Cardiac resynchronisation therapy in patients with left bundle branch block with residual conduction.

AIM: To evaluate whether left bundle branch block with residual conduction (rLBBB) is associated with worse outcomes after cardiac resynchronisation therapy (CRT). METHODS: All consecutive CRT implants at our institution between 2006 and 2013 were identified from our local device registry. Pre- and post-implant patient specific data were extracted from clinical records. RESULTS: A total of 690 CRT implants were identified during the study period. Prior to CRT, 52.2% of patients had true left bundle branch block (LBBB), 19.1% a pacing-induced LBBB (pLBBB), 11.2% a rLBBB, 0.8% a right bundle branch block (RBBB), and 16.5% had a nonspecific intraventricular conduction delay (IVCD) electrocardiogram pattern. Mean age at implant was 67.5 years (standard deviation [SD] = 10.6), mean left ventricular ejection fraction (LV EF) was 25.7% (SD = 7.9%), and mean QRS duration was 158.4 ms (SD = 32 ms). After CRT, QRS duration was significantly reduced in the LBBB (p < 0.001), pLBBB (p < 0.001), rLBBB (p < 0.001), RBBB (p = 0.04), and IVCD groups (p = 0.03). LV EF significantly improved in the LBBB (p < 0.001), rLBBB (p = 0.002), and pLBBB (p < 0.001) groups, but the RBBB and IVCD groups showed no improvement. There was no significant difference in mortality between the LBBB and rLBBB groups. LV EF post-CRT, chronic kidney disease, hyperkalaemia, hypernatremia, and age at implant were significant predictors of mortality. CONCLUSION: CRT in patients with rLBBB results in improved LV EF and similar mortality rates to CRT patients with complete LBBB. Predictors of mortality post-CRT include post-CRT LV EF, presence of CKD, hyperkalaemia, hypernatremia, and older age at implant.

Safety and outcome of very high-power short-duration ablation using 70 W for pulmonary vein isolation in patients with paroxysmal atrial fibrillation.

AIMS: Pulmonary vein isolation (PVI) using radiofrequency ablation (RFA) in patients with paroxysmal atrial fibrillation (PAF) is effective but hampered by pulmonary vein reconnection due to insufficient ablation lesions. High-power delivery over a short period of time (HPSD) in RFA is stated to create more efficient lesions. The aim of this study was to compare intraprocedural safety and outcome of HPSD ablation to conventional power settings in patients undergoing PVI for PAF. METHODS AND RESULTS: We included 197 patients with PAF that were scheduled for PVI. An ablation protocol with 70 W and a duration cut-off of 7 s at the anterior left atrium (LA) and 5 s at the posterior LA (HPSD group; n = 97) was compared to a conventional power protocol with 30-40 W for 20-40 s (standard group; n = 100) in terms of periprocedural complications and a 1-year outcome. The HPSD group showed significantly less arrhythmia recurrence during 1-year follow-up with 83.1% of patients free from atrial fibrillation compared to 65.1% in the standard group (P < 0.013). No pericardial tamponade, periprocedural thromboembolic complications, or atrio-oesophageal fistula occurred in either group. Mean radiofrequency time (12.4 ± 3.4 min vs. 35.6 ± 12.1 min) and procedural time (89.5 ± 23.9 min vs. 111.15 ± 27.9 min) were significantly shorter in the HPSD group compared to the standard group (both P < 0.001). CONCLUSION: High-power short-duration ablation demonstrated a comparable safety profile to conventional ablation. High-power short-duration ablation using 70 W for 5-7 s leads to significantly less arrhythmia recurrences after 1 year. Radiofrequency and procedural time were significantly shortened.

Early recurrence after pulmonary vein isolation is associated with inferior long-term outcomes: Insights from a retrospective cohort study.

