Petr Peichl

Atrial fibrillation ablation using a robotic catheter remote control system: initial human experience and long-term follow-up results.

OBJECTIVES We present the initial clinical human experience with the use of a robotic remote navigation system (Hansen Medical, Mountain View, California), to perform left and right atrial mapping and radiofrequency ablation of atrial fibrillation (AF) and atrial flutter (AFL). BACKGROUND Catheter ablation is an established curative modality for various arrhythmias. A robotic steerable sheath system (SSS) (Hansen Medical) allows better catheter stability and greater degrees of freedom of catheter movement. METHODS A total of 40 patients (mean age 57 years) with antiarrhythmic drug (AAD)-refractory AF (23 had also concomitant documented typical AFL) were studied. Three-dimensional reconstruction of the corresponding atrial chamber anatomy was performed with the CARTO electroanatomic mapping system (Biosense Webster, Diamond Bar, California or the EnSite NavX system (St. Jude Medical, Minneapolis, Minnesota) in combination with the Artisan catheter (Hansen Medical). In patients undergoing AF ablation, 2 transseptal punctures were performed under intracardiac ultrasound (ICE) guidance, with one of the punctures being performed using SSS. Pulmonary vein antrum isolation was performed with a 3.5-mm thermocool catheter manipulated with the use of the SSS and was verified by circular mapping. Patients were followed clinically for recurrence of arrhythmia with an event transmitter and ambulatory holter monitoring. Clinical recurrence of AF/AFL was defined as AF/AFL episodes >1 min in duration. RESULTS Pulmonary vein antrum isolation was performed in 40 patients, including 23 with concomitant typical AFL ablation. All pulmonary veins, including the superior vena cava, were successfully isolated. In 23 of 40 patients, cavotricuspid ablation was also performed with bidirectional block obtained. At 1-year follow-up, 34 patients (86%) and 5 patients were free from atrial arrhythmia off AADs and on AADs, respectively. CONCLUSIONS This preliminary human experience suggests that mapping and ablation of AFL and AF using this novel robotic catheter with remote control system is feasible with similar results to conventional approach.

EFFICAS II: optimization of catheter contact force improves outcome of pulmonary vein isolation for paroxysmal atrial fibrillation

Aims A challenge of pulmonary vein isolation (PVI) in catheter ablation for paroxysmal atrial fibrillation (PAF) is electrical reconnection of the PV. EFFICAS I showed correlation between contact force (CF) parameters and PV durable isolation but no prospective evaluation was made. EFFICAS II was a multicentre study to prospectively assess the impact of CF guidance for an effective reduction of PVI gaps. Methods and results Pulmonary vein isolation using a radiofrequency (RF) ablation catheter with an integrated force sensor (TactiCath™) was performed in patients with PAF. Operators were provided EFFICAS I-based CF guidelines [target 20 g, range 10–30 g, minimum 400 g s force-time integral (FTI)]. Conduction gaps were assessed by remapping of PVs after 3 months, and gap rate was compared with EFFICAS I outcome. At follow up, 24 patients had 85% of PVs remaining isolated, compared with 72% in EFFICAS I (P = 0.037) in which CF guidelines were not used. The remaining 15% of gaps correlated to the number of catheter moves at creating the PVI line, quantified as Continuity Index. For PV lines with contiguous lesions and low catheter moves, durable isolation was 81% in EFFICAS I and 98% in EFFICAS II (P = 0.005). At index procedure, the number of lesions was reduced by 15% in EFFICAS II vs. EFFICAS I. Conclusion The use of CF with the above guidelines and contiguous deployment of RF lesions in EFFICAS II study resulted in more durable PVI in catheter ablation of PAF.

The durability of pulmonary vein isolation using the visually guided laser balloon catheter: Multicenter results of pulmonary vein remapping studies

BACKGROUND The visually guided laser ablation (VGLA) catheter is a compliant, variable-diameter balloon that delivers laser energy around the pulmonary vein (PV) ostium under real-time endoscopic visualization. While acute PV isolation has been shown to be feasible, limited data exist regarding the durability of isolation. OBJECTIVE We sought to determine the durability of PV isolation following ablation using the balloon-based VGLA catheter. METHODS The VGLA catheter was evaluated in patients with paroxysmal atrial fibrillation (3 sites, 10 operators). Following transseptal puncture, the VGLA catheter was advanced through a 12-F deflectable sheath and inflated at the target PV ostium. Under endoscopic guidance, the 30° aiming arc was maneuvered around the PV and laser energy was delivered to ablate tissue in a contiguous/overlapping manner. At ∼3 months, all patients returned for a PV remapping procedure. RESULTS In 56 patients, 202 of 206 PVs (98%) were acutely isolated. At 105 ± 44 (mean ± SD) days, 52 patients returned for PV remapping at which time 162 of 189 PVs (86%) remained isolated and 32 of 52 patients (62%) had all PVs still isolated. On comparing the operators performing <10 vs ≥ 10 procedures, the durable PV isolation rate and the percentage of patients with all PVs isolated were found to be 73% vs 89% (P = .011) and 57% vs 66% (P = .746), respectively. After 2 procedures and 12.0 ± 1.9 months of follow-up, the drug-free rate of freedom from atrial fibrillation was 71.2%. CONCLUSIONS In this multicenter, multioperator experience, VGLA resulted in a very high rate of durable PV isolation with a clinical efficacy similar to that of radiofrequency ablation.

