Catheter ablation of ventricular tachycardias using remote magnetic navigation: a consecutive case-control study

Remote Magnetic Navigation for VT Ablation. Background: This study aimed to compare acute and late outcomes of VT ablation using the magnetic navigation system (MNS) to manual techniques (MAN) in patients with (SHD) and without (NSHD) structural heart disease. Methods: Ablation data of 113 consecutive patients (43 SHD, 70 NSHD) with ventricular tachycardia treated with catheter ablation at our center were analyzed. Success rate, complications, procedure, fluoroscopy, and ablation times, and recurrence rates were systematically recorded for all patients. Results: A total of 72 patients were included in the MNS group and 41 patients were included in the MAN group. Patient age, gender, and right ventricular and left ventricular VT were equally distributed. Acute success was achieved in 59 patients in the MNS group (82%) versus 27 (66%) patients in the MAN group (P = 0.046). Overall procedural time (177 ± 79 vs 232 ± 99 minutes, P < 0.01) and mean patient fluoroscopy time (27 ± 19 vs 56 ± 32 minutes, P < 0.001) were all significantly lower using MNS. In NSHD pts, higher acute success was achieved with MNS (83,7% vs 61.9%, P = 0.049), with shorter procedure times (151 ± 57 vs 210 ± 96, P = 0.011), whereas in SHD‐VT these were not significantly different. No major complications occurred in the MNS group (0%) versus 1 cardiac tamponade and 1 significantly damaged ICD lead in the MAN group (4.9%, NS). After follow‐up (20 ± 11 vs 20 ± 10 months, NS), VT recurred in 14 pts (23.7%) in the MNS group versus 12 pts (44.4%) in the MAN group (P = 0.047). Conclusions: The use of MNS offers advantages for ablation of NSHD‐VT, while it offers similar efficacy for SHD‐VT. ((J Cardiovasc Electrophysiol, Vol. 23, pp. 948‐954, September 2012)     

Ablation of Atrial Fibrillation Utilizing Robotic Catheter Navigation in Comparison to Manual Navigation and Ablation: Single‐Center Experience

Background: Robotic catheter navigation and ablation either with magnetic catheter driving or with electromechanical guidance have emerged in the recent years for the treatment of atrial fibrillation. Objective: The aim of this study was to compare our center's experience of atrial fibrillation ablation using the Hansen Robotic Medical System with our current manual ablation technique in terms of acute and chronic success, as well as procedure time and radiation exposure to both the patient and the operator. Methods: A total of 390 consecutive patients with symptomatic and drug‐resistant atrial fibrillation (289 males, 62 ± 11 years) were prospectively enrolled in the study. All patients underwent the procedure either with conventional manual ablation (group 1, n = 197) or with the robotic navigation system (RNS) (group 2, n = 193). Results: The success rate for RNS was 85% (164 patients), while for manual ablation it was 81% (159 patients) (p = 0.264) at 14.1 ± 1.3 months with AADs previously ineffective. Fluoroscopy time was significantly lower for RNS (48.9 ± 24.6 minutes for RNS vs. 58.4 ± 20.1 minutes for manual ablation, P < 0.001). Mean fluoroscopy time was statistically reduced after 50 procedures (61.8 ± 23.2 minutes for first 50 cases vs. 44.5 ± 23.6 minutes for subsequent procedures, P < 0.0001). Conclusion: Robotic navigation and ablation of atrial fibrillation is safe and effective. Fluoroscopy time decreases with experience.     

Mitral isthmus ablation with and without temporary spot occlusion of the coronary sinus: a randomized clinical comparison of acute outcomes

Role of CS Occlusion for Mitral Isthmus Ablation . Objective: To evaluate the safety and outcomes of mitral isthmus (MI) linear ablation with temporary spot occlusion of the coronary sinus (CS). Background: CS blood flow cools local tissue precluding transmurality and bidirectional block across MI lesion. Methods: In a randomized, controlled trial (CS‐occlusion = 20, Control = 22), MI ablation was performed during continuous CS pacing to monitor the moment of block. CS was occluded at the ablation site using 1 cm spherical balloon, Swan–Ganz catheter with angiographic confirmation. Ablation was started at posterior mitral annulus and continued up to left inferior pulmonary vein (LIPV) ostium using an irrigated‐tip catheter. If block was achieved, balloon was deflated and linear block confirmed. If not, additional ablation was performed epicardially (power ≤25 W). Ablation was abandoned after ～30 minutes, if block was not achieved. Results: CS occlusion (mean duration ?27 ± 9 minutes) was achieved in all cases. Complete MI block was achieved in 13/20 (65%) and 15/22 (68%) patients in the CS‐occlusion and control arms, respectively, P = 0.76. Block was achieved with significantly small number (0.5 ± 0.8 vs 1.9 ± 1.1, P = 0.0008) and duration (1.2 ± 1.7 vs 4.2 ± 3.5 minutes, P = 0.009) of epicardial radiofrequency (RF) applications and significantly lower amount of epicardial energy (1.3 ± 2.4 vs 6.3 ± 5.7 kJ, P = 0.006) in the CS‐occlusion versus control arm, respectively. There was no difference in total RF (22 ± 9 vs 23 ± 11 minutes, P = 0.76), procedural (36 ± 16 vs 39 ± 20 minutes, P = 0.57), and fluoroscopic (13 ± 7 vs 15 ± 10 minutes, P = 0.46) durations for MI ablation between the 2 arms. Clinically uneventful CS dissection occurred in 1 patient Conclusions: Temporary spot occlusion of CS is safe and significantly reduces the requirement of epicardial ablation to achieve MI block. It does not improve overall procedural success rate and procedural duration. Tissue cooling by CS blood flow is just one of the several challenges in MI ablation. (J Cardiovasc Electrophysiol, Vol. 23, pp. 489‐496, May 2012)     

