Role of inducibility and its dynamic change in the outcome of catheter ablation of atrial fibrillation: a single center prospective study.

BACKGROUND: The role of atrial arrhythmia inducibility as an endpoint of catheter ablation of atrial fibrillation (AF) has been a controversial subject in many studies. Our goal is to evaluate the significance of inducibility, the impact of multiple sites or protocols of stimulation or the change in inducibility status in a prospective study including patients with AF undergoing first catheter ablation. METHODS: We studied 170 consecutive patients with AF (62.9% paroxysmal) undergoing catheter ablation. All patients underwent two separate stimulation protocols before and after the ablation from the coronary sinus ostium and the left atrial appendage: burst pacing at 300, 250, 200 milliseconds (or until refractoriness) for 10 seconds and ramp decrementing from 300 to 200 milliseconds in increments of 10 milliseconds every three beats for 10 seconds. Inducibility was defined as any sustained AF or organized atrial tachycardia (AT) lasting >30 seconds. RESULTS: We had AF/AT inducibility in 55 patients at baseline compared to 36 following ablation. After a mean of 41, 3 months follow-up, 115 patients were free of AF. Inducibility before or after the ablation or change in inducibility status did not influence AF recurrence. There were no significant differences regarding paroxysmal or persistent patients with AF. CONCLUSIONS: Non-inducibility of atrial arrhythmia or change in inducibility status following pulmonary vein (PV) isolation and substrate modification are not associated with long-term freedom from recurrent arrhythmia. Therefore, the use of induction of an endpoint in AF ablation is limited.

Sex differences of resource utilisation and outcomes in patients with atrial arrhythmias and heart failure.

OBJECTIVE: Atrial fibrillation or atrial flutter (AF) and heart failure (HF) often go hand in hand and, in combination, lead to an increased risk of death compared with patients with just one of both entities. Sex-specific differences in patients with AF and HF are under-reported. Therefore, the aim of this study was to investigate sex-specific catheter ablation (CA) use and acute in-hospital outcomes in patients with AF and concomitant HF in a retrospective cohort study. METHODS: Using International Statistical Classification of Diseases and Related Health Problems and Operations and Procedures codes, administrative data of 75 hospitals from 2010 to 2018 were analysed to identify cases with AF and HF. Sex differences were compared for baseline characteristics, right and left atrial CA use, procedure-related adverse outcomes and in-hospital mortality. RESULTS: Of 54 645 analysed cases with AF and HF, 46.2% were women. Women were significantly older (75.4±9.5 vs 68.7±11.1 years, p<0.001), had different comorbidities (more frequently: cerebrovascular disease (2.4% vs 1.8%, p<0.001), dementia (5.3% vs 2.2%, p<0.001), rheumatic disease (2.1% vs 0.8%, p<0.001), diabetes with chronic complications (9.7% vs 9.1%, p=0.033), hemiplegia or paraplegia (1.7% vs 1.2%, p<0.001) and chronic kidney disease (43.7% vs 33.5%, p<0.001); less frequently: myocardial infarction (5.4% vs 10.5%, p<0.001), peripheral vascular disease (6.9% vs 11.3%, p<0.001), mild liver disease (2.0% vs 2.3%, p=0.003) or any malignancy (1.0% vs 1.3%, p<0.001), underwent less often CA (12.0% vs 20.7%, p<0.001), had longer hospitalisations (6.6±5.8 vs 5.2±5.2 days, p<0.001) and higher in-hospital mortality (1.6% vs 0.9%, p<0.001). However, in the multivariable generalised linear mixed model for in-hospital mortality, sex did not remain an independent predictor (OR 0.96, 95% CI 0.82 to 1.12, p=0.579) when adjusted for age and comorbidities. Vascular access complications requiring interventions (4.8% vs 4.2%, p=0.001) and cardiac tamponade (0.3% vs 0.1%, p<0.001) occurred more frequently in women, whereas stroke (0.6% vs 0.5%, p=0.179) and death (0.3% vs 0.1%, p=0.101) showed no sex difference in patients undergoing CA. CONCLUSIONS: There are sex differences in patients with AF and HF with respect to demographics, resource utilisation and in-hospital outcomes. This needs to be considered when treating women with AF and HF, especially for a sufficient patient informed decision making in clinical practice.

In-hospital mortality of patients with atrial arrhythmias: insights from the German-wide Helios hospital network of 161 502 patients and 34 025 arrhythmia-related procedures.

