Author + information
- Received September 23, 2018
- Revision received December 11, 2018
- Accepted December 13, 2018
- Published online March 25, 2019.
- William G. Stevenson, MDa,∗ (, )@utedrow,
- Usha B. Tedrow, MD, MScb,
- Vivek Reddy, MDd,
- Amir AbdelWahab, MDc,
- Srinivas Dukkipati, MDd,
- Roy M. John, MD, PhDa,
- Akira Fujii, MDb,
- Benjamin Schaeffer, MDb,
- Shinichi Tanigawa, MDb,
- Ihab Elsokkari, MDc,
- Jacob Koruth, MDd,
- Tomofumi Nakamura, MD, PhDb,
- Aditi Naniwadekar, MDc,
- Daniele Ghidolie,
- Christine Pellegrinib and
- John L. Sapp, MDc
- aCardiovascular Division, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
- bCardiovascular Division, Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts
- cHeart Rhythm Service, Department of Medicine, Division of Cardiology, QEII Health Sciences Centre, Halifax, Nova Scotia, Canada
- dHelmsley Electrophysiology Center, Icahn School of Medicine at Mount Sinai, New York, New York
- eBiosense Webster, Inc., Irvine, California
- ↵∗Address for correspondence:
Dr. William G. Stevenson, Vanderbilt University Heart and Vascular Institute, 1215 21st Ave South, MCE 5th Floor, South Tower, Nashville, Tennessee 37232.
Background Catheter ablation is effective for eliminating most drug-refractory ventricular arrhythmias (VA). However, a major reason for procedural failure is arrhythmia originating deep within the myocardium where it is inaccessible to conventional endocardial or epicardial approaches. Affected patients have limited therapeutic options.
Objectives The objective of this study was to assess the safety and outcome of a novel radiofrequency ablation catheter that used an extendable/retractable 27-g needle capable of targeting deep arrhythmia (intramural) substrate.
Methods Patients who failed at least one prior catheter ablation procedure for sustained ventricular tachycardia (VT) or nonsustained VA with associated left ventricular dysfunction were enrolled at 3 centers. The target was sustained monomorphic VT in 26 patients, including 8 with recent VT storm or VT requiring intravenous medication, and 5 with incessant VA associated with ventricular dysfunction.
Results Needle ablation was performed in 31 patients (median of 2 failed prior ablation procedures; 71% nonischemic heart disease). After a median of 15 needle lesions/patient, ablation abolished at least 1 inducible VT in 19 of 26 VT patients (73%), and suppressed ambient arrhythmia in 4 of 5 nonsustained arrhythmia patients. At the 6-month follow-up, 48% of patients were free of recurrent arrhythmia and another 19% were improved. Procedure-related complications included a single pericardial effusion treated with percutaneous drainage and a left ventricular pacing lead dislodgement with no deaths.
Conclusions In patients with recurrent ventricular arrhythmias refractory to medications and conventional catheter ablation, intramural needle radiofrequency ablation offers significant arrhythmia control with an acceptable procedural risk.
Catheter ablation is an important therapy to prevent and reduce recurrent episodes of ventricular tachycardia (VT) in patients who have implanted defibrillators (ICDs) and premature ventricular beats and nonsustained VT causing significant symptoms or contributing to depressed ventricular function (1). In multicenter trials, however, approximately one-half of the patients have at least one recurrence of VT (1–3). When ablation and antiarrhythmic drugs fail, therapeutic options are often limited and outcomes are poor (2,4). In one series, patients undergoing additional surgical and/or transcoronary alcohol ablation after catheter ablation failed had a 6-month mortality rate of 17% and a 55% rate of recurrent VT (4).
