Optimizing cryoballoon pulmonary vein isolation: lessons from >1000 procedures- the Frankfurt approach.

AIMS: Cryoballoon (CB) pulmonary vein isolation (PVI) is an accepted ablation strategy for rhythm control in atrial fibrillation (AF). We describe efficacy and safety in a high volume centre with a long experience in the use of the second-generation CB (CB2). METHODS AND RESULTS: Consecutive paroxysmal AF (PAF) or persistent AF (persAF) patients undergoing CB2-PVI were enrolled. Procedural data, efficacy, and safety issues were systematically collected. The 28 mm CB2 was used in combination with an inner lumen spiral catheter, a luminal oesophageal temperature (LET) probe was used with a cut-off of 15°C, the phrenic nerve (PN) monitored during septal PVs ablation. Freeze duration was mainly set at 240 s with a bonus application in case of delayed time-to-isolation (TTI > 75 s). A total of 1017 CB2 procedures were analysed (58% male, 66 ± 12 years old, 70% with PAF). 3964 PVs were identified, 99.8% PVs isolated using solely the 28 mm CB. Mean procedure time was 69 ± 25 min, TTI during the first application was recorded in 77% of PVs after a mean of 48 ± 31 s. We recorded 0.2% cardiac tamponade, 4.8% PN injury (1.6% of PN palsy), and 19% of LET < 15°C. Among 725 patients with follow-up data, 84% with PAF and 75% with persAF were in stable SR at 1 year. Shorter freezing duration and longer TTI were procedural predictors for recurrence. CONCLUSION: Cryoballoon procedures are fast and associated with a benign safety profile. Shorter TTI and longer freeze durations are associated with sinus rhythm during follow-up.

Durability of cryoballoon left atrial appendage isolation: Acute and invasive remapping electrophysiological findings.

BACKGROUND: The left atrial appendage (LAA) has been identified as a potential source of atrial fibrillation (AF) and has been described as the "fifth" pulmonary vein (PV). We report our initial experience in LAA isolation (LAAI) using the cryoballoon (CB) and data on durability of CB-LAAI. METHODS: Patients treated with a CB-LAAI were retrospectively identified. Six weeks after electrical LAAI, patients were scheduled for staged percutaneous LAA closure. During the second procedure, a subset of patients underwent invasive remapping of the LAA. RESULTS: A total of 32 patients (21 males, 68 ± 10 years old) were treated with CB-LAAI. Acute LAAI was achieved in 29 of 32 (91%) patients: single-shot LAAI was observed in 18 of 32 (56%) patients. Acute procedural sustained LAAI was related with a significantly shorter time to LAAI (sustained LAAI: 84 ± 50 s vs nonsustained LAAI: 166 ± 76 s, P = 0.004). Mean procedure and fluoroscopy time were 61 ± 29 and 8 ± 6 min, respectively. One left-sided phrenic nerve palsy occurred. In 25 of 32 (78%) patients, a second procedure for percutaneous LAA closure device implantation was performed. In 22 patients, persistency of LAAI was tested: durable LAAI was documented in 16/22 patients (73%). CONCLUSION: In the present report, CB LAA isolation followed by staged LAA closure appeared to be safe and feasible but more data are required. Time to LAAI played a role in predicting acute sustained LAAI rate. CB LAA ablation leads to 73% of durable LAA isolation.

Electrical isolation of the left atrial appendage by Maze-like catheter substrate modification: A reproducible strategy for pulmonary vein isolation nonresponders?

INTRODUCTION: The ablation strategy for atrial fibrillation (AF) despite pulmonary vein isolation (PVI) is controversial. Left atrial appendage isolation (LAAI) may contribute to improve outcome. We describe an ablation approach ("Maze-like"-LAAI) that (1) modifies the underlying LA substrate by linear ablation (2) eliminates the LAA as a putative AF trigger site and (3) incorporates an unambiguous procedural endpoint. The role of LAA closure (LAAC) after LAAI was investigated. METHODS: Patients with atrial tachyarrhythmias nonresponsive to PVI underwent a LAAI ablation procedure. LAAI was achieved by combining (a) an anterior line, (b) a LA roof line and (c) a mitral isthmus line. Patients continued oral anticoagulation (OAC) therapy or underwent LAAC  ≥6 weeks after LAAI. RESULTS: Maze-like LAAI was attempted in our center in 107 of 3,611 AF ablation procedures (2.9%) and achieved in 88 of 107 patients (82%). In 8 of 107 (7%) patients cardiac tamponade occurred, all managed conservatively. During follow-up sinus rhythm was established in 65% at 1 year. After LAAI, 45 patients remained on OAC and 40 underwent LAAC. In both groups 1 patient experienced a bleeding complication. Thromboembolism exclusively occurred in the OAC group in 3 (7%) patients. CONCLUSION: LAA isolation by Maze-like substrate modification may be considered a viable option for PVI non-responders. It offers a reproducible approach with an unambiguous procedural endpoint and leads to a favorable clinical outcome. However, extensive LA ablation increased the risk of tamponade. Consecutive LAA occlusion may offer a nonpharmacologic strategy to overcome the high thromboembolic risk associated with absent mechanical LAA contraction.