Aims: Atrial fibrillation (AFib) and atrial flutter (AFlut) are common arrhythmias with increased use of invasive procedures. A steady re-evaluation of relevant safety endpoints is recommended and both quality management and pay-for-performance programs are evolving. Therefore, the aims of this study were (i) to investigate and report overall in-hospital mortality and mortality of invasive arrhythmia-related procedures and (ii) to identify mortality predictors in a German-wide hospital network. Methods and results: Administrative data provided by 78 Helios hospitals between 2010 and 2017 were examined using International Statistical Classification of Diseases and Related Health Problems- and Operations and Procedures-codes to identify patients with AFib or AFlut as main discharge diagnosis or secondary diagnosis combined with invasive arrhythmia-related interventions. In 161 502 patients, in-hospital mortality was 0.6% with a significant decrease from 0.75% to 0.5% (P < 0.01) during the observational period. In multivariable analysis, age [odds ratio (OR) 2.69, 95% confidence interval (CI) 2.36-3.05; P < 0.01], high centre volume (OR 0.57, 95% CI 0.50-0.65; P < 0.01), emergency hospital admission (OR 1.57, 95% CI 1.38-1.79; P < 0.01), and Charlson Comorbidity Index (CCI, OR 4.95, 95% CI 4.50-5.44; P < 0.01) were found as independent predictors of in-hospital mortality. Mortality rates were 0.05% for left atrial catheter ablation (CA, n = 21 744), 0.3% for right atrial CA (n = 9972), and 0.56% for implantation of a left atrial appendage occluder (n = 2309), respectively. Conclusion: We analysed for the first time in-hospital mortality rates of patients with atrial arrhythmias in a German-wide, multi-centre administrative dataset. This allows feasible, comparable, and up-to-date performance measurement of clinically important endpoints in a real-world setting which may contribute to quality management programs and towards value-based healthcare.

Cardiac tamponade in catheter ablation of atrial fibrillation: German-wide analysis of 21 141 procedures in the Helios atrial fibrillation ablation registry (SAFER).

Aims: Catheter ablation is an established therapy in patients with symptomatic atrial fibrillation (AF) with increasing popularity. Pericardial effusion requiring intervention (PE) is one of the most threatening adverse outcomes. The aim of this study was to examine rates of PE after catheter ablation in a large 'real-world' data set in a German-wide hospital network. Methods and results: Using ICD and OPS codes, administrative data of 85 Helios hospitals from 2010 to 2017 was used to identify AF catheter ablation cases [Helios atrial fibrillation ablation registry (SAFER)]. PE occurred in 0.9% of 21 141 catheter ablation procedures. Patients with PE were significantly older, to a higher percentage female, had more frequently hypertension, mild liver disease, diabetes with chronic complications, and renal disease. Low hospital volume (<50 procedures per year) and radiofrequency ablation (vs. cryoablation) were significantly associated with PE. Using two logistic regression models, age, female gender, hypertension, mild liver disease, diabetes with chronic complications, renal disease, low hospital volume, and radiofrequency ablation remained independent predictors for PE. Conclusion: Overall PE rate was 0.9%. Predictors for PE occurrence involved factors ascribed to the patient (age, gender, comorbidities), the type of catheter ablation (radiofrequency), and the institution (low-volume centres).

Left ventricular wall motion analysis to guide management of CRT non-responders.

AIMS: A discordant left ventricular (LV) lead position can be responsible for cardiac resynchronization therapy (CRT) non-response. In this study, tailored optimization of the individual LV wall motion was evaluated for the outcome in these patients. METHODS AND RESULTS: Two hundred and forty-six CRT outpatients were screened for non-response due to a discordant LV lead. In 17 patients, three-dimensional data of fluoroscopic rotation scan and echocardiography were integrated to analyse the individual LV wall motion with respect to the LV lead position. Optimization was guided by the systolic dyssynchrony index (SDI) and LV ejection fraction (LVEF) during different interventricular (VV)-delay programming. If re-programming failed, implantation of a second LV lead was performed. A discordant or partly concordant LV lead position was found in nearly all patients (16/17, 94%), which contributed to an unchanged baseline amount of LV dyssynchrony with either CRT on or off (SDI 11.3 vs. 11.0%; P = 0.744). In the majority of patients, VV-delay re-programming achieved better resynchronization, 4/17 patients needed implantation of a second LV lead. After 3 months, significant improvement of NYHA functional class (1 class; P = 0.004), peak oxygen consumption (10 vs. 13 mL/min/kg; P = 0.008), LVEF (27 vs. 39%; P = 0.003), and SDI (11.0 vs. 5.8; P = 0.02) was observed. Clinical and echocardiographic responses were found in 77 and 59%, respectively, with even good results on long-term follow-up. CONCLUSION: Tailored optimization of the individual LV wall motion can lead to significant clinical and echocardiographic improvements in previous CRT non-responders with a discordant LV lead position.

