Safety and Effectiveness of a Next-Generation Contact Force Catheter: Results of the TactiSense Trial.

OBJECTIVES: The objective of this clinical trial was to evaluate the safety and effectiveness of the TactiCath Contact Force Ablation Catheter, Sensor Enabled (TactiCath SE) (Abbott, Abbott Park, Illinois) for the treatment of drug-refractory, symptomatic paroxysmal atrial fibrillation (PAF). BACKGROUND: Catheter ablation of atrial fibrillation (AF) is an established therapy for the treatment of PAF. Ablation technology is evolving with the primary goals of improving efficacy and safety of the procedure. METHODS: This was a multicenter single-arm trial evaluating a novel ablation catheter for the treatment of PAF. A total of 156 subjects were enrolled at 19 sites in the United States, Europe, and Australia. The primary safety endpoint was the rate of device- or procedure-related serious adverse events occurring within 7 days. The primary effectiveness endpoint was acute success defined as pulmonary vein isolation at 30 min after ablation. Two descriptive endpoints were prospectively captured: 1) 1-year freedom from recurrence of symptomatic AF, atrial flutter (AFL), and atrial tachycardia (AT) lasting ≥30 s without a new or increased dose of Class I/III antiarrhythmic drugs; and 2) 1-year drug-free success defined by the absence of any recurrent AF/AFL/AT lasting ≥30 s without using Class I/III antiarrhythmic drugs. RESULTS: Primary safety events occurred in 4.7% of patients (95% confidence interval [CI]: 2.23% to 8.64%), and the procedure was acutely successful in 98.0% of patients (95% CI: 94.95% to 99.46%). According to Kaplan-Meier estimates at 1 year, 82.2% (95% CI: 74.7% to 87.6%) were free from symptomatic recurrence, and 1-year drug-free success was 68.2% (95% CI: 59.9% to 75.1%). CONCLUSIONS: The TactiCath™ Contact Force Ablation Catheter, Sensor Enabled™ is safe and effective for the treatment of paroxysmal AF.

Association between ventricular arrhythmias and myocardial mechanical dispersion assessed by strain analysis in patients with nonischemic cardiomyopathy.

BACKGROUND: Mechanical dispersion (MD), defined as the standard deviation of time to maximum myocardial shortening assessed by 2D speckle tracking echocardiographic strain imaging (2DS), has been recently proposed as a predictor for ventricular tachycardia or fibrillation (VT/VF) in patients with ischemic cardiomyopathy and long QT syndrome. However, the role of MD in patients with non-ischemic cardiomyopathy (NICM) has not yet been studied. METHODS AND RESULTS: In 20 patients with NICM (mean age 62 ± 11 years, 75 % male, mean EF 32 ± 6 %, mean QRS duration 102 ± 14 ms), we measured longitudinal strain by 2DS in a 16-segment left ventricular model and calculated the MD. Patients were divided into two groups, defined by the presence or absence of documented VT/VF. In 11 patients (55 %), VT/VF was documented. The median time from VT/VF to echocardiographic examination was 26 (IQR 15-58) months. There were no significant differences in baseline characteristics between patients with and without index events. MD was significantly greater in patients with VT/VF as compared to those without arrhythmias (84 ± 31 ms vs. 53 ± 16 ms, p = 0.017). The analysis of the ROC curve (AUC 0.81, 95 % CI 0.63-1.00, p = 0.017) revealed that dispersion >50 ms is associated with twelve times higher risk of VT/VF in patients with NICM (OR 12.5, 95 % CI 1.1-143.4, p = 0.024). CONCLUSIONS: In this small cohort of NICM patients, greater MD was associated with a higher incidence of VT/VF.

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.