Locations of High Contact Force During Left Atrial Mapping in Atrial Fibrillation Patients Electrogram Amplitude and Impedance Are Poor Predictors of Electrode-Tissue Contact Force for Ablation of Atrial Fibrillation

Background—During radiofrequency ablation, high electrode-tissue contact force (CF) is associated with increased risk of steam pop and perforation. The purpose of this study, in patients undergoing ablation of paroxysmal atrial fibrillation, was to: (1) identify factors producing high CF during left atrial (LA) and pulmonary vein mapping; (2) determine the ability of atrial potential amplitude and impedance to predict CF; and (3) explore the feasibility of controlling radiofrequency power based on CF. Methods and Results—A high-density map of LA/pulmonary veins (median 328 sites) was obtained in 18 patients undergoing atrial fibrillation ablation using a 7.5-Fr irrigated mapping/ablation catheter to measure CF. Average CF was displayed on the 3D map. For 5682 mapped sites, CF ranged 1–144 g (median 8.2 g). High CF (≥35 g) was observed at only 118/5682 (2%) sites, clustering in 6 LA regions. The most common high CF site (48/113 sites in 17/18 patients) was located at the anterior/rightward LA roof, directly beneath the ascending aorta (confirmed by merging the CT image and map). Poor relationship between CF and either unipolar amplitude, bipolar amplitude, or impedance was observed. During ablation, radiofrequency power was modulated based on CF. All pulmonary veins were isolated without steam pop, impedance rise, or pericardial effusion. Conclusions—High CF often occurs at anterior/rightward roof, where the ascending aorta provides resistance to the LA. Atrial potential amplitude and impedance are poor predictors of CF. Controlling radiofrequency power based on CF seems to prevent steam pop and impedance rise without loss of lesion effectiveness.

Magnetic Resonance Angiography of Pulmonary Veins: Implications for Catheter Ablation of Atrial Fibrillation

Introduction: Catheter ablation of atrial fibrillation (AF) requires exact anatomical information about pulmonary venous (PV) ostia. In this study, anatomy of pulmonary veins (PVs) was assessed using three‐dimensional (3D) reconstructions of magnetic resonance angiography (MRA).

Catheter ablation of electrical storm in patients with structural heart disease

AIMS Electrical storm (ES) adversely affects prognosis of patients and may become a life-threatening event. Catheter ablation (CA) has been proposed for the treatment of ES. Our goal was to evaluate the efficacy of CA ablation both in acute and long-term suppression of ES. METHODS AND RESULTS Fifty consecutive patients with coronary artery disease (38), idiopathic dilated cardiomyopathy (5), arrhythmogenic right ventricular cardiomyopathy (6), and/or with combined aetiology (1) underwent CA for ES. Mean left ventricular ejection fraction (LVEF) was 29 ± 11%. All patients underwent electroanatomical mapping, and CA was performed to abolish all inducible ventricular arrhythmias. The ES was suppressed by CA in 84% of patients. During the follow-up of 18 ± 16 months, 24 patients had no recurrences of any ventricular tachycardia (VT; 48%). Repeated procedure was necessary to suppress the recurrent ES in 13 cases (26%). Statistical analysis revealed that low LVEF (22 ± 3 vs. 31 ± 12%; P < 0.001), increased LVend-diastolic diameter (72 ± 9.1 vs. 64 ± 8.9 mm; P = 0.0135), and renal insufficiency (P < 0.001) were the univariate predictors of early mortality or necessity for heart transplantation. Recurrence of ES despite previous CA procedure was associated with a higher risk of death or heart transplant during follow-up (P < 0.05). CONCLUSION Catheter ablation is effective in acute suppression of ES and often represents a life-saving therapy. In the long term, it prevents recurrences of any VT in about half of the treated patients.