Effective ablation requires identification and damage of the tissue causing the arrhythmia. Endovascular catheters are limited to ablation of tissue within about 7 mm of the endocardial surface (5). Percutaneous access to the pericardial space allows ablation of tissue in the subepicardium, but is often limited by epicardial fat, inaccessibility due to pericardial adhesions in patients who have had prior cardiac surgery, and risk of collateral injury to adjacent coronary arteries. Inaccessibility of arrhythmogenic areas is an important cause of ablation failure and likely explains the worse outcome of ablation in nonischemic heart disease, as compared with coronary artery disease (6–10).
To identify and ablate arrhythmia substrate that is deep to the endocardium, we developed a technique of radiofrequency (RF) needle infusion ablation for myocardial use (11,12). An initial study with a prototype catheter in 8 patients demonstrated feasibility (13). Following enhancements to the catheter design, this U.S. Food and Drug Administration investigational device exemption trial was initiated to assess the safety and outcome of RF needle infusion ablation in patients with recurrent ventricular arrhythmias that had failed control with conventional irrigated RF ablation and antiarrhythmic drug therapy.
Patients were enrolled under institutional review board–approved protocols at Brigham Hospital, Queen Elizabeth II Health Sciences Centre, Halifax Nova Scotia, and Mount Sinai Medical Center, New York, New York (NCT01791543, NCT03204981). All patients gave informed consent. U.S. use of the catheter was conducted under Investigational Device Exemptions from the U.S. Food and Drug Administration. Canadian use was conducted through the Special Access Program, Health Canada.
Patients with episodes of sustained monomorphic VT or incessant ventricular arrhythmia for >20% of beats in a 24-h period associated with reduced ventricular function (ejection fraction <40%) that had failed to respond to antiarrhythmic drug therapy due to inefficacy or intolerance and failed catheter ablation due to spontaneous recurrence of the arrhythmia were offered participation in the study. Exclusion criteria included: idiopathic VT not causing depressed ventricular dysfunction, protruding left ventricle (LV) thrombus, myocardial infarction within 2 months, Class IV heart failure or cardiogenic shock unless due to VT, contraindication to heparin, allergy to radiographic contrast dye, severe aortic stenosis or mitral regurgitation with a flail mitral leaflet, unstable angina, thrombocytopenia <50,000, and other disease processes likely to limit survival to <12 months.
Mapping and ablation were performed with patients under conscious sedation or general anesthesia. Electrophysiological catheters and an intracardiac echocardiography (ICE) catheter were placed from femoral arteries or veins. LV access was achieved by a retrograde aortic or transseptal atrial approach. Systemic anticoagulation was achieved with heparin. Electroanatomical maps were created using a 3-D mapping system (CARTO 3; Biosense Webster, Irvine, California). Ventricular anatomy and catheter position were observed with ICE (SoundStar; Biosense Webster or Viewflex; Abbott Medical). Endocardial voltage maps of the chamber of interest were generated in sinus or paced rhythm with a 3.5-mm tip standard ablation catheter (ThermoCool SmartTouch, CF-sensing catheter; Biosense Webster) or a multi-electrode catheter (PentaRay NAV Catheter; Biosense Webster). Low-voltage scar was defined as an area having a bipolar electrogram amplitude <1.5 mV; low unipolar LV voltage was defined as <8.3 mV for septum and LV and <5.5 mV for right ventricle (RV) free wall (9). Intracardiac electrograms were recorded in digital format (Cardiolab EP system; General Electric Healthcare, Barrington, Illinois and CARTO electroanatomic mapping system; Biosense Webster).