AIMS: The aim of this retrospective cohort study was to assess the influence of early recurrence (ER) after pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (AF) on long-term outcomes and to identify clinical variables associated with ER. METHODS: We retrospectively collected clinical and procedural data from 1285 patients with paroxysmal AF who underwent PVI from 2011 to 2016. Kaplan-Meier, receiver operating characteristic (ROC) curve, logistic and Cox regression analyses were performed to analyze the influence of ER on long-term outcomes. RESULTS: ER was observed in 13% of patients. Kaplan-Meier analyses showed significantly different outcomes in 1285 patients with and without ER (49% vs 74%, log rank P < .01) and in 286 patients in the subgroup that underwent reablation (44% vs 79%, log rank P < .01). The hazard ratio (HR) of ER was 1.7 within 48 hours (5% of patients), 2.7 within 1 month (5%), 3.0 within 2 months (2%), and 6.4 within 3 months (1%) for late recurrence (LR), P < .01. ROC analysis (area under the curve [AUC] = 0.79) resulted in 70.3% sensitivity and 74.2% specificity for a 14-day blanking period, and 53.1% sensitivity and 85.5% specificity for a 30-day blanking period. Female patients (odds ratio [OR] 1.69, P < .01) and those with diabetes (OR 1.95, P = .01) were at higher risk for ER. CONCLUSIONS: ER is observed in a substantial number of patients with paroxysmal AF after PVI and has a continuous direct effect on LR according to the timing of ER. Randomized trials are required to assess the safety and effects of reablations in a shortened blanking period on long-term outcomes.

EP radiofrequency generators: Significant offsets between selected and delivered power?

INTRODUCTION: For radiofrequency (RF) ablation, the EP Shuttle® (Stockert GmbH, Freiburg, Germany), Ampere® (St. Jude Medical, St. Paul, MN, USA), and SmartAblate® (Biosense Webster, Diamond Bar, CA, USA) generator models are most frequently used in clinical practice. The aim of this study was to assess the correlation between selected and delivered RF power for different generators. METHODS AND RESULTS: In an experimental setup, ablation catheters were connected to the EP Shuttle® , Ampere® , and SmartAblate® generators. The power delivered by the generators was measured using a current converter and an oscilloscope. The selected power displayed on the generator was compared to the actually delivered power measured by the experimental setup (n = 800 measurements). The offsets between selected and delivered power increased significantly with impedance (EP Shuttle® ). For example, at a selected power of 30 W, the delivered power was 40.3 W (EP Shuttle® ), 30.1 W (Ampere® ), and 28.1 W (SmartAblate® ) at an impedance of 200 Ω. In addition, ablation lesions (n = 80) were created in ex vivo porcine cardiac muscle preparations. The resulting ablation lesion size was calculated in caliper measurements. When the EP Shuttle® generator was operated at 200 Ω, the resulting lesion size was significantly larger than at 100 Ω. There were no significant offsets between power delivery and lesion size when using the Ampere® or SmartAblate® generators. CONCLUSIONS: The Ampere® and SmartAblate® generator models deliver accurate power as selected by the user. The power delivered by the EP Shuttle® generator exceeds the selected power by up to 40% depending on impedance. The findings were confirmed in ex vivo porcine heart experiments and should be considered in clinical practice.

Ablation of Complex Fractionated Electrograms With or Without ADditional LINEar Lesions for Persistent Atrial Fibrillation (The ADLINE Trial).

BACKGROUND: For persistent atrial fibrillation (AF) ablation, different strategies including complex fractionated atrial electrograms (CFAE) ablation and linear lesions (LL) have been used in addition to pulmonary vein isolation (PVI). However, it is still a matter of debate if extended substrate modification improves long-term outcome. The aim of this study was to determine the benefit of LL in addition to PVI and CFAE ablation regarding freedom from arrhythmia recurrence in patients with persistent AF. METHODS: The study was a prospective randomized trial including 90 patients with persistent and longstanding persistent AF. All patients underwent PVI and CFAE ablation. If AF did not terminate to atrial tachycardia (AT) or sinus rhythm, patients were randomized to direct current cardioversion (Group 1; n = 45) or LL (Group 2; n = 45). Primary endpoint was freedom from any atrial arrhythmia off antiarrhythmic drugs at 12 months. (NCT02059369) RESULTS: Baseline characteristics were similar between the two groups with more than half of the patients having structural heart disease. The primary endpoint was reached in 37% in Group 1 (G1) and 16% in Group 2 (G2; P = 0.03). After a total number of 1.4 ± 0.5 (G1) versus 1.7 ± 0.4 (G2; P = 0.01) procedures, freedom from any arrhythmia was reached in 54% in G1 and 65% in G2 (P = 0.35). CONCLUSION: In persistent AF ablation, LL in addition to PVI and CFAE show a significantly lower success rate after a single procedure compared to PVI and CFAE. Following LL, significantly more patients needed a reablation to reach a similar success rate during a 12-month follow-up.

