Contact Force Catheter Research Articles

Reconstruction left atrium and isolation pulmonary veins of paroxysmal atrial fibrillation using single contact force catheter with zero x-ray exposure: A CONSORT Study.

Background:Conventional ablation of paroxysmal atrial fibrillation (PAF) is associated with radiation risks for patients and laboratory staff. Three-dimensional (3D) mapping system capable of showing contact force (CF) and direction of catheter tip may compensate for nonfluoroscopic safety issues.Objective:The aim of this study was to investigate the feasibility of zero x-ray exposure during reconstruction left atrium (LA) and ablation.Methods:Single, CF catheter, and 3D mapping system were used to reconstruct LA and isolate pulmonary veins (PV) in all patients. The patients were randomly divided into 2 groups after LA angiography. In group 1, reconstruction LA and isolation PV was performed with the help of 3D system (without x-ray), whereas in group 2, x-ray and 3D system were utilized to reconstruct LA and ablate PV antrum. After ablation, Lasso catheter was used to confirm the PV isolation. All patients were followed up to 12 months.Results:A total of 342 PAF patients were continuously enrolled. The basic clinical characteristics between the 2 groups had no significant difference. Parameters related to the procedure, average procedure time, ablation procedure time, average contact force (CF) applied, the percentage of time within CF settings, and average power applied during radiofrequency application showed no significant difference between the 2 groups. In group 1, the average fluoroscopy time before LA reconstruction was similar to that in group 2 (2.8 ± 0.4 vs. 2.4 ± 0.6 minutes, P = .75). The average fluoroscopy time during ablation was significantly lower than that in group 2 (0 vs. 7.6 ± 1.3 minutes, P < .001). The total x-ray exposure dose of the procedure in group 1 was significantly lower than that in group 2 (19.6 ± 9.4 vs. 128.7 ± 62.5 mGy, respectively, P < .001). Kaplan-Meier analysis indicated that there were no statistical differences in the probability of freedom from atrial arrhythmia (AF/AFL/AT) recurrence at 12 months between group 1 and group 2 (P = .152). The success rate after a single ablation procedure and without drugs (Class I/III AAD) at 12 months was not significantly different between the 2 groups (67.6%, 95% confidence interval [CI]: 62%–79.5% in group 1 and 68.9%, 95% CI: 63%–80.7% in group 2, P = .207). Procedural-related adverse events showed no significant different incidence between group 1 and group 2. A multivariate logistic regression analysis of risk factors was performed to evaluate the effectiveness outcome, which demonstrated that the percentage of CF (within the investigator-selected work ranges) during therapy was significantly associated with positive outcomes (odds ratio: 3.68; 95% CI: 1.65–10.6, P = .008), whereas the LA dimension was negatively associated with effectiveness outcomes (odds ratio: 0.72; 95% CI: 0.52–0.84, P = .016).Conclusions:Reconstruction LA and isolation PV ablation using single CF-assisted catheter without x-ray exposure was both safe and effective. CF was positively associated with effective outcomes and LA dimensions negatively with effective ones.

Randomised clinical trial of cryoballoon versus irrigated radio frequency catheter ablation for atrial fibrillation—the effect of double short versus standard exposure cryoablation duration during pulmonary vein isolation (CIRCA-DOSE): methods and rationale

IntroductionPulmonary vein isolation (PVI) is an effective therapy for paroxysmal atrial fibrillation (AF), but it has limitations. The two most significant recent advances have centred on the integration of real-time...

Novel Electrophysiology Signal Recording System Improves Signal Acquisition and Appreciation of Catheter Contact Force.

Catheter stability and adequate tissue contact are recognized as being fundamental to achieving favorable outcomes in ablation procedures. Conversely, excessive contact is associated with procedural complications. At present, electrogram amplitude and impedance are poor predictors of electrode-

P1719Efficiency and predictability in paroxysmal atrial fibrillation ablation with contact force catheter and stability module integration

P1719Efficiency and predictability in paroxysmal atrial fibrillation ablation with contact force catheter and stability module integration

Relationship between left atrium catheter contact force and pacing threshold.

