Safety and mid-term outcome of catheter ablation of ventricular tachycardia in octogenarians

Abstract

Aims

Radiofrequency (RF) catheter ablation (CA) is superior to standard medical therapy in controlling recurrent ventricular tachycardia (VT). The majority of procedures have been performed in a middle-aged population. The outcome of VT ablation in the elderly has not been described.

Methods and results

We retrospectively studied the outcome and safety of CA of VT in octogenarians performed in four European centres. The population consisted of patients presenting with recurrent VT refractory to medical therapy. Patients aged over 80 years were compared with younger patients undergoing CA. Clinical characteristics, procedural data, complications, and outcomes were examined. Implantable cardioverter-defibrillator (ICD) therapy data were collected. A total of 54 consecutive octogenarian patients underwent RF CA of VT and represented the study group (42 males, age 82.8 ± 2.7 years) compared with a control group of 104 younger patients (85 males, age 66.7 ± 8.9 years). Mean follow-up was 33 ± 48 months. Implantable cardioverter-defibrillators were present in 81 and 86% of patients, respectively (P = 0.93). Left ventricular ejection fraction was 29% ± 8.2 in octogenarians vs. 34% ± 10.2 in the younger group (P < 0.01). More major complications occurred in octogenarians (18 vs. 2%, P < 0.01). During follow-up, there were more ICD shocks in the octogenarians (28 vs. 15%, P < 0.01). The Kaplan–Meier curve of survival after VT ablation confirms comparable survival rates at 1 year, but the elderly have poor survival in the mid-term. Survival in the elderly post VT ablation is comparable with that in an age-matched cohort with ICDs but no VT storm.

Conclusion

Octogenarians undergoing CA of VT have more risk factors, higher risk of complications and ICD shocks, but demonstrate comparable short-term survival rates.

Introduction

Elderly people are often under-represented in clinical trials including studies investigating the efficacy of catheter ablation (CA) in patients with ventricular tachycardia (VT). The incidence of symptomatic arrhythmias in the elderly is increasing¹ due to the high incidence of structural heart disease in this population, especially ischaemic cardiomyopathy. This is reflected by the rising numbers of implantable cardioverter-defibrillators (ICDs) encountered in those over 80 years of age and the rising demand for CA in this patient group. Ventricular arrhythmias (VAs) are a common and often fatal consequence of impaired ventricular function. Last European guidelines suggest that elderly patients with VA should be treated in the same manner as younger individuals (Class I, level of Evidence A)² with pharmacological therapy as the first-line option. Amongst antiarrhythmic drugs, amiodarone is the only agent that may improve prognosis in survivors of cardiac arrest, based on a meta-analysis of randomized trials.³ Aside from medical therapy, the main intervention available to reduce mortality after VA is the implantable cardioverter-defibrillators (ICDs). These have been shown to reduce all-cause mortality in patients and reduce the risk of sudden cardiac death (SCD).^4,5 However, ICD shocks and recurrent episodes of VT are associated with reduced survival,⁶ especially when more than five shocks are delivered.⁷ Additionally, repeated shocks are also painful and result in reduced quality of life.⁸ Hence, recurrent shocks delivered during electrical storms represent a clinical indication to treat the substrate of the VT.⁹ In this context, radiofrequency (RF) CA has proved to be an effective therapy to reduce the burden of VT with a reported success rate of 70–80% in the general population.¹⁰ A recent study reports a 6.2% incidence of major complications, which were commonly related to vascular access problems (3.6%).¹¹ The safety and efficacy of RF CA in the elderly remain unknown. The current retrospective study was initiated to enhance our understanding of the utility of RF CA in octogenarians in a real-world cohort.

Methods

Population

From January 2009 to December 2013, consecutive elderly patients (age > 80 years) with VT on the background of structural heart disease were included. These patients underwent RF CA in four tertiary-care electrophysiology European centres (Bristol Heart Institute, Royal Brompton Hospital, Barts Heart Centre, England, UK, and Hôpital Haut Lèvéque, CHU Bordeaux, France). The control group consisted of consecutive patients aged 59–79 years undergoing RF CA of VT at the same institutions during the same time period. Statistical analysis confirmed that the clinical characteristics of the younger cohort at the time of enrolment were representative of the general VT population at each institution involved.