Robotically Assisted Ablation Produces More Rapid and Greater Signal Attenuation Than Manual Ablation

Introduction: Robotic remote catheter ablation potentially provides improved catheter‐tip stability, which should improve the efficiency of radiofrequency energy delivery. Percentage reduction in electrogram peak‐to‐peak voltage has been used as a measure of effectiveness of ablation. We tested the hypothesis that improved catheter‐tip stability of robotic ablation can diminish signals to a greater degree than manual ablation. Methods: In vivo NavX? maps of 7 pig atria were constructed. Separate lines of ablation were performed robotically and manually, recording pre‐ and postablation peak‐to‐peak voltages at 10, 20, 30, and 60 seconds and calculating signal amplitude reduction. Catheter ablation settings were constant (25W, 50°, 17 mL/min, 20–30 g catheter tip pressure). The pigs were sacrificed and ablation lesions correlated with NavX maps. Results: Robotic ablation reduced signal amplitude to a greater degree than manual ablation (49 ± 2.6% vs 29 ± 4.5% signal reduction after 1 minute [P = 0.0002]). The mean energy delivered (223 ± 184 J vs 231 ± 190 J, P = 0.42), power (19 ± 3.5 W vs 19 ± 4 W, P = 0.84), and duration of ablation (15 ± 9 seconds vs 15 ± 9 seconds, P = 0.89) was the same for manual and robotic. The mean peak catheter‐tip temperature was higher for robotic (45 ± 5°C vs 42 ± 3°C [P < 0.0001]). The incidence of >50% signal reduction was greater for robotic (37%) than manual (21%) ablation (P = 0.0001). Conclusion: Robotically assisted ablation appears to be more effective than manual ablation at signal amplitude reduction, therefore may be expected to produce improved clinical outcomes.     

Randomized trial of intracardiac echocardiography during cavotricuspid isthmus ablation

Randomized Trial of ICE During CTI Ablation. Introduction: Despite a high success rate, radio‐frequency ablation (RFA) of the cavotricuspid isthmus (CTI) can be unusually challenging in some cases. We postulated that visualization of the CTI with intracardiac echocardiography (ICE) could maximize the succes rate, decrease the procedure and ablation time, and minimize the radiation exposure. Methods and Results: In our prospective, randomized study, we included 102 patients scheduled for CTI ablation. We randomized patients in 2 groups: guided only by fluoroscopy (n = 52) or ICE‐guided (n = 50) group. Procedure time, fluoroscopy time, and the time spent for RFA were significantly shorter, radiation exposure (dose‐area product‐DAP) and the sum of delivered radio frequency energy were significantly lower in the ICE‐group (68.06 ± 15.09 minutes vs 105.94 ± 36.51 minutes, P < 0.001, 5.54 ± 3.77 minutes vs 18.63 ± 10.60 minutes, P < 0.001, 482.80 ± 534.12 seconds vs 779.76 ± 620.82 seconds, P = 0.001 and 397.62 ± 380.81 cGycm² vs 1,312.92 ± 1,129.28 cGycm², P < 0.001, 10,866.84 ± 6,930.84 Ws vs 16,393.56 ± 13,995.78 Ws, P = 0.048, respectively). Seven patients (13%) from the fluoroscopy‐only group crossed over to ICE‐guidance because of prolonged unsuccessful RFA and were all treated successfully. Four vascular complications and 2 recurrences were equally distributed between the 2 groups. Conclusions: ICE‐guided ablation of the CTI significantly shortens the procedure and fluoroscopy time, markedly decreases radiation exposure, and time spent for ablation in comparison with fluoroscopy‐only procedures. At the same time, visualization with ICE allowed successful ablation in challenging cases. (J Cardiovasc Electrophysiol, Vol. 23, pp. 996‐1000, September 2012)     

Impact of patent foramen ovale on left atrial linear lesions in the context of atrial fibrillation ablation

