Author + information
- Received August 5, 2015
- Revision received October 28, 2015
- Accepted November 3, 2015
- Published online February 16, 2016.
- Francis E. Marchlinski, MDa,∗ (, )
- Charles I. Haffajee, MBBS, MDb,
- John F. Beshai, MDc,
- Timm-Michael L. Dickfeld, MD, PhDd,
- Mario D. Gonzalez, MDe,
- Henry H. Hsia, MDf,
- Claudio D. Schuger, MDg,
- Karen J. Beckman, MDh,
- Frank M. Bogun, MDi,
- Scott J. Pollak, MDj and
- Anil K. Bhandari, MDk
- aCardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
- bDivision of Cardiovascular Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
- cDivision of Cardiovascular Diseases, Mayo Clinic Foundation, Phoenix, Arizona
- dDivision of Cardiology, School of Medicine, University of Maryland, Baltimore, Maryland
- ePenn State Heart and Vascular Institute, Penn State Milton S. Hershey Medical Center, Penn State College of Medicine, Hershey, Pennsylvania
- fCardiology Department, San Francisco Veterans Affairs Medical Center, University of California San Francisco, California
- gDivision of Cardiology, Henry Ford Hospital, Detroit, Michigan
- hHeart Rhythm Institute, University of Oklahoma, Oklahoma City, Oklahoma
- iDivision of Cardiology, University of Michigan Health System, Ann Arbor, Michigan
- jCardiovascular Institute, Florida Hospital, Orlando, Florida
- kLos Angeles Cardiology Associates, Los Angeles, California
- ↵∗Reprint requests and correspondence:
Dr. Francis E. Marchlinski, Hospital of the University of Pennsylvania, Cardiovascular Division, 3400 Spruce Street, Founders 9, Philadelphia, Pennsylvania 19104-4206.
Background Radiofrequency catheter ablation is used to treat recurrent ventricular tachycardia (VT).
Objectives This study evaluated long-term safety and effectiveness of radiofrequency catheter ablation using an open-irrigated catheter.
Methods Patients with sustained monomorphic ventricular tachycardia associated with coronary disease were analyzed for cardiovascular-specific adverse events within 7 days of treatment, hospitalization duration, 6-month sustained monomorphic ventricular tachycardia recurrence, quality of life measured by the Hospital Anxiety and Depression Scale, long-term (1-, 2-, and 3-year) survival, symptomatic VT control, and amiodarone use.
Results Overall, 249 patients, mean age 67.4 years, were enrolled. The cardiovascular-specific adverse events rate was 3.9% (9 of 233) with no strokes. Noninducibility of targeted VT was achieved in 75.9% of patients. Post-ablation median hospitalization was 2 days. At 6 months, 62.0% (114 of 184) of patients had no sustained monomorphic ventricular tachycardia recurrence; the proportion of patients with implantable cardioverter-defibrillator shocks decreased from 81.2% to 26.8% (p < 0.0001); the frequency of VT in implantable cardioverter-defibrillator patients with recurrences was reduced by ≥50% in 63.8% of patients; and the proportion with normal Hospital Anxiety and Depression Scale scores increased from 48.8% to 69.1% (p < 0.001). Patient-reported VT remained steady for 1, 2, and 3 years at 22.7%, 29.8%, and 24.1%, respectively. Amiodarone use and hospitalization decreased from 55% and 77.2% pre-ablation to 23.3% and 30.7%, 18.5% and 36.7%, 17.7% and 31.3% at 1, 2, and 3 years, respectively.
Conclusions Radiofrequency catheter ablation reduced implantable cardioverter-defibrillator shocks and VT episodes and improved quality of life at 6 months. A steady 3-year nonrecurrence rate with reduced amiodarone use and hospitalizations indicate improved long-term outcomes. (NaviStar ThermoCool Catheter for Endocardial RF Ablation in Patients With Ventricular Tachycardia [THERMOCOOL VT]; NCT00412607)
Patients with sustained ventricular tachycardia (VT) are at risk for recurrent episodes and sudden cardiac death. Whereas implantable cardioverter-defibrillators (ICD) effectively terminate VT, shocks are often painful, reduce quality of life (QOL) (1–4), and may increase mortality (5). Adjunctive antiarrhythmic medications may decrease the number of ICD shocks (6); however, limited efficacy and serious adverse events are common (7).
