Abstract
Aims
Catheter ablation (CA) plays a central role in the management of electrical storm (ES). PAINESD and iVT are two validated scores commonly used to assess periprocedural risk in patients undergoing ventricular tachycardia (VT) ablation. This study aimed to evaluate the association between CA and mortality in ES patients stratified by PAINESD and iVT risk scores.
Methods and results
We included 606 patients admitted for ES across four French centres. Risk was assessed using PAINESD and iVT scores. Mortality at 1 year was compared according to risk group and CA status. Baseline differences were adjusted using inverse probability of treatment weighting (IPTW) based on predefined clinical variables. Forty-one per cent of patients were classified as high-risk using the PAINESD score, and 39.4% using the iVT score. Catheter ablation was performed in 42.4% of the cohort, including 39.4% of hi-PAINESD and 35.5% of hi-iVT patients. After adjustment, CA was associated with lower 1-year mortality in both high- and low-risk groups (adjusted HR: 0.42 [95% CI: 0.26–0.66], P = 0.0002 for hi-PAINESD; 0.31 [0.18–0.53], P < 0.0001 for hi-iVT). Inverse probability of treatment weighting-weighted models yielded consistent results. In exploratory interaction analyses, the iVT score—but not PAINESD—identified high-risk patients who may derive earlier survival benefit from VT ablation.
Conclusion
In patients with electrical storm, VT ablation was associated with lower 1-year mortality across both low- and high-risk profiles. The iVT score may help identify high-risk patients who derive earlier benefit from ablation.
Keywords: Ventricular tachycardia, Catheter ablation, Heart failure, Electrical storm
Graphical Abstract
Graphical Abstract.
What’s new?
Catheter ablation is a cornerstone in the management of patients presenting electrical storm (ES). PAINESD and iVT are two scoring tools commonly used to assess periprocedural risks associated with ventricular tachycardia (VT) ablation. The effectiveness of VT ablation in ES patients with a high risk of acute haemodynamic decompensation (AHD) and mortality remains uncertain.
Approximately 40% of ES patients are classified as high-risk for AHD or postoperative mortality, whether assessed by PAINESD or iVT scores. VT ablation is associated with a significantly lower occurrence of 1-year mortality across both low- and high-risk groups. Notably, the iVT score may help identify high-risk patients who derive an earlier survival benefit from ablation.
Introduction
Electrical storm (ES) is a life-threatening condition and a major cardiological emergency, defined by the occurrence of at least three sustained ventricular arrhythmias within 24 h.1 Despite advancements in the management of structural heart diseases, the incidence of ES remains significant, ranging from 10% to 30% in patients with implantable cardioverter-defibrillators (ICDs) for secondary prevention. ES is strongly associated with increased mortality, reaching up to 40% at one year.2 Patients presenting with ES generally require intensive care unit admission and multidisciplinary management through multimodal therapeutic approaches.
Catheter ablation (CA) has become a cornerstone for treating recurrent ventricular tachycardia (VT) despite optimal medical treatment.3 Although significant progress was made in VT ablation techniques over the last decade, postoperative mortality remains significant, particularly for patients at high risk of acute haemodynamic decompensation (AHD).4 When performed in the context of ES, VT ablation is associated with a higher postoperative mortality and an increased rate of VT recurrences.4 The PAINESD and iVT scores are two scoring tools that allow clinicians to estimate postoperative mortality in patients undergoing VT ablation, stratifying them into low vs. high risk for postoperative mortality.5,6 Our group recently provided additional data suggesting a benefit of VT ablation in the setting of ES based on a propensity matching approach in a large cohort.7 However, the effect of VT ablation according to patient risk stratification has not been reported, particularly in those with the highest risk profiles. Since high postoperative mortality was reported among high-risk patients, the relevance of VT ablation vs. medical treatment can be questioned.
Thus, the aim of this study was to investigate the prognostic impact of VT ablation in patients exhibiting high-risk profiles as assessed by the PAINESD and the iVT score.
Methods
Study population
This multicentre retrospective study included all consecutive patients admitted in the intensive care units of four French tertiary centres (Saint-Etienne, Rennes, Lille and Dijon university hospital centres) for the management of ES in the context of structural heart disease between the 1 January 2010 and the 1 March 2023. ES was consensually defined as the occurrence of at least 3 or more distinct episodes of sustained ventricular arrhythmias [ventricular tachycardia (VT) or ventricular fibrillation (VF)] within 24 h or incessant ventricular arrhythmias for more than 12 h.8,9 In patients with ICD, ES was defined by the occurrence of ≥3 appropriate device therapies within 24 h, separated by at least 5 min.8–10 For patients with several admissions for ES over the observation period, only the first admission was considered for the primary analysis. Adults under legal protection or aged <18 years old were not included. Patients with ES occurring without underlying structural heart disease (e.g. channelopathy, idiopathic VF, and drug-induced torsade de pointes) were also excluded from the analyses. This study was approved by the local ethic committee and patients gave their informed consent to participate in the study.
Data collection
Baseline data, including demographic characteristics, past medical history, type of cardiomyopathy, left ventricular ejection fraction (LVEF), history of ventricular arrhythmias prior to the ES, history of previous CA, presence of an ICD and treatment at the time of ES admission were collected from medical files for all enrolled patients. In-hospital data were collected including clinical presentation, laboratory parameters, ES tolerance, and ES treatment (type of antiarrhythmic drugs used, use of deep sedation and intubation, use of invasive haemodynamic support, use of sympathetic blockade). Cardiogenic shock was defined as a systolic blood pressure < 90 mmHg with appropriate fluid resuscitation with clinical and laboratory evidence of end-organ damage and the requirement for inotropic drug.11 Occurrence of in-hospital death, as well as date and causes of death after discharge, were also collected using data from each tertiary centre. Medical records from facilities outside of the main centres were also reviewed through a linked electronic medical record system or by contacting the referring physicians.
PAINESD and iVT score assessment
The PAINESD score includes the following components: history of respiratory diseases (5 points); age > 60 years (3 points); history of ischaemic cardiomyopathy (6 points); NYHA > II (6 points); LVEF < 25% (3 points); ES (5 points); and diabetes (3 points). Patients were considered as high risk for PAINESD ≥ 15. The iVT score was computed using the online calculator https://www.vtscore.org.