Impact of PFO on LA Linear Ablation. Introduction: We investigated the impact of the mode of left atrial (LA) access via patent foramen ovale (PFO) versus transseptal (TS) puncture on LA linear lesions during atrial fibrillation (AF) ablation. Methods and Results: We investigated 139 (PFO: 25) consecutive patients who underwent mitral isthmus (MI) and/or LA roof linear ablation. Technical endpoint was completeness of linear lesions and duration of radiofrequency (RF) application. During the initial procedure, complete MI and LA roof blocks were created in 13 of 19 (68%) and 14 of 17 (82%) patients in the PFO group, and in 57 of 94 (61%) and 54 of 70 (74%) patients in the TS group, respectively (P = NS). There was no significant difference in RF durations at MI (11.1 ± 8.9 and 15.1 ± 7.6 minutes, P = 0.11), and LA roof (10.1 ± 3.5 and 8.3 ± 5.0 minutes, P = 0.21) between the 2 groups. Among 28 patients who underwent repeat linear ablation, complete MI and LA roof blocks were created in 3 of 4 (75%) and 0 of 1 (0%) patients in the PFO group, and in 16 of 21 (76%) and 7 of 10 (70%) patients in the TS group, respectively (P = NS). There was no significant difference in RF durations at MI (15.3 ± 8.3 and 19.5 ± 18.3 minutes, P = 0.71), and LA roof (19.0 and 10.3 ± 5.4 minutes, P = 0.19) between the 2 groups. Clinical outcomes at 12 months were also similar. Conclusion: There were no significant differences in the procedural success rates, durations of RF application, 12‐month clinical outcomes, and complication rates of LA linear ablation between the PFO and TS groups. Accessing the LA via a PFO is not an unfavorable approach toward LA linear ablation . (J Cardiovasc Electrophysiol, Vol. 22, pp. 846‐850, August 2011)     

Image Integration Using Intracardiac Ultrasound and 3D Reconstruction for Scar Mapping and Ablation of Ventricular Tachycardia

Background: Ablation of ventricular tachycardia (VT) reduces implantable cardioverter defibrillator shocks. Intracardiac ultrasound (ICE) can visualize and quantify the function of all left ventricular wall segments. We thus hypothesized that ICE could identify scar tissue and provide a guide to facilitate substrate‐guided VT ablation. Methods: Eighteen patients underwent VT ablation with real time ICE mapping from the right atrium and ventricle with online 3D‐image reconstruction of scar segments. The left ventricle was also scar mapped by traditional electroanatomic mapping (CARTO) for comparison. Images from these 2 scar mapping techniques were compared to each other as well as to a preprocedure transthoracic echocardiogram. Results: The average age was 65 ± 12 years and 12 (67%) were male (15 [83%] had ischemic cardiomyopathy). Two patients (12%) had recurrence of their clinical VT (1 remained on an antiarrhythmic medication, the other had a repeat ablation) over a follow‐up of 127 ± 33 days. No periprocedural or long‐term adverse events occurred. A total of 248 wall segments were analyzed. All 3 modalities were concordant in scar identification in 193 (78%) segments. The ICE segments correlated with the electroanatomic map in 213 (86%) segments versus 198 (80%), which correlated with transthoracic echocardiography and electroanatomic mapping (P = 0.046). Specifically, the ICE wall motion scores were closer to the electroanatomic mapping in the basal segments and showed a higher accuracy in ischemic heart disease. Conclusion: These data demonstrate that real time ICE images provide accurate chamber geometries and scar boundaries of the left ventricle. These scar borders were more accurate than transthoracic echocardiography and illustrate the feasibility of ICE for substrate‐based ablation for VT. (J Cardiovasc Electrophysiol, Vol. 21, pp. 678‐684, June 2010)     

Noradrenaline reduces ischemia-induced arrhythmia in anesthetized rats: involvement of alpha1-adrenoceptors and mitochondrial K ATP channels