Catheter ablation is an alternative approach to VT prevention (8,9). The multicenter THERMOCOOL VT (NaviStar ThermoCool Catheter for Endocardial RF Ablation in Patients With Ventricular Tachycardia) trial evaluated irrigated radiofrequency catheter ablation (RFCA) guided by electroanatomic mapping for recurrent VT after myocardial infarction (MI) (9). RFCA abolished inducible VT in 49% of 231 patients with multiple unmappable VT caused by previous MI. At 6 months post-ablation, 53% of patients reported freedom from recurrent VT. Importantly, VT episodes were significantly reduced in 142 patients with ICD. Results of this study supported the U.S. Food and Drug Administration’s approval of the open-irrigated catheter for VT ablation in drug-refractory post-MI patients.
Prospective longitudinal data regarding effects of long-term ablation-related VT control and associated mortality has been limited (10–12). We report results of a prospective post-approval study that monitored long-term safety and effectiveness of RFCA using the study catheter for ablation of recurrent VT in the setting of coronary artery disease.
Patients who underwent RFCA for sustained monomorphic ventricular tachycardia (SMVT) or incessant VT associated with coronary disease were enrolled at 18 U.S. centers (Online Table 1) into a prospective, nonrandomized, single-arm study between April 3, 2007, and May 18, 2009, and patient follow-up was completed on June 8, 2012.
Study patients were ≥18 years of age, with left ventricular ejection fraction (LVEF) of ≥10% as estimated by echocardiography, contrast ventriculography, or radionuclide imaging within 90 days before enrollment, and had any of the following patterns of sustained episodes of VT (VT terminated by ICD are not necessarily sustained): 1) ≥4 documented episodes in patients with ICD; 2) ≥2 documented episodes within 2 months (assessed by electrocardiograms [ECG] and hospitalization records) in patients without ICD; 3) incessant VT (>1 h and refractory to, or immediately recurrent after, administration of antiarrhythmic medication and cardioversion) due to MI ≥3 weeks previously; and/or 4) spontaneous occurrence of symptomatic VT despite antiarrhythmic medications or ICD intervention. Exclusion criteria included the following: a mobile LV thrombus; MI within the preceding 2 months (except patients with incessant VT, who were eligible to be enrolled if MI occurred ≥3 weeks previously); idiopathic VT; disease process likely to limit survival to <12 months; class IV heart failure; serum creatinine ≥2.5 mg/dl; thrombocytopenia or coagulopathy; contraindications to heparin; pregnancy; surgical ventriculotomy or atriotomy within the past 2 months; acute illness or active systemic infection; unstable angina; severe aortic stenosis or flail mitral valve; uncontrolled heart failure; significant congenital anomalies or congenital medical problems; or enrollment in an investigational study evaluating another device or drug.
Echocardiograms and ICD interrogations (95% of patients) were conducted before index ablation, at discharge, and at 6-month follow-up. Echocardiograms were used to evaluate LV thrombus, LVEF, LV diastolic dimension, and valve function. In the 5% of patients without ICD, ECG recordings of arrhythmia events were used to document VT recurrence at 6 months.
After 6-month follow-up, patients were assessed annually for up to 3 years using a telephone questionnaire. Antiarrhythmic drug therapy was assessed for 3 years post-ablation. Antiarrhythmic drug therapy was not dictated by the study protocol and could be terminated based on toxicity, intolerance, or physicians’ discretion at any time. Anticoagulation with aspirin or warfarin was permitted as indexed by clinical conditions and physician preference.
Electrophysiological study and ablation procedure
Patients underwent irrigated RFCA guided by electroanatomic mapping as previously described (9). Briefly, programmed stimulation was used for initiation of VT using up to 3 extra stimuli during 2 paced cycle lengths from 2 successive right ventricular sites. Systemic anticoagulation with heparin was required for LV mapping. Mapping was performed during VT or sinus rhythm with the CARTO electroanatomic mapping system (Biosense Webster Inc., Diamond Bar, California) and NAVISTAR THERMOCOOL catheter (Biosense Webster).
