Twenty-five years of catheter ablation of ventricular tachycardia: a look back and a look forward

Excellent Outcomes After First-Line Ablation in Post-MI Patients With Tolerated VT and LVEF >35

BACKGROUND

Post-myocardial infarction (MI) patients with ventricular tachycardia (VT) are considered at risk for VT recurrence and sudden cardiac death (SCD). Recent guidelines indicate that in selected patients catheter ablation should be considered instead of an implantable cardioverter-defibrillator (ICD).

OBJECTIVES

This study aimed to analyze outcomes of patients referred for VT ablation according to left ventricular ejection fraction (LVEF), tolerance of VT, and acute ablation outcome.

METHODS

Post-MI patients without prior ICD undergoing VT ablation at a single center between 2009 and 2022 were included. Patients who presented with tolerated VT and who had an LVEF >35% were offered catheter ablation as first-line therapy. ICD implantation was offered to all patients but was subject to shared decision according to clinical presentation, LVEF, and ablation outcome.

RESULTS

Eighty-six patients (mean age 69 ± 9 years, 84% male, mean LVEF 41 ± 9%) underwent VT ablation. In 66 patients, LVEF was >35%, of whom 51 had tolerated VT. Of these 51 patients, 37 (73%) were rendered noninducible. In 5 of 37 noninducible and in 11 of 14 inducible patients, an ICD was implanted. During a median follow-up of 40 months (Q1-Q3: 24-70 months), 10 of 86 patients had VT recurrence. The overall mortality was 27%, and 1 patient with ICD died suddenly. Among the 37 patients (none on antiarrhythmic drugs) with LVEF >35%, tolerated VT, and noninducibility, no SCD or VT recurrence occurred. Among the 14 patients with LVEF >35%, tolerated VT, and inducibility after ablation, no SCD occurred, but VT recurred in 29%.

CONCLUSIONS

Post-MI patients with LVEF >35%, tolerated VT, and noninducibility after ablation have an excellent prognosis. Deferring ICD implantation seems to be safe in these patients.

Acute post-procedural inducibility is a poor predictor of clinical outcomes in high-risk patients (PAINESD > 17) undergoing scar-related ventricular tachycardia ablation

AIMS

Ventricular tachycardia (VT) non-inducibility in response to programmed ventricular stimulation (PVS) is a widely used procedural endpoint for VT ablation despite inconclusive evidence with respect to clinical outcomes in high-risk patients. The aim is to determine the utility of acute post-ablation VT inducibility as a predictor of VT recurrence, mortality, or mortality equivalent in high-risk patients.

METHODS AND RESULTS

We conducted a retrospective analysis of high-risk patients (defined as PAINESD > 17) who underwent scar-related VT ablation at our institution between July 2010 and July 2022. Patients' response to PVS (post-procedure) was categorized into three groups: Group A, no clinical VT or VT with cycle length > 240 ms inducible; Group B, only non-clinical VT with cycle length > 240 ms induced; and Group C, all other outcomes (including cases where no PVS was performed). The combined primary endpoint included death, durable left ventricular assist device placement, and cardiac transplant (Cox analysis). Ventricular tachycardia recurrence was considered a secondary endpoint (competing risk analysis). Of the 1677 VT ablation cases, 123 cases met the inclusion criteria for analysis. During a 19-month median follow-up time (interquartile range 4-43 months), 82 (66.7%) patients experienced the composite primary endpoint. There was no difference between Groups A and C with respect to the primary [hazard ratio (HR) = 1.21 (0.94-1.57), P = 0.145] or secondary [HR = 1.18 (0.91-1.54), P = 0.210] outcomes. These findings persisted after multivariate adjustments. The size of Group B (n = 13) did not permit meaningful statistical analysis.

CONCLUSION

The results of post-ablation PVS do not significantly correlate with long-term outcomes in high-risk (PAINESD > 17) VT ablation patients.

Periprocedural acute haemodynamic decompensation during substrate-based ablation of scar-related ventricular tachycardia: a rare and unpredictable event

AIMS

Patients with structural heart disease (SHD) undergoing catheter ablation (CA) for ventricular tachycardia (VT) are at considerable risk of periprocedural complications, including acute haemodynamic decompensation (AHD). The PAINESD score was proposed to predict the risk of AHD. The goal of this study was to validate the PAINESD score using the retrospective analysis of data from a large-volume heart centre.