Catheter ablation of left atrial arrhythmias on uninterrupted oral anticoagulation with vitamin K antagonists: What is the relationship between international normalized ratio, activated clotting time, and procedure-related complications?

BACKGROUND: Ablation of atrial fibrillation (AF) on uninterrupted phenprocoumon reduces periprocedural thromboembolic and bleeding complications. Heparin is administered intraprocedurally to achieve activated clotting times (ACT) of 300-400 seconds. We investigated the effect of international normalized ratio (INR) on ACT and intraprocedural heparin requirements. Moreover, safety of a target ACT of 250-300 seconds was investigated. METHODS AND RESULTS: We studied 949 patients referred for AF or left atrial tachycardia ablation. Patients were divided into Group 1 (n = 249) with an INR <2 and Group 2 (n = 700) with an INR ≥2. Mean INR was 1.7 ± 0.13 in Group 1 and 2.3 ± 0.25 in Group 2. Baseline, mean, minimum and maximum ACT were significantly lower in Group 1 (138 ± 17 seconds vs. 145 ± 21 seconds; 281 ± 28 seconds vs. 288 ± 29 seconds; 251 ± 36 seconds vs. 258 ± 34 seconds; 307 ± 32 seconds vs. 316 ± 40 seconds; P <0.05). Intraprocedural heparin requirements adjusted to body weight were lower in Group 1 (127 ± 41 U/kg vs. 122 ± 40 U/kg). Weak correlations between INR and baseline, mean, minimum and maximum ACT as well as intraprocedural heparin requirements were observed. No differences regarding major or minor complications were found. INR and periprocedural anticoagulation parameters had no influence on major complications. No thromboembolic complications were observed in both groups with a target ACT value of 250-300 seconds. CONCLUSIONS: There is only a weak correlation between INR, intraprocedural ACT, and intraprocedural heparin requirements. Periprocedural target ACT of 250-300 seconds seems safe and does not increase periprocedural bleeding and thromboembolic complications in patients undergoing RF ablation on uninterrupted phenprocoumon therapy.

Irrigated-tip catheters for radiofrequency ablation of right-sided accessory pathways in adolescents.

BACKGROUND: Catheter ablation of right-sided accessory pathways (APs) has lower success and higher recurrence rates compared to left-sided substrates. Irrigated-tip catheter (ITC) ablation might offer an advantage in this setting but data about its use in patients below 18 years are scarce. The aim of this study was to compare an ITC approach to conventional catheter ablation. METHODS: A retrospective analysis of all patients <18 years undergoing radiofrequency ablation (RFA) for right-sided APs from 2004 to 2014 at our institution was performed. Patients either underwent an ITC approach in combination with 3-D mapping (Group 1; n  =  53) or a conventional non-ITC approach (Group 2; n  =  52). Study endpoints were acute procedural success, safety, and recurrence rate. A total of 105 mostly adolescent patients (56.2% male; median age 14 years) with 107 right-sided APs were included. RESULTS: The prevailing anatomic AP locations were right posteroseptal (44.9%), right anterior/anterolateral (24.3%), and right lateral (13.1%). Acute success (94.3% vs 94.2%) did not differ between the groups. One major complication (pericardial effusion) occurred in the non-ITC group. Overall, freedom from AP recurrence was 94% at 4 years in the ITC group, and 81% at 4 years in the non-ITC group (P  =  0.04). CONCLUSIONS: The use of ITCs in combination with 3-D mapping system for ablation of right-sided APs in adolescents has a high acute success rate, is safe, and associated with a significantly reduced recurrence rate compared to a non-ITC/conventional approach. It might be considered as alternative approach in this age group.

Transseptal Puncture Guided by CT-Derived 3D-Augmented Fluoroscopy.