Follow-up
Outpatient follow-up after discharge was performed according to local hospital protocol. Telephone interviews were also performed in some patients to confirm survival when information was not available from other sources.
Study endpoints
The primary clinical outcome was 1-year mortality following ES.
Statistical analysis
Continuous variables were tested for normality with the Shapiro test. Continuous variables with Gaussian distribution are given as mean ± SD. Continuous variables with non-Gaussian distribution are given as median (IQR). Categorical variables are given as percentages of individuals. Bivariate comparisons were performed using the t-test for normally distributed continuous variables or the Mann–Whitney U test for not normally distributed variables. Bivariate comparisons of categorical variables were done with the χ2 test.
To assess the impact of VT ablation on primary outcome following ES, a log-rank test was performed as a first step and unadjusted hazard ratios (HRs) (95% confidence intervals [CIs]) were computed. Univariate Cox analysis was performed to identify variables of interest for multivariable adjustment. A multivariable Cox model was then performed and included competing variables associated with the primary outcome in univariate analysis and adjusted HRs (95% [CIs]) were computed. A value of P < 0.05 was judged to be statistically significant. To further investigate the effect of VT ablation across different risk profiles, inverse probability of treatment weighting (IPTW) was applied, based on propensity scores derived from a logistic regression model including predefined clinically relevant variables: age, NYHA class, acute pulmonary oedema or cardiogenic shock, history of electrical storm, LVEF, catecholamine use, prior ICD implantation, and atrial fibrillation. Baseline characteristics between groups were assessed using standardized mean differences (SMD), with a threshold of 0.1 indicating a meaningful imbalance. Stabilized IPTW weights were trimmed at the 1st and 99th percentiles to mitigate the influence of extreme values. These weights were applied to compute weighted means and standard deviations for continuous variables, and weighted proportions for categorical variables, using the survey package in R. Survival analyses were conducted using Cox proportional hazards models. Next, we created discrete follow-up endpoints censoring each patient at 90, 180, and 365 days post-admission. For each horizon we fit an IPTW-weighted Cox proportional hazards model of time to death that included main effects for ablation and risk group and their multiplicative interaction. The interaction P-value at each time point tested whether the HR for ablation differed significantly between low- and high-risk patients. Kaplan–Meier survival curves were generated for both unadjusted and IPTW-weighted cohorts. All statistical analyses were performed with R (version 4.5.1).
Results
Population baseline characteristics
A total of 807 patients admitted for ES between 2010 and 2023 in the four participating centres were screened for inclusion. Among them, 201 patients presented acute coronary syndrome, channelopathy, idiopathic VF, drug-induced torsades de pointes, or had missing data required for PAINESD/iVT score assessment. A total of 606 patients met the inclusion criteria and were considered for analysis in the study. Figure 1 provides the study flow chart. Median age was 67 [59; 74], 14.6% were female, 64.9% had ischaemic cardiomyopathy, and median LVEF was 30% [20; 42]. Regarding management of ES, 83.6% of patients received amiodarone, 22.8% of patients underwent deep sedation, and 1.7% underwent stellate ganglion block. In addition, 23.4% of patients required catecholamine infusion due to haemodynamic instability. The baseline characteristics of the population are reported in Table 1.
Figure 1.
Population flow chart.
Table 1.
Baseline characteristics according to ventricular tachycardia ablation in the entire cohort
| Overall population n = 606 |
No ablation n = 349 |
Ablation n = 257 |
P-value | |
|---|---|---|---|---|
| Gender (male) | 520 (85.4%) | 289 (82.8%) | 231 (89.9%) | 0.0188 |
| Age | 67 [59; 74] | 67 [56; 76] | 67 [59; 72] | 0.0344 |
| BMI (kg/m2) | 27.08 [24.22; 30.45] | 26.44 [23.56; 30.10] | 27.57 [24.76; 30.86] | 0.0205 |
| Associated comorbidities | ||||
| Hypertension | 337 (55.6%) | 188 (53.9%) | 149 (58%) | 0.3559 |
| Diabetes | 170 (28.1%) | 107 (30.7%) | 63 (24.5%) | 0.1158 |
| Dyslipidaemia | 349 (57.6%) | 201 (57.6%) | 148 (57.6%) | 0.9348 |
| Active smokers | 247 (40.8%) | 140 (40.1%) | 107 (41.6%) | 0.7698 |
| Peripheral artery disease | 85 (14%) | 50 (14.3%) | 35 (13.6%) | 0.8968 |
| History of stoke | 64 (10.6%) | 39 (11.2%) | 25 (9.7%) | 0.6606 |
| Chronic kidney disease | 130 (21.5%) | 82 (23.5%) | 48 (19.7%) | 0.1842 |
| History of atrial fibrillation | 265 (43.7%) | 147 (42.1%) | 118 (45.9%) | 0.3966 |
| Chronic respiratory disease | 71 (11.7%) | 40 (11.5%) | 31 (12.1%) | 0.9207 |
| History of ES | 109 (18%) | 50 (14.3%) | 59 (23%) | 0.0086 |
| History of VT ablation | 89 (14.7%) | 40 (11.4%) | 49 (19.1%) | 0.0125 |
| Underlying cardiomyopathy | ||||
| Ischaemic cardiomyopathy | 393 (64.9%) | 221 (63.3%) | 172 (66.9%) | 0.4055 |
| Non-ischaemic cardiomyopathy | 213 (35.1%) | 128 (36.6%) | 85 (33%) | |
| LVEF (%) | 30 [20; 42] | 30 [20; 40] | 35 [25; 45] | 0.0193 |
| NYHA III–IV | 163 (29.5%) | 107 (31.2%) | 56 (23.5%) | 0.0105 |
| Baseline treatments | ||||
| Amiodarone | 185 (30.6%) | 93 (26.6%) | 92 (35.9%) | 0.0182 |
| Betablockers | 494 (83%) | 266 (77.6%) | 228 (90.5%) | 0.0001 |
| ACE inhibitor | 289 (48.6%) | 154 (44.9%) | 135 (53.6%) | 0.0446 |
| ARB | 60 (10.1%) | 35 (10.2%) | 25 (9.9%) | 0.9806 |
| Aldosterone antagonist | 195 (32.3%) | 99 (28.4%) | 96 (37.6%) | 0.0203 |
| ICD | 412 (68%) | 209 (59.9%) | 203 (79%) | <0.0001 |
| CRT | 135 (22.3%) | 83 (23.8%) | 52 (20.2%) | 0.3478 |
| Admission parameters | ||||
| Acute pulmonary oedema or cardiogenic shock | 99 (16.3%) | 80 (22.9%) | 19 (7.4%) | <0.0001 |
| Creatinine (μg/dL) | 114 [88; 150] | 114 [88; 155] | 106 [88; 141] | 0.0999 |
| Management of ES | ||||
| Amiodarone | 506 (83.6%) | 294 (84.5%) | 212 (82.8%) | 0.6610 |
| Betablockers | 228 (37.6%) | 108 (30.9%) | 120 (46.6%) | 0.1328 |
| Cathecholamines | 142 (23.4%) | 102 (29.2%) | 40 (15.6%) | 0.0001 |
| Dialysis | 26 (4.3%) | 20 (5.7%) | 6 (2.3%) | 0.0664 |
| Deep sedation | 138 (22.8%) | 81 (23.2%) | 57 (22.2%) | 0.8408 |
| Stellate ganglion block | 10 (1.7%) | 5 (1.4%) | 5 (2%) | 0.8562 |
Continuous quantitative variables with a non-normal distribution are presented as median [interquartile range]. Categorical variables are expressed as the number of patients (percentage). Bold values indicate statistically significant P-values (P < 0.05).
