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A simple way to treat chronic atrial fibrillation during mitral valve surgery: the epicardial radiofrequency approach

OBJECTIVE We describe an original radiofrequency ablation technique to treat chronic atrial fibrillation in patients undergoing mitral valve surgery. Most of the procedure is carried out epicardially, in order to avoid an undue increase of surgical time and trauma. METHODS The ablations are performed using a temperature-controlled multipolar radiofrequency catheter. Two encircling lesions around the ostia of the right and of the left pulmonary veins are carried out epicardially, usually before cardiopulmonary bypass. Through a conventional left atriotomy the ablation procedure is completed with two endocardial lesions connecting the two encirclings between them and to the mitral valve annulus. After the mitral valve procedure is performed, the left appendage is sutured. RESULTS From February 1998 to May 1999, 40 patients with chronic atrial fibrillation (43. 1+/-51.9 months) underwent combined radiofrequency ablation and mitral valve surgery. Mean left atrial diameter was 56.8+/-10.7 mm. Mean cardiopulmonary bypass and aortic cross-clamp time were, respectively, 119.1+/-26.3 and 76.7+/-21.0 min. Mean postoperative blood loss was 287.2+/-186.6 ml. No reexploration for bleeding occurred. One patient died of pneumonia 12 days after operation. No patient needed permanent pacemaker implantation. Mean postoperative hospital stay was 7.3+/-5.6 days. At follow-up (mean 11.6+/-4.7 months), 30/39 (76.9%) of the patients were in stable sinus rhythm. All patients in sinus rhythm 3 months after operation recovered both left and right atrial contractility at echocardiographic control (mean 7.3+/-3.4 months). The left atrial diameter decreased significantly in patients recovering sinus rhythm. CONCLUSIONS Epicardial radiofrequency ablation is a safe means to achieve surgical ablation of atrial fibrillation with a high success rate. The simplicity of the technique and the low procedure-related risk should dictate combined treatment virtually in all patients with atrial fibrillation undergoing open heart operations.

Surgical ablation of atrial fibrillation using the epicardial radiofrequency approach: mid-term results and risk analysis

BACKGROUND The minor technical and time requirements with respect to the maze operation combined with a comparable efficacy has led to an increasing popularity of left atrial approaches to treat atrial fibrillation. We report our experience with a left atrial procedure based on extensive use of epicardial radiofrequency ablation in an effort to minimize cardiac arrest time. METHODS A total of 132 consecutive patients with atrial fibrillation (121 chronic, 11 paroxysmal) undergoing open heart surgery had combined intraoperative ablation. An original set of left atrial lesions was performed using a radiofrequency linear catheter. Most of the ablations were performed epicardially before aortic cross-damping. Patients with contraindications to the epicardial approach had the whole lesion set performed endocardially. RESULTS The mean cardiac arrest time spent for open heart ablations was significantly shorter (5.2 +/- 0.9 minutes with modem catheters) when the epicardial approach was used (107 of 132 patients, 81%). Hospital mortality was 0.8%. Freedom from atrial fibrillation was 77% 3 years after the operation. Of all the variables analyzed, only age at surgery and early postoperative arrhythmias increased the risk of recurrent atrial fibrillation. Overall 3-year survival was 94%. The 3-year actuarial freedom from stroke was 98%. No patient required implantation of a permanent pacemaker. Atrial contractility was recovered in all patients with stable sinus rhythm. CONCLUSIONS Left atrial radiofrequency ablation allows recovery of sinus rhythm and atrial function in the great majority of patients with atrial fibrillation who undergo open heart surgery. The epicardial radiofrequency approach is a safe and effective means to cure atrial fibrillation with negligible technical and time requirements.