What Is the Acute Antral Lesion Size After Pulmonary Vein Isolation Using Different Balloon Ablation Technologies?

BACKGROUND: Clinical outcome after pulmonary vein isolation (PVI) may be linked to both durability of PVI and the antral lesion size. Data on balloon-guided technologies are scarce. We investigated the size of the isolated surface area (ISA) acutely after PVI achieved by cryoballoon (CB) or laser balloon (LB), both using voltage mapping.Methods and Results:In 40 patients (73% male, mean age 66±9 years), a bipolar voltage map before and after PVI in sinus rhythm was acquired to delineate the isolated antral surface area (IASA, contiguous area of low voltage <0.5 mV) and the ISA (relative size of the low-voltage area in relation to the whole antral surface area including the posterior wall). IASA (CB: 57±14 cm2vs. LB: 42±15 cm2; P=0.002) as well as ISA (65±8% vs. 54±10%; P=0.001) were significantly larger in the CB than in the LB group. No periprocedural complications occurred. During a mean follow-up of 326±142 days, 4/20 and 5/20 patients experienced an AF/AT recurrence in the CB and LB groups, respectively. No differences in clinical outcome were observed between patients with a large (≥55%) or small (<55%) ISA. CONCLUSIONS: Balloon-guided PVI is associated with antral lesion formation. CB-guided PVI is associated with the largest ISA as compared with LB procedures. ISA size did not correlate with clinical outcome after a single procedure in the present study population.

Visually guided pulmonary vein isolation in patients with persistent atrial fibrillation.

AIMS: The role of balloon catheters in patients with persistent forms of atrial fibrillation (AF) remains ill defined. We therefore sought to assess the safety and efficacy of a laser balloon (LB)-guided pulmonary vein isolation (PVI) in consecutive all-comers with persistent AF. METHODS AND RESULTS: All patients undergoing an LB-guided PVI procedure for persistent AF between January 2011 and December 2012 were matched to patients undergoing circumferential PVI using irrigated radiofrequency (RF) current ablation for date of procedure, age, gender, AF duration, left atrial (LA) size, and left ventricular ejection fraction. The primary endpoint was freedom from AF between 90 and 365 days post-ablation after a single procedure. Eighty patients (mean age 66 ± 9; 71% male) with a median (Q1-Q3) AF episode duration of 2 (1-3) months underwent successful PVI in the two groups. The primary endpoint of 1-year single procedure AF/atrial tachycardia (AT) recurrences was reached by 11/40 (27.5%) patients in the LB group and in 9/40 (22.5%) patients in the RF group (P = 0.87). During a mean follow-up of 517 ± 170 days, 13 (32.5%) and 16 (40%) patients in the LB and RF groups, respectively, experienced AF/AT recurrences (P = 0.64). Procedural complications occurred in one patient in the LB group and in six patients in the RF group. CONCLUSION: A subset of patients with drug-refractory persistent AF of short duration benefit from pure PVI without additional substrate modification. A LB-based strategy showed similar outcomes as an irrigated RF-guided circumferential PVI and may be considered an alternative option for the index ablation.

Decennial Analysis of Interventional Left Atrial Appendage Closure.