The purpose of this study is to analyze the relationship between contact force (CF) and pacing threshold in left atrium (LA). Six to ten LA sites were studied in 28 consecutive patients with atrial fibrillation undergoing pulmonary vein isolation. Median CF, bipolar and unipolar electrogram voltage, impedance, and bipolar and unipolar thresholds for consistent constant capture and for consistent intermittent capture were measured at each site. Pacing threshold measurements were performed at 188 LA sites. Both unipolar and bipolar pacing thresholds correlated significantly with median CF; however, unipolar pacing threshold correlated better (unipolar: Pearson R -0.45; p<0.001; Spearman Rho -0.62; p<0.001, bipolar: Pearson R -0.39; p<0.001; Spearman Rho -0.52; p<0.001). Consistent constant capture threshold had better correlation with median CF than consistent intermittent capture threshold for both unipolar and bipolar pacing (Pearson R -0.45; p<0.001 and Spearman Rho -0.62; p<0.001 vs. Pearson R -0.35; p<0.001; Spearman Rho -0.52; p<0.001). The best pacing threshold cutoff point to detect a good CF (>10g) was 3.25mA for unipolar pacing with 69% specificity and 73% sensitivity. Both increased to 80% specificity and 74% sensitivity for sites with normal bipolar voltage and a pacing threshold cutoff value of 2.85mA. Pacing thresholds correlate with CF in human not previously ablated LA. Since the combination of a normal bipolar voltage and a unipolar pacing threshold <2.85mA provide reasonable parameters of validity, pacing threshold could be of interest as a surrogate for CF in LA.

MEMS-Based Flexible Force Sensor for Tri-Axial Catheter Contact Force Measurement.

Atrial fibrillation (AFib) is a significant healthcare problem caused by the uneven and rapid discharge of electrical signals from pulmonary veins (PVs). The technique of radiofrequency (RF) ablation can block these abnormal electrical signals by ablating myocardial sleeves inside PVs. Catheter contact force measurement during RF ablation can reduce the rate of AFib recurrence, since it helps to determine effective contact of the catheter with the tissue, thereby resulting in effective power delivery for ablation. This paper presents the development of a three-dimensional (3D) force sensor to provide the real-time measurement of tri-axial catheter contact force. The 3D force sensor consists of a plastic cubic bead and five flexible force sensors. Each flexible force sensor was made of a PEDOT:PSS strain gauge and a PDMS bump on a flexible PDMS substrate. Calibration results show that the fabricated sensor has a linear response in the force range required for RF ablation. To evaluate its working performance, the fabricated sensor was pressed against gelatin tissue by a micromanipulator and also integrated on a catheter tip to test it within deionized water flow. Both experiments simulated the ventricular environment and proved the validity of applying the 3D force sensor in RF ablation.

Abstract 13948: High Intraprocedural Atrial Fibrillation Termination Rate by Large Area Rotor Ablation Combined With Pulmonary Vein Isolation

Introduction: There remains contradictory data about the optimal ablation technique and the type of termination of atrial fibrillation (AF) ablation particularly in patient (pt) with persistent AF. The aim of this study was to determine the type of the termination of persistent AF during combined conventional and rotor ablation. Method: This is a single-center, prospective, observational study enrolled thirty-eight pts (24/63% male, mean age 63 years) with AF (mean left atrial size: 46,2 ± 7 mm), who underwent focal impulse and rotor modulation (FIRM) mapping and large area ablation around the core of the identified rotor(s), followed by conventional pulmonary vein isolation(PVI) using contact force catheter aiming 10-20 gr depending on the location. Two distinctive types of the AF termination were defined: sub-acute termination related to rotor elimination, furthermore acute termination due to PVI. Electric cardioversion (ECV) was executed only in the absence of spontaneous conversion to sinus rhythm (SR). Result: In 10(26%) pts acute AF termination after PVI was observed. In further 12 (31%) pts sub-acute termination of the AF could be observed after the identified rotor ablation. The combined technique of conventional and rotor ablation of pts with persistent AF resulted in 57,8% of termination rate. Spontaneous cardioversion could not be reached in 16 (42%) pts however 15 out of them were converted to SR by ECV. Procedural complication occurred in 3 pts presenting with groin hematoma, in one patient left atrial appendage (LAA) thrombus was revealed by transoesophageal echocardiography performed right after the ablation for guiding the planned LAA closure. Conclusion: Large area rotor ablation drag technique combined with contact force sensing technique results in a high termination rate of persistent AF. More studies are warranted to define the clinical significance and long term success rate of rotor ablation in pts with persistent atrial fibrillation.