Needle ablation catheter
The needle ablation catheter is an 8-French catheter with a dome (tip) electrode and single ring electrode (Figure 1). The dome electrode has a single hole through which the 27-g needle electrode can be extended for up to 10 mm. The needle is electrically isolated from the dome electrode and contains a thermocouple within its lumen near the tip. A position sensor allows display of the dome electrode and distal catheter shaft position on the electroanatomic mapping system. The length of the needle was adjusted to be less than myocardial thickness in the targeted region, and was initially set to 6 to 9 mm (median, 7 mm). The dome electrode port and needle are each independently irrigated with heparinized saline at 1 ml/min during mapping. The needle is used as an electrode for recording unipolar electrograms and bipolar electrograms (between the needle and the dome or ring electrodes). Unipolar needle and dome electrograms are recorded on multiple channels to allow high-pass filtering at different settings of 0.5, 30, or 40 Hz. Bipolar recordings were high-pass filtered at 30 or 40 Hz. Pacing can be performed from the needle or dome electrode. Failure to capture with unipolar pacing at 10 mA and ≥2 ms pulse width was considered an indication of electrically unexcitable tissue due either to scar or acute RF lesion creation.
The workflow is shown in Figure 2. Initial mapping to identify ablation targets was performed as previously described with a standard irrigated ablation or multispline mapping catheter (13,14). Ventricular geometry was defined with ultrasound and voltage mapping. If the arrhythmia was not present at baseline it was induced with programmed stimulation with up to 4 extrastimuli and burst pacing and with epinephrine or isoproterenol infusion if required. Hemodynamically unstable arrhythmias were terminated by pacing or cardioversion. The initial mapping catheter was then exchanged for the needle ablation catheter. If VT produced hemodynamic instability, activation and entrainment were assessed at only selected sites during brief episodes. Because needle ablation can spare the endocardium, conventional endocardial irrigated RF ablation was allowed at the discretion of the investigator (Biosense Webster, ThermoCool, or Surround Flow with maximum power of 50 W).
Endocardial sites thought to be closest to the arrhythmia origin were selected for needle deployment. For scar-related arrhythmias, areas of low bipolar or unipolar voltage thought to be closest to the VT circuit based on activation and entrainment mapping, or for unstable VTs, pace-mapping, were initially evaluated. For premature ventricular complexes (PVCs), the area of earliest endocardial activation was initially evaluated. Using ICE and fluoroscopic guidance to attempt to achieve a perpendicular position of the catheter tip to the endocardium, the needle was extended into the myocardium and the needle irrigation was paused. Unipolar pacing from the needle electrode was performed to assess tissue excitability at 10 mA, 2 ms pulse width stimulus strength. If there was no capture pacing at 10 mA, 9 ms pulse width could be assessed. If no capture was detected, the needle was retracted and mapping continued. At sites selected for ablation 1 ml of 50:50 saline and radiographic contrast (iopamidol [76%]) solution was injected manually and tissue staining was assessed with fluoroscopy. If the site was still selected for ablation, normal saline was infused through the needle at 2 ml/min for 60 s (CoolFlow pump; Biosense Webster) followed by initiation of RF energy during continued saline irrigation at 2 ml/min. Dome irrigation was 1 ml/min for mapping and ablation. RF was applied in a temperature-controlled mode set to 60°C and with power initially limited to 15 to 35 W and manually increased to achieve a temperature of 60°C (11,13). Maximum power and lesion duration were 50 W and 120 s, respectively. Needle infusion was then paused and unipolar needle pacing was performed to assess post-ablation capture. Absence of capture at the stimulus output that had previously captured was taken as evidence of lesion creation. RF was terminated for an increase in impedance of >2 to 3 ohms after the initial fall.
The procedure goal was abolition of all inducible sustained monomorphic VTs, or abolition of the ambient or provokable nonsustained arrhythmia that was the ablation target, or absence of further identifiable target sites. For scar-related VTs we sought to render the target region unexcitable to needle pacing that captured prior to ablation. In patients with low-voltage scar, ablation was performed at multiple sites that captured surrounding the initially identified site. Programmed stimulation was then typically repeated and other induced VTs were targeted. For septal arrhythmias, needle insertion could start from either the right or left side of the septum, followed by the opposite side if ablation at the initial sites was ineffective or good target sites were not identified.