INTRODUCTION: Data on long-term follow-up (LTFU) after interventional closure of the left atrial appendage (LAAC) in patients with nonvalvular atrial fibrillation (AF) are scarce. We sought to determine the outcome of patients after LAAC with the first generation device. METHODS AND RESULTS: The Cardioangiologisches Centrum Bethanien (CCB) LAAC registry database was analyzed. Between October 2001 and July 2007, 45 AF patients (23 male, mean age 71 ± 6 years; mean CHA2 DS2 -VaSc 4.3 ± 1.7 [range 1-7]; mean HASBLED score 3.3 ± 1.2 [1-5]) received LAAC. Postimplant dual-platelet inhibition with clopidogrel 75 mg/day and aspirine (ASA) 300 mg/day was prescribed for 6 months, followed by ASA 300 mg indefinitely. The primary endpoint was defined as any thrombembolic complication and/or any bleeding complication. The median FU was 7.4 years (1-12.4 years) resulting in 292 patient years. Fourteen patients died due to heart failure (n = 4), noncardiac reasons (n = 7), or due to unknown etiology (n = 3). No patient died from a bleeding or a stroke. Five ischemic strokes occurred at a median of 794 days (range 304-3,706 days) after LAAC. The observed annual stroke rate was 1.7% (RR 0.43; 95% CI 0.24-0.74; P = 0.0028). In 6 patients bleeding occurred (2 acute procedural, 4 during follow-up). The observed annual bleeding rate was 2.1% (RR 0.56; 95% CI 0.48-0.66; P < 0.0001). CONCLUSION: During LTFU after LAAC in patients with nonvalvular AF, lower event rates than expected are observed for both thrombembolic and bleeding complications.

Comparison of balloon catheter ablation technologies for pulmonary vein isolation: the laser versus cryo study.

INTRODUCTION: Balloon catheters have been developed to facilitate pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (PAF). We sought to compare the safety and efficacy of the cryoballoon (CB) and the laserballoon (LB) in a pilot study. METHODS AND RESULTS: One hundred and forty patients with drug-refractory PAF were prospectively allocated in a 1:1 fashion to undergo a PVI procedure with the 28 mm CB or the LB and were followed for 12 months using 3-day Holter ECG recording. The primary efficacy endpoint was a documented AF recurrence ≥ 30 seconds between 90 and 365 days after the index ablation. In total, 269 of 270 PVs (99.6%) and 270 of 273 PVs (98.9%) were acutely isolated in the CB and LB group, respectively. Mean procedural time was 136 ± 30 minutes for the CB group and 144 ± 33 minutes for the LB group (P = 0.13). Mean fluoroscopy time was longer in the CB group (21 ± 9 minutes vs 15 ± 6 minutes; P < 0.001). During 12 months follow-up, 37% of patients in the CB group and 27% in the LB group experienced an AF recurrence (P = 0.18). Phrenic nerve palsies occurred in 5.7% (CB) and 4.2% (LB) of patients, respectively. CONCLUSION: Balloon catheters are a viable option to safely perform a PVI procedure in patients with drug-refractory PAF. Ninety-nine percent of PVs may be acutely isolated with a single balloon catheter. The AF free survival rate after a single ablation procedure was not statistically different between groups.

Long-term outcome after catheter ablation for left posterior fascicular ventricular tachycardia without development of left posterior fascicular block.

BACKGROUND: Catheter ablation of left posterior fascicular (LPF) ventricular tachycardia (VT) is commonly performed during tachycardia. This study reports on the long-term outcome of patients undergoing ablation of LPF VT targeting the earliest retrograde activation within the posterior Purkinje fiber network during sinus rhythm (SR). METHODS: This study retrospectively analyzed 24 consecutive patients (8 female; mean age 26 ± 11 years) referred for catheter ablation of electrocardiographically documented LPF VT. Programmed stimulation was performed to induce tachycardia, while mapping and ablation was aided by use of a 3D electroanatomical mapping system. Catheter ablation targeted the earliest potential suggestive of retrograde activation within the posterior Purkinje fiber network (retro-PP) recorded along the posterior mid-septal left ventricle during SR if LPF VT was noninducible. RESULTS: Overall, 21/24 (87.5%) patients underwent successful catheter ablation in SR targeting the earliest retro-PP, while 3/24 (12.5%) patients were successfully ablated during tachycardia. In none of the patients, ablation resulted in LPF block. No procedure-related complications occurred. After a median follow-up period of 8.9 (4.8-10.9) years, 22/24 (92%) patients were free from recurrent VT. CONCLUSION: In patients presenting with LPF VT, ablation of the earliest retro-PP along the posterior mid-septal LV during SR results in excellent long-term outcome during a median follow-up period of almost 9 years.

