Minimally Invasive Stand-Alone Cox Maze Procedure for Persistent and Long-Standing Persistent Atrial Fibrillation: Perioperative Safety and 5-Year Outcomes.

BACKGROUND: Rhythm control is challenging in patients with extended atrial fibrillation (AF) duration and persistent/long-standing persistent AF. Among surgical approaches to treat AF, the Cox maze procedure performed using alternative energy sources remains superior to other beating heart techniques. We examined permanence of safety and success for the on-pump, minimally invasive, stand-alone Cox maze procedure 5 years after surgery. METHODS AND RESULTS: Stand-alone, right 5 cm minithoracotomy, Cox maze III/IV procedure for nonparoxysmal AF was conducted in 133 patients (mean follow-up=65±34 months). Data collected prospectively at 3, 6, 9, 12, 18, 24 months and yearly thereafter and reported per Heart Rhythm Society Guidelines. Paired-samples t tests evaluated quality of life changes. Mean age was 57.3±9.2 years, mean LA size was 4.9±1.1 cm, median AF duration was 51 months, and 78% had long-standing persistent AF. All procedures performed with no conversion to midsternotomy, no renal failure, strokes, or operative mortality (<30 days), transient ischemic attack in 1 patient, reoperation for bleeding in 2 patients, and median length of stay was 4 days [3-5.5 days]. At 5 years, 73% were in sinus rhythm off antiarrhythmic medications after single intervention, 1 stroke (718 patient-years) with 81% off anticoagulation, catheter ablation reinterventions in 13 patients for atrial arrhythmia, and cardioversions in 15 patients. Quality of life scores improved significantly by 12 months after surgery. CONCLUSIONS: Successful ablation for nonparoxysmal AF is challenging. Therefore, periprocedural safety and long-term efficacy of minimally invasive Cox maze procedures should be noted. Continued refinement of decision-making techniques is warranted to improve patient selection for the appropriate intervention to treat AF.

Right Ventricular Pacing for Assessment of Cavo-Tricuspid Isthmus Block.

Background: Cavo-tricuspid isthmus (CTI) dependent atrial flutter is typically treated with cardiac ablation. Standard techniques to assess CTI block after ablation can be technically challenging. Right ventricular (RV) pacing may allow for another technique to assess CTI block after ablation. Objective: The purpose of this study was to evaluate RV pacing as a method to assess CTI block after ablation of CTI dependent atrial flutter, and define endpoints of ablation using this technique. Methods: 28 patients undergoing ablation of CTI dependent atrial flutter with intact ventriculoatrial (VA) conduction were prospectively enrolled in this study and underwent the RV pacing protocol, as well as standard coronary sinus (CS) pacing techniques to assess CTI block. Results: The mean trans-isthmus conduction interval during CS pacing (TICICS) at 600 and 400ms after CTI ablation was 168 +/- 9ms and 175 +/- 18ms, respectively. The mean trans-isthmus conduction interval during RV pacing (TICIRV) at 600ms and 400ms after CTI ablation was 109 +/- 5ms and 111 +/- 5ms, respectively. A TICIRV >100ms was associated with a successful outcome after CTI ablation. Conclusions: RV pacing may add incremental value in the assessment of CTI block in patients undergoing ablation of CTI dependent atrial flutter.

Infection and mortality after implantation of a subcutaneous ICD after transvenous ICD extraction.

BACKGROUND: The subcutaneous implantable cardioverter-defibrillator (S-ICD) provides an alternative to the transvenous implantable cardioverter-defibrillator (TV-ICD). Patients undergoing TV-ICD explantation may be eligible for reimplantation with an S-ICD; however, information on safety outcomes in this complex population is limited. OBJECTIVE: This analysis was designed to provide outcome and safety data from S-ICD patients who received their device after TV-ICD explantation. METHODS: Patients in the S-ICD IDE Study and EFFORTLESS Registry with a prior TV-ICD explantation, as well as those with no prior implantable cardioverter-defibrillator (ICD), were included. Patients were divided into 3 groups: those implanted with the S-ICD after TV-ICD extraction for system-related infection (n = 75); those implanted after TV-ICD extraction for reasons other than system-related infection (n = 44); and patients with no prior ICD (de novo implantations, n = 747). RESULTS: Mean follow-up duration was 651 days, and all-cause mortality was low (3.2%). Patients previously explanted for TV-ICD infection were older (55.5 ± 14.6, 47.8 ± 14.3 and 49.9 ± 17.3 years in the infection, noninfection, and de novo cohorts, respectively; P = .01), were more likely to have received the ICD for secondary prevention (42.7%, 37.2% and 25.6%; P < 0.0001) and had higher percentages of comorbidities, including atrial fibrillation, congestive heart failure, diabetes mellitus, and hypertension, in line with the highest mortality rate (6.7%). Major infection after S-ICD implantation was low in all groups, with no evidence that patients implanted with the S-ICD after TV-ICD explantation for infection were more likely to experience a subsequent reinfection. CONCLUSION: The S-ICD is a suitable alternative for TV-ICD patients whose devices are explanted for any reason. Postimplantation risk of infection remains low even in patients whose devices were explanted for prior TV-ICD infection.