Characteristics of Cavotricuspid Isthmus Ablation for Atrial Flutter Guided by Novel Parameters Using a Contact Force Catheter.

This study sought to investigate specific contact force (CF) parameters to guide cavotricuspid isthmus (CTI) ablation and compare the outcome with a historical control cohort. Patients (30) undergoing CTI ablation were enrolled prospectively in the Study cohort and compared with a retrospective Control cohort of 30 patients. Ablation in the Study cohort was performed using CF parameters >10 g and <40 g and a Force Time Integral (FTI) of 800 ± 10 g. The Control cohort underwent traditionally guided CTI ablation. Traditional parameters (electrogram and impedance change) were assessed in both cohorts. All ablations regardless of achieving targets were included in data analysis. Bidirectional CTI block was achieved in all of the Study and 27 of the Control cohort. Atrial flutter recurred in 3 (10%) patients (follow-up 564 ± 212 days) in the study cohort and in 3 (10%) patients (follow-up 804 ± 540 days) in the Control cohort. There were no major complications in either cohort. Traditional parameters correlated poorly with CF parameters. In the Study cohort, flutter recurrence was associated with significantly lower FTI and ablation duration, but was not associated with total average CF. CTI ablation can be safely performed using CF parameters guiding ablation, with similar long-term results to a historical ablation control group. Potentially CF parameters may provide adjunctive information to enable a more efficient CTI ablation. Further research is required to confirm this.

216-12: The Efficacy of Contact Force Catheter for Ablation of Atrial Fibrillation: Reduction of Dormant Conduction, Procedure Time and Fluoroscopy Time

Purpose of the study: Catheter ablation is being increasingly employed for the treatment of atrial fibrillation (AF). Catheter contact is an important determinant of lesion size. Contact force (CF) catheter technology may improve the ablation quality. The purpose of this study is to evaluate the procedural benefit of CF catheter. Method used: Sixty-eight consecutive patients, who underwent initial AF ablation including pulmonary vein isolation, were enrolled. We divided them to CF group (n = 52) and non-CF group (n = 16) according to the ablation catheter type. Dormant conduction was investigated by a bolus administration of 30mg of adenosine triphosphate during a continuous isoproterenol infusion (1.0-2.0 µg/min). Incidence of dormant conduction, procedure time and fluoroscopy time were compared between two groups. Summary of results: Dormant conduction, procedure time and fluoroscopy time were significantly reduced in CF group compared with non-CF group (Table1). Using multivariate analysis, dormant conduction was significantly associated with contact force catheter use (p = 0.018, 95% CI 0.020-0.708), not associated with atrial fibrillation type (persistent/paroxysmal: p = 0.675, 95% CI 0.165-11.108, long-standing/paroxysmal: p = 0.724, 95% CI 0.200-8.750) or left atrial diameter (p = 0.393, 95% CI 0.926-1.228)(Table2). Conclusion: Contact force catheter is effective to reduce dormant conduction, procedure time and fluoroscopy time during AF ablation. Table1 Table1

Acute Cardiac Tamponade after Left Sided Premature Ventricular Contraction Ablation

