Catheter Ablation Of Ventricular Tachycardia Research Articles

Outcomes in Catheter Ablation of Sustained Ventricular Tachycardia in Myocarditis Compared with Ischemic Heart Disease.

The substrates for arrhythmias in myocarditis and ischemic heart disease (IHD) are different, but it is yet to be determined whether there is a difference in outcomes following catheter ablation (CA) for ventricular tachycardia (VT) associated with these two conditions. This study aimed to compare outcomes after CA of VT in patients with myocarditis versus those with IHD. Patients undergoing CA for sustained VT confirmed by endomyocardial biopsy as myocarditis, and patients with IHD experiencing sustained VT undergoing CA were retrospectively enrolled from February 2017 to March 2023. Initially, an endocardial approach was employed, reserving epicardial ablation procedures for non-responders. The primary endpoint was VT recurrence during follow up. All-cause mortality, repeat CA for VT and implantable cardioverter-defibrillator (ICD) implantation served as secondary endpoints. Kaplan-Meier curves compared outcomes between patient groups. This study included 109 patients with IHD and 20 patients with myocarditis who underwent CA for sustained VT, from February 2017 to March 2023. Compared with IHD patients, myocarditis patients had a statistically significant lower complete short-term success rate of CA (60.0% vs. 85.3%, p = 0.013). During a follow-up period of 37 ± 21 months, 8 (40.0%) myocarditis patients experienced VT recurrence compared to 57 (52.3%) IHD patients, with no statistically significant difference between the two groups. During follow-up, 2 (10.0%) myocarditis patients died and 2 (10.0%) underwent repeat CA for VT recurrence, while 9 (8.3%) IHD patients died, 14 (12.8%) underwent a second CA for VT recurrence, and 8 (7.3%) received an ICD implantation. Additionally, there were no notable variations between the two groups regarding all-cause mortality, repeat CA for VT and ICD implantation. It was demonstrated that the efficacy of CA in sustained VT in myocarditis patients was similar to that in IHD. For myocarditis patients with VT, CA might be equally effective.

Intrapericardial Corticosteroids and Colchicine Prevent Pericarditis and Atrial Fibrillation After Epicardial Ablation of Ventricular Arrhythmias.

Postprocedural pericarditis (PP) can occur inup to 29.4% of patients undergoing epicardial catheter ablation of ventricular tachycardia (VT). Despite several proposed strategies to mitigate this adverse outcome, rates of PPand pericarditic pain remain high. This study sought to assess the impact of intrapericardial steroids instillation (ISI) combined with periprocedural colchicine on PP after epicardial VT ablation. This prospective multicenter study included patients undergoing epicardial VT ablation between June 2021 and December 2023. The primary outcome was the occurrence of pericarditis, defined as the presence of pericarditic chest pain and pericarditic electrocardiographic (ECG) changes. Secondary outcomes included the pericarditic pain score at 6, 12, 24, and 48 hours after the procedure, pericardial effusion, postprocedural new-onset atrial fibrillation (AF), constrictive pericarditis, admission due to pericarditis, and gastrointestinal side effects. A systematic literature search was performed to identify historical control groups to compare with our cohort. A total of 129 patients underwent epicardial VT ablation with subsequent ISI and colchicine therapy. The combination of ISI and colchicine resulted in a nonsignificant trend of lower rates of pericarditis when compared with all historical control groups (3.1% [4 of 129] vs 7.0% [12 of 172]; P=0.109) and a significant difference when compared to intrapericardial steroids (3.1% vs 13.2%; P = 0.030). The rates of pericarditic pain (10.9% [14 of 129] vs 30.9% [21 of 68]; P=0.001), pericarditic ECG changes (5.4% [7 of 129] vs 33.8% [23 of 68]; P< 0.001) and new-onset atrial fibrillation (0.8% vs 19.5%; P = <0.001) were significantly lower in our study than in historical control groups. The instillation of intrapericardial steroids along with periprocedural colchicine after epicardial VT ablation led to a decreased incidence of adverse effects associated with pericardial inflammation when compared with historical control groups. Further research with contemporary control groups is needed to confirm the suggested impact of the strategy described here.

Personalized Heart Digital Twins Detect Substrate Abnormalities in Scar-Dependent Ventricular Tachycardia.