Anticoagulation and arrhythmia drug management were left to the discretion of the treating physicians as per usual laboratory protocols. Patients underwent anticoagulation treatment with heparin overnight and then either aspirin, warfarin, or a direct-acting anticoagulant for at least 3 months. Follow-up visits occurred 3 to 6 weeks and 5 to 7 months after ablation. An echocardiogram was obtained prior to hospital discharge and 5 to 7 months after ablation.
The prespecified efficacy endpoint for sustained VT was control of VT defined by freedom from hospitalization for recurrent VT during the 6 months following ablation. For the purposes of this analysis, we report occurrence of any sustained VT requiring an intervention for termination, including ICD anti-tachycardia pacing or shocks.
Efficacy endpoint for ventricular arrhythmia causing significant ventricular dysfunction was a decrease in ambient ventricular arrhythmia to <5,000 ventricular beats daily.
Safety endpoint was absence of all serious adverse events that are potentially device related and occur within 30 days of the ablation procedure (Online Table 1).
A clinical or presumptive clinical VT is one that has been documented to occur spontaneously or is within 20 ms in cycle length of a VT that has been documented to occur spontaneously.
Modification of the VT substrate was defined as abolition of at least one inducible sustained VT but continued presence of another inducible sustained VT.
To achieve 80% power to detect a reduction in VT in 40% of patients with 2-tailed 10%, we initially planned to enroll 20 patients, estimating this to be a minimal clinically significant benefit. After favorable safety in the initial cohort, the sample size was expanded to increase detection of safety events.
Continuous variables are displayed as median (quartile 1 to quartile 3). Categorical data are displayed as counts and percentages.
A total of 42 patients met the entry criteria and were consented for the procedure (Online Figure 1). Ablation with the needle catheter was not performed in 11 patients: in 10 because the arrhythmia origin was identified on the endocardium and conventional irrigated ablation was successful and in 1 because the procedure was aborted when intracardiac ultrasound identified a large mobile thrombus in the right ventricle prior to placement of electrophysiological catheters.
A total of 31 patients had ablation with the needle catheter (Table 1). Individual patient details are provided in Online Table 2. Median age was 62 years; 9 had coronary artery disease only, 22 had non-ischemic forms of heart disease, and 2 had nonischemic cardiomyopathy and coronary artery disease. Failed therapies included a median of 2 antiarrhythmic drugs and a median of 2 prior catheter ablation procedures (2 or more procedures in 71%), including epicardial procedures in 12 (39%) patients. Eight patients were receiving intravenous antiarrhythmic medications to control VT and 4 had a history of VT storm within the preceding 24 h of the procedure. Of the remaining patients, ICD interrogations to confirm arrhythmia frequency were available in 16, revealing a median VT frequency of 2.5 episodes per month (range, 0.25 to 17/month). Antiarrhythmic medications at the time of hospitalization are shown in Figure 3.
The primary arrhythmia target was sustained monomorphic VT in 26 patients and frequent PVCs associated with depressed ventricular function in 5 patients, 2 of whom also had a history of sustained VT. In patients with a history of sustained VT, a median of 3 morphologies of sustained monomorphic VT were inducible, 1 had no sustained VT inducible, 2 had inducible nonsustained VTs that were thought to be relevant, and another had only pleomorphic VT inducible. Untolerated VTs were induced in 23 patients, and at least 1 hemodynamically tolerated VT was observed in 14 patients. Ablation target regions included the septum in 24 patients, and the needle was inserted from both the left and right sides of the septum in 16 of these patients (Figure 4). Ablation included the periaortic region in 18 patients. Percutaneous epicardial mapping was not performed in any patient.