Introduction: We have evaluated the part played by the mitochondrial ATP‐sensitive potassium (mK_ATP) channels on effect of α₁‐adrenoceptor activation by noradrenaline in ischemia‐induced ventricular arrhythmia. Methods and Results: Anesthetized rats were subjected to 25 minutes of regional ischemia, and infarct size (IS) and ischemia‐induced ventricular arrhythmia were measured. Group I served as saline control with ischemia (n = 9). In group II (n = 9), the ischemic period was preceded by three short episodes of ischemia, followed by reperfusion. In group III, noradrenaline (2 μg/kg, IV, n = 9) was injected prior to ischemia. In group IV, an α₁‐adrenoceptor blocker (prazosin, 0.5 mg/kg, IV, n = 6) was administrated prior to noradrenaline injection. In Groups V and VI, rats received a specific mitochondrial K_ATP channel inhibitor [5‐hydroxydecanoic acid (5‐HD), 10 mg/kg, IV, n = 6] prior to or after noradrenaline injection. Ischemic preconditioning (IPC) and noradrenaline markedly reduced incidences of ventricular fibrillation (VF) (0%, 0% vs. 55.5% in control, P < 0.05) and ventricular tachycardia (VT) (11%, 44.5% vs. 100% in control, P < 0.001 and P < 0.05), duration of VF + VT (3 ± 1 seconds, 4.7 ± 2.1 seconds vs. 52.9 ± 6 seconds in control, P < 0.001), number of VF + VT episodes (1.7 ± 1.7, 5.75 ± 2.4 vs. 60.5 ± 8 in control, P < 0.001), severity of arrhythmias (0.3 ± 0.3, 1.7 ± 0.5 vs. 3.9 ± 0.3 in control rats, P < 0.001 and P < 0.01), and IS (13.6 ± 1.8%, 18.2 ± 1.5% vs. 49.6 ± 2.4% in control, P < 0.001). Administration of prazosin or 5‐HD prior to or after noradrenaline injection intensified incidences of VF (66.6%, 66.6% and 50%, P < 0.05) and VT (100%, 100%, and 100%, P < 0.05), duration of VF + VT episodes (70.2 ± 10.5 seconds, 69.8 ± 6.75 seconds, and 60.8 ± 14.9 seconds, P < 0.001), number of VF + VT episodes (56 ± 16.4, 67 ± 11, and 45 ± 3.5, P < 0.01, P < 0.001, and P < 0.05), severity of arrhythmias(3.8 ± 0.3, 4 ± 0.5, and 3.7 ± 0.2, P < 0.01, P < 0.05, and P < 0.01), and IS (45.5 ± 3%, 46.8 ± 3.4%, and 43 ± 2.5%, respectively, P < 0.001) compared with the noradrenaline‐treated group. Conclusion: Prazosin or 5‐HD treatment eliminated the beneficial effects of noradrenaline on arrhythmogenesis and infarct size.     

Long‐Term Outcome of Catheter Ablation in Patients with Atrial Fibrillation Originating from Nonpulmonary Vein Ectopy

Long‐Term Outcome of NPV AF Ablation . Introduction: Data regarding the long‐term outcome of catheter ablation in patients with nonpulmonary vein (NPV) ectopy initiating atrial fibrillation (AF) are limited. We aimed to evaluate the long‐term result of patients with AF who had NPV triggers and underwent catheter ablation. Methods and Results: The study included 660 consecutive patients (age 54 ± 11 years old, 477 males) who had undergone catheter ablation for AF. Group 1 consisted of 132 patients with AF initiating from the NPV, and group 2 consisted of 528 patients with AF initiating from pulmonary vein (PV) triggers only. Patients from Group 1 were younger than those from Group 2 (51 ± 12 years old vs 54 ± 11 years old, P = 0.001) and were more likely to be females (34.4% vs 25.8%, P = 0.049). The incidences of nonparoxysmal AF (36.4% vs 16.3%, P < 0.001) and right atrial (RA) enlargement (31.3% vs 19%, P = 0.004) were higher, and the biatrial substrates were worse in Group 1 than those in Group 2 (left atrial voltage 1.5 ± 0.7 mV vs 1.9 ± 0.7 mV, P < 0.001, RA voltage 1.6 ± 0.5 mV vs 1.8 ± 0.6 mV, P = 0.014). During a follow‐up period of 46 ± 23 months, there was a higher AF recurrence rate in Group 1 than in Group 2 (57.6% vs 38.8%, P < 0.001). The independent predictors of AF recurrence were NPV trigger (P < 0.001, HR 2, 95% CI 1.4–2.85), nonparoxysmal AF (P = 0.021, HR 1.55, 95% CI 1.07–2.24), larger left atrial diameter (P = 0.002, HR 1.04, 95% CI 1.02–1.07) and worse left atrial substrate (P = 0.028, HR 1.3, 95% CI 1.03–1.64). Conclusion: Compared to AF originating from the PV alone, AF originating from the NPV ectopy showed a worse outcome. (J Cardiovasc Electrophysiol, Vol. 24, pp. 250‐258, March 2013)     

Ultra High‐Density Multipolar Mapping With Double Ventricular Access: A Novel Technique for Ablation of Ventricular Tachycardia

Ultra High‐Density Multipolar Mapping With Double Ventricular Access . Background: Analogous to the use of circular loop catheters to guide ablation around the pulmonary veins, it may be advantageous to use a multipolar catheter in the ventricle for rapid mapping and to guide ablation. We describe a technique using double access into the left ventricle for multipolar electroanatomic mapping and ablation of scar‐mediated ventricular tachycardia (VT). Methods: Double access into the left ventricle was obtained via transseptal technique. Endocardial mapping was performed via the first transseptal sheath using a steerable duodecapolar catheter. Higher density mapping was performed in areas of dense scar (<0.5 mV) and border zone (0.5–1.5 mV). All late potentials (LPs) observed on the 20 poles were tagged and pacemapping was performed at these sites for comparison with the clinical or induced VT 12‐lead template. If VT was hemodynamically tolerated, entrainment mapping was attempted at sites demonstrating diastolic activity. Ablation was performed through the second transseptal sheath with an open‐irrigated catheter at target sites identified by LPs, pacemapping, and/or entrainment on the duodecapolar catheter. Results: Seventeen patients (88% ischemic cardiomyopathy) underwent electroanatomic mapping and ablation with double transseptal access. The mean number of endocardial mapping points was 819 ± 357 with an average mapping time of 31 ± 7 minutes. The mean number of VTs induced was 2.8 ± 1.6, mean cycle length 418 ms ± 101. LPs were seen in all patients during endocardial mapping with the duodecapolar catheter. Good (56%) and perfect (44%) pacemaps were seen in all patients when performed. Concealed entrainment, guided by the earliest diastolic activity seen on the duodecapolar catheter, was demonstrated in 4 patients (24%). Acute success was achieved in 94% of patients with complete success in 47% and partial success in 47%. The intermediate success rate (free of VT recurrence) was 69%, with an average follow‐up of 8 ± 3 months. Conclusion: Mapping and ablation of scar‐mediated VT using a multipolar catheter results in ultra high‐density delineation of the left ventricular substrate. A novel double ventricular access strategy has the potential to facilitate identification of LPs, pacemapping, and entrainment mapping. (J Cardiovasc Electrophysiol, Vol. 22, pp. 49‐56, January 2011)     