Ventriculoatrial conduction and related pacemaker-mediated arrhythmias in patients implanted for atrioventricular block: an old problem revisited.

INTRODUCTION: Ventriculoatrial (VA) conduction and related pacemaker-mediated tachyarrhythmias (PMT) have not been systematically investigated in a large cohort of patients implanted for symptomatic atrioventricular (AV) block. METHODS AND RESULTS: Two hundred fifty consecutive patients (71±14 years, 63% male) implanted for symptomatic second- or third-degree AV block were screened for retrograde VA conduction and related PMTs including endless loop tachycardia (ELT) and repetitive nonreentrant VA synchrony (RNRVAS). After a mean post-implantation period of 38±12 months, AV block was persistent in 137 (55%) and variable in 113 (45%) patients. Retrograde 1:1 conduction was present in 76 patients (30%) with a mean VA conduction time of 258±65 ms. The incidence of VA conduction varied considerably according to the presence and type of anterograde conduction block. Retrograde conduction was present in 24 of 137 patients (18%) with persistent AV block. Fifteen of the 76 patients (20%) with VA conduction had ≥1 documented PMT. The recorded arrhythmias were ELT in 11 and RNRVAS in 4 patients. VA conduction time was significantly longer in patients with than without PMT (297±64 vs. 249±62 ms, resp., P<0.01). None of the patients without VA conduction had documented PMTs. CONCLUSIONS: Retrograde VA conduction and related PMTs are not uncommon in patients implanted for symptomatic AV block. Testing for retrograde conduction should therefore be performed in all patients with AV block in order to optimize device programming and prevent PMTs.

Diagnosis of arrhythmias in athletes using leadless, ambulatory HR monitors.

Exercise-related palpitations, vertigo, and syncope may be caused by benign etiologies but can also herald life-threatening arrhythmias. The precise diagnosis of these findings is therefore essential and potentially life saving but often is a challenge for sports physicians and cardiologists. Leadless, ambulatory HR monitors with chest strap transmitters have been designed to steer exercise intensity in athletes with a baseline sinus rhythm. However, they also can capture arrhythmias. Presented here are three cases of varying arrhythmias: atrial fibrillation, atrioventricular nodal reentrant tachycardia, and ectopic atrial tachycardia that demonstrate the utility of HR monitors designed for athletic purposes in facilitating the diagnosis of arrhythmias and guiding appropriate treatment.

Individually tailored left ventricular lead placement: lessons from multimodality integration between three-dimensional echocardiography and coronary sinus angiogram.

AIMS: Non-responder rates for cardiac resynchronization therapy (CRT) vary from 11% to 46%. Retrospective data imply a better outcome with stimulation of the latest contracting left ventricular (LV) region. Our study analysed the feasibility, safety and clinical outcome of prospectively planned LV lead placement at the site of latest mechanical activation. METHODS AND RESULTS: Thirty-eight heart failure patients with CRT indication were assessed by three-dimensional (3D) transoesophageal echocardiography and rotation angiography of the coronary sinus (CS). Both images were merged into a single 3D-model to identify CS target veins close to the site of latest mechanical activation. Subsequently, LV lead deployment was attempted at the desired target position. Patients were clinically and echocardiographically evaluated at baseline, after 3 and 6 months. The area of latest mechanical activation covered 6 ± 2 segments (38 ± 13% of LV surface) and was found lateral in 24 of 37 (65%), anterior in 11 of 37 (30%), inferior in 2 of 37 (5%), and septal in 1 of 37 (3%) patients. In 36 of 37 (97%) patients an appropriate target vein was identified and successful implantation could be performed in 34 of 37 (92%) patients. Among those patients clinical and echocardiographic response was observed in 91% and 81%, respectively. CONCLUSION: Individualized lead placement at the latest contracting LV site can be performed safely and successfully in the majority of patients. Initial clinical outcome data are encouraging. Identification of target sites requires multimodality integration between LV wall motion data and CS anatomy. Future developments need to improve those technologies and require randomized data on clinical outcome parameters.

