Author + information
- Received January 5, 2015
- Revision received February 9, 2015
- Accepted February 17, 2015
- Published online March 1, 2015.
- Jackson J. Liang, DO∗,
- Shaan Khurshid, MD†,
- Robert D. Schaller, DO∗,
- Pasquale Santangeli, MD∗,
- Francis E. Marchlinski, MD∗ and
- David S. Frankel, MD∗∗ ()
- ∗Electrophysiology Section, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania
- †Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
- ↵∗Reprint requests and correspondence:
Dr. David S. Frankel, Hospital of the University of Pennsylvania, 9 Founders Pavilion, 3400 Spruce Street, Philadelphia, Pennsylvania 19104.
Objectives This study sought to determine the safety and efficacy of ventricular tachycardia (VT) ablation in elderly patients with structural heart disease.
Background As patients with cardiomyopathy live longer, the number of elderly patients with VT is increasing. Catheter ablation is an effective treatment for VT; however, outcomes may differ among elderly patients.
Methods We studied 238 consecutive patients with ischemic or nonischemic cardiomyopathies who underwent catheter ablation for VT refractory to antiarrhythmic medications. Patients were divided into 3 age groups (Group A, <65 years; Group B, 65 to 75 years; and Group C, >75 years).
Results Compared with Groups A and B, patients in Group C were more likely to have ischemic cardiomyopathy, lower left ventricular ejection fraction, longer mean VT cycle length, and less likely to undergo epicardial ablation. Acute procedural success, complications, 28-day survival, and 1-year VT-free survival rates were similar across groups (p = 0.9, 0.3, 0.3, and 0.9, respectively). As expected, Group C patients had worse survival in long-term follow-up (p < 0.001).
Conclusions VT ablation can be performed in elderly patients with structural heart disease with similar efficacy and complication rates as in younger patients. VT ablation should not be withheld for older age alone.
Ventricular tachycardia (VT) is a major cause of death and suffering in patients with structural heart disease. Although implantable cardioverter-defibrillators (ICDs) improve survival in appropriately selected patients, ICD shocks are themselves associated with worse survival and quality of life. Antiarrhythmic medications may be effective in suppressing VT, but options are restricted in patients with structural heart disease (1). Side effects and long-term organ toxicities may further limit their usefulness (2). Catheter ablation is an effective treatment option for patients with recurrent VT (3–5). VT ablation reduces ICD shocks and may increase survival and decrease heart failure hospitalizations compared with medical therapy alone (6,7).
Medications and implantable cardiac devices have significantly prolonged life expectancy in patients with heart failure, with many surviving into the 8th decade of life and beyond (8). Elderly patients have been underrepresented in prior studies of VT ablation. Providers may be less likely to refer elderly patients for VT ablation because of concern for increased procedural risk and decreased efficacy.
We hypothesized that VT ablation could be accomplished in elderly patients with structural heart disease with similar complication rates, acute procedural outcomes, and long-term arrhythmia control as in younger patients.
We studied consecutive patients with structural heart disease undergoing catheter ablation for VT at the Hospital of the University of Pennsylvania between January 1, 2008, to June 1, 2011. Per institutional guidelines of the University of Pennsylvania Health System, all patients provided written informed consent both for catheter ablation, and for their anonymized medical information to be included in research studies. Study participants were divided into 3 groups according to age: <65 years (Group A); 65 to 75 years (Group B); and >75 years (Group C).
Conscious sedation was used preferentially; general anesthesia was induced before obtaining epicardial access or when necessary for patient comfort or stability. Intravenous heparin was administered to maintain an activated clotting time above 300 s and left ventricular access obtained either via retrograde aortic or transseptal approach. An electroanatomic map (CARTO, Biosense Webster, Diamond Bar, California) was created during sinus or paced rhythm to identify areas of low voltage and abnormal electrograms, consistent with scar (9,10).