Abstract Introduction: Premature ventricular complex (PVC) is the most common cardiac arrhythmia, which in some circumstances can lead to syncope, arrhythmia-induced cardiomyopathy and sudden death. In idiopathic PVCs, the first choice of treatment is radio-frequency ablation. Identification of the substrate location makes it possible to determine the ablation site, leading to an increased success rate. Complications are related mainly to the ablation technique, peri-procedural anticoagulation therapy, and the access site. Pericardial tamponade is a rare complication. A case in which the ablation procedure of idiopathic PVCs, complicated by cardiac tamponade, is presented in this paper. Case presentation: A 56-year-old female presented with symptomatic premature ventricular contractions. She had frequent palpitations, dyspnea, and exercise intolerance for ten years. Holter-monitoring demonstrated a total burden of 30,549 PVCs with monomorphic morphology, and with both bigeminal and trigeminal patterns. Surface ECG suggested a left-sided, left aortic cusp localization of the PVC, with a possible epicardial origin. Three-dimensional mapping was performed including the RVOT (right ventricular outflow tract) region, aorta, and coronary sinus. The ablation clinical status suggested a cardiac tamponade, which was confirmed by echocardiography. Radioscopy-controlled pericardial puncture was performed with the extraction of 300 ml of blood. Following this maneuver, the general status of the patient improved. During follow-up checks after twenty-four hours, Holter-monitoring recorded 5000 PVCs with a significant improvement in the clinical status of the patient. Discussions: Pericardial tamponade after radio-frequency ablation is a rare complication. The risk of tamponade in a right chamber perforation is more dangerous in patients on anticoagulation therapy or with pulmonary hypertension. In order to prevent this side effect complication of the interventional procedures, certain safety maneuvers should be followed, including the use of irrigated-type catheters, or when possible, contact force catheters, ensuring invasive arterial blood pressure monitoring during intervention, and after heparin administration and the determination of ACT every twenty minutes. Transthoracic echocardiograph examination and pericardial puncture set should be readily available in the electrophysiology laboratory.

16-17: Contact-force guided single catheter approach for pulmonary vein antrum isolation: procedural feasibility

Purpose: Wedging a circular mapping catheter (CMC) into pulmonary vein (PV) is recommended to validate their isolation during wide antral circumferential ablation (WACA). Since appropriate catheter contact has proved crucial for lesion quality, we hypothesize that a contact-force (CF) guided single catheter approach might be suitable and effective for PV isolation (PVI). Methods: With the use of a CF ablation catheter, WACA was performed for both sets of PVs in 50 patients with paroxysmal AF. Antral exit block was demonstrated by sequential pacing at 9 equidistant points within the circular WACA lesion set (including the carina), with a target force ≥ 10g. Sites displaying persistent left atrial capture underwent additional pacing maneuvers and electrogram analysis, in order to detect and close residual gaps. Once exit block was deemed achieved, PVI was validated by conventional CMC-based analysis. Results: The mean procedural duration, fluoroscopy exposure time, total ablation time and force applied per-procedure were respectively of 101 ± 17 min, 5.6 ± 2.2 min, 23.2 ± 7.1 min and 17.8 ± 2.6 grams. 84 of 100 PV antra were disconnected after an exclusive anatomical approach, while 16 displayed residual gaps. Of the latter, 14 were isolated with the sole CF catheter. The positive predictive value of antral exit block reached 100% for predicting PVI as assessed with CMC. Conclusions: CF-guided single catheter technique is a feasible method for PVI in patients with paroxysmal AF. This simplified approach proves as effective as the standard CMC-based approach for residual gaps identification and conduction block validation.