Effects of acute mental stress and exercise on T-wave alternans in patients with implantable cardioverter defibrillators and controls.

BACKGROUND: Malignant cardiac arrhythmias can be triggered by exercise and by mental stress in vulnerable patients. Exercise-induced T-wave alternans (TWA) is an established marker of cardiac electrical instability. However, the effects of acute mental stress on TWA have not been investigated as a vulnerability marker in humans. METHODS AND RESULTS: TWA responses to mental stress (anger recall and mental arithmetic) and bicycle ergometry were evaluated in patients with implantable cardioverter defibrillators (ICDs) and documented coronary artery disease (n=23, age 62.1+/-12.3 years) and controls (n=17, age 54.2+/-12.1 years). TWA was assessed from digitized ECGs by modified moving average analysis. Dual-isotope single photon emission computed tomography was used to assess myocardial ischemia. TWA increased during mental stress and exercise (P values <0.001), and TWA responses were higher in ICD patients than in controls (arithmetic Delta=8.9+/-1.4 versus 4.3+/-2.2 microV, P=0.043; exercise Delta=21.4+/-2.8 versus 13.8+/-3.2 microV, P=0.038). TWA increases with mental stress occurred at substantially lower heart rates (anger recall Delta=9.7+/-7.7 bpm, arithmetic Delta=14.3+/-13.3 bpm) versus exercise (Delta=53.7+/-22.7 bpm; P values <0.001). After adjustment for heart rate increases, mental stress and exercise provoked increased TWA in ICD patients (P values <0.05), but not in controls (P values >0.2). Ejection fraction and stress-induced myocardial ischemia were not associated with TWA. CONCLUSIONS: Mental stress can induce cardiac electrical instability, as assessed via TWA, among patients with arrhythmic vulnerability and occurs at lower heart rates than with exercise. Pathophysiological mechanisms of mental stress-induced arrhythmias may therefore involve central and autonomic nervous system pathways that differ from exercise-induced arrhythmias.

Radiofrequency catheter ablation of type 1 atrial flutter using large-tip 8- or 10-mm electrode catheters and a high-output radiofrequency energy generator: results of a multicenter safety and efficacy study.

OBJECTIVES: We studied the safety and efficacy of atrial flutter (AFL) ablation using 8- or 10-mm electrode catheters and a 100-W radiofrequency (RF) generator. BACKGROUND: Large-tip electrode catheters may be more effective for ablation of AFL. METHODS: There were 169 patients (age 61 +/- 12 years). Short-term end points were bidirectional isthmus block and no inducible AFL. After ablation, patients were seen at one, three, and six months, with event monitoring performed weekly and for any symptoms. Three quality-of-life (QOL) surveys were completed during follow-up. RESULTS: Short-term success was achieved in 158 patients (93%), with 12 +/- 11 RF applications. The efficacy of 8- and 10-mm electrodes was similar (p = NS). The number of RF applications (10 +/- 8 vs. 14 +/- 8) and ablation time (0.5 +/- 0.4 h vs. 0.8 +/- 0.6 h) were less with the 10- versus 8-mm electrode, respectively (p < 0.01). Of 158 patients with short-term success, 42 patients were not evaluated for success at six months because of study exclusions. Of 116 patients with short-term success evaluated at six months, 112 (97%) patients had no AFL recurrence. Of those without AFL recurrence at six months, 95% and 93% remained free of symptoms at 12 and 24 months, respectively. Ablation of AFL improved QOL scores (p < 0.05) and reduced anti-arrhythmic and rate-control drug use (p < 0.05). Complications occurred in 6 (3.6%) of 169 patients, but there were no deaths. CONCLUSIONS: Ablation of AFL with 8- or 10-mm electrode catheters and a high-power RF generator was safe and effective and improved QOL. The number and duration of RF applications were lower with 10- versus 8-mm electrode catheters.