Programmed ventricular stimulation was then performed with single, double, and triple extrastimuli delivered to refractoriness at drive cycles of 600 and 400 ms. Stimulation was initially delivered from the right ventricle. If this failed to induce VT, stimulation was delivered from the left ventricle. If VT was hemodynamically tolerated, entrainment mapping was used to identify critical VT circuitry. If VT was not hemodynamically tolerated, pace mapping was performed along the scar border zone and within the scar at areas with abnormal potentials, to similarly define the VT circuit. Radiofrequency ablation was delivered using an open-irrigated 3.5-mm tip catheter (Navistar Thermocool, Biosense Webster) with power 30 to 45 W and temperature limit 42°C to achieve impedance drops of 10 to 15 Ω. When endocardial ablation failed to eliminate VT or the 12-lead electrocardiogram suggested epicardial VT exit, epicardial access was obtained using the technique described by Sosa et al. (11). Coronary angiography was performed before epicardial ablation, to ensure a safe distance from major coronary arteries.
Following ablation, VT inducibility was reassessed with the same stimulation protocol. If clinical VT remained inducible, the procedure was classified as a failure. If nonclinical VT only remained inducible, the procedure was classified as a partial success. If no VT was inducible, the procedure was classified as a complete success. Clinical VT was defined by comparison with 12-lead electrocardiograms of spontaneous VT. When 12-lead electrocardiograms of spontaneous VT were not available, stored ICD electrograms were used instead (12,13).
Patients were evaluated clinically and with ICD interrogation 6 weeks following ablation and every 3 to 6 months thereafter. For patients not followed at the University of Pennsylvania, referring cardiologists were contacted and records reviewed. All VT recurrences were adjudicated by review of ICD electrograms or 12-lead electrocardiograms. Vital status was assessed using the Social Security Death Index.
Continuous variables are expressed as mean ± SD. Differences in continuous variables between any of the 3 age groups were assessed using the analysis of variance test. When significant differences were detected, the Student t test was then used to compare individual groups. Categorical variables are expressed as percentages and compared using Pearson chi-square test. We constructed separate Kaplan-Meier curves to illustrate survival and survival free of recurrent VT. Survival was compared among Groups A, B, and C using the log-rank test. Cox proportional hazards modeling was used to identify predictors of shorter time to VT recurrence and shorter time to death. The proportional hazards assumption was met. Variables showing significant associations with recurrent VT or death on univariate testing were further assessed in a multivariate model. We considered p values of <0.05 to indicate statistical significance. Analyses were performed using SPSS software (version 20.0, SPSS Inc., Chicago, Illinois).
During the study period, 238 patients underwent catheter ablation. Cardiomyopathy was ischemic in 53.8% and nonischemic in 46.2%. Of the 110 patients with nonischemic cardiomyopathy, etiologies were idiopathic (60.9%), hypertrophic (10.0%), valvular (10.0%), arrhythmogenic right ventricular (9.1%), congenital (3.6%), sarcoidosis (2.7%), myocarditis (1.8%), and alcoholic (1.8%). There were 122 (51.2%) patients younger than 65 years (Group A), 69 (29.0%) patients age 65 to 75 years (Group B), and 47 (19.7%) patients older than 75 years (Group C).
Baseline characteristics are compared among age groups in Table 1. There was a strong male predominance (90.3%), but gender distribution did not differ among age groups (p = 0.6). Group C patients were more likely to have ischemic cardiomyopathy (74.5 vs. 41.8 and 63.8% for Groups A and B, respectively; p < 0.001) and cardiac resynchronization therapy devices (53.2 vs. 25.4 and 43.5%; p = 0.001). They were more likely to have undergone prior cardiac surgery (55.3 vs. 33.6 and 36.2%; p = 0.03) but less likely to have undergone prior ventricular tachycardia ablation (17.0 vs. 42.6 and 42.0%; p = 0.006). Finally, Group C patients had lower left ventricular ejection fraction (27.8 vs. 33.5 and 28.2%; p = 0.01) and were more likely to be treated with amiodarone (72.3 vs. 54.1 and 71.0%; p = 0.02).