Precise selection of target sites for ablation was left to the investigator. For hemodynamically tolerated VT, it was recommended that activation and entrainment mapping be routinely used to guide targeted ablation. For unmappable VT, it was recommended that RF ablation be guided on the basis of detailed characterization of the substrate defined by voltage mapping in sinus rhythm and/or ventricular pacing, including identification of split or late potentials, discrete higher voltage channels in the low-voltage region, and/or pace maps with long stimulus to QRS intervals in which the QRS with pacing mimics induced and/or spontaneous VT.
During mapping, saline was infused at 2 ml/min through the mapping catheter tip. For RF application, the infusion rate was increased to 30 ml/min and continued for the duration of the RF application (up to 120 s). Initial ablation energy was 30 W, titrating up to 50 W if needed per investigator’s discretion, provided that temperature recorded from the electrode remained <50°C. Energy application was terminated immediately if temperature exceeded 50°C or an impedance increase ≥20 Ω occurred.
The recommended goal of the ablation procedure was the elimination of inducible sustained monomorphic VT, with the complete stimulation protocol. Both spontaneous and inducible VT could be targeted per investigators’ discretion. Data are presented for all spontaneous and inducible monomorphic VT, because recordings of all VT before and after ablation were not reliably obtainable to define clinically relevant VT. Investigators could terminate the procedure if they judged it to be in the best interest of the patient. Additional ablation procedures before hospital discharge were permitted for inducible or spontaneous VT. All time periods presented reflect time after index ablation. The acute procedural endpoint was assessment of inducibility of the targeted VT.
Repeat ablations were performed at the discretion of the investigator, followed the institutions’ standard of care, and were not dictated by the study protocol.
Safety and late outcome endpoints
The acute primary safety endpoint was defined as cardiovascular-specific adverse events (CSAE) during and within 7 days post-ablation. CSAE included cardiac perforation, pericardial effusion with hemodynamic compromise, pulmonary embolus, complete heart block, stroke, acute MI, new acute severe mitral or aortic regurgitation, deep venous thrombosis, arterial dissection, injury that required surgical treatment, and death.
The long-term primary safety endpoint was all-cause mortality at 12 months post-ablation, but all-cause and cardiovascular-specific mortality were also collected over 3 years post-ablation. Routine telephone contact with the patient, patient’s physician, or Social Security Death Index were used to assess mortality throughout the study.
Secondary endpoints were immediate post-ablation hospitalization duration and 6-month and long-term (up to 3 years) effectiveness, QOL, and hospitalizations. The 6-month effectiveness was defined as the percentage of patients without recurrence of VT, confirmed by ICD interrogation at the 6-month follow-up visit. For patients with ICD, recurrences of VT were defined as appropriate ICD pacing or shock therapies or on the basis of ECG-documented arrhythmia if the VT was below the programmed device cutoff. For patients without ICD, recurrences of VT were noted on the basis of ECG-documented arrhythmia. The number of patients with ICD shocks, ICD antitachycardia pacing (ATP) therapies, and any VT episodes were assessed at 6 months. Long-term effectiveness was defined as patient-reported nonrecurrence of VT at 1-, 2-, and 3-year telephone follow-up. To assess QOL, patients completed the Hospital Anxiety and Depression Scale (HADS) (13) prior to and 6 months after index ablation. Correlation of QOL was also assessed among patients with ICD shocks, ICD ATP therapies, and any VT episodes. Hospitalization data (hospitalizations for ICD shocks, sustained VT, stroke, heart surgery, MI, heart failure, and other arrhythmias) were collected before ablation and at the 6-month and 1-, 2-, and 3-year follow-up visits. Subgroup analyses of baseline characteristics, 6-month effectiveness, LVEF status, primary safety (CSAE), and all-cause mortality were also performed.
All adverse events were evaluated and adjudicated by a medical monitor after review of CSAE report forms and source documents as required. All other data analyzed were based on reports from individual investigators and were not subject to additional review.
The sponsor performed statistical analyses and data management in compliance with good clinical practice standards. All authors had full access to data.