BACKGROUND: Transseptal puncture for left atrial (LA) access is still mainly performed using fluoroscopy and transesophageal or intracardiac echocardiography. We present an easily applicable approach for the guidance of transseptal puncture that uses the combination of a 3D-mapping system and CT-derived 3D-overlayed anatomy. METHODS AND RESULTS: A computer tomographic (CT) LA-angiography was performed in n = 65 patients prior to a scheduled atrial fibrillation ablation procedure. The CARTO3 (Biosense Webster, Diamond Bar, CA, USA) segmentation tool was used to create a 3D-reconstruction of cardiac anatomy and the spine. The CARTO UNIVU module was then used to overlay and register the segmented 3D-anatomy onto fluoroscopy. The 3D-reconstructed spine and cardiac anatomy were congruently aligned to their fluoroscopic counterparts in fluoroscopic views. The feasibility of the technique, its safety, and accuracy (assessed as contour offsets between 3D-overlay and angiographic LA anatomy) were evaluated. Overlay registration accuracy was analyzed by CARTO3 registration matrices. Transseptal puncture was feasible without complications in all 65 patients using the new 3D-overlay technique. Three-dimensional-overlay contour offsets were 1.6 ± 1.2 mm in left PV, 1.7 ± 1.2 mm in right PV, and 1.3 ± 1.0 mm in the LA roof region. Overlay registration accuracy was 4.9 ± 2.7 mm. The average time needed for anatomy segmentation was 204 ± 61 seconds, time needed for overlay registration was 18 ± 8 seconds. CONCLUSIONS: Three-dimensional-augmented fluoroscopy is feasible, safe, and easy to apply as guidance for transseptal puncture and demonstrates a high level of accuracy.

Electromagnetic Contact-Force Sensing Electrophysiological Catheters: How Accurate is the Technology?

BACKGROUND: Contact-force (CF) sensing catheters are increasingly used in clinical electrophysiological practice due to their efficacy and safety profile. As data about the accuracy of this technology are scarce, we sought to quantify accuracy based on in vitro experiments. METHODS AND RESULTS: A custom-made force sensor was constructed that allowed exact force reference measurements registered via a flexible membrane. A Smarttouch Surround Flow (ST SF) ablation catheter (Biosense Webster, Diamond Bar, CA, USA) was brought in contact with the membrane of the force sensor in order to compare the ST SF force measurements to force sensor reference measurements. ST SF force sensing technology is based on deflection registration between the distal and proximal catheter tip. The experiment was repeated for n = 10 ST SF catheters, which showed no significant difference in accuracy levels. A series of measurements (n = 1200) was carried out for different angles of force acting to the catheter tip (0°/perpendicular contact, 30°, 60°, 90°/parallel contact). The mean absolute differences between reference and ST SF measurements were 1.7 ± 1.8 g (0°), 1.6 ± 1.2 g (30°), 1.4 ± 1.3 g (60°), and 6.6 ± 5.9 g (90°). Measurement accuracy was significantly higher in non-parallel contact when compared with parallel contact (P < 0.01). CONCLUSIONS: Catheter force measurements using the ST SF catheters show a high level of accuracy regarding differences to reference measurements and reproducibility. The reduced accuracy in measurements of 90° acting forces (parallel contact) might be clinically important when creating, for example, linear lesions.

Evaluation of a new very low dose imaging protocol: feasibility and impact on X-ray dose levels in electrophysiology procedures.