Thromboangiitis obliterans of coronary and internal thoracic arteries in a young woman

Coronary artery disease may rarely be due to vasculitis. Angina pectoris and acute myocardial infarction have been reported in patients with Takayasus disease, polyarteritis nodosa, and thromboangiitis obliterans. TM In this article we report a case of Buergers disease localized to coronary and internal thoracic arteries (ITAs) in a young nonsmoking woman. The diagnosis was made by histologic examination of the ITAs that were discarded at the time of bypass surgery. A 39-year-old woman had a 2-year history of epigasmc pain of unknown origin and sporadic episodes of typical angina for the past 8 months. Because of worsening of symptoms she underwent a treadmill exercise test. which showed signs of myocardial ischemia. The patient appeared to be otherwise in good health, without evidence of risk factors including diabetes mellitus, hypercholesterolemia, hypertension, obesity, or family history of isch-

Comparison of minimally invasive closed circuit versus standard extracorporeal circulation for aortic valve replacement: a randomized study

To evaluate the clinical results of aortic valve replacement performed with a miniaturized closed circuit extracorporeal circulation (MECC) system and to compare it to standard cardiopulmonary bypass (CPB). One hundred and twenty consecutive patients undergoing isolated aortic valve replacement were randomly assigned to either a miniaturized closed circuit CPB with the maquet-cardiopulmonary MECC System (study group, n=60) or to a standard CPB (control group, n=60). Demographic characteristic and operative data were similar in the two groups. No hospital death occurred in either group and no difference in intensive care unit (ICU) stay and in-hospital stay was observed. Patients in the study group showed lower chest tube drainage (212+/-62 ml vs. 420+/-219 ml, P<0.05) and lower need for blood products (6.1% vs. 40.4%, P<0.05) than patients in the control group. Platelet count at ICU arrival was significantly higher in the study group (139+/-40 x 10(9)/l vs. 164+/-75 x 10(9)/l, P=0.05). Peak postoperative troponin I release was significantly lower in the MECC group (3.81+/-2.7 ng/dl vs. 6.6+/-6.8 ng/dl, P<0.05). In this randomized study the MECC system has demonstrated best postoperative clinical results in terms of need for transfusion, platelets consumption and myocardial damage as compared to standard CPB.

A tailored anatomical approach to prevent complications during left atrial ablation.

Atrial fibrillation ablation surgery has grown very popular in recent years. Modern techniques involve creation of linear scars on the left atrial wall using different ablation devices. That raises the concern about new major surgical complications that can be caused by the ablation procedure. Postablation coronary obstruction and esophageal injury have been described. We report our present strategy for left atrial ablation in which the lesion set is tailored to the specific coronary anatomy. Safeguards to prevent esophageal and bronchial injury are also outlined.

Complete left atrial ablation with bipolar radiofrequency

OBJECTIVE Despite its efficacy and swiftness, bipolar radiofrequency is generally not used on the left isthmus for concern of injuring a coronary branch. Incomplete lesion sets or use of an additional unipolar device are often considered. We report a technique to perform a full left lesion set involving the mitral line using a standard bipolar radiofrequency device. METHODS An innovative complete left atrial lesion set was performed using only bipolar radiofrequency in 70 consecutive patients (study group). In 67/70 patients (96%) mitral valve disease was the main indication to surgery. Atrial fibrillation was permanent in 42 patients (60%), persistent in 25 (36%) and paroxysmal in three patients (4%). After beating-heart pulmonary vein isolation on-pump, the coronary-free area of the AV groove was marked epicardially by sticking a needle into the left atrial wall, behind the coronary sinus. The projection of the needle marker on the mitral annulus was then identified through the atriotomy and an endo-epicardial ablation was performed with the bipolar device involving the atrial wall, the coronary sinus, up to the annulus. The lesion set was then completed by connecting the encirclings and the left appendage, which was then sutured. Follow-up was 100% complete. Results were compared with those of a control group of 33 patients receiving bipolar radiofrequency left atrial ablations and a mitral connecting line with a second unipolar device. RESULTS All patients survived. No major complication occurred. Haematoma of the AV groove was observed during retrograde cardioplegia in one case. No myocardial ischaemia or re-exploration for bleeding (median 325 cc, interquartile range 250-442) occurred. Two out of 70 patients required a permanent pacemaker for AV block. Freedom from atrial fibrillation was 84% (95% CI: 75%, 93%) at 6 months and 81% (95% CI: 70%, 93%) at 1 year. One patient had left flutter. Comparison with the control group did not show any difference in clinical outcomes, but revealed bipolar ablation to the mitral annulus to abate the per patient cost of the ablation devices (1245+/-50 euro vs 2403+/-17 euro; p<0.0001). CONCLUSIONS Performing the mitral line with bipolar radiofrequency is safe and cost-effective. A complete left atrial ablation with a single bipolar radiofrequency device yields excellent clinical mid-term results.