Patients’ baseline characteristics and disposition were summarized using numbers and percentages for categorical variables and descriptive statistics for continuous variables. The safety analysis cohort included patients who underwent insertion of the catheter with or without ablation. The efficacy cohort included patients who were enrolled and treated with catheter ablation for study-related arrhythmia in compliance with the protocol.
CSAE rate and its 95% upper confidence bound (1-sided confidence interval) were calculated for the acute primary safety endpoint in the safety cohort and compared with the protocol-established performance criteria of 17%, which was the clinically acceptable adverse event rate mutually agreed upon by the clinician advisory board and the U.S. Food and Drug Administration.
Changes from baseline (pre-ablation) to 6 months post-ablation in VT frequency (excluding incessant VT) were summarized using descriptive statistics in patients who completed 6-month follow-up and were assessed using the paired Wilcoxon signed rank test. Statistically significant differences between the number of patients taking amiodarone before and immediately after ablation were assessed using McNemar 2-sided test. Proportions of patients with ICD shocks, ICD ATP therapies, and any VT episodes at baseline and 6 months after ablation were compared, and differences in the proportions were assessed using the McNemar test.
Association between 6-month effectiveness and all-cause mortality or cardiovascular-related deaths at 3 years post-ablation was assessed using the Fisher exact test. Statistical significance of the change at 6 months in the proportion of patients with normal anxiety HADS scores, mild-to-severe anxiety scores, and depression scores were assessed using the Bowker test of symmetry. We used the Cochran-Armitage trend test to assess the association of ICD shocks, ICD ATP therapies, and any VT episodes with anxiety and depression classes. Exact McNemar test was used to perform pairwise comparison for proportions of patients with hospitalization, ICD shocks, sustained VT, stroke, heart surgery, myocardial infarction, heart failure, and other arrhythmias pre-ablation and post-ablation. No multiple comparison adjustments were made for these analyses.
This study was approved by the institutional review boards at the participating centers, and written informed consent was obtained from all patients.
Demographics and baseline characteristics
A total of 249 study patients were enrolled (Figure 1). Most were male (94.0%) and Caucasian (92.0%), with a mean age of 67.4 years (range 38 to 89 years). Coronary artery disease was confirmed in 95.4% of patients, and 85.4% of patients had previous MI. ICD implantation occurred in 95.0% and hypertension in 69.0% of patients (Table 1). Baseline characteristics of patients with previous MI were similar to the full study cohort (Online Table 2). Previous ablation for VT had been performed in 69 patients (28.8%).
The safety analysis cohort comprised 233 patients, including 224 evaluable and 9 discontinued patients who were documented to have supraventricular arrhythmias as the cause of the wide complex rhythm at presentation (Figure 1). Of the evaluable patients, 8 withdrew consent to participate in the study or were withdrawn due to patient preference and/or failure to comply with follow-up schedule, and 18 were lost to follow-up after 3 documented, unanswered attempts to contact each patient. Data available for these 26 patients were used for analyses whenever possible. In the efficacy analysis cohort, 184 patients had available data for the 6-month assessment. For 1-, 2-, and 3-year assessments, data were available for 176, 161, and 141 patients, respectively.
A summary of relevant ablation procedure parameters is provided in Online Table 3. Data available from 224 index procedures show mean procedure time was 4.5 h, mean ablation time was 1.9 h, mean fluoroscopy time was 1.0 h, and mean RF applications was 33.9. Mean fluid volume infused by study catheter was 1,492 ml.
Acute efficacy, acute and long-term primary safety endpoints
Noninducibility of targeted VT was achieved in 75.9% of patients after index ablation. A mean of 1.06 ablation procedures (median: 1; minimum-maximum: 1 to 3) were done during the index admission. The median immediate post-ablation hospitalization period for the safety cohort (228 of 233) was 2 days (minimum-maximum: 0 to 33).
The CSAE rate was 3.9%, and the upper confidence bound was 6.6%, which was lower than the protocol-established performance criteria of 17%. Specific CSAE were cardiac perforation (n = 1), complete heart block (n = 2), pericardial effusion (n = 3), and death (n = 3). All deaths occurred within 7 days of ablation and were preceded by recurrent VT. LVEF in those cases were <25% (range 18% to 23%).