METHODS AND RESULTS

Patients who had their first radiofrequency CA for SHD-related VT between August 2006 and December 2020 were included in the study. Procedures were mainly performed under conscious sedation. Substrate mapping/ablation was performed primarily during spontaneous rhythm or right ventricular pacing. A purposely established institutional registry for complications of invasive procedures was used to collect all periprocedural complications that were subsequently adjudicated using the source medical records. Acute haemodynamic decompensation triggered by CA procedure was defined as intraprocedural or early post-procedural (<12 h) development of acute pulmonary oedema or refractory hypotension requiring urgent intervention. The study cohort consisted of 1124 patients (age, 63 ± 13 years; males, 87%; ischaemic cardiomyopathy, 67%; electrical storm, 25%; New York Heart Association Class, 2.0 ± 1.0; left ventricular ejection fraction, 34 ± 12%; diabetes mellitus, 31%; chronic obstructive pulmonary disease, 12%). Their PAINESD score was 11.4 ± 6.6 (median, 12; interquartile range, 6-17). Acute haemodynamic decompensation complicated the CA procedure in 13/1124 = 1.2% patients and was not predicted by PAINESD score with AHD rates of 0.3, 1.8, and 1.1% in subgroups by previously published PAINESD terciles (<9, 9-14, and >14). However, the PAINESD score strongly predicted mortality during the follow-up.

CONCLUSION

Primarily substrate-based CA of SHD-related VT performed under conscious sedation is associated with a substantially lower rate of AHD than previously reported. The PAINESD score did not predict these events. The application of the PAINESD score to the selection of patients for pre-emptive mechanical circulatory support should be reconsidered.

Use of three-dimensional electroanatomic mapping for epicardial access: needle tracking, electrographic characteristics, and clinical application

AIMS

Pericardiocentesis is usually completed under fluoroscopy. The electroanatomic mapping (EAM) system allows visualizing puncture needle tip (NT) while displaying the electrogram recorded from NT, making it possible to obtain epicardial access (EA) independent of fluoroscopy. This study was designed to establish and validate a technique by which EA is obtained under guidance of three-dimensional (3D) EAM combined with NT electrogram.

METHODS AND RESULTS

3D shell of the heart was generated, and the NT was made trackable in the EAM system. Unipolar NT electrogram was continuously monitored. Penetration into pericardial sac was determined by an increase in NT potential amplitude and an injury current. A long guidewire of which the tip was also visible in the EAM system was advanced to confirm EA. Epicardial access was successfully obtained without complication in 13 pigs and 22 patients. In the animals, NT potential amplitude was 3.2 ± 1.0 mV when it was located in mediastinum, 5.2 ± 1.6 mV when in contact with fibrous pericardium, and 9.8 ± 2.8 mV after penetrating into pericardial sac (all P ≤ 0.001). In human subjects, it measured 1.54 ± 0.40 mV, 3.61 ± 1.08 mV, and 7.15 ± 2.88 mV, respectively (all P < 0.001). Fluoroscopy time decreased in every 4-5 cases (64 ± 15, 23 ± 17, and 0 s for animals 1-4, 5-8, 9-13, respectively, P = 0.01; 44 ± 23, 31 ± 18, 4±7 s for patients 1-7, 8-14, 15-22, respectively, P < 0.001). In five pigs and seven patients, EA was obtained without X-ray exposure.

CONCLUSION

By tracking NT in the 3D EAM system and continuously monitoring the NT electrogram, it is feasible and safe to obtain EA with minimum or no fluoroscopic guidance.

Impact of ventricular tachycardia ablation in subcutaneous implantable cardioverter defibrillator carriers: a multicentre, international analysis from the iSUSI project

AIMS

Catheter ablation (CA) of ventricular tachycardia (VT) has become an important tool to improve clinical outcomes in patients with appropriate transvenous implantable cardioverter defibrillator (ICD) shocks. The aim of our analysis was to test whether VT ablation (VTA) impacts long-term clinical outcomes even in subcutaneous ICD (S-ICD) carriers.

METHODS AND RESULTS

International Subcutaneous Implantable Cardioverter Defibrillator (iSUSI) registry patients who experienced either an ICD shock or a hospitalization for monomorphic VT were included in this analysis. Based on an eventual VTA after the index event, patients were divided into VTA+ vs. VTA- cohorts. Primary outcome of the study was the occurrence of a combination of device-related appropriate shocks, monomorphic VTs, and cardiovascular mortality. Secondary outcomes were addressed individually. Among n = 1661 iSUSI patients, n = 211 were included: n = 177 experiencing ICD shocks and n = 34 hospitalized for VT. No significant differences in baseline characteristics were observed. Both the crude and the yearly event rate of the primary outcome (5/59 and 3.8% yearly event rate VTA+ vs. 41/152 and 16.4% yearly event rate in the VTA-; log-rank: P value = 0.0013) and the cardiovascular mortality (1/59 and 0.7% yearly event rate VTA+ vs. 13/152 and 4.7% yearly event rate VTA-; log-rank P = 0.043) were significantly lower in the VTA + cohort. At multivariate analysis, VTA was the only variable remaining associated with a lower incidence of the primary outcome [adjusted hazard ratio 0.262 (0.100-0.681), P = 0.006].

CONCLUSION

In a real-world registry of S-ICD carriers, the combined study endpoint of arrhythmic events and cardiovascular mortality was lower in the patient cohort undergoing VTA at long-term follow-up.