Effects of baseline P-wave duration and choice of atrial septal pacing site on shortening atrial activation time during pacing.

BACKGROUND: Atrial septal pacing (ASP) has been shown to shorten P-wave duration (PWD) and reduce recurrence of atrial fibrillation (AF) in patients with bradyarrhythmias. However, variability of interatrial connections and atrial conduction properties may explain ASP's modest clinical benefit. The aim of this study was to assess the effect of ASP site on the duration of the paced P wave. METHODS AND RESULTS: Atrial septal pacing at high atrial septum (HAS), posterior septum behind the fossa ovalis (PSFO), and coronary sinus ostium (CSo) was performed in 69 patients admitted for electrophysiological study (52 ± 16 years, 41 men). Twelve-lead electrocardiogram was recorded at baseline and during pacing, signal-averaged for analysis of PWD and P-wave shortening achieved by ASP (ΔPWD = paced PWD-baseline PWD). Baseline PWD was 128 ± 15 ms. The shortest PWD during pacing was achieved at CSo (112 ± 15 ms) followed by HAS (122 ± 14 ms, P< 0.001 vs. CSo) and PSFO (124 ± 21 ms, P< 0.001 vs. CSo). P wave was shortened during pacing in patients with baseline PWD of > 120 ms (n= 50), whereas those with PWD of ≤ 120 ms showed PWD lengthening (n= 19) when paced at HAS (8 ± 17 vs. -12 ± 15 ms, P< 0.001), PSFO (15 ± 17 vs. -12 ± 26 ms, P< 0.001) and CSo (6 ± 16 vs. -25 ± 18 ms, P< 0.001). CONCLUSION: Pacing at CSo is associated with the shortest PWD. P-wave shortening is greatest in patients with baseline PWD of > 120 ms regardless of the pacing site. The results may have implications on the selection of candidates for ASP and the placement of the atrial septal lead, and warrant further evaluation in cases of permanent pacing in patients with paroxysmal AF.

Long-term efficacy of single procedure remote magnetic catheter navigation for ablation of ischemic ventricular tachycardia: a retrospective study.

BACKGROUND: Remote magnetic navigation (RMN) aims to reduce some inherent limitations of manual radiofrequency (RF) ablation. However, data comparing the effectiveness of both methods are scarce. This study evaluated the acute and long-term success of RMN guided versus manual RF ablation in patients with ischemic sustained ventricular tachycardia (sVT). METHODS: One hundred two consecutive patients (age 68 ± 10 years, LVEF 32 ± 12%, 88 men) with ischemic sVT were ablated with RMN (Stereotaxis; 49%) or manually (51%) using substrate and/or activation mapping (Carto) and open-irrigated-tip catheters. All received implantable defibrillators or loop recorders. Acute success was defined as noninducibility of any sVT at the end of the ablation procedure and long-term success as freedom from VT upon follow-up. RESULTS: There was no difference in the baseline characteristics between the groups. Three patients died in hospital. Acute success rate was similar for RMN and manual ablation (82% vs 71%, P = 0.246). RMN was associated with significantly shorter fluoroscopy time (13 ± 12 minutes vs 32 ± 17 minutes, P = 0.0001) and RF time (2337.59 ± 1248.22 seconds vs 1589.95 ± 1047.42 seconds, P = 0.049), although total procedure time was similar (157 ± 40 minutes vs 148 ± 50 minutes, P = 0.42). There was a nonsignificant trend toward better long-term success in RMN group: after a median of 13 (range 1-34) months, 63% in the RMN and 53% in the manual ablation group were free from VT recurrence (P = 0.206). CONCLUSION: RMN guided RF ablation of ischemic sustained VT is equally efficient compared with manual ablation in terms of acute and long-term success rate. These results are achieved with a significantly reduced fluoroscopy time and shorter RF time.

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

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.

Performance of an implantable automatic atrial fibrillation detection device: impact of software adjustments and relevance of manual episode analysis.