AIMS: This study presents and evaluates the impact of a new lowest-dose fluoroscopy protocol (Siemens AG), especially designed for electrophysiology (EP) procedures, on X-ray dose levels. METHODS AND RESULTS: From October 2014 to March 2015, 140 patients underwent an EP study on an Artis zee angiography system. The standard low-dose protocol was operated at 23 nGy (fluoroscopy) and at 120 nGy (cine-loop), the new lowest-dose protocol was operated at 8 nGy (fluoroscopy) and at 36 nGy (cine-loop). Procedural data, X-ray times, and doses were analysed in 100 complex left atrial and in 40 standard EP procedures. The resulting dose-area products were 877.9 ± 624.7 µGym² (n = 50 complex procedures, standard low dose), 199 ± 159.6 µGym² (n = 50 complex procedures, lowest dose), 387.7 ± 36.0 µGym² (n = 20 standard procedures, standard low dose), and 90.7 ± 62.3 µGym² (n = 20 standard procedures, lowest dose), P < 0.01. In the low-dose and lowest-dose groups, procedure times were 132.6 ± 35.7 vs. 126.7 ± 34.7 min (P = 0.40, complex procedures) and 72.3 ± 20.9 vs. 85.2 ± 44.1 min (P = 0.24, standard procedures), radiofrequency (RF) times were 53.8 ± 26.1 vs. 50.4 ± 29.4 min (P = 0.54, complex procedures) and 10.1 ± 9.9 vs. 12.2 ± 14.7 min (P = 0.60, standard procedures). One complication occurred in the standard low-dose and lowest-dose groups (P = 1.0). CONCLUSION: The new lowest-dose imaging protocol reduces X-ray dose levels by 77% compared with the currently available standard low-dose protocol. From an operator standpoint, lowest X-ray dose levels create a different, reduced image quality. The new image quality did not significantly affect procedure or RF times and did not result in higher complication rates. Regarding radiological protection, operating at lowest-dose settings should become standard in EP procedures.

Impact of the Right Ventricular Lead Position on Clinical End Points in CRT Recipients--A Subanalysis of the Multicenter Randomized SPICE Trial.

BACKGROUND: The impact of right ventricular (RV) lead location on clinical end points in patients undergoing cardiac resynchronization therapy (CRT) is unclear. We evaluated the impact of different RV lead locations on clinical outcome in CRT patients enrolled in the Septal Positioning of ventricular implantable cardioverter-defibrillator (ICD) Electrodes (SPICE) trial, which randomized recipients of implantable cardioverter defibrillators to apical versus midseptal RV lead positioning. METHODS: Ninety-eight CRT recipients were included in the multicenter SPICE trial and followed for 12 months: Fifty-three patients were randomized to receive an apical (A) and 45 to receive a midseptal (S) lead position. We compared echocardiographical and electrocardiographical parameters and outcome. RESULTS: Echocardiographic response with respect to improvement of left ventricular ejection fraction (A: +15.8 ± 14.6%, S: +9.7 ± 12.6%, P = 0.156) and reduction of left ventricular end-diastolic diameter (A: -4.2 ± 10.7 mm, S: -7.5 ± 10.7 mm, P = 0.141) was comparable in apical and midseptal groups. Paced QRS width neither differed at prehospital discharge (A: 129 ± 21 ms, S: 135 ± 21 ms, P = 0.133) nor at 12-month follow-up (A: 131 ± 23 ms, S: 134 ± 28 ms, P = 0.620). No differences were found with respect to the risk of ventricular tachyarrhythmia or ICD therapy. Septal RV lead position, however, was associated with a significant longer time to a first heart failure event (P = 0.040) and a longer survival time (P = 0.019). CONCLUSIONS: In CRT recipients, midseptal RV lead position was not superior with respect to improvement of echocardiographic parameters or paced QRS width. It did not predispose to ventricular arrhythmias or ICD therapy. The finding that midseptal lead position was associated with a longer time to first heart failure event and a longer survival time deserves further investigation.

Atrial Tachycardias Following Persistent Atrial Fibrillation Ablation: Predictors of Recurrence After the Repeat Ablation.

BACKGROUND: Repeat procedures after persistent atrial fibrillation (AF) ablation are frequently performed for secondary atrial tachycardias (AT). Predictors of AT recurrence after the first repeat ablation have not yet been studied. METHODS: We investigated predictors of AT recurrence in 117 patients who underwent ablation for secondary AT arising after a previous ablation for persistent AF using the Cox proportional hazards model. RESULTS: Acute ablation success rate was 94%. Over a follow-up period of 12 months, 61 patients (53%) were free from AT recurrence. Of the assessed predictors of AT recurrence, the number of ablated AT forms (>1 vs. 1) was significantly associated with AT recurrence (hazard ratio 2.01, 95% CI 1.18-3.43, P = 0.01). Other variables including left atrial diameter, AT mechanism, or the characteristics of previous AF ablation did not have significant influence on AT recurrence (P>0.05). Men had a tendency toward fewer AT recurrences than women (OR 0.60, 95% CI 0.34-1.05, P = 0.07). During a second AT ablation procedure, 19 (49%) patients were identified to have a recurrence of the previously ablated AT, whereas in 20 patients (51%) a new AT form was diagnosed. CONCLUSION: Ablation of atrial tachycardias following persistent AF ablation has a high acute success rate. However, a substantial number of patients develop new onset AT during follow-up. The occurrence of multiple AT forms during the repeat ablation procedure was the only predictive factor for AT recurrence.