Current outcomes from catheter ablation for scar-dependent ventricular tachycardia (VT) are limited by high recurrence rates and long procedure durations. Personalized heart digital twin technology presents a noninvasive method of predicting critical substrate in VT, and its integration into clinical VT ablation offers a promising solution. The accuracy of the predictions of digital twins to detect invasive substrate abnormalities is unknown. We present the first prospective analysis of digital twin technology in predicting critical substrate abnormalities in VT. Heart digital twin models were created from 18 patients with scar-dependent VT undergoing catheter ablation. Contrast-enhanced cardiac magnetic resonance images were used to reconstruct finite-element meshes, onto which regional electrophysiological properties were applied. Rapid-pacing protocols were used to induce VTs and to define the VT circuits. Predicted optimum ablation sites to terminate all VTs in the models were identified. Invasive substrate mapping was performed, and the digital twins were merged with the electroanatomical map. Electrogram abnormalities and regions of conduction slowing were compared between digital twin-predicted sites and nonpredicted areas. Electrogram abnormalities were significantly more frequent in digital twin-predicted sites compared with nonpredicted sites (468/1029 [45.5%] versus 519/1611 [32.2%]; P<0.001). Electrogram duration was longer at predicted sites compared with nonpredicted sites (82.0±25.9 milliseconds versus 69.7±22.3 milliseconds; P<0.001). Digital twins correctly identified 21 of 26 (80.8%) deceleration zones seen on isochronal late activation mapping. Digital twin-predicted sites display a higher prevalence of abnormal and prolonged electrograms compared with nonpredicted sites and accurately identify regions of conduction slowing. Digital twin technology may help improve substrate-based VT ablation. URL: https://www.clinicaltrials.gov; Unique identifier: NCT04632394.

Percutaneous VT Ablation via RA-to-LV Access in Patients With Double Mechanical Valves: A Multicenter Registry.

In patients with mechanical aortic and mitral valves requiring catheter ablation of ventricular tachycardia (VT), a technique for access from the right atrium (RA) to the left ventricle (LV) via puncture of the inferoseptal process of the LV was previously described in a single-center series. This study sought to report the multicenter experience of VT ablation using this novel LV access approach. We assembled a multicenter registry of patients with double mechanical valves who underwent VT ablation with RA-to-LV access. Eighteen patients from 10 VT ablation centers were included (15 men; age: 63.9 ± 10 years, LV ejection fraction: 32% ± 10%). In 14 patients, the procedure was performed on uninterrupted anticoagulation, and 4 patients underwent bridging with heparin. A mean of 2.5 VTs were inducible at procedure onset. LV access was successful in all cases with intracardiac echocardiography-guided puncture with a radiofrequency wire (n=16) or standard transseptal needle (n=2), followed by balloon dilation. Postablation, complete noninducibility of VT was achieved in 17 (94%) patients. One intramural perimitral annular hematoma was noted after LV access that was managed conservatively without sequelae. No other procedure-related complications were noted, such as new AV block. LV-RA shunt was present by echocardiogram within 24 to 72 hours in 10 (56%) patients. A small residual shunt was noted in 1 of them more than 3months postablation. During the median follow-up of 10.4months, 3 (17%) patients experienced VT recurrence. In this multicenter registry of patients with double mechanical valves, VT ablation with RA-to-LV access was feasible, safe, and effective.

Ten-Year Outcomes and Predictors of Mortality Following Catheter Ablation of Ventricular Tachycardia.

Catheter ablation is the primary treatment option for idiopathic ventricular tachycardia (VT). It plays a key role in acute therapy of electrical storm, treatment of VTs in patients with structural heart disease (SHD), and can reduce VT burden. Here we report on 10-year clinical outcomes following VT ablation from patients enrolled in the prospective German Ablation Registry. Long-term follow-up was conducted on 334 patients undergoing VT ablation (118/334, 35%) with structurally normal hearts and 216 out of 334 (65%) with SHD, including 161 out of 216 (75%) with ischemic heart disease at 38 centers. Follow-up was completed in 94.8% of patients. Median observation time was 10.8 (4.3-12.3) years, with a 10-year all-cause mortality rate of 39.4%. VT ablation in patients with SHD was associated with worse outcome when compared with patients with structurally normal hearts (estimated 10-year mortality for SHD 54.8% versus structurally normal hearts 12.1%). Estimated 10-year mortality following VT ablation was highest in patients with ischemic heart disease (62.4%). Significant predictors of mortality following VT ablation included age (hazard ratio [HR], 2.35 [1.90-2.92] per decade), left ventricular ejection fraction ≤30% (HR, 2.11 [1.44-3.10]), diabetes (HR, 1.73 [1.14-2.61]), incessant VT (HR, 2.96 [1.74-5.03]), linear lesion (HR, 1.46 [0.99-2.16]), and acute procedural failure (HR, 2.57 [1.39-4.77]). Procedural failure was the only statistically significant predictor for VT recurrence during follow-up (HR, 3.76 [1.59-8.91]). Within an all-comer patient cohort, estimated 10-year all-cause mortality following VT ablation is 39.4%. Mortality after VT ablation is worse in patients with SHD and highest for patients with ischemic heart disease. Acute procedural success plays a major role in predicting VT recurrence and long-term mortality.