A total of 667 RF needle applications were delivered, a median of 15 per patient (range: 5 to 66) per procedure (including repeat needle ablation procedures in 2 patients) (Table 2, Online Table 2). Conventional endocardial RF applications were delivered at the same procedure in 14 (45%) of the patients. In 4 patients, endocardial ablation was performed before needle ablation and failed to abolish VT. In 2 patients, an arrhythmia was successfully ablated endocardially but other arrhythmias remained and were targeted with the needle catheter. In 2 patients, VT that remained inducible after needle ablation was targeted with further endocardial ablation, but in both cases the arrhythmia remained inducible. In 6 patients, needle ablation was thought to have abolished inducible VT, but the endocardial area over the ablation site could be captured with endocardial pacing, and additional endocardial ablation was performed due to concern for endocardial sparing.
Following ablation, no VT was inducible in 15 patients, at least 1 VT was no longer inducible in 4 patients, the targeted VT remained inducible in 1 patient, and complete programmed stimulation was not performed in 6 patients to avoid further hemodynamic stress. In the 5 patients for whom PVCs were the target, the targeted PVCs were no longer present in 4 patients and were less frequent in the fifth patient.
Any adverse event requiring therapy within 30 days occurred in 7 patients (23%) (Table 3). One patient developed a pericardial effusion that was drained percutaneously without sequelae (described in detail in Online Figure 2). One patient experienced LV lead dislodgement. One patient developed heart block from septal ablation, which was expected. One patient with a left ventricular ejection fraction of 39%, but heart failure related to catecholamine cardiomyopathy from a recently resected pheochromocytoma and VT storm experienced heart failure exacerbation requiring diuresis after the procedure. One patient experienced a pulmonary embolism 4 days after the procedure following a long airplane flight and recovered after thrombolytic therapy.
A very small amount of coagulum on the dome electrode of the needle catheter was observed during the procedure in 12 patients. This occurred following an impedance rise. No clinically evident embolic events occurred.
Echocardiograms were obtained prior to hospital discharge in 28 patients, and were interpreted by the respective institution’s imaging specialists independent of the study. Left ventricular ejection fraction decreased by >5% in 2 patients, increased by >5% in 4 patients, and changed <5% in the remainder. A new small pericardial effusion was noted in the patient who had pericardiocentesis at the time of the procedure. In 2 patients, mitral regurgitation that was mild pre-procedure was mild to moderate after the procedure with no new structural abnormalities of the valve identified.
At discharge, antiarrhythmic drugs were unchanged in 10 patients and decreased in 21 patients (Figure 3). During a median follow-up of 259 (range, 204 to 339) days from the initial procedure, 15 patients were free from recurrent arrhythmia: 4 for whom PVCs were the predominant target and 11 with sustained VT (Table 4, Figure 5). In addition, 6 patients, who had frequent or incessant VT episodes prior to ablation, had marked improvement with 1 to 6 episodes in the 6 months after ablation (Online Table 2). There was 1 death from pneumonia 6 months after ablation in a patient who suffered recurrent VT that was not related to the death.
Repeat catheter ablation was performed in 5 patients in the failed group (Figure 5B). Repeat needle ablation was performed in 2 patients. One patient with nonischemic cardiomyopathy who required intravenous lidocaine for VT suppression prior to his initial procedure had 2 VT episodes terminated by his ICD after ablation. After a second needle ablation 9 weeks after initial ablation, he remained free of further VT (last follow-up at 201 days after the second procedure). A patient with hypertrophic cardiomyopathy who continued to have inducible and spontaneous VT from the basal LV after 2 needle ablation procedures had surgical septal myectomy, but continued to have occasional VT. Three patients had subsequent endocardial ablation procedures with conventional irrigated catheters. Two had endocardial ablation that acutely modified inducible VT in 1 patient and abolished inducible VT in the other. The fifth patient had multiple morphologies of PVCs that were abolished acutely with ablation, but had recurrent PVCs with different morphologies during follow-up.