ACE inhibitor, angiotensin-converting enzyme inhibitor; ARB, angiotensin II receptor blocker; BMI, body mass index; CRT, cardiac resynchronization therapy; ES, electrical storm; VT, ventricular tachycardia; ICD, implantable cardioverter-defibrillator; LVEF, left ventricular ejection fraction.
A total of 257 patients (42.4%) underwent VT ablation. Patients who underwent VT ablation were younger, had higher BMI, higher rate of history of ES or VT ablation, higher LVEF, and lower NHYA status (Table 1).
Risk stratification according to PAINESD and iVT scores
Forty-one per cent of patients were classified as high risk for VT ablation based on the PAINESD score (hi-PAINESD), and 39.4% were considered high risk according to the iVT score (hi-iVT), with 24.7% of patients identified as high risk by both scores (Figure 2A). As expected, high-risk patients tended to be older, more frequently had ischaemic cardiomyopathy, exhibited lower left ventricular ejection fraction (LVEF), presented more severe NYHA status, had more critical conditions upon admission, and required catecholamines more often. Baseline characteristics according to risk profile are reported as supplementary materials (Supplementary material online, Tables S1 and S2).
Figure 2.
Risk stratification according to iVT and PANESD scores and risk profiles overlap. (A) Concordance of PAINESD and iVT scores. Inner circle: risk stratification according to the PAINESD score. Middle circle: risk stratification according to the iVT score. Outer circle: concordance between the two scores, patients classified as high risk by both scores, patients classified as low risk by both scores, discordance between the scores. (B) Proportion of patients undergoing VT ablation according to risk stratification based on the PAINESD and the iVT scores.
The proportion of high-risk patients undergoing VT ablation was 39.4% for hi-PAINESD and 35.5% for hi-iVT. Among patients stratified as low-intermediate risk based on the PAINESD score (lo-PAINESD) 43% underwent VT ablation and 47% in patients stratified as low risk based on iVT score (lo-iVT) (Figure 2B). Among patients who underwent VT ablation, the mean procedure time was 186 ± 55 min. In 42 cases, epicardial approach was performed. The rate of postoperative complications was 5.4%, including 2 tamponade, 7 ischaemic strokes, and 3 arteriovenous fistula. No procedure-related death occurred (see Supplementary material online, Table S3).
VT ablation according to risk profile
High-risk patients who underwent ablation were more likely to have a history of ES, while they were less likely to require catecholamine support. Hi-PAINESD patients who underwent VT ablation also had higher LVEF and were more likely to have an ICD prior to admission (Tables 2 and 3).
Table 2.
Baseline characteristics according to VT ablation in high-risk patients based on the PAINESD score
| Variable | Overall population (n = 249) | No ablation (n = 151) | Ablation (n = 98) | P-value | SMD (pre-IPTW) | No ablation IPTW | Ablation IPTW | SMD (post-IPTW) |
|---|---|---|---|---|---|---|---|---|
| Male gender | 223 (89.6%) | 134 (88.7%) | 89 (90.8%) | 0.7559 | −0.006 | 90% | 91% | −0.02 |
| Age, years | 70 [68; 71] | 71 [65; 77] | 68 [65; 87] | 0.236 | −0.09 | 70 ± 8.9 | 70 ± 7.5 | 0.033 |
| BMI (kg/m²) | 27.4 [26.7; 28] | 26.8 [24.2; 30.8] | 27.7 [25.3; 31.8] | 0.1211 | 0.12 | 28.3 ± 5.3 | 27.6 ± 5.1 | −0.03 |
| Associated comorbidities | ||||||||
| Hypertension | 171 (68.7%) | 100 (66.2%) | 71 (72.4%) | 0.3710 | 0.06 | 65% | 72% | 0.09 |
| Diabetes | 130 (52.2%) | 83 (55%) | 47 (48%) | 0.3413 | −0.09 | 62% | 48% | −0.08 |
| Dyslipidaemia | 177 (71.1%) | 106 (70.2%) | 71 (72.4%) | 0.8107 | 0.02 | 73% | 72% | 0006 |
| Active smokers | 111 (44.6%) | 67 (44.4%) | 44 (44.9%) | 0.9611 | 0005 | 45% | 45% | 0001 |