Impact of pulmonary vein anatomy assessed by cardiac magnetic resonance imaging on endoscopic pulmonary vein isolation in consecutive patients.

AIMS: Recently, the novel endoscopic ablation system (EAS) was introduced and proved its potential for successful pulmonary vein isolation (PVI) in patients suffering from paroxysmal atrial fibrillation (PAF). The current study will investigate the impact of pulmonary vein (PV) anatomy assessed by pre-interventional cardiac magnetic resonance imaging (CMRI) on endoscopic PVI. METHODS AND RESULTS: Fifty-one patients (23 females, age 57 ± 9 years) with a long history (5 ± 5 years) of drug-refractory PAF were included into our analysis. Cardiac magnetic resonance imaging was performed in all patients before ablation. Each CMRI was evaluated for the number of PVs, for separate or common insertion of ipsilateral PVs, for the PV diameter and PV shape (round vs. oval), for the level of first PV branching, and for the level of insertion of the right inferior PV (RIPV) into the left atrium (LA), respectively. Pulmonary vein isolation was performed using exclusively the novel EAS. The CMRI findings were correlated with the ablation results. A total of 195 PVs were identified and targeted. In 192 of 195 (98%) PVs successful isolation was achieved using the novel EAS irrespective of the PV diameter, the PV shape, the level of PV branching, or the type of insertion of the PV into the LA. There was no statistical significance when correlating the CMRI findings with acute isolation success of the respective PVs or the number of laser applications needed until PVI (P> 0.05). A low level of insertion of the RIPV into the LA was not associated with PVI failure or a higher number of laser applications (P> 0.05). CONCLUSIONS: The majority of PVs could have been targeted and successfully isolated using exclusively the novel EAS irrespective of their anatomy assessed by pre-interventional CMRI. Considering the economical impact of CMRI and its minor influence on ablation strategy, success, and safety it is not an essential pre-requisite for subsequent successful EAS-based PVI.

Long-term results of catheter ablation in paroxysmal atrial fibrillation: lessons from a 5-year follow-up.

BACKGROUND: Paroxysmal atrial fibrillation (AF) naturally progresses toward chronic AF at an estimated rate of 15% to 30% over a 1- to 3-year period. Pulmonary vein (PV) isolation is increasingly performed for the treatment of drug-refractory paroxysmal AF. The long-term data on clinical outcome after circumferential PV isolation are limited. METHODS AND RESULTS: From 2003 to late 2004, 161 patients (121 men; age, 59.8±9.7 years) with symptomatic paroxysmal AF and normal left ventricular function underwent circumferential PV isolation guided by 3-dimensional mapping and double Lasso technique. Right-sided and left-sided continuous circular lesions encircling the ipsilateral PVs were placed with irrigated radiofrequency energy. The procedure end point was the absence of all PV spikes for at least 30 minutes after PV isolation verified by 2 Lasso catheters placed within the ipsilateral PVs. Sinus rhythm was present in 75 patients (46.6%) after the initial procedure during a median follow-up period of 4.8 years (0.33 to 5.5 years). A second procedure was performed in 66 and a third procedure in 12 patients. Recovered PV isolation conduction was observed in 62 of 66 patients (94.0%) during the second and in 8 of 12 patients (66.7%) during the third procedure. After a median of 1 (1 to 3) procedure, stable sinus rhythm was achieved in 128 of 161 patients (79.5%), whereas clinical improvement occurred in an additional 21 of 161 patients (13.0%) during a median follow-up of 4.6 years (0.33 to 5.5 years). Four patients in stable sinus rhythm died during follow-up. Progression toward chronic AF was observed in 4 patients (2.4%); however, only 2 patients reported symptoms. CONCLUSION: In patients with paroxysmal AF and normal left ventricular function, circumferential PV isolation results in stable sinus rhythm in the majority of patients, and low incidence of chronic AF was observed after ablation during up to 5 years of follow-up.

Catheter ablation of long-standing persistent atrial fibrillation: a lesson from circumferential pulmonary vein isolation.