Echocardiography-determined LVEF before and after ablation and at the 6-month follow-up are presented in Online Table 4. No significant differences were noted in LVEF following ablation.
All-cause mortality rates were 13.4%, 18.8%, and 25.4% at 1, 2, and 3 years post-ablation, respectively. All-cause mortality, and cardiovascular-related and non-cardiovascular-related deaths are shown in Figure 2. All-cause mortality rates among patients with previous MI were similar to the full cohort (Online Figure 1). Logistic regression analysis and limitations for predictors of survival are presented in Online Table 5.
VT during follow-up
Of 184 patients with available data, 114 (62%) had no VT recurrence during the first 6 months. There was no difference in recurrence rate between patients with or without previous VT ablation (60% vs. 63%) (Online Table 6). Frequency of VT was significantly reduced from a median of 13 episodes in the 6 months pre-ablation to a median of 0 episodes in the 6 months post-ablation (lower quartile: 0, upper quartile: 2; p < 0.0001) in 139 patients with ICD implants who survived for 6 months (excluding 10 who presented with incessant VT) (Figure 3). The reduction in the frequency of any VT was ≥75% in 82.0% of these 139. In patients with previous MI only, rate of nonrecurrence of VT was 60.8% (Online Table 7). No associations between 6-month effectiveness and all-cause mortality (odds ratio [OR]: 0.97; p = 1.00) or cardiovascular-related mortality (OR: 0.80; p = 1.00) were observed at 3 years post-ablation. Noninducibility was not associated with a lower mortality at 3-year follow-up (p = 0.21).
ICD shocks and ICD ATP therapies at 6 months post-ablation
Among patients with pre- and post-ablation data, the percentage with ICD shocks and ICD ATP therapies decreased significantly from baseline to 6 months (Figure 4).
A significant reduction in the percentage of patients taking amiodarone occurred during the immediate post-ablation period versus pre-ablation period (31.3% vs. 55%; p < 0.0001). Similar significant reductions in amiodarone continued at 1 (23.3%), 2 (18.5%), and 3 (17.7%) years.
The percentage of patients with no reported VT recurrence at any 12-month period over 3 years post-ablation remained steady (Table 2). A gradual decrease in patient-reported cumulative nonrecurrence of any VT episodes—from 67.9% at 12 months to 52.0% at 2 years and 41.3% at 3 years—was observed.
QOL and hospitalizations
The percentage of patients with normal anxiety HADS scores increased significantly from baseline to 6 months post-ablation, whereas the percentage with mild-severe anxiety decreased (Table 3). Similar but not statistically significantly changes were observed for depression HADS scores. Correlation of QOL and ICD shocks at 6 months showed that anxiety and depression levels were significantly higher among patients who had ICD shocks than those who did not (p = 0.03 for anxiety and p = 0.04 for depression). No correlation was noted between QOL and patients with ICD ATP therapies.
Pair-wise comparisons of cardiac-related hospitalizations revealed a significant decrease in the percentage of patients with hospitalizations for ICD shocks, sustained VT, and MI pre- and post-ablation (Figure 5). This decrease was sustained over the 3-year follow-up period.
Results of this prospective, multicenter study indicate that acute and long-term success rates with RFCA for VT associated with coronary artery disease are high and that the CSAE rate is acceptably low at 3.9% with no strokes. Frequency of VT was significantly reduced post-ablation—62% of patients had no SMVT recurrence at the 6-month follow-up visit, and the percentage of patients with no symptomatic VT recurrence at any 12-month period over 3 years post-ablation remained stable. Importantly, 41.3% of patients reported being free of any VT at the 3-year mark. Reductions in SMVT and resultant ICD shocks appeared to translate into improvements in anxiety and depression, and a decrease in hospitalizations—specifically hospitalizations for ICD shocks, sustained VT, and MI (Central Illustration).