| Peripheral artery disease | 57 (22.9%) | 36 (23.8%) | 21 (21.4%) | 0.7731 | 0.02 | 28% | 21% | 0.06 |
| History of stroke | 26 (10.4%) | 16 (10.6%) | 10 (10.2%) | 0.9098 | 0003 | 11% | 10% | 0.008 |
| Chronic kidney disease | 65 (26.1%) | 40 (26.5%) | 25 (25.5%) | 0.9806 | 0.01 | 32% | 26% | 0.07 |
| Atrial fibrillation | 112 (45%) | 60 (39.7%) | 52 (53.1%) | 0.0530 | 0.13 | 52% | 53% | 0.01 |
| Chronic respiratory disease | 30 (25.4%) | 29 (19.2%) | 24 (24.5%) | 0.4027 | 0.05 | 21% | 24% | 0.04 |
| History of ES | 49 (19.7%) | 20 (13.2%) | 29 (29.6%) | 0.0026 | 0.1635 | 18% | 19% | 0.017 |
| History of VT ablation | 39 (15.6%) | 20 (13.2%) | 19 (19.4%) | 0.2608 | 0.0731 | 16% | 15% | −0.0148 |
| Underlying cardiomyopathy | ||||||||
| Ischaemic cardiomyopathy | 224 (90%) | 134 (88.7%) | 90 (91.8%) | 0.5632 | 0.03 | 88% | 92% | 0.04 |
| Non-ischaemic cardiomyopathy | 25 (10%) | 17 (11.3%) | 8 (8.2%) | 0.5362 | 0.03 | 12% | 8% | 0.04 |
| LVEF (%) | 22 [20; 25] | 20 [17; 30] | 25 [20; 35] | 0.0257 | 0.23 | 25.9 ± 11.8 | 24.9 ± 11.8 | 0.02 |
| NYHA III–IV | 127 (55%) | 83 (55%) | 44 (44.9%) | 0.1547 | 0.10 | 57% | 45% | 0.011 |
| Baseline treatments | ||||||||
| Amiodarone at baseline | 84 (33.7%) | 44 (29.1%) | 40 (40.8%) | 0.0773 | 0.12 | 35% | 41% | 0.005 |
| Betablocker at baseline | 204 (83.6%) | 118 (80.3%) | 86 (88.7%) | 0.1199 | 0.09 | 82% | 80% | 0.06 |
| ACE inhibitor | 123 (50.4%) | 74 (50.3%) | 49 (50.5%) | 0.9172 | 0.009 | 50% | 50% | 0.0003 |
| ARB | 26 (10.7%) | 14 (9.5%) | 12 (12.4%) | 0.6217 | 0.085 | 13% | 13% | 0.078 |
| Aldosterone antagonist | 97 (39%) | 53 (35.1%) | 44 (44.9%) | 0.1568 | 0.09 | 36% | 45% | 0.09 |
| ICD | 175 (70.3%) | 79 (80.6%) | 96 (63.6%) | 0.0063 | 0.17 | 79% | 81% | 0.01 |
| CRT | 65 (26.1%) | 41 (27.2%) | 24 (24.5%) | 0.7492 | −0.061 | 22% | 35% | 0.292 |
| Admission parameters | ||||||||
| Acute pulmonary oedema or cardiogenic shock | 65 (26.1%) | 53 (35.1%) | 12 (12.2%) | <0.0001 | −0.24 | 14% | 13% | −0.01 |
| Creatinine (µg/dL) | 123 [119; 132] | 138 [106; 167] | 122 [97; 150] | 0.1180 | −0.24 | 145.5 ± 64.2 | 128.2 ± 53.8 | −0.28 |
| Management of ES | ||||||||
| Amiodarone in OR | 215 (86.3%) | 132 (88%) | 83 (84.7%) | 0.5767 | −0.03 | 82% | 85% | 0.03 |
| Betablocker in OR | 88 (75.2%) | 48 (31.7%) | 40 (40.8%) | 0.8669 | 0.09 | 34% | 41% | 0.06 |
| Cathecholamines | 85 (34.1%) | 62 (41.1%) | 23 (23.5%) | 0.0065 | −0.18 | 25% | 23% | −0.01 |
| Dialysis | 12 (4.8%) | 10 (6.6%) | 2 (2%) | 0.1782 | −0.05 | 4% | 2% | −0.02 |
| Deep sedation | 72 (28.9%) | 44 (29.1%) | 28 (28.6%) | 0.9629 | −0.005 | 19% | 29% | 0.09 |
| Stellate ganglion block | 3 (1.2%) | 2 (1.3%) | 1 (1%) | 0.6950 | −0.003 | 0% | 1% | 0.005 |
Continuous quantitative variables with a non-normal distribution are presented as median [interquartile range]. Categorical variables are expressed as the number of patients (percentage). Inverse probability of treatment weighting (IPTW) models were based on propensity scores derived predefined variables (age, NYHA class, acute pulmonary oedema or cardiogenic shock, history of electrical storm, LVEF, catecholamine use, prior ICD implantation, and atrial fibrillation). Standardized mean differences (SMD) are reported before and after IPTW. A post-IPTW SMD below 0.1 was considered indicative of acceptable covariate balance. Weighted means ± SD and proportions were calculated using inverse-probability-of-treatment weights truncated at the 1st and 99th percentiles, with estimates derived via the R survey package. Bold values indicate statistically significant P-values (P < 0.05).
ACE inhibitor, angiotensin-converting enzyme inhibitor; ARB, angiotensin II receptor blocker; BMI, body mass index; CRT, cardiac resynchronization therapy; ES, electrical storm; VT, ventricular tachycardia; ICD, implantable cardioverter-defibrillator; LVEF, left ventricular ejection fraction.
Table 3.