Minimally invasive stand-alone Cox-maze procedure for patients with nonparoxysmal atrial fibrillation.

BACKGROUND: Catheter-based ablation for atrial fibrillation (AF) performed percutaneously is shown to be limited in patients with nonparoxysmal AF (non-PAF). The full Cox-Maze surgical procedure demonstrated good success with non-PAF, but concerns were raised regarding increased morbidity eliminating the effect of the success rate. This study assessed the safety and efficacy of a stand-alone on-pump Cox-Maze procedure for non-PAF. METHODS: Since 2005, 104 stand-alone Cox-Maze procedures for non-PAF were performed through a right minithoracotomy (6 cm) with femoral cannulation. Patients were monitored prospectively through our AF registry. Rhythm was verified by electrocardiogram and 24-hour Holter monitoring. Health-related quality of life (SF-12 Health Survey, Quality Metric, Lincoln, RI) and AF symptoms were assessed. RESULTS: Patients were a mean age of 55.9±9.0 years, and 78% had long-standing persistent AF. Patient outcomes included no operative (30 days) deaths or renal failure, 1 pacemaker, and 1 transient ischemic attack. The return to sinus rhythm at 6, 12, 24, 36 months was 94%, 94%, 92%, 92%, and off antiarrhythmic drugs was 87%, 87%, 79%, 80%, respectively. The success rate at 6 months after the initial 20 patients improved from 89% to 94%. Multivariate analysis found duration of AF predicted rhythm at 6 months (odds ratio, 1.15; 95% confidence interval, 1.01 to 1.31; p=0.04). Significant improvement was noted for health-related quality of life and decreased AF symptoms at 1 year. CONCLUSIONS: The long-term success rate after the Cox-Maze III procedure in a challenging group of non-PAF patients is acceptable. Our experience suggests the development of educational strategies to overcome the initial learning curve and patient selection criteria for AF surgical ablation.

Percutaneous catheter ablation treatment of recurring atrial arrhythmias after surgical ablation.

BACKGROUND: Surgical ablation for atrial fibrillation is associated with early and late recurrence of atrial arrhythmias. Although early arrhythmias may be controlled with conventional treatment, late arrhythmias are often highly symptomatic and relatively hard to manage with antiarrhythmic drugs and electrical cardioversion. This study explores a single-center experience with catheter ablation to treat late failures (>3 months) after surgery. METHODS: This is a prospective longitudinally designed study assessing all patients who underwent surgical treatment for atrial fibrillation as a standalone or concomitant with other procedures by multiple surgeons. All patients were monitored according to the Heart Rhythm Society guidelines. RESULTS: From January 2005 to present, 400 consecutive patients operated on by multiple surgeons were enrolled. The overall success rate per the Heart Rhythm Society guidelines was 87% and 84% (off antiarrhythmic drugs, 78% and 73%) at 12 and 24 months, respectively. Sixteen patients (4%) were referred for electrophysiology study after the surgical procedure (15 Cox-maze III or IV, 1 pulmonary vein isolation). The average age was 61.1+/-15.2 years; the mean left atrium size was 5.1+/-0.7 cm; and the mean time to ablation was 16.9+/-10 months. In 16 patients radiofrequency ablation was applied to treat the following atrial arrhythmias: 7 right atrial flutter or tachycardia, 3 left atrial flutter, 1 biatrial flutter, and 5 left atrial tachycardia. Six patients required a subsequent radiofrequency ablation intervention including 4 patients who required atrioventricular nodal ablations. The long-term success rate for the subsequent catheter ablation in these 16 patients (follow-up of 42.9+/-9.8 months) determined by the rate of sinus rhythm as captured by electrocardiography was 94%. Fifty-three percent of the patients (n=8) in sinus rhythm were still taking antiarrhythmic drugs; 8 patients remained on warfarin. There was 1 late noncardiac death and no late strokes. CONCLUSIONS: In a certain subset of patients, unsuccessful surgical ablation of atrial fibrillation may result in symptomatic atrial arrhythmia. If indicated, catheter ablation is a safe and effective intervention with a relatively high success rate. The combination of the two treatment modalities, catheter and surgical ablation, can improve the outcome even in complex patients.