AIMS: Implantable loop recorders (ILRs) with specific atrial fibrillation (AF) detection algorithms (ILR-AF) have been developed for continuous AF monitoring. We sought to analyse the clinical value of a new AF monitoring device and to compare it to serial 7-day Holter. METHODS AND RESULTS: Sixty-four consecutive patients suffering from paroxysmal AF were included in this prospective analysis and received an ILR-AF. Manual electrogram analysis was performed for each automatically detected episode and each was categorized into one of three possible diagnoses: 'no AF', 'definite AF', and 'possible AF' (non-diagnostic). Analysis was performed separately before and after a software upgrade that was introduced during the course of the study. A subgroup of patients (51 of 64) underwent AF catheter ablation with subsequent serial 7-day Holter in comparison with the ILR-AF. A total of 333 interrogations were performed (203 before and 130 after software upgrade). The number of patients with AF misdetection was significantly reduced from 72 to 44% following the software upgrade (P = 0.001). The number of patients with non-diagnostic interrogations went from 38 to 16% (P = 0.001). Compared with serial 7-day Holter, the ILR-AF had a tendency to detect a higher number of patients with AF recurrences (31 vs. 24%; P = 0.125). CONCLUSIONS: The rate of AF detection on ILR-AF may be higher compared with standard AF monitoring. However, false-positive AF recordings hamper the clinical value. Developments in device technology and device handling are necessary to minimize non-diagnostic interrogations.

Steerable versus nonsteerable sheath technology in atrial fibrillation ablation: a prospective, randomized study.

BACKGROUND: Steerable sheath technology is designed to facilitate catheter access, stability, and tissue contact in target sites of atrial fibrillation (AF) catheter ablation. We hypothesized that rhythm control after interventional AF treatment is more successful using a steerable as compared with a nonsteerable sheath access. METHODS AND RESULTS: One hundred thirty patients with paroxysmal or persistent drug-refractory AF undergoing their first ablation procedure were prospectively included in a randomized fashion in 2 centers. Ablation was performed by 10 operators with different levels of clinical experience. Treatment outcome was measured with serial 7-day Holter ECGs and additional symptom-based arrhythmia documentation. Single procedure success (freedom from AF and/or atrial macroreentrant tachycardia) was significantly higher in patients ablated with a steerable sheath (78% versus 55% after 3 months, P=0.005; 76% versus 53% after 6 months, P=0.008). Rate of pulmonary vein isolation, procedure duration, and radiofrequency application time did not differ significantly, whereas fluoroscopy time was lower in the steerable sheath group (33±14 minutes versus 45±17 minutes, P<0.001). Complication rates showed no significant difference (3.2% versus 5%, P=0.608). On multivariable analysis, steerable sheath usage remained the only powerful predictor for rhythm outcome after 6 months of follow-up (hazard ratio, 2.837 [1.197 to 6.723]). CONCLUSIONS: AF catheter ablation using a manually controlled, steerable sheath for catheter navigation resulted in a significantly higher clinical success rate, with comparable complication rates and with a reduction in periprocedural fluoroscopy time. CLINICAL TRIAL REGISTRATION: URL: http://clinicaltrials.gov. Unique identifier: NCT00469638.

Catheter ablation of atrial fibrillation using remote magnetic catheter navigation: a case-control study.

AIMS: To compare the acute and the 6 month outcome of catheter ablation of atrial fibrillation (AF) using irrigated tip magnetic catheter and remote magnetic cathter navigation (RMN) with manual catheter navigation (MCN) in patients with paroxysmal and persistent AF. METHODS AND RESULTS: In this retrospective analysis 356 patients (235 male, mean age: 57.9 ± 10.9 years) with AF (70.5%, paroxysmal) who underwent catheter ablation between August 2007 and May 2008 using either RMN (n = 70, 46 male, mean age: 57.9 ± 10.1 years, 50% paroxysmal) or MCN (n = 286, 189 male, mean age: 58.0 ± 13.9 years, 75.5% paroxysmal) were included. All patients completed an intensive follow-up strategy. Complete pulmonary vein isolation was achieved in 87.6 and 99.6% of patients in RMN and MCN groups, respectively (P < 0.05). The procedure, fluoroscopy, and radiofrequency application times were 223 ± 44 vs. 166 ± 52 min (P < 0.0001), 13.7 ± 7.8 vs. 34.5 ± 15.1 min (P < 0.0001), and 75.4 ± 20.9 vs. 53.2 ± 21.4 min (P < 0.0001) in RMN and MCN groups, respectively. Seven (10.0%) and 28 (9.8%) patients in RMN and MCN groups received antiarrhythmic medications during the follow-up (P = 0.96). All the patients completed the 6 month follow-up. Freedom from AF at 6 months was achieved in 57.8 and 66.4% of the patients in RMN and MCN groups, respectively (P = 0.196). In patients without previous AF catheter ablation procedure the freedom from AF at 6 months were 68.2 and 60.5% in the MCN and RMN groups, respectively (P = 0.36). CONCLUSION: Catheter ablation using irrigated tip magnetic catheter and RMN is an effective and safe method for catheter ablation of AF. Compared to manual catheter navigation, the procedure and radiofrequency application times were longer and fluoroscopy time was shorter in the RMN group compared with the MCN group.