Heme oxygenase-1 expression in the left atrial myocardium of patients with chronic atrial fibrillation related to mitral valve disease: its regional relationship with structural remodeling.

Atrial fibrillation becomes a self-perpetuating arrhythmia as a consequence of electrophysiologic and structural remodeling involving the atrium. Oxidative stress may be a link between this rhythm disturbance and electrophysiologic remodeling. The aim of this study was to evaluate whether the heme oxygenase-1 (HO-1) marker of oxidative stress was more expressed in left atrial sites with stronger structural remodeling in patients affected by chronic atrial fibrillation (CAF) and mitral valve disease (MD). Myocardial samples were taken from the left atrial posterior wall (LAPW) and left atrial appendage (LAA) of 24 patients with CAF-MD in addition to 10 autopsy controls. The levels of HO-1 messenger RNA (mRNA) and HO-1 protein in each pathologic LAPW and LAA were quantified using reverse transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay. Furthermore, light microscopy was used to morphometrically evaluate the differential myocyte and interstitial changes in the same CAF-MD LAPW and LAA samples. In controls, HO-1 protein was quantified using enzyme-linked immunosorbent assay. Unlike controls, patients with CAF-MD had higher levels of HO-1 mRNA and its protein product, expressed as LAPW/LAA ratios, in the LAPW (2.18 +/- 1.18, P < .0001, and 1.55 +/- 0.67, P < .005), and their LAPW also showed greater histologic changes in myocytolytic myocytes (15.1% +/- 3.1% versus 6.9% +/- 3.3%, P < .0001), interstitial fibrosis (8.2% +/- 2.2% versus 2.8% +/- 1.2%, P < .0001), and capillary density (816 +/- 120 number/mm(2) versus 1114 +/- 188 number/mm(2); P < .05). In addition, markers of oxidative stress were immunohistochemically studied with antinitrotyrosine and anti-iNOS antibodies. In patients with CAF-MD, the inducible enzyme HO-1 is more expressed in the left atrial areas that show greater structural remodeling. This finding strongly suggests a pathogenetic relationship between oxidative stress and the degree of histologic change.

Complete Right Atrial Ablation With Bipolar Radiofrequency

PURPOSE Although it is deemed important, right atrial ablation is not considered feasible with bipolar radiofrequency alone. Normally, unipolar devices are used to complete the tricuspid connecting lines. We describe a simple technique to achieve a complete maze-like set of right ablations using a standard bipolar radiofrequency device. DESCRIPTION Thirty-four patients underwent concomitant ablation with a right set of lines performed using bipolar radiofrequency only. The epicardium adjacent to the right atriotomy was entered and after separating the sulcus fat from the atrial wall, the deepest portion of the atrioventricular groove was developed bluntly with the scissors down to the tricuspid annulus. The tricuspid connecting lines were then performed with bipolar radiofrequency in an endo-epicardial fashion. EVALUATION No ablation-related complications occurred. No patient died. Three patients required pacemaker implantation. At a mean follow-up of 8 +/- 5, 85% of the patients were free from arrhythmias. At 6 months 20 of 24 patients (83%) were in stable sinus rhythm. CONCLUSIONS All the maze III right atrial ablations can be performed using a bipolar radiofrequency device alone. The procedure is safe and easily reproducible on a regular basis.