CLINICALTRIALS.GOV IDENTIFIER

NCT0473876.

Area-weighted unipolar voltage to predict heart failure outcomes in patients with ischaemic cardiomyopathy and ventricular tachycardia

AIMS

Patients with ischaemic cardiomyopathy (ICM) referred for catheter ablation of ventricular tachycardia (VT) are at risk for end-stage heart failure (HF) due to adverse remodelling. Local unipolar voltages (UV) decrease with loss of viable myocardium. A UV parameter reflecting global viable myocardium may predict prognosis. We evaluate if a newly proposed parameter, area-weighted unipolar voltage (awUV), can predict HF-related outcomes [HFO; HF death/left ventricular (LV) assist device/heart transplant] in ICM.

METHODS AND RESULTS

From endocardial voltage maps of consecutive patients with ICM referred for VT ablation, awUV was calculated by weighted interpolation of local UV. Associations between clinical and mapping parameters and HFO were evaluated and validated in a second cohort. The derivation cohort consisted of 90 patients [age 68 ±8 years; LV ejection fraction (LVEF) 35% interquartile range (IQR) (24-40)] and validation cohort of 60 patients [age 67 ± 9, LVEF 39% IQR (29-45)]. In the derivation cohort, during a median follow-up of 45 months [IQR (34-83)], 36 (43%) patients died and 23 (26%) had HFO. Patients with HFO had lower awUV [4.51 IQR (3.69-5.31) vs. 7.03 IQR (6.08-9.2), P < 0.001]. A reduction in awUV [optimal awUV (5.58) cut-off determined by receiver operating characteristics analysis] was a strong predictor of HFO (3-year HFO survival 97% vs. 57%). The cut-off value was confirmed in the validation cohort (2-year HFO-free survival 96% vs. 60%).

CONCLUSION

The newly proposed parameter awUV, easily available from routine voltage mapping, may be useful at identifying ICM patients at high risk for HFO.

Management of ventricular tachycardias: insights on centre settings, procedural workflow, endpoints, and implementation of guidelines-results from an EHRA survey

Ventricular tachycardia (VT), and its occurrence, is still one of the main reasons for sudden cardiac death and, therefore, for increased mortality and morbidity foremost in patients with structural heart [Kahle A-K, Jungen C, Alken F-A, Scherschel K, Willems S, Pürerfellner H et al. Management of ventricular tachycardia in patients with ischaemic cardiomyopathy: contemporary armamentarium. Europace 2022;24:538-51]. Catheter ablation has become a safe and effective treatment option in patients with recurrent VT [Cronin EM, Bogun FM, Maury P, Peichl P, Chen M, Namboodiri N et al. 2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias. Heart Rhythm 2020;17:e2-154]. Previous and current guidelines provide guidance on indication for VT ablation and risk assessment and evaluation of underlying disease. However, no uniform recommendation is provided regarding procedural strategies, timing of ablation, and centre setting. Therefore, these specifics seem to differ largely, and recent data are sparse. This physician-based European Heart Rhythm Association survey aims to deliver insights on not only infrastructural settings but also procedural specifics, applied technologies, ablation strategies, and procedural endpoints. Therefore, these findings might deliver a real-world scenario of VT management and potentially are of guidance for other centres.

Prevention of venous thromboembolism in right heart-sided electrophysiological procedures: results of an European Heart Rhythm Association survey

Limited data are available regarding venous thromboembolism (VTE), specifically deep vein thrombosis (DVT) and pulmonary embolism (PE), following right-sided ablations and electrophysiological (EP) studies. Compared to left-sided procedures, no guidelines on antithrombotic management strategies for the prevention of DVT and PE are available. The main purpose of the present European Heart Rhythm Association (EHRA) survey is to report the current management of right-sided EP procedures, focusing on anticoagulation and prevention of VTE. An online survey was conducted using the EHRA infrastructure. A total of 244 participants answered a 19-items questionnaire on the periprocedural management of EP studies and right-sided catheter ablations. The right femoral vein is the most common access for EP studies and right-sided procedures. An ultrasound-guided approach is employed by more than 2/3 of respondents. Intravenous heparin is not commonly given by the majority of participants. About 1/3 of participants (34%) routinely prescribe VTE prophylaxis during (mostly aspirin and low molecular weight heparin) and 1/4 of respondents (25%) commonly prescribe VTE prophylaxis after discharge (mostly aspirin). Of note, respectively 13% and 9% of participants observed at least one DVT and one PE related to right-sided ablation or EP study within the last year in their center. The present survey shows that only a minority of operators routinely gives intraprocedural intravenous heparin and prescribes VTE prophylaxis after right-sided EP procedures. Compared to left-sided procedures like atrial fibrillation (AF) ablation, there are no consistent systematic antithrombotic management strategies.