Baseline characteristics according to VT ablation in high-risk patients based on the iVT score
| Variable | Overall population (n = 239) | No ablation (n = 154) | Ablation (n = 85) | P-value | SMD (pre-IPTW) | No ablation IPTW | Ablation IPTW | SMD (post-IPTW) |
|---|---|---|---|---|---|---|---|---|
| Male gender | 209 (87.4%) | 135 (87.6%) | 74 (87%) | 0.9449 | −0.006 | 88% | 84% | −0.02 |
| Age, years | 67 [65; 68] | 66 [57; 76] | 68 [58; 71] | 0.5386 | 0.099 | 65.5 ± 13 | 65 ± 12 | 0.027 |
| BMI (kg/m²) | 26.4 [25.7; 27.1] | 25.7 [23.4; 29.4] | 27.4 [24.4; 29.5] | 0.1194 | 0.11 | 26.8 ± 5 | 26.6 ± 4.5 | −0.03 |
| Associated comorbidities | ||||||||
| Hypertension | 137 (57.3%) | 85 (55.2%) | 52 (61.2%) | 0.4482 | 0.06 | 54% | 59% | 0.09 |
| Diabetes | 73 (30.5%) | 52 (33.8%) | 21 (24.7%) | 0.1905 | −0.09 | 33% | 25% | −0.08 |
| Dyslipidaemia | 143 (59.8%) | 91 (29.1%) | 52 (61.2%) | 0.8595 | 0.02 | 59% | 58% | −0.008 |
| Active smoking | 102 (42.7%) | 71 (46.1%) | 31 (36.5%) | 0.1920 | −0.09 | 48% | 35% | −0.13 |
| Peripheral artery disease | 38 (15.9%) | 23 (14.9%) | 15 (17.6%) | 0.7158 | 0.03 | 14% | 17% | 0.03 |
| History of stroke | 32 (13.4%) | 20 (13%) | 12 (14.1%) | 0.9623 | 0.011 | 14% | 12% | −0.02 |
| Chronic kidney disease | 65 (27.2%) | 42 (27.3%) | 23 (27.1%) | 0.9074 | −0.002 | 29% | 22% | −0.07 |
| Atrial fibrillation | 101 (42.3%) | 61 (39.6%) | 40 (47.1%) | 0.3275 | 0.07 | 43% | 45% | 0.006 |
| Chronic respiratory disease | 31 (13%) | 20 (13%) | 11 (12.9%) | 0.8485 | −0.005 | 12% | 10% | −0.02 |
| History of ES | 47 (19.7%) | 23 (14.9%) | 24 (28.2%) | 0.0211 | 0.1330 | 19% | 20% | 0.0498 |
| History of VT ablation | 27 (11.2%) | 14 (9.1%) | 13 (15.3%) | 0.2162 | 0.0422 | 9% | 10% | −0.0236 |
| Underlying cardiomyopathy | ||||||||
| Ischaemic cardiomyopathy | 171 (71.5%) | 104 (67.5%) | 67 (78.8%) | 0.0887 | 0.11 | 66% | 75% | 0.09 |
| Non-ischaemic cardiomyopathy | 68 (28.5%) | 50 (32.5%) | 18 (21.2%) | 0.11 | 34% | 25% | 0.09 | |
| LVEF (%) | 20 [19.3; 20.8] | 20 [15; 25] | 20 [20; 25] | 0.0722 | 0.22 | 20 ± 6 | 19 ± 6 | −0.096 |
| NYHA III–IV | 94 (42.9%) | 68 (44%) | 26 (30.5%) | 0.0552 | −0.14 | 40% | 44% | 0.039 |
| Baseline treatments | ||||||||
| Amiodarone at baseline | 74 (31%) | 43 (27.9%) | 31 (36.5%) | 0.2216 | 0.09 | 30% | 31% | 0.005 |
| Betablocker at baseline | 192 (81.7%) | 119 (78.3%) | 73 (88%) | 0.0980 | 0.086 | 80% | 72% | −0.079 |
| ACE inhibitor | 113 (48.1%) | 70 (46.1%) | 43 (51.8%) | 0.4794 | 0.05 | 46% | 51% | 0.046 |
| ARB | 23 (9.8%) | 13 (8.6%) | 10 (12%) | 0.5272 | 0.033 | 9% | 11% | 0.028 |
| Aldosterone antagonist | 98 (41.2%) | 55 (35.7%) | 43 (51.2%) | 0.0292 | 0.15 | 37% | 39% | 0.016 |
| ICD | 167 (69.9%) | 96 (62.3%) | 71 (83.5%) | 0.0011 | 0.21 | 69% | 65% | −0.04 |
| CRT | 64 (26.8%) | 43 (27.9%) | 21 (24.7%) | 0.7003 | −0.027 | 18% | 14% | −0.07 |
| Admission parameters | ||||||||
| Acute pulmonary oedema or cardiogenic shock | 70 (29.3%) | 57 (37%) | 13 (15.3%) | 0.0007 | −0.21 | 30% | 33% | 0.03 |
| Creatinine (µg/dL) | 123 [114; 132] | 123 [98; 159] | 122 [88; 156] | 0.2492 | −0.21 | 140 ± 68 | 126 ± 51 | −0.23 |
| Management of ES | ||||||||
| Amiodarone in OR | 205 (85.7%) | 131 (85.6%) | 74 (87.1%) | 0.9109 | 0.02 | 84% | 89% | 0.05 |
| Betablocker in OR | 74 (75.5%) | 45 (29.2%) | 29 (34.1%) | 0.5213 | 0.05 | 31% | 30% | −0.004 |
| Cathecholamines | 85 (35.6%) | 63 (40.9%) | 22 (25.9%) | 0.0291 | −0.15 | 42% | 49% | 0.055 |
| Dialysis | 17 (7.1%) | 15 (9.7%) | 2 (2.4%) | 0.0623 | −0.07 | 2% | 2% | −0.028 |
| Deep sedation | 69 (28.9%) | 46 (29.9%) | 23 (27.1%) | 0.7565 | −0.028 | 27% | 37% | 0.11 |
| Stellate ganglion block | 3 (1.3%) | 3 (2%) | 0 (0%) | 0.4938 | −0.019 | 1% | 0% | −0.018 |
Continuous quantitative variables with a non-normal distribution are presented as median [interquartile range]. Categorical variables are expressed as the number of patients (percentage). Inverse probability of treatment weighting (IPTW) models were based on propensity scores derived predefined variables (age, NYHA class, acute pulmonary oedema or cardiogenic shock, history of electrical storm, LVEF, catecholamine use, prior ICD implantation, and atrial fibrillation). Standardized mean differences (SMD) are reported before and after IPTW. A post-IPTW SMD below 0.1 was considered indicative of acceptable covariate balance. Weighted means ± SD and proportions were calculated using inverse-probability-of-treatment weights truncated at the 1st and 99th percentiles, with estimates derived via the R survey package. Bold values indicate statistically significant P-values (P < 0.05).