Successful correction of a total anomalous venous connection in a 63-year-old male--case report and review of the literature.

Total anomalous pulmonary venous connection is a rare variant of cyanotic congenital heart disease and usually requires surgical correction within the first few months of life. We report midterm results of a 63-year-old male with intracardiac total anomalous venous return into the coronary sinus who presented with congestive predominantly right heart failure and underwent corrective surgery with unroofing of the coronary sinus and patch closure of the secundum atrial septal defect.

Catheter ablation of scar-related ventricular tachycardia in patients with electrical storm using remote magnetic catheter navigation.

BACKGROUND: A remote magnetic navigation system (MNS) has been used for ablation of ventricular arrhythmias. However, irrigated tip catheter has not been evaluated in large series of patients. OBJECTIVE: To evaluate acute and long-term efficiency of the newly available irrigated tip magnetic catheter for radiofrequency (RF) ablation of scar-related ventricular tachycardia (VT) in patients with ischemic heart disease. METHODS: Between January 2008 and October 2009, a total of 30 consecutive patients with ischemic heart disease (26 men, age 70.1 ± 8.7 years, left ventricular ejection fraction: 30 ± 9%) and electrical storm due to monomorphic VT underwent RF ablation using a remote MNS and a magnetic irrigated tip catheter. RESULTS: Acute success was defined as noninducibility of any monomorphic VT during programmed right and left ventricular stimulation, and obtained in 24 (80%) patients. A total of 1-6 VTs (mean 2.3 ± 1.2, 394 ± 108 ms, 210-660 ms) were inducible during each procedure. The duration of RF energy application was 41.2 ± 23.3 minutes, with total procedure and fluoroscopy times of 158 ± 47 minutes and 9.8 ± 5.3 minutes, respectively. No acute complications were observed during the procedures. During mean follow-up of 7.8 months, 21 patients (70%) had no recurrence of VT and received no implantable cardioverter defibrillator therapy. Among patients who were noninducible during programmed right ventricular stimulation (n = 25), ≥1 monomorphic VT was inducible during programmed left ventricular stimulation in four (16%) that was ablated successfully in three of them. CONCLUSIONS: Irrigated ablation of scar-related VT using remote MNS is an effective modality for management of the monomorphic VT in patients with ischemic cardiomyopathy with minimal radiation exposure. Programmed left (in addition to right) ventricular stimulation might be necessary to assess acute outcome of the ablation procedure.

Six-month follow-up of isthmus-dependent right atrial flutter ablation using a remote magnetic catheter navigation system: a case-control study.

OBJECTIVE: The objective of this study was to compare results between the magnetic navigation system (MNS) and conventional catheter ablation of cavo-tricuspid isthmus (CTI)-dependent right atrial flutter (AFL) in a case control study. BACKGROUND: A remote MNS has been used for ablation of various arrhythmias including CTI-dependent AFL but comparative results between MNS and conventional ablation are not available. METHODS: Between May and September 2007, a total of 51 consecutive patients (45 men, mean age 65.4 +/- 9.4 years) had undergone catheter ablation for CTI-dependent AFL. The catheter ablation (70 degrees C, 70 W, 90 s) was performed with either an 8-mm-tip magnetic catheter using MNS (case group, n = 26, 23 men, mean age 64.6 +/- 9.6 y) or a conventional 8-mm catheter (case group, n = 25, 22 men, mean age 65.4 +/- 9.1 y). Acute procedural success was defined as complete bidirectional isthmus block and success at six months was defined as absence of AFL during the six months follow-up. RESULTS: With respect to baseline characteristics there were no differences between the two groups. The procedure time in MNS and conventional group was [median (range)] 53 (30-130) min and 45 (30-100) min, respectively (P = 0.12). Acute success was achieved by MNS and conventional ablation in 25/26 (96.2%) and 25/25 (100%) of patients, respectively (P = 0.53). During the six months of follow-up 4 patients, 2 in each group, experienced recurrence (P = 0.90). No major complication occurred during the procedure. Charring on the catheter tip occurred in 5 patients (19.2%) in MNS and none of the patients in the control group (P <0.05). CONCLUSION: This case-control study demonstrated the acute and mid-term efficacy and safety of catheter ablation by MNS for CTI-dependent AFL, similar to rates achieved by conventional radiofrequency catheter ablation.

