Safety and Clinical Outcome of Catheter Ablation of Ventricular Arrhythmias Using Contact Force Sensing: Consecutive Case Series.

BACKGROUND: Poor catheter-to-myocardial contact can lead to ineffective ablation lesions and suboptimal outcome. Contact force (CF) sensing catheters in ventricular tachyarrhythmia (VT) ablations have not been studied for their long-term efficacy. PURPOSE: The aim of this study was to compare CF ablation to manual ablation (MAN) and remote magnetic navigation (RMN) ablation for safety and efficacy in acute and long-term outcome. METHODS: A total of 239 consecutive patients who underwent VT ablation with the use of MAN, CF, or RMN catheters were included in this single-center cohort study from January 2007 until March 2014. The primary endpoints were procedural success, acute major complications, and VT recurrences at follow-up. The median follow-up period was 25 months. RESULTS: Acute success was achieved in 182 out of 239 procedures (76%). Acute success in manual ablation, CF ablation and RMN ablation was 71%, 71%, and 86%, respectively (P = 0.03). Major complications occurred in 3.3% and there were less major complications (P = 0.04) in the RMN group. After an initial successful procedure, 66 of 182 patients (36%) had a recurrence during follow-up. This was not significantly different between groups. Using an intention-to-treat analysis, 124 patients (52%) had a recurrence. The recurrence rate was lowest in the RMN group. CONCLUSION: The use of CF sensing catheters did not improve procedural outcome or safety profile in comparison to non-CF sensing ablation in this observational study of ventricular arrhythmia ablations.

The Effect of Elapsed Time from Myocardial Infarction on Mortality and Major Adverse Cardiac and Cerebrovascular Events in ICD Patients.

BACKGROUND: Despite the effectiveness of implantable cardioverter defibrillator (ICD) therapy in reducing mortality, the optimal timing of ICD implantation after myocardial infarction (MI) remains inconclusive. The aim of this study is to evaluate the association of elapsed time from MI to ICD implantation on mortality and major adverse cardiac and cerebrovascular events (MACCEs) in patients with prior MI. METHODS: We studied 974 patients who underwent a first ICD implantation between October 1998 and August 2011. The median time from MI to ICD implantation was 7.2 years. Elapsed time from MI to ICD was categorized into tertiles (<2.5 years, 2.5-12.1 years, >12.1 years). Additionally, the time from most recent MI to ICD implantation was dichotomized at 18 months. RESULTS: During a median follow-up of 3.4 years, 287 patients died. Cumulative mortality rates at 3 years, 5 years, and 8 years were 19%, 29%, 47%, respectively. In univariate analysis, there was a significant difference in mortality for patients in the highest tertile compared to those in the lowest tertile (hazard ratio: 1.50; 95% confidence interval: 1.12-2.02; P = 0.007). After adjusting for baseline characteristics, there was no association between time from MI and mortality. At 8-year follow-up, the cumulative MACCE rate excluding mortality was 22%. No association between time from MI and MACCE was found. CONCLUSION: In this study, we found no association between the elapsed time from MI to ICD implantation and 8-year all-cause mortality or MACCE in post-MI ICD patients.

Novel robotic catheter manipulation system integrated with remote magnetic navigation for fully remote ablation of atrial tachyarrhythmias: a two-centre evaluation.

AIMS: Studies have shown that remote magnetic navigation is safe and effective for ablation of atrial arrhythmias, although optimal outcomes often require frequent manual manipulation of a circular mapping catheter. The Vdrive robotic system ('Vdrive') was designed for remote navigation of circular mapping catheters to enable a fully remote procedure. This study details the first human clinical experience with remote circular catheter manipulation in the left atrium. METHODS AND RESULTS: This was a prospective, multi-centre, non-randomized consecutive case series that included patients presenting for catheter ablation of left atrial arrhythmias. Remote systems were used exclusively to manipulate both the circular mapping catheter and the ablation catheter. Patients were followed through hospital discharge. Ninety-four patients were included in the study, including 23 with paroxysmal atrial fibrillation (AF), 48 with persistent AF, and 15 suffering from atrial tachycardias. The population was predominately male (77%) with a mean age of 60.5 ± 11.7 years. The Vdrive was used for remote navigation between veins, creation of chamber maps, and gap identification with segmental isolation. The intended acute clinical endpoints were achieved in 100% of patients. Mean case time was 225.9 ± 70.5 min. Three patients (3.2%) crossed over to manual circular mapping catheter navigation. There were no adverse events related to the use of the remote manipulation system. CONCLUSIONS: The results of this study demonstrate that remote manipulation of a circular mapping catheter in the ablation of atrial arrhythmias is feasible and safe. Prospective randomized studies are needed to prove efficiency improvements over manual techniques.