Clinical data

Demographic data were collected at the time of procedure. This included age, gender, body mass index (BMI), cardiovascular risk factors, aetiology of heart disease (ischaemic, dilated, or idiopathic cardiomyopathy), and New York Heart Association (NYHA) class. Biochemical data including estimated glomerular filtration rate (eGFR) expressed in ml/min were documented. International normalized ratio (INR) was measured before each procedure. The number of cerebrovascular accidents (CVAs) was retrospectively collected and recorded as either ischaemic or haemorrhagic stroke. Periprocedural mortality was defined as death occurring during the procedure or in the next 24 h.

Echocardiographic analysis

All patients had echocardiograms performed before the procedure. Data collected included left ventricular ejection fraction (LVEF %), LV end-diastolic volumes, and diameters.

Procedural data

The use of antiarrhythmic medication periprocedure and the choice between conscious sedation and general anaesthetic were at the discretion of the operator. Venous sheaths generally ranged between 6 and 8 Fr (89% of patients). An 11 Fr steerable introducer sheath (Agilis NxT, St. Jude Medical) was used in the minority of patients (11%). Arterial sheaths size was 5 Fr (for invasive pressure monitoring) or 8 Fr (in case of retrograde approach). The electrophysiological procedures were performed using a retrograde (via aorta) or anterograde (transseptal puncture) approach based on the experience of the operator. A bolus of heparin was given intravenously according to body weight (1.5 mg/kg) at the time of the transseptal puncture, or when the ablation catheter entered the LV retrogradely. Intravenous heparin boluses were administered to maintain the activated clotting time of >300 s. A 3.5 mm irrigated-tip catheter (Smartouch or NaviStar, Biosense Webster, Diamond Bar, CA) was used at all centres with RF ablation parameters selected at the operator's discretion (power settings ranged between 20 and 50 w). Catheter irrigation during endocardial mapping was set between 8 and 30 mL/min, while for epicardial mapping at 1 mL/min. When the clinical VT was easily inducible and the patient was haemodynamically stable, an activation map was created with a 3D mapping system (CARTO, Biosense Webster, Diamond Bar, CA) to build up the endocardial and/or epicardial map with the aim of clear identification of the critical isthmus. When the clinical VT was not inducible, the ablation strategy was characterized by substrate mapping with elimination of local abnormal ventricular activity.¹² Epicardial access, when required, was obtained via a percutaneous subxiphoid puncture under X-ray guidance in anteroposterior projection (English centres) or in latero-lateral projection (Bordeaux centre),¹³ using an epidural needle (Tuohy bevel, 18G, 80 or 150 mm; Braun, Kronberg, Germany). Acute success of the ablation procedure was considered when tachycardia was abolished during RF application, and it was not inducible during programmed ventricular stimulation with up to three extra stimuli.

Complications

These were grouped into two categories.

(1) Major or life-threatening complications: death, myocardial infarction, embolic stroke, persistent unintentional heart block (second or third degree), valve damage, pericardial effusion requiring drainage, vascular access complication requiring intervention or transfusion [pseudoaneurysm, haematoma, arteriovenous (A/V) fistula]. (2) Minor complications (requiring no intervention): haematoma (with no more than 1 g/L haemoglobin drop), pericardial effusion not requiring drainage.

Follow-up

All patients were observed with continuous ECG monitoring until discharge and had follow-up in outpatient clinics at 3 months, 1 year, 2 years, and 3 years post-ablation. All patients were followed up at the centres where their ablation was performed. Rates of hospitalization due to a cardiac diagnosis were recorded.