Pulmonary vein isolation in the treatment of atrial fibrillation

Pulmonary vein isolation in the treatment of atrial fibrillation Saurabh Kumar, Gregory F Michaud Cardiac Arrhythmia Service, Cardiovascular Division, Brigham and Women&#39;s Hospital, Boston, MA, USA Abstract: Atrial fibrillation (AF) is the commonest arrhythmia in humans and is associated with marked reduction in quality of life and an elevated thromboembolic risk. Paroxysmal, persistent, and permanent forms of AF have been recognized. Whilst antiarrhythmic drugs are considered as first-line therapy, the role of catheter ablation is increasing due to its superior efficacy in terms of quality of life and reduction in AF burden. The central paradigm for catheter ablation of AF is that triggers for AF are located near and within the pulmonary veins (PVs), and electrical isolation of the PVs from the left atrium forms the cornerstone of most catheter ablation strategies. Whilst paroxysmal form is generally trigger dependent, persistent and permanent forms are associated with variable interaction between triggers and &quot;substrate&quot; comprised of atrial and PV electrical and structural remodeling. Nevertheless, isolation of the PVs still forms a critical component of catheter ablation strategies, regardless of AF type. Procedural efficacy, however, is limited by PV conduction recovery. This is likely due to deficiencies in ablation tools or limitations of intraprocedural assessment of lesion efficacy. Careful attention to surrogates of tissue heating, such as impedance decrease and electrogram morphology changes, along with advances in catheter technology like contact force catheters may improve rates of durable PV isolation and single-procedural success. This review discusses the mechanism of paroxysmal AF with particular focus on the role of the PVs in AF initiation and PV isolation in the management of AF. Keywords: contact force, lesion transmurality, radiofrequency catheter ablation, paroxysmal atrial fibrillation, electrophysiology, AF

What have we learned of ablation procedures for atrial fibrillation?

Atrial fibrillation is a widespread disease of growing clinical, economic and social importance. Interventional therapy for atrial fibrillation offers encouraging results, with pulmonary vein isolation (PVI) as the established cornerstone. Yet, the challenge to create durable transmural lesions remains, leading to recurrence of atrial fibrillation in long-term follow-up even after multiple ablation procedures in 20% of patients with paroxysmal atrial fibrillation and approximately 50% with persistent atrial fibrillation. To overcome these limitations, innovative tools such as the cryoballoon and contact force catheters have been introduced and have demonstrated their potential for safe and effective PVI. Furthermore, advanced pharmacological and pacing manoeuvres enhance evaluation of conduction block in PVI.

Design and Evaluation of a Catheter Contact-Force Controller for Cardiac Ablation Therapy.

Maintaining a constant contact force (CF) of an ablation catheter during cardiac catheter ablation therapy is clinically challenging due to inherent myocardial motion, often resulting in poor ablation of arrhythmogenic substrates. To enable a prescribed contact force to be applied during ablation, a catheter contact force controller (CCFC) was developed. The system includes a hand-held device attached to a commercial catheter and steerable sheath. A compact linear motor assembly attaches to an ablation catheter and autonomously controls its relative position within the shaft of the steerable sheath. A closed-loop control system is implemented within embedded electronics to enable real-time catheter-tissue contact force control. To evaluate the performance of the CCFC, a linear motion phantom was used to impose a series of physiological CF profiles; lesion CF was controlled at prescribed levels ranging from 15 to 40g. For a prescribed CF of 25g, the CCFC was able to regulate the CF with a root mean squared error of 3.7 ± 0.7g. The ability of the CCFC to retract the catheter upon sudden changes in tissue motion, which may have caused tissue damage, was also demonstrated. Finally, the device was able to regulate the CF for a predetermined amount of time according to a force-time integral model. The developed CCFC is capable of regulating catheter-tissue CF in a laboratory setting that mimics clinical ablation therapy. Catheter-tissue CF control promises to improve the precision and success of ablation lesion delivery.

Analysis of catheter contact force during atrial fibrillation ablation using the robotic navigation system: results from a randomized study.