Dissociated pulmonary vein activity after pulmonary vein isolation for paroxysmal atrial fibrillation: a predictor for recurrence?

BACKGROUND: The role of dissociated pulmonary vein (DPV) activity after pulmonary vein isolation (PVI) is still poorly defined. We evaluated electrophysiological features and clinical impact on long-term outcome of DPV activity. METHODS: A total of 243 patients (mean age 63 ± 11 years; 63% males) undergoing PVI for paroxysmal atrial fibrillation (AF) were included. DPV activity was defined as a residual low frequency irregular PV rhythm. Patients were divided into Group 1 (presence of DPV activity; n = 65) or Group 2 (absence of DPV activity; n = 178). RESULTS: Of 936 isolated PVs, 112 PVs (12%) showed DPV activity. DPV activity was observed more frequently in PVs identified as AF triggers (P = 0.026). During follow-up (mean 12 ± 7 months), 15 of 65 patients of Group 1 (23%) and 57 of 178 patients of Group 2 (32%) had an arrhythmia recurrence (P = 0.23). At linear regression analysis, no independent predictor for clinical recurrence was identified. During the repeat ablation, 62 of 72 patients (86%) showed a recovered PV conduction without difference between the 2 groups. Clinically, all patients of Group 1 with PV reconnection (n = 13/15) had a recurrence of paroxysmal AF. In Group 2, 5 of 52 patients with reconnected PV developed non-PV related arrhythmias. CONCLUSION: DPV activity occurred in 12% of PVs after PVI and was observed more frequently in PVs identified as AF triggers. DPV activity was not predictive for AF recurrence during follow-up. PV-left atrium reconnection involving PVs with DPV activity leads to AF.

Sensor-Based Electromagnetic Navigation (Mediguide®): How Accurate Is It? A Phantom Model Study.

BACKGROUND: Data about localization reproducibility as well as spatial and visual accuracy of the new MediGuide® sensor-based electroanatomic navigation technology are scarce. We therefore sought to quantify these parameters based on phantom experiments. METHODS AND RESULTS: A realistic heart phantom was generated in a 3D-Printer. A CT scan was performed on the phantom. The phantom itself served as ground-truth reference to ensure exact and reproducible catheter placement. A MediGuide® catheter was repeatedly tagged at selected positions to assess accuracy of point localization. The catheter was also used to acquire a MediGuide®-scaled geometry in the EnSite Velocity® electroanatomic mapping system. The acquired geometries (MediGuide®-scaled and EnSite Velocity®-scaled) were compared to a CT segmentation of the phantom to quantify concordance. Distances between landmarks were measured in the EnSite Velocity®- and MediGuide®-scaled geometry and the CT dataset for Bland-Altman comparison. The visualization of virtual MediGuide® catheter tips was compared to their corresponding representation on fluoroscopic cine-loops. Point localization accuracy was 0.5 ± 0.3 mm for MediGuide® and 1.4 ± 0.7 mm for EnSite Velocity®. The 3D accuracy of the geometries was 1.1 ± 1.4 mm (MediGuide®-scaled) and 3.2 ± 1.6 mm (not MediGuide®-scaled). The offset between virtual MediGuide® catheter visualization and catheter representation on corresponding fluoroscopic cine-loops was 0.4 ± 0.1 mm. CONCLUSIONS: The MediGuide® system shows a very high level of accuracy regarding localization reproducibility as well as spatial and visual accuracy, which can be ascribed to the magnetic field localization technology. The observed offsets between the geometry visualization and the real phantom are below a clinically relevant threshold.

Ablation of perimitral flutter: acute and long-term success of the modified anterior line.