Left atrial radiofrequency ablation during cardiac surgery in patients with atrial fibrillation

Introduction: Intraoperative left atrial radiofrequency (RF) ablation recently has been suggested as an effective surgical treatment for atrial fibrillation (AF). The aim of this study was to verify the outcome of this technique in a controlled multicenter trial. Methods and Results: One hundred three consecutive patients (39 men and 65 women; age 62 ± 11 years) affected by AF underwent cardiac surgery and RF ablation in the left atrium (RF group). The control group consisted of 27 patients (6 men and 21 women; age 64 ± 7 years) with AF who underwent cardiac surgery during the same period and refused RF ablation. Mitral valve disease was present in 89 (86%) and 25 (92%) patients, respectively (P = NS). RF endocardial ablation was performed in order to obtain isolation of both right and left pulmonary veins, a lesion connecting the previous lines, and a lesion connecting the line encircling the left veins to the mitral annulus. Upon discharge from the hospital, sinus rhythm was present in 65 patients (63%) versus 5 patients (18%) in the control group (P < 0.0001). Mean time of cardiopulmonary bypass was longer in the RF group (148 ± 50 min vs 117 ± 30 min, P = 0.013). The complication rate was similar in both groups, but RF ablation‐related complications occurred in 4 RF group patients (3.9%). After a mean follow‐up of 12.5 ± 5 months (range 4–24), 83 (81%) of 102 RF group patients were in stable sinus rhythm versus 3 (11%) of 27 in the control group (P < 0.0001). The success rate was similar among the four surgical centers. Atrial contraction was present in 66 (79.5%) of 83 patients in the RF group in sinus rhythm. Conclusion: Endocardial RF left atrial compartmentalization during cardiac surgery is effective in restoring sinus rhythm in many patients. This technique is easy to perform and reproducible. Rare RF ablation‐related complications can occur. During follow‐up, sinus rhythm persistence is good, and biatrial contraction is preserved in most patients. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1289‐1295, December 2003)     

Effect of limb lead electrodes location on ECG and localization of idiopathic outflow tract tachycardia: a prospective study

Role of ECG in Localization of OT‐VT. Background: Different kinds of the surface ECG limb electrode positions may affect the limb lead vector and therefore the accuracy of the 12‐lead ECG in localization of outflow tract ventricular tachycardia (OTVT). This study was intended to evaluate and compare the accuracy of the standard and the modified 12‐lead ECG for localization of OTVT using the current published criteria. Methods and Results: Twenty consecutive patients (10 men, mean age, 51.6 ± 13.4 years) with OT‐VT were included. A standard ECG with the distal placement of the limb lead electrodes and a modified ECG with the limb electrodes placed on the torso were recorded during the OT‐VT and were used for localization by 2 electrophysiologists who were blinded to the successful ablation site to compare the accuracy of the 2 ECGs. The R wave amplitude during OT‐VT in lead I of the standard 12‐lead ECG was significantly higher compared to the modified surface ECG (0.225 ± 0.145 mV vs 0.139 ± 0.111 mV, P = 0.032). The S wave in aVR during OT‐VT was significantly more negative compared to the modified surface ECG (?0.682 ± 0.182 mV vs ?0.527 ± 0.228 mV, P = 0.017). The rate of accurate localization of the successful ablation sites in the anterior versus posterior outflow tract by the 2 observers using standard ECG (70% and 80%) were higher compared to modified ECG (50% and 60%, P = 0.042). Conclusion: The R wave amplitude in lead I and the depth of the S wave amplitude in lead aVR of the standard surface ECG during OT‐VT is significantly larger compared to the modified surface ECG. As the QRS morphology of the OT‐VT is usually the first clue to the possible site of successful ablation, the standard 12‐lead ECG should be used for more accurate localization of the origin of the OT‐VT. (J Cardiovasc Electrophysiol, Vol. 22, pp. 886‐891, August 2011)     

Intracardiac Echocardiography Improves Procedural Efficiency During Cryoballoon Ablation for Atrial Fibrillation: A Pilot Study