Survival data

Survival data post VT ablation were collected and compared in the octogenarian cohort and the younger cohort. To further clarify the prognosis of elderly patients undergoing VT ablation, a further comparison was made to a cohort of octogenarians with ICDs but no VT ablation (previously described by our group).¹⁴ This cohort is formed by patients above 80 years who underwent de novo ICD or cardiac resynchronization therapy (CRT)-D implantation for primary or secondary prevention from January 2006 to July 2012 at the Bristol Heart Institute. Clinical data were collected from the procedural record, medical, and ICD notes. Programming of monitor zone, anti-tachycardia pacing (ATP), and defibrillation zones was at the discretion of the implanting physician. Follow-up was provided at regular intervals up to 6 months.

Arrhythmia recurrence

During the follow-up, the rate of VT recurrence was collected from ICD devices. The number of ICD shocks was recorded, and VT recurrence was defined as sustained VT requiring therapy (either ATP or shocks). Data from accident and emergency (A&E) department were also collected if patients came in VT.

Statistical analysis

Data are presented as mean ± one standard deviation for continuous variables or as percentages for dichotomous variables. Continuous numerical variables were tested for normality using the Shapiro–Wilk test and then compared between groups with unpaired Student's t-test if normally distributed or the Mann–Whitney U-test if not normally distributed. In the case of dichotomous variables, Pearson's χ² or Fisher's exact test was used as appropriate. Estimates of survival were calculated by using the Kaplan–Meier (KM) method. Comparisons of the survival curves were established by using the log-rank test. The cumulative incidence of shock therapy has been calculated accounting for the presence of competing risk events, in order to remove the impact of censored data in KM analysis, using competing risk analysis. Predictors of mortality during follow-up have been identified using Cox proportional hazard model analysis. Predictors of recurrence of shock have been identified with multivariate logistic regression analysis with forward–backward selection method (Akaike's information criterion criteria). The model was calibrated by the Hosmer–Lemeshow goodness-of-fit test; model discrimination was evaluated by using the area under the receiver-operating characteristic (ROC). To further reduce bias due to significant preoperative differences between the two groups, a propensity score matching analysis has been conducted. All the significantly different preprocedural variables have been included in the propensity score. CHA₂DS₂-VASc and HAS-BLED scores were not included in the calculation of the propensity score: age is a component of both scores, and therefore it was not possible to include those two variables in the propensity matching process. After matching, we have obtained two groups (1:1 matching) with 47 patients each. These two groups were compared using paired t-test or paired Wilcoxon's test for continuous variables and the McNemar test for categorical variables. All tests were two-sided with the alpha level set at 0.05 for statistical significance. Clinical data were recorded and subsequently tabulated with Microsoft Excel (Microsoft Corp, Redmond, Washington). The statistical analysis was computed using R version 3.0.2 for Windows (R Foundation for Statistical Computing, Vienna, Austria).

Results

Patient characteristics

This real-world analysis included 158 consecutive patients (80.4% males) enrolled in four European tertiary institutions with a median of 11 (range 10–14) octogenarian patients per centre. The octogenarian group was formed of 54 patients, 42 (77.8%) males, aged 82.8 ± 2.7 years, and was compared with 104 younger patients, 85 (81.7%) males, with a mean age of 66.7 ± 8.9 years. Clinical characteristics between the elderly and younger groups are summarized in Table 1.

Although the two groups were well matched for a number of conventional cardiovascular risk factors, the elderly demonstrated more co-morbidities. In particular, renal and cardiac functions were more impaired in the elderly. Amongst echocardiographic parameters, LVEF was lower (29.1 ± 8.2 vs. 34.1 ± 10.2%, P < 0.01) and LV volume larger (177.5 ± 32.6 vs. 166.2 ± 31.7 mL, P = 0.04) in the octogenarian group. NYHA class was fairly homogeneously distributed amongst octogenarians, whereas in the younger group, 78% were in either NYHA Class II or III. Notably, 19% of octogenarians were in NYHA IV compared with just 11% of younger patients (P = 0.03). Ischaemic cardiomyopathy was seen in 80 and 76% of patients, respectively (P = NS). The elderly group displayed a non-significant trend towards a higher incidence of previous CVAs, represented by increased numbers of ischaemic strokes (11.1 vs. 5.7%, P = 0.09). This is in keeping with their elevated CHA₂DS₂-VASc scores (median value 4 vs. 3). Furthermore, as expected, the octogenarian had worse renal function (eGFR = 46.5 ± 15.04 vs. 54.9 ± 18.9 mL/min, P = 0.02).