VT ablation and complications
Procedural characteristics and complications of ablation are compared among age groups in Table 2. There were no significant differences among groups in the number of inducible VTs (p = 0.4), hemodynamic stability of clinical VTs (p = 0.4), total ablation time (p = 0.9), or acute procedural outcomes (p = 0.9). Epicardial ablation was performed less frequently in Group C patients (12.8 vs. 33.6 and 26.1%; p = 0.02). Mean VT cycle length was longer in Group C (396 vs. 346 and 374 ms; p = 0.002). The overall rate of complication and 28-day mortality did not differ among age groups (p = 0.3 for both comparisons across groups). However, Group C patients had a higher rate of infectious complications (6.4% vs. 0.0% and 0.0%; p = 0.002). One developed Staphylococcus aureus bacteremia following ablation necessitating ICD extraction. A second developed aspiration pneumonia. A third developed urinary tract infection leading to bacteremia. Although all 3 infections prolonged hospitalization and necessitated further interventions, all 3 were successfully treated.
One-year VT recurrence
There was no significant difference among age groups in 1-year VT-free survival following ablation (Figure 1) (70.2% for Group C vs. 63.1% for Group A and 65.2% for Group B; log-rank p = 0.9). In univariate Cox regression, lower left ventricular ejection fraction, diuretic use, greater number of spontaneous or induced VTs, and clinical VT inducible at the end of ablation were all associated with shorter time to VT recurrence (Table 3) (p = 0.01, 0.02, 0.01, and 0.001, respectively). In multivariate testing, only inducibility of clinical VT at the end of ablation remained independently associated with shorter time to VT recurrence (hazard ratio: 2.55; 95% confidence interval: 1.44 to 4.52; p = 0.001).
Over mean follow-up of 2.0 years, survival in Group C was far worse than in Groups A and B (Figure 2) (59.6% vs. 82.0% and 66.7%, respectively; long-rank p < 0.001). Compared with Group A, the hazard ratio for death was 3.76 in Group C and 2.45 in Group B. In univariate Cox regression, older age (p < 0.001), ischemic cardiomyopathy (p = 0.02), lower left ventricular ejection fraction (p < 0.001), greater New York Heart Association heart failure class (p = 0.02), history of cardiac surgery (p = 0.007), diabetes mellitus (p = 0.002), higher creatinine (p < 0.001), beta-blocker use (p = 0.05), diuretic use (p < 0.001), and longer mean VT cycle length (p = 0.02) were all associated with shorter time to death (Table 4). In multivariate modeling, older age (hazard ratio: 1.04 per 1 year increase; 95% confidence interval: 1.01 to 1.07; p = 0.007) and diabetes mellitus (hazard ratio: 1.87; 95% confidence interval: 1.10 to 3.21; p = 0.02) remained independently associated with shorter time to death.
Safety and efficacy of VT ablation in the elderly
The major findings of our study are that VT ablation can be performed in elderly patients with structural heart disease with similar rates of procedural complications, 28-day mortality, acute success, and long-term arrhythmia control, compared with younger patients. These findings are despite the fact that elderly patients had markers of worse heart failure at the time of ablation, including lower left ventricular ejection fraction, and higher rates of previous cardiac surgery and cardiac resynchronization therapy. Not surprisingly, long-term survival was far worse among elderly patients.
Previously reported predictors of mortality following VT ablation include older age, chronic kidney disease, advanced New York Heart Association functional class, wider QRS duration, lower left and right ventricular ejection fraction, pulmonary hypertension, tricuspid regurgitation, greater area of scar defined by electroanatomic mapping, more inducible VTs, poorly tolerated VT, and unsuccessful ablation (3,14–18). On univariate testing, we additionally found ischemic cardiomyopathy, previous cardiac surgery, diabetes, and diuretic use to be associated with shorter time to death, whereas VT storm was only marginally associated with death in our cohort (p = 0.06). Interestingly, we found longer VT cycle lengths to be associated with increased mortality, likely as a marker of more extensive scarring and thereby slow conduction. We did not examine measures of right ventricular function.
Prior studies of catheter ablation for atrial fibrillation and supraventricular tachycardia have demonstrated similar rates of efficacy and complications in elderly patients compared with younger patients (19–23). Inada et al. (24) found similar results for VT ablation among those with ischemic cardiomyopathy. To our knowledge, this is the first study examining VT ablation among elderly patients with a mix of cardiomyopathies.