Intracardiac Echocardiography Guided Cryoballoon Ablation. Background: Cryoballoon ablation is increasingly used for pulmonary vein isolation (PVI) in patients with atrial fibrillation (AF). This new technique aims to perform PVI safer and faster. However, procedure and fluoroscopy times were similar to conventional RF approaches. We compared ICE plus fluoroscopy versus fluoroscopy alone for anatomical guidance of PVI. Methods: Forty‐three consecutive patients with paroxysmal AF were randomly assigned to ICE plus fluoroscopy (n = 22) versus fluoroscopy alone (n = 21) for guidance of cryoballoon PVI. A “single big balloon” procedure using a 28 mm cryoballoon was performed. The optimal ICE‐guided position of the cryoballoon was assessed by full ostial occlusion and loss of Doppler coded reflow to the left atrium (LA). Any further freezes were ICE‐guided only without use of fluoroscopy or contrast media injection. Results: A total of 171 pulmonary veins could be visualized with ICE. 80% of ICE‐guided freezes were performed with excellent ICE quality. Acute procedural success and AF recurrence rate at 6 months were similar in both groups (AF recurrence: ICE‐guided = 27% vs Fluoroscopy = 33%; P = ns). Patients without ICE guidance had significantly longer procedure (143 ± 27 minutes vs 130 ± 19 minutes; P = 0.05) and fluoroscopy times (42 ± 13 minutes vs 26 ± 10, P = 0.01). The total amount of contrast used during the procedure was significantly lower in patients with ICE guidance (88 ± 31 mL vs 169 ± 38 mL, P < 0.001). Conclusion: Additional ICE guidance appears to be associated with lower fluoroscopy, contrast, and procedure times, with similar efficacy rates. Specifically, ICE allows for better identification of the PV LA junction and more precise anatomically guided cryoballoon ablations. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1202‐1207, November 2010)     

A novel finding of the atrial substrate properties and long-term results of catheter ablation in chronic atrial fibrillation patients with left atrial spontaneous echo contrast

Atrial Substrate Properties in Chronic AF Patients with LASEC. Background: The atrial substrate in chronic atrial fibrillation (AF) patients with a left atrial spontaneous echo contrast (LASEC) has not been previously reported. The aim of this study was to investigate the atrial substrate properties and long‐term follow‐up results in the patients who received catheter ablation of chronic AF. Methods: Of 36 consecutive patients with chronic AF who received a stepwise ablation approach, 18 patients with an LASEC (group I) were compared with 18 age‐gender‐left atrial volume matched patients without an LASEC (group II). The atrial substrate properties including the weighted peak‐to‐peak voltage, total activation time during sinus rhythm (SR), dominant frequency (DF), and complex fractionated electrograms (CFEs) during AF in the bi‐atria were evaluated. Result: The left atrial weighted bipolar peak‐to‐peak voltage (1.0 ± 0.6 vs 1.6 ± 0.7 mV, P = 0.04), total activation time (119 ± 20 vs 103 ± 13 ms, P < 0.001) and DF (7.3 ± 1.3 vs 6.6 ± 0.7 Hz, P < 0.001) differed between group I and group II, respectively. Those parameters did not differ in the right atrium. The bi‐atrial CFEs (left atrium: 89 ± 24 vs 92 ± 25, P = 0.8; right atrium: 92 ± 25 vs 102 ± 3, P = 0.9) did not differ between group I and group II, respectively. After a mean follow‐up of 30 ± 13 month, there were significant differences in the antiarrhythmic drugs (1.1 ± 0.3 vs 0.7 ± 0.5, P = 0.02) needed after ablation, and recurrence as persistent AF (92% vs 50%, P = 0.03) between group I and group II, respectively. After multiple procedures, there were more group II patients that remained in SR, when compared with group I (78% vs 44%, P = 0.04). Conclusion: There was a poorer atrial substrate, lesser SR maintenance after catheter ablation and need for more antiarrhythmic drugs in the chronic AF patients with an LASEC when compared with those without an LASEC. (J Cardiovasc Electrophysiol, Vol. pp. 1‐8)     

Influence of Clinical and Procedural Predictors on Ventricular Tachycardia Ablation Outcomes: An Analysis From the Substrate Mapping and Ablation in Sinus Rhythm to Halt Ventricular Tachycardia Trial (SMASH‐VT)