Complications of catheter ablation for atrial fibrillation in a high-volume centre with the use of intracardiac echocardiography

AIMS Catheter ablation (CA) for atrial fibrillation (AF) is a complex procedure that is associated with higher risk of complications. This study aimed at exploring the complication rate and corresponding risk factors in a high-volume centre with routine use of intracardiac echocardiography (ICE). METHODS AND RESULTS In total 1192 consecutive AF ablation procedures (100% ICE-guided; 96.4% 3D-navigated; point-by-point radiofrequency ablation with open-irrigated tip catheter; 22.4% robotic navigation; 25.4% repeated ablation) were performed in 959 patients (aged 58 ± 9 years; 70.8% males; 35.9% persistent AF) between March 2006 and December 2010. Ablation endpoint in paroxysmal AF was complete electrical pulmonary vein isolation (PVI). Complex ablation was defined as PVI plus stepwise strategy for left atrial substrate ablation (43.5%) in persistent AF. Forty major complications (3.3%) during the procedure or within the 3 month follow-up were observed. No death or atrioesophageal fistula occurred. Three patients (0.25%) had cardiac tamponade/hemopericardium and five patients (0.42%) had cerebrovascular embolic event. Vascular injury was the most frequent (2.3%) complication. Low body weight was the only significant risk factor with 0.8% increase of complication rate per 10 kg of body weight decrease (P = 0.013). A trend for increase in complication rate was also observed for advanced age, female gender, and complex procedure. CONCLUSION Atrial fibrillation ablation procedures guided by ICE in a high-volume centre are associated with low rate of serious complications. The composite risk score consisting of body weight, age, gender, and complexity of procedure predicted complications.

Robotic Navigation in Catheter Ablation for Paroxysmal Atrial Fibrillation: Midterm Efficacy and Predictors of Postablation Arrhythmia Recurrences

Robotic Navigation in Ablation of Paroxysmal AF. Introduction: Remote navigation systems represent a novel strategy for catheter ablation of atrial fibrillation (AF). The goal of this study is to describe a single‐center experience with the electromechanical robotic system (Sensei, Hansen Medical) in treatment of patients with paroxysmal AF.

Complications of Catheter Ablation of Ventricular Tachycardia A Single-Center Experience

Background—Catheter ablation has become an established treatment modality for a broad spectrum of ventricular tachycardias (VTs). We analyzed incidence and predictors of major complications of VT ablation procedures in a high-volume expert center. Methods and Results—We evaluated 548 consecutive patients who underwent 722 ablation procedures, 473 (65.5%) for structural heart disease VT in the period 2006 to 2012. There were 45 (6.2%) major complications observed in 44 patients. Access site vascular complications were the most frequent (3.6%). Three patients (0.4%) had cardiac tamponade/hemopericardium, and 5 patients (0.7%) had a thromboembolic event. No procedural deaths occurred. Procedures for structural heart disease VT versus idiopathic VT had a significantly higher complication rate (8.0% versus 2.8%; P=0.006). Similarly, patients with electrical storm (10.1% versus 5.3%; P=0.04) and nonelective procedures (8.4% versus 3.5%; P=0.007) were at higher risk of complications. On multivariate analysis, age >70 years (P=0.01), serum creatinine >115 &mgr;mol/L (P=0.0003), and individual operator (P=0.0001) were the only independent predictors of complications. Overall 30-day mortality in the structural heart disease VT group reached 5.0% (patients) and 3.6% (procedures). Death was associated with early recurrence of VT/ventricular fibrillation (P=0.003) and ablation for electrical storm (P=0.02). Conclusions—Complication rates for VT ablation are significantly lower in idiopathic VT or in elective procedures. Independent predictors of complications include age, renal insufficiency, and individual operator. Postprocedural mortality is predicted by early recurrence of VT/ventricular fibrillation and ablation for electrical storm.

Ablation of atrial tachycardias after correction of complex congenital heart diseases: utility of intracardiac echocardiography

AIMS Our goal was to analyse the utility of intracardiac echocardiography (ICE) for navigation and ablation of atrial tachycardias (ATs) after surgical correction of congenital heart disease (CHD). METHODS AND RESULTS Catheter ablation of ATs was performed in seven patients (one woman, mean age 21 +/- 6 years) after correction of complex CHD: d-transposition of the great arteries (Mustard procedure in two patients, Senning procedure in two patients) and univentricular circulation (total cavopulmonary connection in two patients, atriopulmonary connection in one patient). The ablation was guided by a combination of electroanatomical mapping (CARTO, Biosense-Webster) and ICE (Acuson, Siemens). Intracardiac echocardiography was used during mapping to identify relevant anatomical structures and monitor tissue contact and for guidance of atrial baffle puncture. Biatrial mapping was necessary in six of seven patients and atrial baffle puncture in three. The clinical AT was abolished in all patients. No complications were noted. During follow-up of 23 +/- 13 months, two patients (28%) had arrhythmia recurrence. One patient developed atrial fibrillation, and recurrent AT in the other patient was controlled by re-ablation. CONCLUSION Despite complicated cardiac anatomy, catheter ablation of AT after complex CHD can be performed safely and with a high success rate. Intracardiac echocardiography facilitates mapping, identification of relevant cardiac structures, and could be used for safe guidance of transbaffle puncture.