ACE inhibitor, angiotensin-converting enzyme inhibitor; ARB, angiotensin II receptor blocker; BMI; body mass index; CRT, cardiac resynchronization therapy; ES, electrical storm; VT, ventricular tachycardia; ICD, implantable cardioverter-defibrillator; LVEF, left ventricular ejection fraction.
Forty-three per cent of lo-PAINESD patients and 47% of the lo-iVT patients underwent VT ablation. Among low-risk patients, those who received VT ablation were more often men, had a higher rate of prior VT ablation, and were more likely to receive beta blockers, while they were also less likely to require catecholamine treatment. Lo-iVT patients who underwent VT ablation were also younger and higher rate of amiodarone treatment prior to admission for ES (see Supplementary material online, Tables S4 and S5).
Impact of VT ablation on 1-year mortality across risk profiles
The 1-year mortality was 25.5% in the entire cohort. In high-risk patients, it reached 43% in the hi-PAINESD group and 41% in the hi-iVT group, while in low-risk patients, it was 16% (lo-PAINESD) and 18% (lo-iVT). To mitigate confounding factors, we used IPTW based on propensity scores derived from clinically relevant variables—age, NYHA class, acute pulmonary oedema or cardiogenic shock, history of electrical storm, LVEF, catecholamine use, prior ICD implantation, and atrial fibrillation. After weighting, baseline characteristics were well balanced between groups, with SMD below 0.1 in the four subgroups for most variables (Table 2 for hi-PAINESD, Table 3 for hi-iVT, Supplementary material online, Table S4 for lo-PAINESD, and Supplementary material online, Table S5 for lo-iVT).
In high-risk patients, lower 1-year mortality was observed in those who underwent VT ablation compared with those who did not (Table 4), in both adjusted Cox models (hi-PAINESD: 1-year mortality of 54% in patients without ablation vs. 26% with ablation, HR 0.42 [95% CI: 0.26–0.66], P = 0.0002; hi-iVT: 1-year mortality of 52% in patients without ablation vs. 20% with ablation, HR 0.31 [0.18–0.53], P < 0.0001 Table 5) and in IPTW-weighted models (hi-PAINESD: HR 0.54 [0.31–0.93]; hi-iVT: HR 0.39 [0.21–0.74]).
Table 4.
Cox model for 1-year mortality outcome
| Univariate OR (CI 95%) |
Unadjusted P-value |
Multivariate HR (CI 95%) |
Adjusted P-value |
|
|---|---|---|---|---|
| Overall population | ||||
| VT ablation | 0.34 (0.24–0.50) | <0.0001 | 0.41 (0.28–0.59) | <0.0001 |
| History of ES | NR | NR | NR | NR |
| Ischaemic cardiomyopathy | NR | NR | NR | NR |
| Use of catecholamines | 3.89 (2.85–5.30) | <0.0001 | 3.47 (2.53–4.75) | <0.0001 |
| High-risk population | ||||
| PAINESD | ||||
| VT ablation | 0.36 (0.23–0.57) | <0.0001 | 0.42 (0.26–0.66) | 0.0002 |
| History of ES | NR | NR | NR | NR |
| Ischaemic cardiomyopathy | NR | NR | NR | NR |
| Use of catecholamines | 3.27 (2.23–4.80) | <0.0001 | 2.91 (1.98–4.29) | <0.0001 |
| iVT | ||||
| VT ablation | 0.29 (0.17–0.49) | <0.0001 | 0.31 (0.18–0.53) | <0.0001 |
| History of ES | NR | NR | NR | NR |
| Ischaemic cardiomyopathy | NR | NR | NR | NR |
| Use of catecholamines | 2.68 (1.79–3.99) | <0.0001 | 2.45 (1.64–3.66) | <0.0001 |
| Low-risk population | ||||
| PAINESD | ||||
| VT ablation | 0.31 (0.16–0.60) | 0.0005 | 0.35 (0.18–0.67) | 0.0017 |
| History of ES | NR | NR | NR | NR |
| Ischaemic cardiomyopathy | 0.30 (0.16–0.55) | 0.0001 | 0.31 (0.16–0.57) | 0.0002 |
| Use of catecholamines | 3.14 (1.79–5.50) | 0.0001 | 2.83 (1.61–4.98) | 0.0003 |
| iVT | ||||
| VT ablation | 0.47 (0.28–0.80) | 0.0055 | 0.57 (0.33–0.98) | 0.0436 |
| History of ES | NR | NR | NR | NR |
| Ischaemic cardiomyopathy | NR | NR | NR | NR |
| Use of catecholamines | 4.43 (2.68–7.32) | <0.0001 | 3.96 (2.38–6.60) | <0.0001 |
Hazard ratios (HR) for 1-year mortality associated with VT ablation, derived from a Cox model. Multivariable adjustment included prior history of ES, cardiomyopathy subtype, catecholamine use, and VT ablation as covariates. NR indicates variables not retained in the model.
Table 5.
Inverse probability of treatment weighting-derived Cox model for 1-year mortality outcome
| HR (CI 95%) | Adjusted P-value |
|
|---|---|---|
| High-risk population | ||
| PAINESD | ||
| Adjusted Cox model | 0.42 (0.26–0.66) | 0.0002 |
| IPTW-derived Cox model | 0.54 (0.31–0.93) | 0.026 |
| iVT | ||
| Adjusted Cox model | 0.31 (0.18–0.53) | <0.0001 |
| IPTW-derived Cox model | 0.39 (0.21–0.74) | 0.004 |
| Low-risk population | ||
| PAINESD | ||
| Adjusted Cox model | 0.35 (0.18–0.67) | 0.0017 |
| IPTW-derived Cox model | 0.39 (0.19–0.81) | 0.011 |
| iVT | ||
| Adjusted Cox model | 0.57 (0.33–0.98) | 0.0436 |
| IPTW-derived Cox model | 0.58 (0.33–0.99) | 0.048 |
Hazard ratios (HR) for 1-year mortality associated with VT ablation, derived from conventional multivariable-adjusted Cox models and IPTW-weighted Cox models. Analyses were performed separately in high-risk and low-risk populations, stratified by PAINESD score and iVT risk score. IPTW models were based on propensity scores derived predefined variables (age, NYHA class, acute pulmonary oedema or cardiogenic shock, history of electrical storm, LVEF, catecholamine use, prior ICD implantation, and atrial fibrillation).