INTRODUCTION: Circumferential pulmonary vein isolation (CPVI) is associated with a high success rate in patients with paroxysmal and persistent atrial fibrillation (AF). However, in patients with long-standing persistent AF, the ideal ablation strategy still remains a matter of debate. METHODS AND RESULTS: Two-hundred and five patients underwent catheter ablation for long-standing persistent AF defined as continuous AF of more than 1-year duration. In a first step, all patients underwent CPVI. If direct-current cardioversion failed following CPVI, ablation of complex fractionated atrial electrograms (CFAEs) was performed. The goal was conversion into sinus rhythm (SR) or, alternatively, atrial tachycardia (AT) with subsequent ablation. A total of 340 procedures were performed. CPVI alone was performed during 165 procedures in 124 of 205 (60.5%) patients. In the remaining 81 patients, additional CFAE ablation was performed in 45, left linear lesions for recurrent ATs in 44 and SVC isolation in 15 patients, respectively, resulting in inadvertent left atrial appendage isolation in 9 (4.4%) patients. After the initial ablation procedure, 67 of 199 patients remained in SR during a mean follow-up of 19 ± 11 months. Six patients were lost to follow-up. After a mean of 1.7 ± 0.8 procedures, 135 of 199 patients (67.8%) remained in SR. Eighty-six patients (43.2%) remained in SR following CPVI performed as the sole ablative strategy. CONCLUSIONS: CPVI alone is sufficient to restore SR in 43.2% of patients with long-standing persistent AF. Multiple procedures and additional ablation strategies with a significant risk of inadvertent left atrial appendage isolation are often required to maintain stable SR.

Long-term clinical outcome following pulmonary vein isolation with high-intensity focused ultrasound balloon catheters in patients with paroxysmal atrial fibrillation.

AIMS: High-intensity focused ultrasound (HIFU) applied via a balloon catheter is a novel technology for pulmonary vein isolation (PVI) in patients with paroxysmal atrial fibrillation (PAF). The long-term success rate is unknown. METHODS AND RESULTS: Thirty-two patients (22 male, age 60 +/- 9 years) with a long history [5 (4;9) years] of drug refractory [3 +/- 1 anti-arrhythmic drugs (AADs)], symptomatic PAF were included into the analysis. Pulmonary vein isolation was performed using the first- and second-generation HIFU balloon catheters (ProRhythm, Ronkonkoma, NY, USA). Follow-up (F/U) included regular telephonic interviews, trans-telephonic Holter ECG, and event recording. Recurrence was defined as a documented or symptomatic AF episode >30 s without a blanking period. In total 101/116 targeted PVs (87%) were acutely isolated exclusively using HIFU. During a median F/U of 1400 (930;1568) days, 18 patients (56%) were free of AF without AAD after a single HIFU procedure. In nine patients with AF recurrence, 20 PVs exhibited electrical reconduction and re-isolation was performed using irrigated radiofrequency current (RFC) ablation. CONCLUSION: Patients treated with the first- and second-generation HIFU balloon catheters due to symptomatic PAF show long-term success rates similar to RFC-based PVI procedures. The major determinant of AF recurrence after HIFU treatment seems to be reconduction of previously isolated PVs. However, the favourable effectiveness is offset by the severe complications reported following HIFU treatment. This led to a halt of its clinical use.

Pulmonary vein isolation with high-intensity focused ultrasound: results from the HIFU 12F study.

AIMS: High-intensity focused ultrasound (HIFU) applied via a balloon catheter (BC) is a novel technology for simplified pulmonary vein isolation (PVI). Safety and efficacy of the third generation HIFU-BC were assessed. METHODS AND RESULTS: In 22 patients (10 male, mean age 65 +/- 6 years) with paroxysmal atrial fibrillation (PAF), a PVI during real-time PV spike registration and oesophageal temperature measurement was attempted. In 15 patients, a steerable sheath was used along with the HIFU-BC. In 67 of 83 PVs (81%), PVI was achieved exclusively using HIFU. Using the steerable sheath, the acute PVI rate rose from 50% (10/20 PVs) to 90% (57/63 PVs). In the latter, PVI was achieved with a single HIFU application in 60% (38/63 PVs) and mean sonication time of 11 +/- 7 s. The mean procedure time was 166 +/- 74 min including 58 +/- 25 min of HIFU-BC left atrial indwelling time. In four patients, peri-procedural complications occurred (one transient ischaemic attack, one phrenic nerve palsy, and two vascular access complications). During a median follow-up of 342 days (range 272-378 days), 71% patients remained free of any AF/AT recurrence without antiarrhythmic drugs after a single procedure. CONCLUSION: The novel defocused 12F HIFU-BC used in conjunction with a steerable sheath allows for very rapid PVI in patients with PAF. The enthusiasm for rapid PVI is still dampened by the potential risk of collateral damage.