Electrophysiological findings and long-term outcomes of percutaneous ablation of atrial arrhythmias after surgical ablation for atrial fibrillation

OBJECTIVES Percutaneous ablation (PA) for relapsing atrial tachyarrhythmias after surgical ablation is an emerging therapy. The aim of this study is to report the electrophysiological findings and the procedural long-term outcomes of reablation, in this particular clinical setting. METHODS We retrospectively analysed all patients who were readmitted to our centre for relapsing atrial arrhythmias after surgical ablation for atrial fibrillation (AF). RESULTS From 2000 to 2011, 36 patients with previous surgical ablation of AF received additional percutaneous management. Seven patients had had biatrial Maze, 18 left atrial ablation lesion set and 11 pulmonary vein isolation. Energy sources involved were unipolar radiofrequency (RF) (n = 13), bipolar RF (n = 19), combined bipolar RF and cryoenergy (n = 2), cryoenergy (n = 1) and high intensity focused ultrasound (n = 1). The median time to reablation was 34 months (interquartile range: 10-66). The relapsing arrhythmias were left atrial tachycardia (n = 17), AF (n = 15), right atrial flutter (n = 2), right atrial tachycardia (n = 1) and biatrial atrial tachycardia (n = 1). Origin of re-entrant circuits was perimitral (n = 27), around pulmonary veins (PV) including posterior left atrium (n = 15) and cavotricuspid isthmus (n = 3). Twenty-seven (75%) patients had left isthmus catheter ablation and 11 (30%) reablation of PV. Eighteen out of the 27 perimitral circuits were in patients with previous left-atrial Maze; in 17 patients the mitral line was performed with bipolar RF only, without the addition of cryoenergy. The importance of an appropriate energy source is also underlined by the prevalence of gaps in PV isolation that occurred for two-thirds of patients treated using unipolar RF only, which has been discontinued since 2001. Ten patients (27%) needed more than 1 PA for relapsing arrhythmia. At the last follow-up of 97 ± 42 months, freedom from arrhythmias was 53% after single PAs and 67% after more than one procedure. No morbidity, mortality or strokes were recorded during the follow-up. CONCLUSIONS Percutaneous treatment of highly symptomatic patients with unsuccessful previous surgical ablation is feasible, and relatively effective at the late follow-up. A multidisciplinary approach significantly improves the outcomes in these challenging patients.

Cardiopulmonary bypass strategy during concomitant surgical treatment of mitral valve disease and atrial fibrillation

In recent years, the popularity of simplified intraoperative ablation approaches to treat atrial fibrillation (AF) has been progressively increasing. Our group has described a left atrial procedure based on epicardial radio frequency ablation on cardiopulmonary bypass (CPB). We report our CPB and myocardial protection strategy in 157 patients who underwent AF ablation combined with open-heart surgery from February 1998 to February 2002. Since epicardial ablations are performed on CPB on the beating heart, the CPB strategy is crucial. Total normothermic CPB allows a safe dissection around the pulmonary veins on the decompressed heart; after the ablating catheter has been positioned, an adequate filling of the left atrium favours a uniform contact with the atrial wall. After crossclamping, low-flow retrograde cardioplegia delivery is administered while ablating endocardially to protect the main coronary arteries in the atrio-ventricular groove from radio frequency-related trauma. All patients were successfully weaned from CPB. Sinus rhythm was restored in 152 of 157 (96.8%) patients immediately after surgery. No procedure-related complications were recorded. Epicar-dial ablations allowed us to reduce significantly the aortic crossclamping time required for ablations. The conduct of CPB and myocardial protection play a central role in the surgical strategy by improving intraoperative feasibility and effectiveness of radio frequency ablation and preventing some of the potential postoperative complications related to the procedure.