Catheter ablation of electrical storm due to monomorphic ventricular tachycardia in patients with nonischemic cardiomyopathy: acute results and its effect on long-term survival.

BACKGROUND: Electrical storm due to recurrent ventricular tachycardia (VT) in patients with implantable cardioverter defibrillator (ICD) can adversely affect their long-term survival. This study evaluates the efficiency of the radiofrequency catheter ablation of electrical storm due to monomorphic VT in patients with idiopathic dilated cardiomyopathy (DCM) and assesses its long-term effects on survival. METHODS AND RESULTS: Between April 2004 and October 2008, 13 consecutive patients (nine men, mean age 56.8 ± 17.8 years) with DCM and electrical storm due to monomorphic VT who had ICD underwent 17 catheter ablation procedures, including four epicardial, at our center. Acute complete success was defined as the lack of inducibility of any VT at the end of procedure during programmed right ventricular stimulation and was achieved in eight patients (61.5%). During a median follow-up of 23 months (range 3-63 months) nine patients (69%) were alive and eight patients (61.5%) were free from VT recurrence. Among those with acute complete (n = 8) and partial (n = 5) success, seven patients (87.5%) and one patient (20%) were free from any VT recurrence and ICD therapy, respectively (P = 0.025). Among those with acute complete and partial success, seven patients (87.5%) and two patients (40%) were alive, respectively (Mantel-Cox test P = 0.082). Among those who had an initially failed endocardial ablation (n = 8), four underwent further epicardial ablation that was completely successful in three patients (75%). CONCLUSION: Catheter ablation in patients with DCM and electrical storm due to monomorphic VT who had an ICD prevents further VT recurrence in 61.5% of the patients. Complete successful catheter ablation may play a protective role and was associated with reduced mortality during the follow-up period. More aggressive ablation strategies in patients with initially failed endocardial ablation might improve the long-term survival of these patients; however, further studies are needed to clarify this issue.

Safety of remote magnetic navigation in patients with pacemakers and implanted cardioverter defibrillators.

BACKGROUND: Remote magnetic catheter navigation (MNS) has been shown to be feasible and safe for radiofrequency catheter ablation of various cardiac arrhythmias. However, its safety in patients with implanted pacemakers or cardioverter-defibrillators has not yet been studied. OBJECTIVES: This retrospective case series study intends to assess the acute and short-term safety of remote MNS in patients with implanted pacemakers or cardioverter-defibrillators. METHODS: Between January 2008 and June 2009, a total of 31 patients with implanted pacemakers (n = 5) or cardioverter-defibrillators (n = 26) underwent 32 catheter ablation procedures using the remote MNS. Baseline pacing thresholds, sensed amplitudes, pacing and, if available, shock impedances as well as battery status were measured in all devices before, immediately after, and 1-3 months after catheter ablation. RESULTS: After ablation, no statistically significant difference in atrial sensing (2.7 ± 1.5 mV vs 3.1 ± 1.9 mV, P = 0.18) and impedance (457 ± 104 Ω vs 449 ± 101 Ω, P = 0.37) were observed. After ablation, no statistically significant difference in right ventricular sensing (10.4 ± 3.8 mV vs 10.9 ± 4.9 mV, P = 0.43) and impedance (535 ± 118 Ω vs 534 ± 120 Ω, P = 0.913) were observed. No changes in pacing threshold could be observed in all but 2 patients with biventricular cardioverter-defibrillators who underwent ventricular tachycardia ablation in lateral wall of left ventricle near the implanted epicardial electrode. CONCLUSIONS: Ablation procedures using remote MNS can be performed safely in patients with implanted devices with no significant effects on device system integrity. Long endocardial ablation close to the insertion site of the implanted epicardial left ventricular leads can affect the pacing and/or sensing characteristics of these electrodes.