofrequency Maze procedure is a well-developed technology with an established safety profile. Clinical complications, albeit rare, have been described secondary to usage of unipolar radiofrequency devices. Bipolar radiofrequency devices have virtually eliminated the complications associated with unipolar devices, thereby combining safety with efficacy. We report a case of chylopericardial tamponade and chylothorax following radiofrequency Maze procedure using a bipolar device. 

Novel approaches for the surgical treatment of atrial fibrillation: time for a guideline revision?

Atrial fibrillation is a major health problem in Western countries, and is associated with considerable morbidity and resource consumption. Safe and reliable surgical techniques for the termination of this arrhythmia have been developed since the time of the original Cox "maze I" procedure. Novel equipment based on radiofrequency and microwave technologies can be employed to create transmural atrial lesions, even in the context of minimally invasive surgery to the atrioventricular valves via right minithoracotomy. The aim of this paper is to review the recent literature on this approach, and the clinical results in terms of arrhythmia termination and postoperative morbidity. With the aim to substantiate the practice of a simple, yet reliable, surgical ablation during minimally invasive heart valve surgery, we discuss the results of different patterns of atrial lesions having different degrees of surgical complexity. Finally, minimally invasive epicardial ablation for lone atrial fibrillation represents an emerging surgical indication. The results of state-of-the-art transcatheter ablation represent now its benchmark of comparison.