Illustrative case of septal VTs due to lamin cardiomyopathy
A patient with lamin cardiomyopathy, atrioventricular block, and LV ejection fraction 28% had recurrent VTs originating from the basal septum and periaortic area (Figure 6). Prior ablation included endocardial RF ablation, transcoronary ethanol ablation of proximal septal arteries, and simultaneous unipolar ablation from both sides of the septum. At electrophysiology study, 5 different morphologies of VT were induced by catheter manipulation and pacing but mapping was limited by spontaneous changes in QRS morphology and hemodynamic intolerance. Needle ablation targeted the low-voltage region of the basal to mid septum from the right ventricle and LV. Evidence of intramural substrate included septal areas of pre-systolic potentials on the needle that were not seen from the overlying dome electrode and areas where pacing stimuli delivered from the needle, but not the dome electrode on the overlying endocardium captured (Figure 6). Needle RF lesions were delivered extending from the septum into the periaortic region. Following ablation, burst pacing no longer provoked VT. Amiodarone was reduced to 200 mg daily. He remained free of VT for 21 months when he had a single episode of VT during a heart failure exacerbation.
Ventricular arrhythmia substrate deep to the endocardium is an important cause of failure of VT ablation. An infusion needle ablation catheter was developed to attempt to address this problem. We previously demonstrated feasibility of this approach in 8 patients using a prototype catheter (13). The catheter was then redesigned to irrigate the lumen through which the needle extends, and to reinforce the handle. The present multicenter series with this catheter is the largest experience with intramural needle ablation in humans. In a population of patients with difficult to control arrhythmias who had failed antiarrhythmic drug therapy and a median of 2 prior catheter ablation procedures, abolition of the arrhythmia was achieved in 48% and substantial improvement was achieved in an additional 19% with acceptable safety (Central Illustration). The outcomes and safety are impressive considering the severity of the arrhythmia and heart disease in our population. In a series of 67 patients who had the alternatives of surgery and/or transcoronary ethanol ablation the 30-day and 6-month mortality rates were 10% and 17%, respectively, and more than one-half had arrhythmia recurrences (4). Several interesting observations help improve our understanding of intramural ablation and its potential.
Identification of intramural ablation targets is a major challenge. Initial target sites were selected based on anatomic information from voltage mapping and intracardiac ultrasound imaging along with endocardial mapping. This approach produced reasonable outcomes. Repeated insertion of the 27-gauge needle into the myocardium for mapping was well tolerated. Pre-procedural imaging of scar (7,10), which was not routinely done, would be of great interest to potentially improve mapping guidance.
As expected, many patients had unmappable VTs, leading to a substrate ablation type of approach, with needle insertion into the region below the best endocardial sites and ablation if pacing on the needle captured at these regions. Prior experimental work has shown that creation of large RF ablation lesions with the needle requires infusion of saline into the myocardium (11). This likely creates a “virtual electrode” in the tissue that distributes the RF current; however, continued irrigation during RF also cools the electrode, which also may permit increased current delivery at the target temperature. The injection of saline into the tissue likely has electrophysiological consequences, and we observed arrhythmia suppression (Online Figure 2) by injection of saline into the tissue. Hence, confirmation of the location of the needle in a potential VT circuit by recording or pacing from the needle during VT was more limited than we anticipated.
Infusion needle ablation can spare the endocardium (11), and, hence, additional endocardial ablation will be warranted in some patients. Although all of our patients had failed prior endocardial ablation, we did identify endocardial sites that captured with pacing and we elected to apply additional endocardial RF ablation at these sites in 6 patients after needle ablation was judged acutely effective. The role of this approach remains to be defined, but a favorable effect of endocardial ablation in 2 patients with recurrent VT during follow-up suggests that additional endocardial ablation will be important for some patients.