Comparison with the pre-approval VT ablation trial
Baseline characteristics of the patients in this study were generally comparable to those in the pre-approval THERMOCOOL VT ablation trial, including use of amiodarone (68.3% vs. 70%, respectively) (9); however, some differences are notable. Whereas a majority of the patients in the present study had coronary artery disease (95.4%) and MI (85.4%), only patients with previous MI (100%) were enrolled in the previous study. Also, more patients in the current study had hypertension, coronary angioplasty, and history of atrial fibrillation, as well as slightly higher mean LVEF (30% vs. 25%). Whereas baseline patient characteristics differed somewhat, both studies had almost identical study designs and ablation strategies. Of note, the all-cause mortality rate of 13.4% at 12 months post-ablation in the present study was better than in the previous study, where 1-year mortality was 18%. The improved mortality may be linked to patient selection with a better EF and lower prior MI rate in the current report. The noninducibility of targeted VT post-ablation (75.9%) compares favorably with the pre-approval trial (49%). However, noninducibility was not associated with a lower mortality at 3-year follow-up in the current study.
Our periprocedural CSAE rate (3.9%) compares favorably to the pre-approval trial (7.3%), including the absence of strokes in both studies (9). Periprocedural 7-day mortality in the current report was low (1.3%) and similar to the previous report, and it appears to be related to failure to eliminate VT and recurrent arrhythmias, rather than to anatomically based complications. Improved primary safety may be a consequence of increased operator experience in the described VT ablation strategy, particularly related to volume management from the open irrigated system.
The 6-month effectiveness in reduction in VT episodes was comparable to the initial pre-approval VT trial (9), showing that the apparent improvement in safety over time does not compromise ablation effectiveness. The median number of VT episodes that patients experienced in the 6 months prior to enrollment was similar between trials, suggesting consistent late consideration of RFCA. Long-term effectiveness and survival may be further improved with earlier referral of appropriate patients for RFCA. This hypothesis is supported by results of the SMASH-VT (Substrate Mapping and Ablation in Sinus Rhythm to Halt VT) study, which showed significant improvement in ICD events and survival free from ICD shocks at 2 years with prophylactic RFCA for VT (14). Similar reductions in survival free from VT or ventricular fibrillation were noted for patients who received prophylactic RFCA before ICD implantation in the VTACH (Catheter Ablation of Stable VT Before Defibrillator Implantation in Patients With Coronary Heart Disease) study (15). In addition, Frankel et al. (16) showed that early VT referral (<2 VT episodes) can lead to approximately 25% better survival at 12 months.
Impact of RFCA of VT on amiodarone use
Amiodarone treatment of VT is often limited by suboptimal effectiveness, drug intolerance, and toxicity, and its use may contribute to mortality (7). In this study, RFCA resulted in significant and consistent decreases in use of amiodarone over 3 years. The reduction of amiodarone dosing is even more remarkable given the fact that reduction of amiodarone dosing was at the investigator's discretion and not part of study protocol. Implications of reduction in amiodarone use and/or dosing as a result of successful RFCA, including possible improvements in mortality and QOL require further exploration.
Impact of RFCA of VT on QOL and repeat hospitalizations
This is the first large-scale study of VT ablation to demonstrate that patients experienced improved QOL at 6 months and decrease in long-term cardiac-related hospitalizations sustainable over 3 years post-ablation. Evidence suggests that although ICD shocks can be lifesaving, they can adversely affect patient QOL and lead to anxiety, depression, or both (1–4). RFCA significantly decreased ICD shocks with ICD ATP therapies, and substantially improved patients’ QOL at 6 months post-ablation, providing patients with a clinically meaningful treatment alternative to ICD therapies. The 6-month and long-term success of RFCA was corroborated by a significant decrease in hospitalization rates among patients with ICD shocks and sustained VT starting at 6 months post-ablation and continuing for 3 years. This decrease in long-term hospitalizations may be beneficial for long-term cost containment in managing patients with VT.