Use of antiarrhythmic drugs

Antiarrhythmic drug treatment with amiodarone prior to ablation was ongoing in 37 (68%) patients in the octogenarian group vs. 54 (52%) (P = 0.04) in the younger group. Intravenous loading of amiodarone followed by a maintenance oral dose was started after the procedure in 10 patients (18%) in the elderly group and in 36 (34%) (P = 0.01) patients of the younger group. Therefore, a total of 47 (87%) patients in the octogenarian group were on amiodarone treatment after procedure compared with 90 (86%) in the younger group (P = NS). At the 3 months follow-up, amiodarone use was stopped in those patients asymptomatic and with no ICD therapies. At 1 year follow-up, a total of 52 patients (96%) in the elderly vs. 97 (93%) amongst younger were receiving β-blockers (P = NS), while amiodarone use was 16 vs. 11% (P = NS).

Catheter ablation

Conscious sedation was used in the majority of the cases (139 patients, 88%), while 19 patients (12%) underwent the procedure under general anaesthesia (5 in the elderly group, 14 in the control group). Procedures were performed urgently in 37 (68.5%) of octogenarians patients and in 85 (82%) of younger patients (P = 0.11). Octogenarians were more likely to present with a VT storm (76 vs. 63%, P = 0.15), while more younger patients presented to A&E in cardiac arrest (10 vs. 4% P = 0.22). The majority of patients underwent a single procedure, while redo interventions were 18% in the octogenarians and 22% in the younger group (P = NS). In the whole population, endocardial mapping was performed in 156 patients (99%), while a combined approach (endocardial plus epicardial) was performed in 34 patients (21%), 4 (7%) in the elderly group, and 30 (29%) in the younger group. A solo epicardial approach was performed in three patients (belonging to the younger group). In younger patients, retrograde approach was the preferred operator's approach in 69% of cases. In 12 cases (11%), a switch to epicardial approach was needed. In the octogenarians, the preferred approach was transseptal (57% of patients). A mean of 1 ± 2 VT morphologies were documented per patient in the elderly group, with a mean cycle length of 365 ± 51 ms. The higher incidence of slower VT in this group more often enabled the operator to perform activation mapping and entrainment with successful identification of the critical isthmus of the re-entrant circuit in 47% of cases. Substrate modification with elimination of local abnormal ventricular activity (LAVA) was performed in the 63%. In the younger group, a mean number of 1 ± 3 VT morphologies were documented with a mean CL of 339.6 ± 39.7 ms. Identification of critical isthmus was feasible in the 41% of cases, and substrate modification with LAVA ablation was performed in 72% of cases (Table 2).

Electrophysiological data

Procedure times were comparable between groups (249.6 ± 39.8 min in octogenarian group vs. 264.8 ± 41.1 min, P = 0.6 in the younger group) as were average RF time (27.9 ± 9 vs. 34 ± 8 min, P= 0.10). Acute success was achieved in 38 patients (71%) in the octogenarian group vs. 88 (84%) in the younger group (P = 0.17). Predictors of acute success were found to be younger age and the absence of concomitant acute heart failure.

Implantable cardiac defibrillators

Most patients had an ICD implanted prior to CA: 44 (81.5%) in the elderly group and 90 (86.5%) in the younger group (P = 0.93). Twenty-one patients (16%) had a single-chamber ICD device (only 1 amongst octogenarians), a dual-chamber device was present in 79 patients (59%), and these were more common amongst octogenarian patients (59 vs. 45%). A CRT device was present in 34 patients (25%) (11 vs. 23, respectively). In the remaining patients (10 elderly, 14 younger), an ICD was implanted during the indexed hospitalization after the CA procedure.