Underuse of catheter ablation in elderly patients with VT
In patients with recurrent VT, catheter ablation reduces ICD shocks, decreases heart failure hospitalizations, and may improve long-term survival (3–7). The use of catheter ablation in the United States for post-myocardial infarction VT increased from 2.8% in 2002 to 10.8% in 2011. Although the mean age of patients with ischemic cardiomyopathy undergoing VT ablation increased slightly over this same period (65.9 years in 2002 to 67.3 years in 2011), older patients with post-infarction VT remain less likely to be treated with catheter ablation than younger patients (25). Our institutional experience is similar, with older patients less frequently referred for ablation. The reasons for this underuse of catheter ablation in elderly patients are unclear, but may relate to physician perception of decreased efficacy and increased risk of complications including short-term mortality.
Although we found similar rates of efficacy and complications among the elderly and young, we cannot rule out the following sources of bias. “Healthier” elderly patients may have been more likely to be referred for ablation, whereas “sicker” elderly patients may have been more likely to be managed medically. Elderly patients were more likely to be treated with amiodarone and less likely to have nonischemic cardiomyopathy, both of which could have improved VT-free survival. Arrhythmia control following ablation of nonischemic VT is generally worse than ischemic VT (26). Elderly patients were less likely to undergo epicardial mapping and ablation, which has been shown to add an incremental 5% to 9% risk of complications (27,28). Although overall complication rates did not differ, we did detect an increase in infectious complications among elderly patients. Elderly patients are known to be more susceptible to hospital-acquired infections than younger patients and particular care must therefore be taken to guard against this (29). Because women comprised a small percentage of our cohort, it is possible that outcomes in elderly women differ from those in younger women. Finally, with more than double the rate of 28-day mortality compared with younger patients, a significant increase among the elderly may well have been detected with a larger sample size.
Elderly patients with structural heart disease and VT are less likely to be referred for catheter ablation. In a large series of patients with a mix of cardiomyopathies, we found similar rates of acute procedural success, complications, 28-day mortality, and 1-year VT-free survival. Older age alone should not be a reason to withhold catheter ablation for elderly patients with structural heart disease and VT.
COMPETENCY IN MEDICAL KNOWLEDGE: As patients with cardiomyopathy live longer, the number of elderly patients with VT is increasing. Catheter ablation is an effective treatment for VT; however, elderly patients are less likely to be referred.
TRANSLATIONAL OUTLOOK: VT ablation can be performed in elderly patients with similar rates of procedural complications, acute success, and long-term arrhythmia control, compared with younger patients. Older age alone should not be a reason to withhold catheter ablation for elderly patients with structural heart disease and VT.
This work was supported in part by the F. Harlan Batrus Research Fund and the Susan and Murray Bloom Fund. All authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- implantable cardioverter-defibrillator
- ventricular tachycardia
- Received January 5, 2015.
- Revision received February 9, 2015.
- Accepted February 17, 2015.
- American College of Cardiology Foundation
- Zipes D.P.,
- Camm A.J.,
- Borggrefe M.,
- et al.
- Calkins H.,
- Epstein A.,
- Packer D.,
- et al.
- Stevenson W.G.,
- Wilber D.J.,
- Natale A.,
- et al.
- Bunch T.J.,
- Weiss J.P.,
- Crandall B.G.,
- et al.
- Yancy C.W.,
- Jessup M.,
- Bozkurt B.,
- et al.
- Marchlinski F.E.,
- Callans D.J.,
- Gottlieb C.D.,
- Zado E.
- Hutchinson M.D.,
- Gerstenfeld E.P.,
- Desjardins B.,
- et al.
- Yoshida K.,
- Liu T.Y.,
- Scott C.,
- et al.
- Ujeyl A.,
- Inada K.,
- Hillmann K.,
- et al.
- Tokuda M.,
- Kojodjojo P.,
- Tung S.,
- et al.
- Zado E.S.,
- Callans D.J.,
- Gottlieb C.D.,
- et al.
- Epstein L.M.,
- Chiesa N.,
- Wong M.N.,
- et al.
- Dagres N.,
- Piorkowski C.,
- Kottkamp H.,
- Kremastinos D.T.,
- Hindricks G.
- Kihel J.,
- Da Costa A.,
- Kihel A.,
- et al.
- Dinov B.,
- Fiedler L.,
- Schonbauer R.,
- et al.
- Sacher F.,
- Roberts-Thomson K.,
- Maury P.,
- et al.