Glycoprotein 130 ligand oncostatin-M induces expression of vascular endothelial growth factor in human adult cardiac myocytes.

OBJECTIVE: In murine and rat cardiac myocytes the gp130 system transduces survival as well as hypertrophic signals and via induction of the expression of the potent angiogenic factor VEGF in these cells also indirectly contributes to cardiac repair processes through the development of new blood vessels. There are, however, species differences in receptor specificity and receptor crossreactivity in the gp130-gp130 ligand system. We asked whether gp130 signaling is also involved in the regulation of VEGF in human cardiac myocytes and if so which gp130 ligands are critical for such an effect. METHODS: Human adult cardiac myocytes (HACMs) were isolated from myocardial tissue and characterised by positive staining for myocardial actin, troponin-I and cardiotin. HACMs were treated with the gp130 ligands CT-1, IL-6, LIF or OSM and VEGF-1 was determined by a specific ELISA in the conditioned media of these cells. RT-PCR and Western blot analysis was used in order to detect gp130, IL-6-receptor, LIF-receptor or OSM-receptor specific protein and mRNA in human adult cardiac myocytes and for detection of VEGF-1 specific mRNA in cardiac myocytes after incubation with OSM. Pieces of myocardial tissue were incubated ex vivo in the presence and absence of OSM and VEGF was determined in supernatants of these cultures and immunohistochemistry was performed on the tissue using specific antibodies for VEGF-1. Immunohistochemistry was also employed to detect VEGF in sections from a healthy human heart and in a heart from a patient suffering from acute myocarditis. RESULTS: OSM, but not CT-1, IL-6 or LIF increased VEGF-1 production in human adult cardiac myocytes dose-dependently derived from five different donors. This selective stimulation of VEGF by gp130 ligands was also reflected by a specific receptor expression on these cells. We detected high levels of mRNA for gp130 and the OSM receptor in freshly isolated human cardiac myocytes but only low amounts of mRNA for the IL-6 receptor whereas mRNA for the LIF receptor was hardly detectable by RT-PCR. OSM receptor and IL-6 receptor were also detectable by Western blotting whereas LIF receptor was only present as a faint band. OSM also increased the expression of VEGF-1 mRNA in cardiac myocytes. When pieces of human myocardial tissue were incubated with the gp130 ligands in an ex vivo model only OSM resulted in an increase in VEGF-1 in the supernatants of these cultures. Furthermore, VEGF increased in tissue samples treated with OSM in cardiac myocytes as evidenced by immunohistochemistry. In addition, we found increased VEGF-1 expression in myocardial tissue from a patient suffering from acute myocarditis. CONCLUSION: The gp130-gp130 ligand system is also involved in VEGF regulation in human cardiac myocytes and OSM is the gp130 ligand responsible for this effect in the human system whereas LIF and CT-1 which had been shown to regulate VEGF expression in mouse and rat cardiac myocytes had no effect. Thus we have added OSM, which is produced by activated T lymphocytes and monocytes, to the list of regulatory molecules of VEGF production in the human heart. Our results lend further support to the notion that besides hypoxia, inflammation via induction of VEGF through autocrine or paracrine pathways plays a key role in (re)vascularisation of the myocardium.

Endoscopic ablation systems.

Pulmonary vein (PV) isolation for ablation of atrial fibrillation is a well-accepted therapy option for high symptomatic patients refractory to antiarrhythmic drugs. Radiofrequency point-by-point ablation is the gold-standard technique; however, in the last two decades, many new technologies have been developed. The endoscopic ablation system makes direct PV ostium visualization possible, despite the large anatomy variation thanks to its compliant balloon. The laser generator delivers precise lesions that in the first clinical studies seem to be durable, with a safety and efficacy profile similar to the other PV isolation techniques. If these early results are confirmed by larger clinical studies, the endoscopic ablation system will offer a new paradigm in ablation of cardiac arrhythmias by directly visualizing the target substrate.

Correlation between substrate location and ablation strategy in patients with ventricular tachycardia late after myocardial infarction.