Periprocedural complications

Overall complications occurred in 29 (18%) of the whole population (Table 3). Major complications occurred in 8% of patients and occurred mainly amongst octogenarians (18%) vs. only 2 patients (2%) in the younger group (P < 0.01). Ten major complications occurred in the elderly group including two cardiac tamponades, two infranodal AV blocks following RF ablation, five pseudoaneurysms, and one patient died during the procedure. Two major complications (a pseudoaneurysm and cardiac tamponade) occurred in the younger group. No periprocedural strokes were encountered. Minor complications occurred in 17 vs. 8%, respectively, P = 0.14. Five patients (4.8%) in the younger group had pericardial effusion vs. 4 (7.4%) in the octogenarian group (P = 0.49). The incidence of haematoma was higher in the elderly population (9.3 vs. 2.9%, P = 0.12) and was potentially related to femoral artery catheterization rather than venous (78 vs. 22%). The length of hospital stay was also significantly higher in this group (9.1 ± 8 vs. 6.2 ± 5 days, P = 0.03).

Anticoagulation data

In the elderly group, 52% of patients were receiving anticoagulation therapy, while amongst young patients this percentage was 28% (P < 0.01). In those patients taking anticoagulants, INR range was 0.9–2.9 in the elderly and 1.0–3.8 in the younger group with a mean INR value of 1.45 ± 0.6 vs. 1.55 ± 0.89, respectively (P = NS). Atrial fibrillation was encountered in 12 (22%) elderly patients and in 19 (18%) younger patients (P = NS). Median CHA₂DS₂-VASc score was 4 (octogenarian) vs. 3 (younger group), while HAS-BLED score was 3 vs. 2, respectively.

Ischaemic versus non-ischaemic aetiology

A further sub-analysis of the octogenarians has been conducted to evaluate the impact of the ischaemic aetiology on the outcomes: 43 patients in this group were ischaemic (79.6%), and 75 patients were ischaemic in young group (72.8%) (P= 0.4). In octogenarians, an ischaemic aetiology seems to have no impact on the major post-operative outcomes: in this subgroup of patients, 7 major complications were recorded in the ischaemic patients (16.3%) and 3 (27.3%) were in the non-ischaemic group (P = 0.40). In the young group of patients, the two major complications were noted in those with ischaemic aetiology (2.66%), while no major complications occurred in the non-ischaemic young patients.

In the octogenarian group, survival rate in the ischaemic patients was 95.2% at 1 year and 82.5% at 2 years. Amongst those with non-ischaemic aetiology, survival rate was 81.8% at 1 year and 54.5% at 2 years.

In the young group, the ischaemic patients had a survival rate of 96% at 1 year and 94.6% at 2 years. In the young non-ischaemic patients, the survival rate was 89.4% at the first year and 80.9% at 2 years.

Comparison after propensity score matching

The two groups were comparable in terms of preprocedural variables: particularly important variables like LVEF and LV volumes were comparable after matching. The only remaining differences between the groups were regarding CHA₂DS₂-VASc score (4 ± 1.3 in octogenarians vs. 2.7 ± 1.3 in young group, P < 0.01) and HAS-BLED score (2.8 ± 1.2 vs. 1.4 ± 0.9, respectively). As previously explained in the statistical section, these two scores include age in their calculation, and therefore it was not possible to use them in the matching process without significantly compromising the overall number of matched patients. After matching, the results were similar to the non-matched analysis: in this sub-analysis, 19 patients (20.2%) experienced at least one (Table 4).

Major complications were significantly more frequent in the octogenarians group than in younger group (19.1 vs. 2.1%, respectively, P < 0.01). The data showed a trend towards more minor complications in the elderly population (14.9 vs. 4.3%, P = 0.09). The length of hospital stay was also higher in this group (9.7 ± 7.9 vs. 5 ± 2.9 days, P = 0.08) (Table 5).