AIMS: The modified anterior line (MAL) is an alternative to the mitral isthmus (MI) line for the treatment of perimitral atrial flutter (PMFL). We sought to investigate acute and long-term efficacy of this line if routinely used for PMFL. METHODS AND RESULTS: The cohort included 77 consecutive patients who underwent catheter ablation of PMFL. The anterior line was deployed between the anterolateral mitral annulus and the ostium of the left superior pulmonary vein. Perimitral atrial flutter was either the presenting arrhythmia after persistent atrial fibrillation (AF) ablation (Group 1, n = 42, 54.5%), occurring during AF ablation (Group 2, n = 25, 35%) or presenting as primary arrhythmia (Group 3, n = 8, 10%). Acute success was defined as PMFL termination during MAL deployment with demonstration of bidirectional line block. Acute success was achieved in 68 of 77 patients (88%) without difference between the three groups. In five patients an additional MI line was necessary to terminate PMFL and in four patients both lines failed to achieve termination. During follow-up (16 ± 7 months), 38 of 77 (49%) patients underwent a repeat procedure for a recurrent arrhythmia. During reablation, 13 of 38 (34%) patients were identified to have a PMFL recurrence. Persistent MAL block was demonstrated in 22 of 38 (58%) patients during the repeat ablation. CONCLUSION: The MAL is effective for acute and long-term treatment of PMFL. Maintenance of bidirectional MAL block was shown in 58% of patients during a repeat ablation.

Recurrence of paroxysmal atrial fibrillation after pulmonary vein isolation: is repeat pulmonary vein isolation enough? A prospective, randomized trial.

AIMS: In patients with paroxysmal atrial fibrillation (pAF), pulmonary vein isolation (PVI) has become an accepted treatment option with single procedure success rates of 60-80%. A repeat ablation is performed in ∼30% of patients because of arrhythmia recurrence. The strategy for this repeat procedure is not defined. METHODS AND RESULTS: Patients with pAF recurrence after PVI were prospectively randomized and underwent a second ablation procedure with either PVI of all reconnected veins or PVI with an additional left atrial anterior line. Follow-up in our arrhythmia clinic was every 3 months up to 12 months including 7 day Holter monitoring. A total of 77 patients (mean age 63 ± 9 years, 69% males) were included in the analysis. A repeat PVI was performed in 41 patients, PVI + anterior line in 36 patients. After a follow-up of 12 months, 26 of 41 (63%) patients after repeat PVI and 18 of 36 (50%) patients with PVI + anterior line were in stable sinus rhythm off antiarrhythmic medication (P = 0.26). In most patients (12 of 15 patients with PVI and 14 of 18 patients with PVI + anterior line) with an arrhythmia recurrence after the second procedure, the recurring arrhythmia was paroxysmal AF. In 2 of 15 patients of the PVI group and in 4 of 18 patients of the PVI + anterior line group atypical flutter was the reoccurring arrhythmia (P = NS). CONCLUSION: In this prospective randomized trial, patients with a recurrence of paroxysmal AF had no better outcome after repeat PVI + one left atrial line compared with patients with repeat PVI only.

A stepwise electrocardiographic algorithm for differentiation of mid-septal vs. apical right ventricular lead positioning: the SPICE ECG substudy.

AIMS: Right ventricular (RV) septum is a non-apical site targeted during lead implantation. Electrocardiographic (ECG) recognition of mid-septal lead location is challenging. The aim of the study is to determine ECG correlates of RV mid-septal pacing. METHODS AND RESULTS: The present study is a pre-specified analysis of a prospective, multicenter study, which randomized recipients of an implantable cardioverter defibrillator to an apical vs. mid-septal RV lead positioning. Following implantation, a 12-lead ECG was recorded during intrinsic rhythm and RV pacing. In total, 227 patients, 121 in the apical group (76.9% males, 67.1 ± 11.3 years) and 106 in the mid-septal group (82.1% males, age 64.7 ± 12.7 years) were included. Apically as compared with septally paced patients had significantly longer paced QRS duration (177.0 ± 25.0 vs. 170.4 ± 21.7, respectively, P = 0.03) and significantly more leftward paced QRS axis (-71.6 ± 33.3° vs. 9.4 ± 86.5°, respectively, P < 0.001). A significantly higher proportion of patients in the mid-septal as compared with the apical group displayed predominantly positive QRS in lead V6 (62.3 vs. 4.1%, P < 0.001), predominantly positive QRS in any of the inferior leads (53.8 vs. 4.1%, P < 0.001), and a QR pattern in lead aVL (53.3 vs. 3.3%, P < 0.001). These ECG correlates were incorporated in a stepwise algorithm with total sensitivity of 87% and specificity of 90% for the identification of a mid-septal lead location. CONCLUSION: A mid-septal lead location may be identified using a simple stepwise algorithm, based on the presence of positive QRS in lead V6, positive QRS in any of the inferior leads, and a QR pattern in lead aVL.