BACKGROUND: The requirement for epicardial radiofrequency ablation (RFA) is still undefined in ventricular tachycardia (VT) late after myocardial infarction (MI). OBJECTIVE: The purpose of this study was to evaluate the correlation between the need for epicardial RFA and the clinical and electrophysiologic characteristics of VT late after MI. METHODS: Endocardial mapping and RFA were performed for VT late after MI, followed by epicardial mapping and RFA if no endocardial substrate was present or endocardial RFA failed. RESULTS: Seventy patients with VT late after MI (30 anterior MI [A-MI] and 40 posteroinferior MI [PI-MI]) were included in the study. Forty-one VTs in patients with A-MI and 64 VTs in patients with PI-MI were targeted for RFA. Epicardial mapping and ablation were attempted in 6 patients and performed successfully in only 4 patients. All 6 (100%) patients requiring epicardial access had PI-MIs. Patients with epicardial RFA had endocardial low-voltage areas of smaller size compared to patients without epicardial RFA (21 ± 13 cm(2) vs 68 ± 40 cm(2); P <.01). During 25 ± 19 months of follow-up, recurrence after the initial procedure was noted in 12 of 30 patients (40%) with A-MI and in 18 of 40 patients (45%) with PI-MI. There was no significant difference between groups. CONCLUSION: In the majority of patients, clinical and slower VTs late after MI can be abolished using endocardial RFA. Rarely indicated, epicardial RFA is more commonly required in patients with small-sized PI-MI. During follow-up, VT recurrence after successful RFA is common.

Luminal esophageal temperature rise and esophageal lesion formation following remote-controlled magnetic pulmonary vein isolation.

BACKGROUND: Remote magnetic pulmonary vein isolation (PVI) demonstrates comparable success rate to manual ablation, but thermal effects on esophageal tissue remain undefined. OBJECTIVE: The purpose of this study was to evaluate the potential thermal effects on esophageal tissue during remote magnetic wide-area circumferential pulmonary vein isolation (CPVI). METHODS: Twenty-five patients (23 men, age 57 ± 10 years) in the magnetic navigation system (MNS) group and 25 control subjects (15 men, age 61 ± 12 years) with drug-refractory paroxysmal or persistent atrial fibrillation underwent CPVI. A magnetic 3.5-mm irrigated-tip catheter (NaviStar ThermoCool RMT, Biosense Webster) and a nonmagnetic 3.5-mm irrigated-tip catheter (NaviStar ThermoCool, Biosense Webster) were used in the MNS and control group, respectively. A temperature probe (SensiTherm, St. Jude Medical), containing 3 thermocouples was placed in close proximity to the ablation site monitoring luminal esophageal temperature (LET). LET changes did not guide therapy. Postprocedural esophagogastroduodenoscopy (EGD) was performed in all patients. RESULTS: Successful CPVI was achieved in all patients. No esophageal lesions, minimal lesions, or ulcerations were found in 16 of 25 (64%), 7 of 25 (28%), and 2 of 25 (8%) in the MNS group and in 14 of 25 (56%), 10 of 25 (40%), and 1 of 25 (4%) patients in the control group, respectively. No atrioesophageal fistula occurred. Mean maximum LET in the magnetic group was 43.7°C ± 3.7°C compared to 45.4°C ± 3.5°C in the manual control group (P = .09). CONCLUSION: Remote magnetic PVI is associated with significant rise in LET and development of thermal esophageal lesions. In the MNS group, higher LET recordings were more likely to cause esophageal injury, whereas this association was not seen in the manual group despite a tendency toward higher mean maximum LET recordings.

Esophageal temperature change and esophageal thermal lesions after pulmonary vein isolation using the novel endoscopic ablation system.

BACKGROUND: Pulmonary vein isolation (PVI) is an established treatment option for paroxysmal atrial fibrillation. Recently, a novel endoscopic ablation system (EAS) was introduced. The incidence and severity of ablation-induced esophageal thermal lesions (ETLs) are unknown. OBJECTIVE: The purpose of this study was to investigate the incidence and severity of ablation-induced ETLs. METHODS: This prospective analysis compared two groups: group A underwent EAS-based PVI, and group B received PVI using radio frequency current (RFC). If esophageal temperature measured via an endoluminal temperature probe exceeded 38.5°C, energy application was stopped immediately. Endoscopy was performed 2 days postablation. RESULTS: Forty patients (20 female, mean age 56 ± 10 years) were treated with the EAS system (group A). In 20 patients (seven female, mean age 63 ± 9 years) RFC-based PVI was performed (group B). Esophageal endoscopy was performed 2.1 ± 0.8 (group A) and 2.8 ± 1.2 days postablation (group B), respectively. In 7/40 patients (18%) in group A, thermal lesions (four thermal ulcerations, three minimal thermal lesions) were detected. In group B, 3/20 patients (15%) displayed thermal lesions (three minimal thermal lesions). All thermal lesions resolved upon repeat endoscopy performed 8 ± 6 (group A) and 5 ± 1 days (group B) after initial endoscopy. CONCLUSION: In the EAS group, ETLs were found in 18% of patients, as compared with in 15% in the RFC group. In patients with ETLs, ulcerations were found in 57% in the EAS group, as compared with 0% in the RFC group. This may indicate that the quality of thermal lesions is more severe in the EAS group. Further investigation is required.