Comparison of Multivariate Risk Estimation Models to Predict Prognosis in Patients With Implantable Cardioverter Defibrillators With or Without Cardiac Resynchronization Therapy.

Several multivariate risk score models were developed to predict prognosis of patients with heart failure (HF). We compared 3 models with regard to prediction of mortality in patients with HF who received an implantable defibrillator (ICD) or a cardiac resynchronization therapy defibrillator (CRT-D), as primary prevention of sudden death. The study cohort consisted of 823 patients (ICD = 410; CRT-D = 413). The evaluated models were the Seattle Heart Failure Model (SHFM), the Multicenter Automatic Defibrillator Implantation Trial II (MADIT II) score, and an adjusted Charlson Comorbidity Index (aCCI). End point was the performance of the models to predict all-cause mortality at 5 years. This was determined by c-statistics, for both subgroups. Multivariate analysis was used to analyze the relations between the risk score models, their individual components and mortality, and its applicability to the entire population. Cumulative mortality was 4.9% at 1 year and 21.1% at 5 years. Discriminatory power for 5-year mortality was highest for the SHFM (0.73; p <0.001) compared with the MADIT II score and the aCCI for the entire population. SHFM performed better than the MADIT II score for CRT-D group. In the entire population, the SHFM and the aCCI were significant predictors of mortality in multivariate analysis (hazard ratio 1.90, 95% confidence interval 1.49 to 2.43 vs hazard ratio 1.11, 95% confidence interval 1.01 to 1.22). The strongest individual components were age, HF, impaired renal function, and cancer, whereas CRT-D use was no predictor. In conclusion, the SHFM has the best discriminatory power for 5-year mortality in patients with HF with an ICD or CRT-D. The aCCI and MADIT II scores are less powerful but viable alternatives.

Evaluation of the need of elective implantable cardioverter-defibrillator generator replacement in primary prevention patients without prior appropriate ICD therapy.

OBJECTIVE: It is not clear whether patients who received an implantable cardioverter-defibrillator (ICD) for primary prevention should undergo device replacement if they never experienced an appropriate ICD therapy during the first generator longevity. This study evaluated the incidence and predictors of appropriate ICD therapy after device replacement in this specific population. METHODS: From two large prospective ICD registries, we identified all primary prevention patients who had a first ICD replacement without previous appropriate ICD therapy. Cox regression analysis was used to identify predictors of appropriate ICD therapy. RESULTS: Of 403 primary prevention patients needing first ICD replacement, 275 patients (68%) had not received previous appropriate ICD therapy. Patients without previous appropriate ICD therapy before first ICD replacement (mean age at replacement 62 ± 12 years, 75% male) had a mean follow-up of 86 ± 24 months after the initial implantation and 30 ± 24 months after device replacement. Following replacement, 3-year cumulative incidence of appropriate ICD therapy was 13.7% (95% CI 8.6 to 18.8%). No predictive factors associated with appropriate ICD therapy after replacement could be identified in spite of including seven clinically relevant factors. CONCLUSIONS: A considerable number of primary prevention patients without previous appropriate ICD therapy before first ICD replacement received appropriate ICD therapy after replacement. As there were no predictors of appropriate ICD therapy after replacement, replacing an ICD is still recommended in all primary prevention patients despite the lack of appropriate ICD therapy during first battery service life.

Acute and long-term outcomes of catheter ablation using remote magnetic navigation in patients with congenital heart disease.

The aim of the present study was to assess the feasibility, safety, and long-term results of remote magnetic navigation in arrhythmias associated with complex congenital heart disease (CHD). The improved outcomes for CHD resulted in an increased number of complex arrhythmias requiring distinctive ablation techniques. Thirty-six patients with CHD (age 35 ± 19 years, 21 male) were divided into 3 complexity groups and underwent 43 radiofrequency catheter ablation procedures using the magnetic navigation system (including 7 redo ablations) in combination with the CARTO RMT system. A total of 59 tachyarrhythmias were identified. Most patients had surgical scar-related tachycardia (25 focal, including 4 microreentrant atrial tachycardia, and 27 macroreentrant atrial tachycardia). Four accessory pathways and three ventricular tachycardias were diagnosed and treated. In 31 patients, ablation was successful, with an end point of noninducibility (86%). The success rate for CHD complexity of type I, II, and III was 50%, 88%, and 89%, respectively. The mean procedure and fluoroscopy time was 216 ± 101 minutes and 40 ± 34 minutes, respectively. The number of radiofrequency applications was 42 ± 47. No major complications related to the procedures occurred. Of the patients, 67% remained free of recurrence during a mean follow-up of 26 ± 4 months. Recurrence developed in 0%, 16%, and 45% of patients with CHD type I, II, and III, respectively. In conclusion, the magnetic navigation system is feasible to treat arrhythmias with reasonable success rates and good long-term outcomes in adult patients with CHD. The use of the magnetic navigation system offers advantages in complex anatomic situations.