Procedural Predictors in SMASH‐VT . Background: The Substrate Mapping and Ablation in Sinus Rhythm to Halt Ventricular Tachycardia (SMASH‐VT) trial is the largest randomized trial in substrate‐based ablation. We performed a retrospective analysis of patients randomized to prophylactic ablation of ventricular tachycardia to determine the predictive value of clinical and procedural variables on outcomes. Methods: In patients treated with catheter ablation, we examined predictors of ICD‐therapy free survival using Cox proportional hazards models. Procedural variables tested included the scar location, number of VT morphologies (VTs) induced, tachycardia cycle length, catheter irrigation, catheter approach, procedural duration, and VT inducibility after ablation. Clinical variables including age, index arrhythmia, NYHA class, ejection fraction, prior revascularization, and baseline medication use were also analyzed. Results: Among 64 patients randomized to ablation, 61 received the assigned therapy and complete procedural data were available for 54 patients. Thirteen percent (7 of 54) experienced ICD therapies during 2‐year follow‐up. Patients with subsequent ICD therapies had significantly more VTs induced during the ablation procedure than those without (3.9 ± 2.1 vs 1.9 ± 1.8, P = 0.05). The hazard ratio for each additional VT induced was 1.51 (95% CI 1.07–2.13, P = 0.02). Two‐year Kaplan–Meier event‐free survival rates were 96% for 0–1 VTs induced, and 78% for two or more. The use of irrigated catheters was not predictive of ablation success. Conclusion: In this small retrospective analysis, the number of VTs induced during the procedure was predictive of 2‐year outcomes. This likely reflects a more complex arrhythmia substrate in patients who fail ablation. (J Cardiovasc Electrophysiol, Vol. pp. 799‐803, July 2010)     

QRS characteristics fail to reliably identify ventricular tachycardias that require epicardial ablation in ischemic heart disease

Criteria for Epicardial Origin in Ischemic VT. Objectives: We tested proposed algorithms for idiopathic and nonischemic tachycardias for their ability to identify epicardial LV‐VT origins. Backgroud: Several ECG features have been reported to identify epicardial origins for left ventricular tachycardias (LV‐VTs) in the absence of myocardial infarction. Only limited data exist in postinfarction patients. Methods: The QRS features of 24 VTs that were ablated from the epicardium and 39 left ventricular VTs ablated from the endocardium were retrospectively analyzed for various 12‐lead ECG features previously reported. Results: No ECG feature consistently predicted an epicardial LV‐VT origin in infarct‐related tachycardias, with epicardial VTs showing slightly longer QRS durations (189 ± 32 ms in epicardial vs 179 ± 37 ms in endocardial, P = 0.28). Pseudo‐delta duration was 38 ± 27 versus 47 ± 27 ms (P = 0.2), intrinsicoid deflection time 93 ± 35 versus 86 ± 32 ms (P = 0.4), shortest RS 97 ± 38 versus 99 ± 32 ms (P = 0.77), and median deflection index 0.82 ± 0.25 versus 0.87 ± 0.22 (P = 0.43). The finding of a Q wave in lead I and the absence of a Q wave in the inferior leads failed to predict an epicardial origin in superior LV‐VT sites. Q waves in any inferior lead and aVR/aVL‐ratio<1 were not specific for an epicardial origin in inferior sites (all P = ns). Furthermore, all inferior LV‐VTs showed a Q wave in the inferior leads which correlated with pre‐existing Q‐waves in sinus rhythm (P = 0.045). Conclusion : Proposed 12‐lead ECG features for differentiation of epicardial versus endocardial sites for nonischemic LV‐VTs do not reliably identify VTs that require ablation from the epicardium. Endocardial mapping should be the first approach to catheter ablation for VTs in patients with ischemic heart disease. (J Cardiovasc Electrophysiol, Vol. 23, pp. 188‐193, February 2012)     

Prospective assessment of short- and long-term quality of life after ablation for atrial fibrillation

Quality of Life After Ablation for Atrial Fibrillation. Background : This study prospectively assesses different aspects of short‐ and long‐term quality of life (QoL) after catheter ablation for atrial fibrillation (AF). An analysis of 7 validated generic and tailored questionnaires was performed with regard to the relation of QoL to ablation success. Methods : The study included 133 patients (74% men, age 57±10) who underwent pulmonary vein isolation ± linear or electrogram‐guided substrate modification for AF. QoL was quantitatively assessed at baseline, 3 months after ablation and at a median of 4.3 ± 0.5 years after ablation by the AF severity scale (AFSS), AF symptom checklist (AFSC), WHO‐5‐Well‐Being‐Index (WHO), Major Depression Inventory (MDI), Sleep and Vegetative disorder (SV), Vital Exhaustion (VE), and Illness intrusiveness (Ii). Results: QoL was improved significantly 3 months after ablation in all patients (regardless of ablation success or AF type) and stayed significantly improved after a median of 4.3±0.5 years (AFSS, AFSC, WHO, MDI, VE, PE (all P < 0.001), and SV (P = 0.007)). Patients who had a successful ablation improved significantly more than patients with an unsuccessful ablation in the AFSS, AFSC, and MDI questionnaire (delta change from baseline to long‐term follow‐up P = <0.001, P = <0.001, and P = 0.039, respectively). Conclusion: Overall, all patients significantly improved their QoL irrespective of the AF type in all questionnaires 3 months and 4 years after ablation. The increase in QoL was significantly greater in patients who underwent a successful ablation than patients with unsuccessful ablation in the AFSS, AFSC, and MDI questionnaire. Cardiovasc Electrophysiol, Vol. 23, pp. 121‐127, February 2012)     