Among low-risk patients, lower 1-year mortality was observed in those who underwent VT ablation compared with those who did not (lo-PAINESD: 21% mortality without ablation vs. 8% with ablation, adjusted Cox model: HR 0.35 [95% CI: 0.18–0.67], P = 0.0017; lo-iVT: 22% without ablation vs. 11% with ablation, adjusted Cox model: HR 0.57 [0.33–0.98], P = 0.0436 Table 5). These findings were consistent in IPTW-weighted models (lo-PAINESD: HR 0.39 [0.19–0.82]; lo-iVT: HR 0.58 [0.33–0.99]). These results were consistently supported by Kaplan–Meier survival curves in both unadjusted and IPTW-weighted analyses (Figure 3 and Supplementary material online, Figure S1), which confirmed the association between VT ablation and improved survival in both high- and low-risk patients. Figure 4 displays a forest plot illustrating the association between VT ablation and 1-year mortality across risk groups, stratified by the statistical model used.
Figure 3.
Weighted 1-year survival according to CA-based management in high-risk patients, as defined by PAINESD and iVT scores based on IPTW. IPTW-derived weighted Kaplan–Meier curves for 1-year mortality according to CA-based management for Hi-iVT (A), Hi-PAINESD (B), Lo-iVT (C), and Lo-PAINESD (D).
Figure 4.
Impact of VT ablation on 1-year mortality across risk profiles. Forest plots illustrating the impact of catheter ablation on 1-year mortality after electrical storm in the overall population and among low- and high-risk patients as assessed by the PAINESD and iVT scores. Adjusted multivariable Cox models included prior history of ES, cardiomyopathy subtype, and the use of catecholamines as competing variables. Inverse probability of treatment weighting (IPTW) models were based on propensity scores derived predefined variables (age, NYHA class, acute pulmonary oedema or cardiogenic shock, history of electrical storm, LVEF, catecholamine use, prior ICD implantation, and atrial fibrillation).
We then formally tested whether the survival benefit of VT ablation differed between low- and high-risk patients by fitting IPTW-weighted Cox models with an ablation × risk-group interaction at 90, 180, and 365 days. In IPTW-weighted interaction analyses, stratification by the iVT score—but not by PAINESD—identified a subgroup of high-risk patients who derive a significantly earlier survival benefit from VT ablation, with the interaction reaching significance at 90 days (P = 0.043) and trending at 180 days (P = 0.095) and 365 days (P = 0.091) (Figure 5A). In contrast, stratification by PAINESD yielded no significant interaction at any time-point (P = 0.61, 0.59, and 0.96 for 90, 180, and 365 days, respectively), demonstrating that the timing and magnitude of benefit were similar in low- and high-PAINESD patients (Figure 5B). Taken together, these findings raise the possibility that the iVT score could help identify high-risk patients who may experience a more rapid mortality reduction following VT ablation.
Figure 5.
Time-dependent effect of ventricular tachycardia (VT) ablation on mortality, weighted by IPTW, stratified by iVT and PAINESD risk scores. Panels show weighted hazard ratios (HRs) and 95% confidence intervals for all-cause mortality at 90, 180, and 365 days following electrical storm, estimated by IPTW-adjusted Cox models: (A) Stratification by iVT score. (B) Stratification by PAINESD score. The horizontal dashed red line indicates HR = 1 (no effect). Brackets above each time point display the P-value for the ablation × risk group interaction test at each horizon.
Discussion
To the best of our knowledge, this study is the first to report the impact of CA of ES in different level of risk profile. The main findings are: (i) a significant proportion of high-risk patients among patients presenting ES—41% based on the PAINESD score and 39.4% based on the iVT score, (ii) a rate of VT ablation reaching 42.4% in the overall population, with rates of 39.4% in hi-PAINESD patients and 35.5% in hi-iVT patients, and (iii) lower 1-year mortality associated with CA in high-risk patients.
ES in structural heart disease
Patients with structural heart disease who present with ES are typically older, more often male, have lower LVEF, advanced HF, and more cardiovascular comorbidities compared to those without ES.12,13 These distinct clinical characteristics add considerable complexity to ES management and affect prognosis significantly.14 Consequently, ES poses a major mortality risk, especially within the first three months following onset. Additionally, the 1-year mortality rate after hospitalization for ES is alarmingly high at ∼35%,2 increasing to 40–45% in patients who do not respond to CA. Our findings are in line with these previous studies, reaching 12% at 1 month and 26% at one year.15
VT ablation in the setting of ES
ES represents a high-risk scenario for patients undergoing VT ablation. In a study of 2061 patients who underwent VT ablation, Santangeli et al.6 reported that patients with ES faced a 3.61-fold higher risk of early mortality post-ablation. Additionally, a 5.12-fold increase in the risk of acute haemodynamic decompensation was previously reported in this context.4 While no randomized trials have yet evaluated the benefits of VT ablation specifically for ES, observational studies have suggested that ablation in this setting may be associated with reduced mortality.16 Previous results from this cohort demonstrated a significant benefit from VT ablation, with a 59% lower 1-year mortality using propensity-matched analysis.7 However, the current definition of ES includes a broad range of clinical situations, reflecting varying VT burdens and risk profiles based on underlying conditions, raising questions about the effect of ablation across different risk profiles.
VT ablation in high-risk profiles
VT ablation is a key strategy for managing drug-refractory VT-ES, though it carries a substantial risk of periprocedural complications and adverse outcomes.17 A particular concern is periprocedural AHD, which is closely linked to higher short-term mortality following the procedure. Consequently, there is increasing interest in identifying patients at high risk for adverse outcomes after VT ablation.