One-year clinical outcome after pulmonary vein isolation using the novel endoscopic ablation system in patients with paroxysmal atrial fibrillation.

BACKGROUND: Pulmonary vein isolation (PVI) is an established treatment option for atrial fibrillation (AF). Recently the novel endoscopic ablation system (EAS) was introduced and proved potential for successful acute PVI. OBJECTIVE: This study sought to investigate the 1-year follow-up results after EAS-based PVI. METHODS: A total of 40 patients (20 female, age 57 ± 9 years) with a long history (5 ± 4 years) of drug-refractory (2 ± 1 antiarrhythmic drugs) paroxysmal AF were included into our analysis. PVI was performed using exclusively the novel EAS. Follow-up included regular telephonic interviews, Holter electrocardiographic (ECG) and transtelephonic ECG recordings. A symptomatic or documented AF episode >60 seconds after a blanking period of 3 months was defined as recurrence. RESULTS: A total of 155 PVs were targeted; 153 of 155 (99%) PVs were isolated successfully using exclusively the novel EAS. During a median follow-up of 402 (331 to 478; quartile 1 to quartile 3) days, 24 of 40 patients (60%) remained free of any symptomatic or documented AF episode without antiarrhythmic drugs after a single procedure. Seven patients suffering from AF recurrence underwent radiofrequency current-based Re-PVI 203 ± 102 days after the index EAS-based procedure. Left atrium to pulmonary vein reconduction was found in 17 of 25 initially isolated PVs. No PV stenosis was detected based on magnetic resonance imaging 3 months postablation. CONCLUSION: Patients after EAS-based PVI due to paroxysmal AF demonstrate 1-year single-procedure success rates similar to those of other ablation techniques and ablation energies. The major determinant for AF recurrence after EAS treatment seems to be reconnection of previously isolated PVs. More patients and longer follow-up periods are mandatory before final conclusions can be drawn regarding the efficacy and safety of the EAS.

Feasibility of circumferential pulmonary vein isolation using a novel endoscopic ablation system.

BACKGROUND: Pulmonary vein isolation (PVI) is an established treatment option for patients with drug refractory paroxysmal atrial fibrillation. A novel compliant endoscopic ablation system housing a 980-nm-diode laser allows for discrete point-by-point ablation enabling a true circumferential ablation line design. We sought to determine the feasibility and safety of a circumferential ablation using endoscopic ablation system. METHODS AND RESULTS: Thirty patients (17 female; mean age, 58±9 years) with a median paroxysmal atrial fibrillation history of 3 years (range, 1 to 17 years) were treated. PVI was achieved in 114 of 116 (98%) PVs (4 left common PVs), thereby achieving simultaneous PVI for separate ipsilateral PVs in 19 of 26 (73%) left PVs and 6 of 30 (20%) right PVs. The total procedure time was 250±62 minutes. Procedure time decreased from 310±59 to 220±37 minutes (P=0.0001) between the first 10 and the last 20 cases. Mean fluoroscopy time was 30±18 minutes. Twenty-seven patients underwent postoperative endoscopy showing no or minimal thermal lesions in the esophagus in 21 (78%) and 2 (7%), respectively. In 4 (15%) patients, an esophageal ulceration was found that healed without sequelae. One pericardial tamponade and 1 right-sided phrenic nerve palsy occurred. During a median follow-up of 168 days (113 to 203 days; q1-q3), 24 of 30 patients (80%) remained free of atrial fibrillation recurrence. CONCLUSIONS: Circumferential PVI using the novel compliant endoscopic ablation system was feasible in the majority of left PVs and minority of right PVs accompanied by a complication rate comparable to established approaches. To minimize the risk for thermal esophageal injury temperature monitoring is recommended.