Impact of RFCA of VT on mortality
All-cause mortality rates in this study were 13.4%, 18.8%, and 25.4% at 1, 2, and 3 years post-ablation, respectively, and were similar to those previously reported (9,11,14,17). Comparison of the 3-year mortality rate (25.4%) in this study with early reports of patients treated with ICD only (24.6%) (18) suggests that RFCA does not negatively affect mortality rate. Apart from procedural skills, success of ablation depends on various factors, including disease duration, disease severity, comorbidities, and underlying conditions of the heart (19). Not unexpectedly, variations in long-term mortality rates have been reported across trials with variable sample sizes: 9% with ICD and ablation at 22.5 ± 5.5 months in 64 patients with MI (14); 9% at 12 ± 3 months follow-up in 63 patients with remote MI (20); and approximately 25% at 243 ± 153 days follow-up in 146 patients with ischemic and nonischemic cardiomyopathy (17). Similar variation was noted for the 3-year mortality rate of 25.4% in the current study versus 32% reported by Sauer et al. (11) in ischemic/non-ischemic VT ablation patients. Larger-scaled analysis of outcomes is needed to determine whether definitive mortality benefit can be obtained by VT control and elimination of antiarrhythmic drug therapy.
Our study lacked pre-ablation VT storm data to facilitate comparison to other reports, and ICD programming was not dictated by the study protocol or subsequently monitored. Long-term outcome data, which were dependent on patient reporting, are subject to recall bias and under-reporting of asymptomatic VT episodes treated with pacing. Nonetheless, long-term, patient-reported outcomes, such as hospitalizations because of ICD shocks and sustained VT, are consistent with objective ICD interrogation data acquired at the 6-month follow-up. These results were also consistent over the 3-year period, suggesting considerable value in VT control by RFCA in this patient cohort. This study was not designed to assess the best ablation strategy—guidelines for mapping and ablation were provided, but details of the techniques used were not required to be reported. Decrease in amiodarone use was at the investigators’ discretion, suggesting that patients not requiring amiodarone may have continued to receive the drug.
VT ablation has become an integral part of VT management, with an acceptable, low risk (19,21). Results of this study indicate that, in patients with recurrent VT associated with coronary artery disease, RFCA provides dramatic short-term and maintains steady long-term nonrecurrence rates over 3 years, with an acceptable procedural safety profile. The decrease in reported ICD shocks, amiodarone use, and long-term hospitalizations suggests a clinically meaningful improvement in QOL that is likely to be reflected in overall patient satisfaction and potential for associated long-term cost containments.
COMPETENCY IN PATIENT CARE AND PROCEDURAL SKILLS: Radiofrequency ablation of VT is effective in preventing recurrent VT and ICD shocks, reducing post-procedural cardiac-related hospitalization, and improving quality of life for ≥3 years.
TRANSLATIONAL OUTLOOK: Additional investigations are needed to compare various VT ablation strategies and determine whether this type of procedure reduces mortality rates over long-term follow-up.
The authors express appreciation to all the study investigators (Online Table 1) and the following individuals for their contribution to the study conduct, statistical analysis, and editorial assistance with the manuscript: Karen Cropper, Stephanie Plaza, Brian Ramos, Hui Wang, William Reichenbach, and Lee Ming Boo. Additional editorial support, in the form of assembling tables and creating high-resolution images based on authors’ detailed directions, collating authors’ comments, copyediting, and referencing, was provided by Annirudha Chillar of Cactus Communications.
For supplemental tables and a figure, please see the online version of this article.
This paper was funded by an F. Harlan Batrus Research Grant at the University of Pennsylvania. The study was sponsored by Biosense Webster, Inc., and editorial support was funded by Biosense Webster. Dr. Marchlinski has received consulting fees and/or honorarium from Biosense Webster, St. Jude Medical, Medtronic, Biotronik, Boston Scientific, CardioInsight, and Abbott Laboratories. Dr. Dickfeld has received consulting fees and grant support from Biosense Webster. Dr. Gonzalez has received consulting fees and fellowship support from Biosense Webster. Dr. Hsia has received honorarium from Biosense Webster, Medtronic, and VytronUs. Dr. Bogun has received a research grant from Biosense Webster. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- antitachycardia pacing
- cardiovascular-specific adverse event
- Hospital Anxiety and Depression Scale
- implantable cardioverter-defibrillator
- left ventricle
- left ventricular ejection fraction
- myocardial infarction
- odds ratio
- quality of life
- radiofrequency catheter ablation
- sustained monomorphic ventricular tachycardia
- ventricular tachycardia
- Received August 5, 2015.
- Revision received October 28, 2015.
- Accepted November 3, 2015.
- American College of Cardiology Foundation
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