Follow-up

At 1 year, VT recurrence was 28% in the elderly and 15% in the younger group (P < 0.01). Predictors of shocks were found to be age (>80 years) OR 2.65 (CI 1.13–6.37), P = 0.02; heart failure OR 2.45 (CI 1.05–5.9), P = 0.01; and LV volume OR 1.01 (CI 1–1.02), P = 0.03 (Table 6).

Competing risk analysis confirms that after adjustment for death, more shocks occurred in the elderly group, with a median number of shocks of 4 and 2 at 2-year follow-up, respectively (Figure 1).

Anti-tachycardia pacing intervention was recorded in 27 patients (50%) in octogenarian group vs. 47 patients (45%) in younger group (P = NS). Periprocedural death occurred in 1 octogenarian patient only due to cardiogenic shock (2%). During follow-up, hospital re-admission for cardiovascular causes occurred in 23 patients in the elderly group (42.6%) vs. 20 (19.2%) of the younger patients (P = 0.04). The Kaplan–Meier analysis performed on the two groups who underwent VT ablation (Figure 2) confirmed comparable survival rates at 1 year, 93.1% younger vs. 92.5% in elderly, but the latter have poorer survival rate in the long term (P < 0.01).

Mean follow-up was 33 ± 48 months (33.8 ± 18.6 in elderly group and 34.1 ± 19 in young group). Predictors of mortality were age (hazard ratio (HR) 1.10, CI 1.04–1.18; P = 0.01), heart failure (HR 3.37, CI 1.11–12.6; P = 0.04), and recurrence of shock (HR 2.77, CI 0.96–8.09; P = 0.05) (Table 7).

Survival of octogenarians who underwent VT ablation was comparable with a historic cohort of octogenarians with ICD but not requiring VT ablation (Figure 3).

Discussion

As the number of patients with ischaemic heart disease in an ageing population continues to increase, more elderly patients will present with VT. The success rate of RF CA for VAs has not been firmly established in this population. The goal of this study was to determine outcome, safety, and efficacy of VT ablation procedures in four high-volume European centres.

The key finding of our study is that the octogenarian cohort undergoing VT ablation represents a high-risk cohort (reflecting their increased co-morbidity) who experience a greater number of procedural complications and higher rate of ICD therapy, mainly shocks; however, survival in the short term is comparable with younger patients. Long-term survival is unsurprisingly not as good as the younger group but is similar to a matched cohort of elderly ICD patients that never experience VT storm. Our multicentre European study outlines the high-risk characteristics of octogenarians who present with VT. The elderly were more likely to present with VT storm, to have heart failure, and demonstrated lower ejection fraction as well as more impaired kidney function. This is in line with the literature¹⁵ where advanced age, low ejection fraction, and higher NYHA class have been described as predictive factors for electrical storms.

The octogenarians also had higher CHA₂DS₂-VASc scores and, in keeping with this, there was a greater incidence of atrial fibrillation and ischaemic strokes preprocedure in this cohort.

Different electrophysiological characteristics of the VT were documented in the two groups. The younger were more likely to have faster VT offering less chance to map and to ablate the critical isthmus and documentation of more inducible non-clinical VT circuits during the electrophysiological study. Strategy of ablation also differed between the two groups: substrate modification with elimination of local abnormal activity was performed in the 72% of younger patients vs. 63% of the younger (P = 0.05). Differences between the two groups could be explained by differing patterns and volumes of scar in the two groups. The younger patients had higher ejection fractions and therefore a lower scar burden.

Success rates of ventricular tachycardia ablation in the elderly

Our research demonstrates that VT ablation can be accomplished in patients of all ages, but importantly the elderly have lower rates of acute success (71 and 84%, respectively). These data are comparable with acute success rates reported by other studies.¹⁶

Freedom from VT recurrence at 1 year follow-up was lower in the elderly (72 and 85%, respectively, P < 0.01), and this finding is consistent in the medium- and long-term follow-up data. A competing risks analysis was performed to determine whether rates of appropriate shock remained higher in the octogenarian group compared with the younger group when the competing risk of death prior to shock therapy was accounted for (Figure 1). The octogenarian group continued to demonstrate a significantly higher rate of shock therapy following VT ablation compared with the younger group. The estimate of shock therapy at 36 months is ∼19% in the younger group and 59% in the older group (sub-HR 4.23, P < 0.001, 95% CI 1.89–9.44; Figure 1).