Preprocedural imaging guiding ventricular tachycardia ablation in structural heart disease.

Integration of preprocedural imaging techniques in ventricular tachycardia (VT) ablation may improve the identification of arrhythmogenic substrates, particularly relevant for patients with nonischemic cardiomyopathy (NICM) with sub-optimal outcomes. We assessed the impact of advanced preprocedural imaging on the safety and long-term efficacy of radiofrequency catheter ablation (RCA) for VT, comparing patients with NICM and ischemic cardiomyopathy (ICM). In this prospective, single-center study, consecutive patients referred for scar-related VT ablation underwent multidetector computed tomography (MDCT) and late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Images were segmented with ADAS 3D software and integrated into mapping systems. Substrate map collection targeted the imaging-predicted area of interest and the ablation aimed at eliminating all local abnormal ventricular activities. Procedural safety was evaluated with 30-day mortality. Long-term efficacy was assessed by survival free from appropriate ICD shocks at 36 months. 102 patients were included (67 ± 11 years, 94% male; 75 ICM, 27 NICM). All patients underwent MDCT and 35% also underwent LGE-CMR. Procedural safety (4% 30-day mortality, p = .95) and 36-month efficacy were similar in both groups (88.0% vs. 74.1%, HR 2.09; p = .13 in ICM and NICM). Efficacy was higher in patients when VT activation mapping with VT isthmus ablation complemented substrate ablation compared to substrate-based ablation alone (94.5% vs. 80.6%, HR 4.00; p < .05). A preprocedural imaging protocol integrated into the invasive mapping system may improve safety and long-term efficacy, with NICM patients exhibiting outcomes comparable to those with ICM. Activation mapping of the VT on top of substrate ablation may improve prognosis.

Termination Without Global Propagation in Re-Entrant Ventricular Tachycardia: Electrophysiologic Characteristics and 3D-Electroanatomical Mapping Analysis.

Termination of ventricular tachycardia (VT) by a pacing stimulus that does not generate a QRS complex (termination without global propagation [TWGP]) can be a marker for a critical re-entry circuit isthmus. However, the electrophysiologic and anatomic features of these sites and their relation to VT substrate defined by 3-dimensional electroanatomical maps (3D-EAM) remain unknown. This retrospective study aimed to characterize TWGP sites and their relation to VT substrate identified by 3D-EAM. A total of 632 consecutive cases of catheter ablation for scar-related VT at 2 University medical centers were reviewed to identify TWGP. TWGP was observed 12 times at 11 different sites in 10 patients (5 ischemic cardiomyopathy). The TWGP stimulus fell immediately before or synchronous with the QRS in all cases, and evidence of local capture despite absence of a QRS complex was observed 6 times. In 5 sites, pacing after VT termination produced a QRS different than the VT. Four sites were in dense scar areas (<0.1mV), and 6 in abnormal low voltage zone (0.1-1.5mV). Additional mapping or ablation that abolished VT were consistent with the TWGP site being in a VT isthmus. A substrate marker for VT of late potentials, evoked delayed potentials, or slow conduction was present at 6 of 11 TWGP sites. TWGP may be a marker for detecting a re-entry circuit isthmus that has escaped detection based on electrogram or pace mapping-based substrate mapping.

Catheter Ablation for Ventricular Tachycardias: Current Status and Future Perspectives.