Contact with cardiac tissue is an important determinant of lesion efficacy during atrial fibrillation (AF) ablation. The Sensei X™ robotic navigation system (RNS) (Hansen Medical, Mountain View, CA, USA) has been validated for contact force (CF) sensing expressed in grams (g). The Thermocool® SmartTouch™ catheter enables the measurement of catheter tip CF and direction inside the heart. We aimed to investigate the catheter CF with and without RNS during pulmonary vein isolation (PVI) procedures. Eighty patients with symptomatic AF (56 males, age 63 ± 18) were enrolled in this study. Fifty-seven patients had paroxysmal AF and 23 early persistent AF. All procedures were performed with the Thermocool® SmartTouch™ ablation catheter. Forty patients were randomized to perform PVI with the Sensei X™ RNS (group 1), while in the other 40 patients (group 2), PVI was performed without the RNS. AF ablation was performed successfully in all patients without complications, while contact force was kept in the established 10-40g range. A significantly higher CF was documented on the PVs in group 1 compared to group 2. The 1-year freedom from AF recurrence was higher in group 1 compared to group 2 (90 vs. 65%, p = 0.04). Moreover, a significant reduction of fluoroscopy time was noted in the RNS group (13 ± 10 vs. 20 ± 10min, respectively, p = 0.05). The Sensei X™ RNS permits a significantly higher CF during transcatheter AF ablation with a low rate of AF recurrence at clinical follow-up.

Impact of Catheter Contact Force on Superior Vena Cava Mapping and Localization of the Right Phrenic Nerve by High Output Pacing.

Right phrenic nerve injury (PNI) is a major concern during superior vena cava (SVC) isolation. Phrenic nerve (PN) localization by high-output pacing is a standard technique for anticipating PNI. This study evaluated the impact of catheter contact force (CF) on SVC mapping and PN localization. Twenty-one atrial fibrillation patients undergoing cardiac enhanced computed tomography (CT) were prospectively enrolled. SVC geometries were created at the SVC-right atrium junction level with low (<10 × g) and high (>10 × g) CFs. The PN was localized by high-output pacing (10 V, 2 milliseconds) at the SVC and anterior right superior pulmonary vein (RSPV) with different CFs. The SVC cross-sectional area was significantly greater when created with high (22.1 ± 4.9 × g) compared with low CFs (4.2 ± 1.3 × g) (5.3 ± 1.4 cm2 vs. 2.3 ± 0.7 cm2 , P < 0.0001). High CFs distorted the SVC and anterior RSPV by a mean of 4.8 ± 2.5 and 4.4 ± 1.7 mm, with minimal distortion at the anteroseptal SVC. The PN was more frequently captured with a high compared with low CF at the SVC (95.2% vs. 71.4%, P = 0.038) and RSPV (66.7% vs. 14.3%, P = 0.0005). The PN capture area was also wider with a high compared with low CF at the SVC (9.0 ± 4.1 mm vs. 4.5 ± 2.8 mm, P = 0.001). The PN location was at the anterolateral, lateral, and posterolateral SVC in 3 (14.3%), 13 (61.9%), and 5 (23.8%) patients, respectively, which was identical to that identified on CT. No PNs located >1.98 mm from the RSPV were captured by RSPV pacing. CF impacted the SVC mapping and PN localization. Cardiac CT identified the PN location, and the distance from the pacing site influenced PN capture.

Clinical impact of contact force and its regional variability on efficiency and effectiveness of pulmonary vein isolation for atrial fibrillation