The entirely subcutaneous implantable cardioverter-defibrillator: initial clinical experience in a large Dutch cohort.

OBJECTIVES: The purpose of the study was to evaluate the efficacy and safety of the entirely subcutaneous implantable cardioverter-defibrillator (S-ICD). BACKGROUND: A new entirely S-ICD has been introduced, that does not require lead placement in or on the heart. The authors report the largest multicenter experience to date with the S-ICD with a minimum of 1-year follow-up in the first 118 Dutch patients who were implanted with this device. METHODS: Patients were selected if they had a class I or IIa indication for primary or secondary prevention of sudden cardiac death. All consecutive patients from 4 high-volume centers in the Netherlands with an S-ICD implanted between December 2008 and April 2011 were included. RESULTS: A total of 118 patients (75% males, mean age 50 years) received the S-ICD. After 18 months of follow-up, 8 patients experienced 45 successful appropriate shocks (98% first shock conversion efficacy). No sudden deaths occurred. Fifteen patients (13%) received inappropriate shocks, mainly due to T-wave oversensing, which was mostly solved by a software upgrade and changing the sensing vector of the S-ICD. Sixteen patients (14%) experienced complications. Adverse events were more frequent in the first 15 implantations per center compared with subsequent implantations (inappropriate shocks 19% vs. 6.7%, p = 0.03; complications 17% vs. 10%, p = 0.10). CONCLUSIONS: This study demonstrates that the S-ICD is effective in terminating ventricular arrhythmias. There is, however, a considerable percentage of ICD related adverse events, which decreases as the therapy evolves and experience increases.

Clinical experience with a novel subcutaneous implantable defibrillator system in a single center.

BACKGROUND: Implantable cardioverter-defibrillators (ICDs) reduce mortality in both primary and secondary prevention, but are associated with substantial short- and long-term morbidity. A totally subcutaneous ICD (S-ICD) system has been developed. We report the initial clinical experience of the first 31 patients implanted at our hospital. METHODS: All patients had an ICD indication according to the ACC/AHA/ESC guidelines. The first 11 patients were part of the reported CE trial. The implantation was performed without fluoroscopy. The device was implanted subcutaneously in the anterior axillary line, with a parasternal lead tunneled from the xiphoid to the manubrial-sternal junction. Ventricular fibrillation (VF) was induced to assess detection accuracy and defibrillation efficacy using 65 J shocks. RESULTS: Post-implant, 52 sustained episodes of VF were induced. Sensitivity was 100% and induced conversion efficacy was 100% (with standard polarity in 29 patients). Mean time to therapy was 13.9 ± 2.5 s (range 11-21.6 s). Late procedure-related complications were observed in 2 of the first 11 implantations (lead migration). During follow-up, spontaneous ventricular arrhythmias occurred in four patients, with accurate detection of all episodes. Inappropriate therapy was observed in five patients. Recurrences were prevented with reprogramming. CONCLUSIONS: The S-ICD system can be implanted without the use of fluoroscopy by using anatomical landmarks only. Episodes of VF were accurately detected using subcutaneous signals, and all induced and clinical episodes were successfully converted. The S-ICD system is a viable alternative to conventional ICD systems for selected patients.

Assessment of left atrial shape and volume in structural remodeling secondary to atrial fibrillation.

PURPOSE: Assessment of volume in relation with left atrial (LA) shape alteration before and after PV isolation. METHODS: We compared trapezoidal modification of LA using echocardiography with the ellipsoid formula (EEL: ) and CT, with both ellipsoid (CTEL: ) and truncated cone formulas (CTTR: ), in 40 patients, before and +/-3 months after AF ablation. RESULTS: A trapezoidal shape was present in 76.3% of patients. The different volume measurements were statistically correlated (r = 0.603-0.837, p < 0.001) irrespective of the formula used. After reverse remodeling, with 77.5% of patients in stable sinus rhythm, correlation coefficient for volume remained significant (p < 0.001). CONCLUSIONS: In AF, dilation of the LA is associated with a geometrical trapezoidal change in many cases. The CT truncated cone formula applies best for precise evaluation of trapezoidal shape alteration in dilated AF atria. There is a good correlation between CTTR: and echocardiography which remains a valuable estimation for volume calculation in clinical practice.