This study provides important insights into the safety of intramural saline injection into the ventricular myocardium. With each needle ablation we injected 3 ml of saline/contrast prior to RF application and continued infusing at 2 ml/min for the duration of the RF application, hence, another 3 ml of saline for a 90-second RF application. The myocardium is organized in layers and appears to easily accommodate this volume of fluid, which likely drains through lymphatics, and Thebesian vessels. In 1 case, however, we did raise an epicardial bleb likely due to dissection of fluid through the tissue (Online Figure 2). This occurrence raises an important safety concern, exposing a potential mechanism of tamponade. Indeed, this occurred in 1 patient with a focal LV outflow tract arrhythmia, in whom scar may have been absent. On the other hand, despite multiple RF applications, up to 66 applications in a patient with scar-related VT, intramural fluid collections and significant pericardial effusion were not observed in other patients. All procedures used intracardiac ultrasound that is very sensitive to detection of pericardial effusions. Dissecting intramural hematomas have been reported with endocardial RF ablation, possibly related to intramural hemorrhage (15). We believe it is prudent to limit saline injection to sites where ablation is being performed and otherwise avoid myocardial fluid injection, particularly when there is no evidence of scar.
We occasionally observed small impedance rises and a very small amount of coagulum at the dome electrode port for the needle, similar, but smaller, than that which we have seen with currently approved irrigated and nonirrigated RF ablation catheters. We speculate that this may occur when the needle is not completely inserted into the myocardium. With a gap between the dome electrode and the tissue, the portion of the needle in the blood pool may reach temperatures sufficient for coagulum formation despite irrigation of the lumen in the dome. Whether increasing this irrigation rate would be beneficial is not known. In all cases, the coagulum was small and adherent to the dome electrode. The catheter was always inspected for coagulum when removed. No coagulum was observed without a prior impedance increase during RF. We did not observe coagulum when RF delivery was promptly terminated for any impedance increase. This precaution may be important for preventing coagulum formation. No clinically evident embolic events occurred, but we did not obtain pre-procedure and post-procedure magnetic resonance imaging.
This is an observational series of patients who had failed available ablation and antiarrhythmic drug therapies. There is no control group. We did not mandate another endocardial or epicardial ablation be performed at the same procedure prior to using the needle, but as noted did withdraw 10 patients after endocardial mapping suggested, and ablation confirmed, that the VT could be interrupted without needle ablation. The prespecified follow-up period of a minimum of 6 months is relatively short, but was thought to be sufficient in view of the severity of the arrhythmias. Procedures were performed at a small number of experienced centers. Ablation technologies are evolving and we do not have direct comparison data for needle ablation versus bipolar ablation, which was investigational during this study, although bipolar ablation and simultaneous 2-site unipolar ablation had failed in 2 patients who had successful needle ablation. Our prior work supported the safety of the saline infusion and energy parameters used (12,14); it is possible that lesion size could be further increased by altering injectate conductivity or other parameters (16).
Infusion needle RF ablation offers a new ablation therapy for patients with recurrent VT that, in this multicenter series, provided significant potential benefit and acceptable safety. A strategy of targeting VT based on endocardial mapping data appears reasonable. Further studies to refine methods for targeting intramural substrate and confirm efficacy and safety are warranted.
COMPETENCY IN PATIENT CARE AND PROCEDURAL SKILLS: RF energy delivered through an infusion needle can be effective in controlling ventricular arrhythmias originating deep in the myocardium that are refractory to antiarrhythmic drug therapy or conventional catheter-based endocardial or epicardial ablation.
TRANSLATIONAL OUTLOOK: Additional work is needed to improve mapping methodology to localize arrhythmogenic intramyocardial substrate and confirm the efficacy of this method of ablation.