Impact of a patent foramen ovale on paroxysmal atrial fibrillation ablation

Introduction: A patent foramen ovale (PFO) is located at the anterior and superior part of the anatomical interatrial septum, the area that is targeted during transseptal puncture. This study sought to investigate the impact of accessing the left atrium via a PFO on paroxysmal AF ablation. Methods: From March 2004, 203 patients (55 ± 11 years) underwent catheter ablation for paroxysmal AF (80 ± 71 months), with the endpoint being electrical isolation of all pulmonary veins (PV) and AF noninducibility. The presence of a PFO was determined by both transesophageal echocardiography and catheter probing. Procedural difficulty was evaluated by radiofrequency (RF), procedural, and fluoroscopic durations. Clinical follow‐up was also investigated. Results: A PFO was detected in 27 patients (13%) by transesophageal echocardiography and in 22 additional patients (total 49 patients, 24%), by catheter probing (P < 0.001). A PFO was associated with longer total RF applications (57 ± 19 vs 51 ± 18 min, P = 0.04) and RF applications to isolate the PVs (42 ± 16 vs 35 ± 12 min, P = 0.001). Procedural and fluoroscopic times were unaffected. Seventy‐three patients (36%) required a second procedure; there was no difference in the number of PV reconnections (1.3 vs 1.8 veins, P = NS). After a mean follow‐up of 19 ± 9 months, 194/203 patients (96%) were free of AF, with no difference in patients in whom a PFO had been used. Conclusion: Although isolation of PVs is longer, overall procedural duration and success is not affected when using a PFO compared with a transseptal puncture. The presence of a PFO is underestimated by transesophageal echocardiography with brachial injection when compared with catheter probing.     

Ablation of unstable ventricular dysrhythmias guided by non contact mapping system among patients with cardiomyopathy in a growing single center experience

We report our local experience in using the non contact mapping system in guiding catheter ablation of unstable/non sustained Ventricular tachycardia (VT) and its short and long term implications.Patients and methodsThis report includes 18 cardiomyopathic patients, 13 males, age 40.5 ± 15 yrs, who presented to our centre with VT that share in common being unstable or non sustained. The patients were subjected to radiofrequency catheter ablation guided by the non contact mapping system.ResultsAcute successful outcome was obtained in 6 out of 8 (75%) patients with scar related VTs (post myocardial infarction and arrhythmogenic right ventricular dysplasia) and 9 of 10 (90%) patients with idiopathic dilated cardiomyopathy. Long term follow up for 6–24 (16 ± 8) months showed recurrence in one case of the scar related group and in two cases of the idiopathic group, so the overall long term success rates were 62.5% vs 70% (P. NS). Regular Echocardiographic showed an improvement of 10–15% in the Ejection Fraction in successful cases of the idiopathic group (Average Post-ablation EF in the idiopathic group of 49 ± 5% vs pre-ablation EF of 41 ± 4% while 42 ± 6 pre Vs 42 ± 7% post ablation in the scar related group) (P < 0.01).ConclusionNon contact mapping guided RF ablation of unstable VT in patients with cardiomyopathy showed good immediate results and long term outcome both in scar related and in idiopathic cardiomyopathy patients. Successful RF ablation of non sustained ventricular dysrhythmias among patients with idiopathic Cardiomyopathy may improve LV dysfunction.     

Mapping of Atrial Tachycardia by Remote Magnetic Navigation in Postoperative Patients With Congenital Heart Disease

Remote Magnetic Mapping in Congenital Heart Disease . Objectives: The purpose of this study was to investigate if remote magnetic navigation (RMN) offers a reduction of fluoroscopy time when used for atrial tachycardia (AT) mapping in a spectrum of patients with congenital heart disease (CHD) after “simple” or “complex” atrial surgery. Background: Data about AT mapping using RMN in larger populations of patients with CHD are scarce. Methods: RMN in combination with electroanatomic mapping was used for AT mapping in 22 patients. According to anatomic complexity, patients were classified into 3 groups: Group 1: patients after minor atrial surgery (n = 7); Group 2: patients after the Fontan operation (n = 9); and group 3: patients after the Senning/Mustard operation (n = 6). Results: Atrial mapping with a nonirrigated tip RMN catheter was completed successfully in all patients. In Group 1 no significant reduction in fluoroscopy time was noticed over time (mean fluoroscopy time 7.9 minutes). In the 15 patients of group 2 and group 3 with complex CHD, the fluoroscopy time for mapping in the last 9 patients (6.4 ± 2.8 minutes) was significantly shorter than in the first 6 patients (29.7 ± 10.5 minutes, P < 0.0001). Acutely successful ablation was achieved in 21 of 22 patients (97%) using the RMN catheter (n = 3) or a conventional catheter (n = 18) without procedural complications. Conclusions: RMN for AT mapping in patients with complex atrial anatomy leads to a significant reduction of fluoroscopy time. (J Cardiovasc Electrophysiol, Vol. pp. 751‐759, July 2010)