BackgroundThe purpose of this study is to analyze the impact of average contact force (CF) and its regional variability during pulmonary vein isolation (PVI) for atrial fibrillation (AF) on periprocedural parameters and midterm outcome. MethodsThis retrospective cohort study enrolled 57 drug-refractory AF patients who underwent initial PVI for AF using an open-irrigated CF catheter (SmartTouch Thermocool, Biosense Webster, Diamond Bar, CA, USA). Thirty patients were assigned to a lower CF (LCF) group (average CF≤10g) and 27 patients to a higher CF (HCF) group (average CF>10g). The relationship between CF and clinical outcome was analyzed. ResultsPatients were followed-up for 317±57 days after PVI. The CF was 8.1±1.3g in the LCF group and 12.4±1.5g in the HCF group. Higher average CF was associated with shorter ablation time (28±6min vs. 36±9min, p=0.0002) and lower radiofrequency energy delivery (79±18 vs. 99±26, p=0.0016) for PVI. The rate of acute PV reconnection (APVR) was similar in both groups (LCF group 60% vs. HCF group 44%, p=0.36). Four patients (13%) in the LCF group and nine patients (33%) in the HCF group experienced AF-recurrence. Average CF did not impact on AF-recurrence during midterm clinical outcome (p=0.09 by log-rank test). In the non-recurrence group (n=44), average CF was higher at left posterosuperior PV and right anteroinferior PV than that in the recurrence group (n=13) (p=0.012 and p=0.004, respectively). ConclusionsHigher average CF decreased ablation time and radiofrequency energy delivery for PVI, but did not decrease APVR rate or improve midterm clinical outcome.

Abstract 9860: Safety and Clinical Outcome of Catheter Ablation of Ventricular Arrhythmias Using Contact Force Sensing, Consecutive Case Series

Introduction: Poor catheter-to-myocardial contact can lead to ineffective ablation lesions and suboptimal outcome. Contact force (CF) sensing catheters in ventricular tachycardia (VT) ablations has not been studied for their long term efficacy. Hypothesis: The hypothesis is that CF ablation is superior to manual ablation (MAN) and non-inferior to remote magnetic navigation (RMN) ablation for safety and efficacy in acute and long term outcome. Methods: A total of 249 consecutive patients 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 average follow-up period was ± 20 months. Results: Acute success was achieved in 191 out of 249 procedures (75.9%). Acute success in manual ablation, CF ablation and RMN ablation was 70.1%, 72.3% and 85.2% respectively (P = 0.038). Major complications occurred in 3.2% and there was a trend towards less major complications (P = 0.055) in the RMN group. Thirty-six percent of the patients with an initially successful procedure had a recurrence during follow-up (CF 41.2% MAN 37.5% RMN 32.0% P = NS). Conclusions: The use of CF sensing catheters does not improve the procedural outcome or safety profile in comparison to non-CF sensing ablation in ventricular arrhythmias. RMN non-CF sensing ablation has the highest procedural success rate. Future studies are necessary to investigate the role of CF in VT ablation and to define the optimal force.

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

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. 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. 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. 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. 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.

Contact force threshold for permanent lesion formation in atrial fibrillation ablation: A cardiac magnetic resonance–based study to detect ablation gaps

Catheter contact force (CF) has a strong correlation with lesion formation during radiofrequency ablation. Delayed-enhancement cardiac magnetic resonance (DE-CMR) provides lesion information in patients with prior atrial fibrillation (AF) ablation. The aim of this study was to determine the CF threshold to create permanent lesions detected by DE-CMR. A total of 36 patients referred for AF ablation were included. A CF catheter was used during the ablation procedure, and DE-CMR was performed 3 months after the ablation procedure. Eighteen pulmonary vein (PV) segments were defined, and 3-dimensional (3D) reconstructions of the left atrium (LA) derived from the DE-CMR images were obtained. One observer evaluated the presence of any discontinuity of previous ablation lesions (gap) in the 3D reconstructions of the LA, and another observer (blinded to the gap findings) determined the minimum CF value in each PV segment. The PV segments where a gap was observed had a lower maximal CF value than did the segments without gap in the 3D LA reconstructions (6.7 ± 4.4 g vs 12.2 ± 4.7 g; P < .001). In receiver operating characteristic analysis, a CF threshold of >8 g provided 73% sensitivity and 81% specificity in the prediction of a complete PV lesion (positive predictive value [PPV] 84%). A CF threshold of >12 g had a specificity of 94% and increased the PPV to 91% in creating a complete lesion in the LA wall (area under the curve 0.834). A CF threshold of >12 g H5H20 predicts a complete lesion with high specificity and PPV when a dragging ablation strategy is used in AF ablation.