Our study adds further evidence to the potential benefits of VT ablation in patients with ES across various risk profiles. In this study, which focused exclusively on ES patients, we found that nearly 40% fell into high-risk categories based on PAINESD and iVT scores—a previously unreported proportion. Compared to the original study defining the iVT score, where about one-third of patients had a high risk of postoperative mortality, this higher proportion may reflect the greater comorbidity burden in the ES population relative to a broader VT ablation group. However, high-risk patients in the iVT cohort showed a 1-year mortality risk of up to 20%, consistent with the rates observed in our high-risk (hi-iVT) group undergoing VT ablation.
Notably, we found that high-risk patients who underwent VT ablation had lower mortality rates than those who did not undergo the procedure. The lower occurrence of mortality was evident across both low- and high-risk profiles, though with different timelines In time-stratified IPTW-weighted Cox analyses, VT ablation was linked to a survival benefit in hi-iVT patients as early as 90 days (interaction P = 0.043), which persisted at 6 months and 1 year, whereas among low-risk patients a statistically significant association emerged only at 1 year. This clear temporal heterogeneity indicates that high-risk individuals derive the most rapid mortality reduction from ablation, highlighting the need to prioritize and expedite the procedure in this subgroup following an electrical storm. At the same time, these findings must be interpreted against the backdrop of current European practice. The 2023 EHRA survey revealed substantial variability across Europe in the use and timing of VT ablation and adjunctive therapies.18 Such heterogeneity highlights the need for more standardized management pathways to ensure that high-risk iVT patients can access timely ablation and realize the early survival benefits suggested here.
While our data emphasize the need to streamline access to VT ablation for high-risk iVT patients, this strategy must be balanced against the procedure’s inherent risks. The rate of ischaemic stroke rate observed in our cohort (2.7%) was higher than previously reported in VT ablation series performed in elective settings, where rates typically range between 0.5% and 1.0%. This higher ischaemic stroke rate may be explained by the clinical severity of our population, characterized by frequent haemodynamic instability and emergent procedures in the context of electrical storm. These factors may have limited the possibility of optimal periprocedural anticoagulation management. Furthermore, the inclusion of patients referred to tertiary centres for complex or high-risk procedures likely contributed to an overestimation of complication rates compared with elective ablation series. Our findings are consistent with previous reports indicating increased procedural risk in unstable patients undergoing VT ablation.6 The timing of VT ablation procedures (emergency vs. elective, weekdays vs. weekends) was not systematically recorded in this cohort, thus limiting our ability to assess potential differences in outcomes related to procedural timing. Recent literature indicates that emergency or out-of-hours VT ablation procedures might be associated with different outcomes due to logistical, resource-based, or clinical severity factors.19 Future studies should explore how these factors might influence patient outcomes in the context of electrical storm.
Study limitations
This study has several limitations. As an observational study conducted across four tertiary arrhythmia centres, patient characteristics and outcomes may be influenced by referral bias, though they are representative of patients admitted for ES in similar institutions. CA for ES is frequently performed in high-volume ablation centres with expertise in ventricular arrhythmia ablation and access to advanced heart failure support. The relative low rate of adverse events reported in this population may not be representative of larger scale registries. Despite these limitations, this study provides, for the first time, a comprehensive overview of the impact of CA for ES on survival outcomes in ES patients at high risk for postoperative mortality. Furthermore, the consistency of our findings across both multivariable-adjusted Cox models and IPTW-weighted survival analyses further reinforces the robustness of the observed association between VT ablation and improved survival. This convergence of analytical approaches supports the validity of our results despite the inherent limitations of observational data. However, even with these adjustments, residual confounding—particularly related to unmeasured variables and selection bias—cannot be excluded. As such, our findings should be interpreted with caution and considered hypothesis-generating rather than definitive evidence of a causal relationship.
Conclusion
In this French multicentre population of patients experiencing electrical storm, 41% were considered as high risk of acute haemodynamic decompensation and mortality according to the PAINESD score, and 39.4% according to the iVT score. VT ablation was associated with a lower 1-year mortality in low- and high-risk patients, with a clinical benefit appearing earlier in high-risk patients.
Supplementary Material
Contributor Information
Sandro Ninni, Department of Cardiology, Lille University Hospital, 59000 Lille, France.
Charles Guenancia, Department of Cardiology, Dijon University Hospital, Dijon, France.
Ophélie Bourdrel, Department of Cardiology, Lille University Hospital, 59000 Lille, France.
Rayan Mohammed, Section of Cardiac Electrophysiology, Saint-Etienne University Hospital, Saint-Etienne, France.
Donovan Decaudin, Section of Cardiac Electrophysiology, Rennes University Hospital, Rennes, France.
Cédric Klein, Department of Cardiology, Lille University Hospital, 59000 Lille, France.
Alexandre Salaun, Department of Cardiology, Dijon University Hospital, Dijon, France.
Ruxandra Sava, Section of Cardiac Electrophysiology, Saint-Etienne University Hospital, Saint-Etienne, France.
Amine Tazibet, Department of Cardiology, Lille University Hospital, 59000 Lille, France.
Soundous M'Rabet, Department of Cardiology, Dijon University Hospital, Dijon, France.
Pierre Grégoire Guinot, Department of Cardiology, Dijon University Hospital, Dijon, France.
Pierre Groussin, Section of Cardiac Electrophysiology, Rennes University Hospital, Rennes, France.
Antoine Da Costa, Section of Cardiac Electrophysiology, Saint-Etienne University Hospital, Saint-Etienne, France.
Dominique Pavin, Section of Cardiac Electrophysiology, Rennes University Hospital, Rennes, France.
Didier Klug, Department of Cardiology, Lille University Hospital, 59000 Lille, France.
Raphaël Martins, Section of Cardiac Electrophysiology, Rennes University Hospital, Rennes, France; INSERM-LTSI, Rennes U1099, France.
Karim Benali, Section of Cardiac Electrophysiology, Saint-Etienne University Hospital, Saint-Etienne, France; IHU Liryc, Electrophysiology and Heart Modeling Institute, Bordeaux, France; Haut-Leveque University Hospital, Bordeaux, France.
Supplementary material
Supplementary material is available at Europace online.
Funding
None.
Data availability
Data supporting the findings of this study are available from the corresponding author upon reasonable request.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Data Availability Statement
Data supporting the findings of this study are available from the corresponding author upon reasonable request.