In line with the higher incidence of VT episodes post-ablation, the elderly also had higher rates of hospital re-admission due to cardiovascular problems. Hospital stay is increased significantly amongst the elderly (9.1 ± 8 vs. 6.2 ± 5 days, P = 0.03). These differences are likely to be explained by the significantly poorer LV function and the higher NYHA classification in the elderly compared with the younger patients, alongside other comorbidities such as stroke and renal impairment.

Despite the increased incidence of VT post-ablation in the octogenarian group, 1-year survival rates were comparable (92.5 vs. 93.1%). However, the survival curves started to diverge in parallel to the VT burden. During the 33 months of follow-up, as expected, there were more deaths (35%) in the elderly. We sought to determine if these patients had worse survival due to their old age and co-morbidities—as it is expected that survival would be worse than in a younger cohort. We performed a further analysis comparing our octogenarian VT ablation patients with a similar population (same mean age) who received an ICD but had never experienced a VT storm or undergone a VT ablation procedure. As shown in Figure 3, the octogenarians who had a VT storm with RF CA had comparable survival with those who never had a VT storm or the procedure. We would therefore argue that octogenarians enduring a VT storm and VT ablation demonstrate acceptable rates of survival during long-term follow-up. It is noteworthy that the price of comparable survival at 1 year is the increased number of ICD shocks noted in the elderly group. Hence, ICD intervention plays an important role in maintaining survival rates in the elderly cohort despite the VT ablation procedure.

Ventricular tachycardia ablation in the elderly is associated with a higher incidence of complications

A major finding of this study was the higher incidence of major procedural complications in the octogenarian group (19.1 vs. 2.1%, P < 0.01). Vascular access complications (pseudoaneurysm) accounted for the 50% of major complications in the octogenarians. In this population, we documented two cardiac tamponades both due to perforation at the apex of the LV chamber via transseptal approach. There were also two cases of AV block due to damage to the conduction system as consequence of RF delivery. No AV block was seen in the younger patients. This complication is described in 1% of VT ablation patients with structural heart disease.¹¹ The current data suggest that this may predominantly be a risk in the elderly due to pre-existing conduction disease. A single death occurred in this cohort. The patient was an 84-year-old male who died during the procedure secondary to pump failure and cardiogenic shock.

Our study demonstrates a low incidence of major complications in the younger cohort (2%), noticeably lower than the incidence of 6% that has been described in the literature.¹⁷ This could be explained by involvement of four high-volume experienced tertiary centres. Alternatively, this may represent a fair reflection of procedural risk if high-risk elderly patients are excluded from the analysis. Advanced age and heart failure were found to be independent clinical predictors of complications. Our data differ from that published by Inada et al.¹⁸ in a single-centre study in the USA, in which the complication rate was not statistically different, in elderly patients (defined as >75 years) compared with younger patients.

Limitations

The primary limitation of this study is that it is a retrospective analysis of a real-world cohort rather than a randomized, controlled trial. The ablation protocols differed amongst centres during the course of the study. This study has also statistical limitations: the control group is non-randomly selected; to reduce this limitation, we performed a propensity score matching analysis, although this was involving only 47 patients per group and the matching process could not include the entire cohort of preoperative variables. Nonetheless, in order to analyse the potential benefits of VT ablation in octogenarians with VT storm, a control group of octogenarian patients with VT storm not undergoing VT ablation would be required.

Conclusion

After CA of VT, the elderly experience more complications and a higher rate of ICD therapy during follow-up when compared with younger patients. These factors should be taken into account when VT ablation is considered in this patient cohort. Despite this, survival rates are acceptable after VT ablation and comparable with those seen in elderly ICD recipients that do not suffer a VT storm.

Conflict of interest: none declared.

References