Catheter ablation for ventricular tachycardia (VT) in patients with systolic heart failure remains a critical yet challenging area of non-pharmacological therapy. Despite positive outcomes in atrial fibrillation, evidence for the efficacy of VT ablation in reducing cardiac mortality is inconclusive due to the absence of standardized ablation strategies. The primary challenges include difficulties in identifying suitable ablation targets and their deep locations within myocardial tissue. Current techniques, such as voltage mapping, provide valuable insights; however, they are limited by the presence of numerous bystander areas and the occurrence of incomplete transmural scarring. Recent advancements in functional substrate mapping have focused on identifying critical isthmuses without requiring hemodynamic stabilization during VT, thereby shifting the emphasis to the analysis of potentials during baseline rhythm. While methods like isochronal late activation mapping have improved target identification, they primarily address conduction abnormalities without adequately considering repolarization heterogeneity. This review highlights emerging technologies that utilize unipolar potentials to assess repolarization heterogeneities and identify VT isthmuses. Furthermore, novel ablation sources such as pulsed-field ablation, bipolar ablation, and ultra-low temperature cryoablation are being explored to create deeper and more durable lesions, addressing the limitations of traditional radiofrequency ablation. These advancements aim to reduce VT recurrence and improve overall treatment efficacy. Ultimately, understanding these innovative strategies is expected to optimize procedural outcomes and significantly enhance the management of patients with scar-related VT.

Abstract 4113336: Characteristics and Outcomes of Ventricular Tachycardia Ablation in Patients with the HeartMate 3 Left Ventricular Assist Devices: Results From a Large Single-Center Registry

HeartMate 3 (HM3) is a fully magnetically levitated continuous flow left ventricular assist device (LVAD). In patients with HM3 and recurrent ventricular tachycardia (VT), data on the outcomes of catheter ablation (CA) are insufficient. We report our institutional experience with CA of VT in patients with the HM3.Consecutive patients with HM3 and recurrent drug-refractory VT undergoing CA were included. Ablation sites were identified using activation/entrainment mapping (stable VTs) and/or late/fractionated potential ablation and pace-mapping (unstable VTs). Between 2016-2023 a total of 431 patients (age 58±13, INTERMACS 3±0.98, 44% ischemic cardiomyopathy) received an HM3 LVAD at our institution. Of these, 15 (3.4%) underwent CA for recurrent VT despite therapy with 1.3±0.8 antiarrhythmic drugs a median of 700 days from the LVAD surgery (2 patients &lt;1 month from the surgery). The LV access was transseptal in 12 (80%) cases, retrograde aortic in 2 (13%) and both in 1 (7%). A total of 23 distinct VTs were targeted. Of these, 21 (91%) were mapped with activation/entrainment mapping, always utilizing an intracardiac RV reference due to excessive surface ECG noise, and 2 (9%) were hemodynamically unstable with reduced LVAD flows and targeted with substrate-based ablation. A total of 3 (13%) VTs were targeted adjacent to the HM3 inflow cannula, and 20 (87%) from substrate remote from the HM3 cannula. At post-procedural programmed ventricular stimulation, non-inducibility of all targeted VTs was achieved in 13 (87%) patients, 1 patient had residual inducible clinical VT, and in 1 patient no post-procedural programmed stimulation was performed. Periprocedural complications occurred in 1 (7%) case (small pericardial effusion not requiring intervention). At 12 months follow-up following the index procedure, no death occurred and one patient received heart transplantation. Of the remaining 14 patients, 6 (42%) remained free from VT (2 with VT ablation &lt;1 month post-LVAD and 12 with VT ablation &gt;=1 month post-LVAD). In this large single-center HM3 registry, a minority of patients underwent CA for recurrent drug-refractory VT (3.4% over a 7-year period). CA of VT in HM3 recipients is feasible and appears safe also when performed soon after LVAD surgery. Myocardial scar from the underlying cardiomyopathic process rather than the apical cannula is the dominant substrate responsible for VT in these patients.