Dr. AbdelWahab has received speaking honoraria from Medtronic and Abbott Medical, Inc. Dr. Dukkipati has received a research grant from Biosense Webster, Inc.; and is on the Advisory Board of Abiomed. Daniele Ghidoli is an employee of Biosense Webster, Inc. Dr. John has received speaking honoraria from Biosense Webster, Inc. and Abbott Inc. Dr. Koruth has received research grants from Bioscience Webster, Luxcath, Farapulse, Affera, Cardiofocus, and Vytronus; and has served on the Advisory Board of or as a consultant for Abbott, Farapulse, Medtronic, Cardiofocus, and Vytronus. Dr. Reddy has received consulting fees and research grants from Biosense Webster; has served as a consultant for Abbott, Acutus Medical, Affera, Apama Medical, Autonomix, Axon, Backbeat, BioSig, Biotronik, Boston Scientific, Cardiofocus, Cardionomics, CardioNXT/AFTx, Circa Scientific, Corvia Medical, East End Medical, EBR, EPD, Epix Therapeutics, EpiEP, Eximo, Impulse Dynamics, Farapulse, Javelin, Keystone Heart, LuxCath, Medlumics, Medtronic, Middlepeak, Northwind, Valcare, and VytronUS; has received grant support from Abbott, Boston Scientific, Cardiofocus, CardioNXT/AFTx, Medtronic; and has equity in Acutus Medical, Affera, Apama Medical, Autonomix, Backbeat, BioSig, Circa Scientific, Corvia Medical, East End Medical, EPD, Epix Therapeutics, EpiEP, Eximo, Farapulse, Javelin, Keystone Heart, LuxCath, Manual Surgical Sciences, Medlumics, Middlepeak, Newpace, Northwind, Surecor, Valcare, and VytronUS. Dr. Stevenson is co-holder of U.S. patent #7207989 “Method for ablating with needle electrode” for irrigated needle ablation that is consigned to Brigham Hospital (to date no royalties have been received); and has received speaking honoraria from Abbott Medical, Boston Scientific, Inc., and Medtronic, Inc. Dr. Sapp is co-holder of U.S. patent #7207989 “Method for ablating with needle electrode” for irrigated needle ablation that is consigned to Brigham Hospital (to date no royalties have been received); has received research grants and honoraria from Biosense Webster and Abbott Medical, Inc.; and has received honoraria from Medtronic, Inc. Dr. Schaeffer has received a scholarship from the German Cardiac Foundation (Deutsche Herzstiftung e.V.); and an education grant from Biosense Webster. Dr. Tedrow has received speaking honoraria from Abbott Medical, Biosense Webster, Medtronic, and Boston Scientific, Inc. Dr. Nakamura has received a scholarship from the Japanese Heart Rhythm Society. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose. Melvin Scheinman, MD, served as Guest Editor for this paper.
Listen to this manuscript's audio summary by Editor-in-Chief Dr. Valentin Fuster on JACC.org.
- Abbreviations and Acronyms
- implantable cardiac defibrillator
- intracardiac echocardiography
- left ventricle
- premature ventricular contraction
- ventricular arrhythmia
- ventricular tachycardia
- Received September 23, 2018.
- Revision received December 11, 2018.
- Accepted December 13, 2018.
- 2019 The Authors
- Al-Khatib S.M.,
- Stevenson W.G.,
- Ackerman M.J.,
- et al.
- Tung R.,
- Vaseghi M.,
- Frankel D.S.,
- et al.
- Sapp J.L.,
- Wells G.A.,
- Parkash R.,
- et al.
- Kumar S.,
- Barbhaiya C.R.,
- Sobieszczyk P.,
- et al.
- Koruth J.S.,
- Iwasawa J.,
- Enomoto Y.,
- et al.
- Dinov B.,
- Fiedler L.,
- Schonbauer R.,
- et al.
- Oloriz T.,
- Silberbauer J.,
- Maccabelli G.,
- et al.
- Berte B.,
- Cochet H.,
- Magat J.,
- et al.
- Sapp J.L.,
- Beeckler C.,
- Pike R.,
- et al.
- Abdel Wahab A.,
- Stevenson W.,
- Thompson K.,
- et al.
- Jimenez A.,
- Kuk R.,
- Ahmad G.,
- et al.
- Nguyen D.T.,
- Tzou W.S.,
- Zheng L.,
- et al.