Catheter Ablation of Ventricular Arrhythmias using a Fluoroscopy Image Integration Module.

BACKGROUND: The impact of the CartoUnivu™ technology (Biosense Webster, Diamond Bar, CA, USA) on fluoroscopy exposure compared to a conventional approach using electroanatomical mapping (Carto 3™) was evaluated in patients undergoing radiofrequency ablation for ventricular tachyarrhythmias (VT). METHODS AND RESULTS: We prospectively evaluated 23 patients undergoing VT ablation using the CartoUnivu™ technology. The CartoUnivu™ Module integrates fluoroscopic images and cine loops into the electroanatomical mapping system. As a control group, 23 out of 88 VT patients (ablated using conventional fluoroscopy supplemented by electromagnetic mapping with the Carto 3™ System) were matched for age, gender, body surface area, operator, redo-procedure, presence of coronary artery disease, and left ventricular dysfunction using propensity score matching. A significant reduction in fluoroscopy exposure was observed in the CartoUnivu™ group when compared to the conventional group (10.57 ± 7.93 minutes vs 18.52 ± 11.24 minutes, P_= 0.008; 611 cGy/cm(2) vs 1650 cGy/cm(2) , P = 0.001). In multivariate analysis, the CartoUnivu™ module was an independent predictor of reduced fluoroscopy use. CONCLUSION: This is a report on the clinical application of the CartoUnivu system for VT ablation. CartoUnivu™ markedly reduced fluoroscopy time and dose compared to conventional fluoroscopy/electroanatomical mapping.

Pulmonary vein isolation using new technologies to improve ablation lesion formation: Initial results comparing enhanced catheter tip irrigation (Surround Flow(®)) with contact force measurement (Smarttouch(®)).

INTRODUCTION: Pulmonary vein reconnection after pulmonary vein isolation (PVI) is a significant problem in the treatment of paroxysmal atrial fibrillation (AF). We report about patients who underwent contact force (CF) guided PVI using CF catheter and compared them to patients with PVI using an ablation catheter with enhanced tip irrigation. METHODS: A total of 59 patients were included in the analysis. In 30 patients circumferential PVI was performed using the Thermocool Smarttouch(®) ablation catheter (ST) whereas in 29 patients circumferential PVI using the Thermocool Surround Flow SF(®) ablation catheter (SF) was performed. Patients were compared in regard to procedure time, fluoroscopy time/dose as well as RF-application duration and completeness of PVI. Adverse events (pericardial effusion, PV stenosis, stroke, death) were evaluated. The presence of sinus rhythm off antiarrhythmic medication was assessed during 6 months follow-up using multiple 7 day Holter-ECGs. RESULTS: In both groups, all PVs were isolated without serious adverse events. Procedure time was 2.15 ± 0.5 h (ST) vs. 2.37 ± 1.13 h (SF) (p = 0.19). Duration of RF-applications was 46.6 ± 18 min (ST) and 49.8 ± 19 min (SF) (p = 0.52). Fluoroscopy time was 25.2 ± 13 min (ST) vs. 29 ± 18 min (SF), fluoroscopy dose 2675.6 ± 1658 versus 3038.3 ± 1997 cGym(2) (p = 0.36 and 0.46 respectively). Sinus rhythm off antiarrhythmic medication validated with 7 day Holter ECGs was present in both groups in 72% of patients after 6 months of follow up. CONCLUSION: PVI using the new contact force catheter is safe and effective in patients with paroxysmal AF.