Abstract 4119658: Catheter Ablation for Ventricular Arrhythmias in Transthyretin Cardiac Amyloidosis: A Single Center Experience

Background: Transthyretin cardiac amyloidosis (ATTR-CA) carries an elevated risk of developing ventricular arrhythmias (VA) but there remains limited evidence supporting the role of catheter ablation in this population. Purpose: To assess the safety and efficacy of catheter ablation for VA in ATTR-CA. Methods: An electronic database was used to identify all patients suspected of having ATTR-CA who underwent catheter ablation for VA at our institution between January 2010 and December 2023. Patients who did not meet the diagnosis of ATTR-CA and had a negative workup who underwent catheter ablation for ventricular tachycardia (VT) or premature ventricular contractions (PVCs) were used to form a control group matched for age, sex and left ventricular ejection fraction at a ratio of 2:1. Results: 20 controls and 10 cases of ATTR-CA were identified. Examining the two groups at baseline (Table 1), the mean age at index ablation was 67.7±7.0 and 68.6±8.1 years (p=0.359), mean follow-up time was 4.1±3.1 and 4.2±2.6 years (p=0.494), and the proportion of males was 100% and 90% respectively. The ATTR-CA group had a significantly higher proportion of chronic kidney disease (90% vs. 50%, p=0.032) and prior stroke or thrombotic events compared to the control group (50% vs. 10%, p=0.026) with similar CHA 2 DS 2 VASc scores (4.2±1.6 vs. 3.8±1.3, p=0.233). Both groups had comparable left ventricular ejection fraction (41.4%±14% vs. 46.9%±15.2%, p=0.173), VT/PVCs at presentation (40%/60% vs. 25%/75%, p=0.77), use of antiarrhythmics (70% vs. 60%, p=0.592), and high proportion of atrial fibrillation/flutter (70% vs. 90%, p=0.168). Procedural (261.2±101.2 vs. 265.7±125.6 mins, p=0.449) and total energy delivery time (1442.9±1509.1 vs. 1744.6±956.2 secs, p=0.296) was not significantly different in the two groups. Both groups had a significant decrease in PVC burden postablation with a reduction from 26.8% to 3.8% (p=0.024) and from 27.1% to 13.6% (p=0.028) in the ATTR-CA and control group respectively. A downward trend was seen in antitachycardia pacing events for VT postablation in the ATTR-CA (14.7±9.8 vs. 5.3±6.7, p =0.184) and control (193±387.6 vs. 0.67±1.2. p=0.139) groups. No major complications occurred after ablation (Table 2). Mean time to recurrence post-index ablation was similar between both groups (1620.4±483.8 vs. 1498.8±291.4 days, p=0.987, Figure 1). Conclusions: Catheter ablation appears to be safe and effective for VT and PVCs in patients with ATTR-CA.

Contemporary outcomes of catheter ablation of the structural ventricular tachycardias in severe ischemic and non-ischemic cardiomyopathies in Turkish population.

Currently, there are no data regarding outcomes of the catheter ablation for structural ventricular tachycardia (VT) in Türkiye. In this observational study, we aim to investigate cardiac outcomes of patients undergoing catheter VT ablation at a tertiary center in Türkiye. This was a retrospective observational study performed at a single university center. Patients with a confirmed ischemic or non-ischemic cardiomyopathy, undergoing structural VT ablation were included. Procedural and mid-term outcomes were analyzed. A total of 124 patients were enrolled in the study. 54(43.5%) patients presented with an electrical storm. During the mean follow-up of 351 ± 232 days 10(8.1%) patients experienced a recurrence. There was only one peri-procedural death and cardiac tamponade occurred in two patients.14(11.3%) patients died during the follow-up, most commonly due to a cardiovascular death. In the multivariate analysis only age >70 was found to be correlated with death during follow-up, with p =.008, HR = 4.923. A good acute success with low complications was observed in patients undergoing VT ablation for structural heart disease in a tertiary center in Türkiye. Mid-term outcomes are comparable with international studies with no difference in VT recurrence in ischemic and non-ischemic patients. Similar to international studies, significant mid-term mortality was observed.

Speckle tracking echocardiography as a predictor of location of ablation sites in candidates to catheter ablation for recurrent ventricular tachycardia

Abstract Background Preoperative imaging is essential before a ventricular tachycardia (VT) ablation procedure, to improve operative outcomes and reduce procedural times. Although MRI is the gold standard, it has several limitations, including patient compliance, possible presence of non-MRI-compatible devices, and long acquisition time. Speckle tracking echocardiography (STE) is a reliable and appealing technique that quantifies regional and global myocardial deformation, as well as layer-specific (endo-, mid- and epicardial) longitudinal strain, without MRI limitations. Purpose This study aimed to evaluate the efficacy of STE in predicting VT ablation sites. Methods In this study, we compared the bull’s eye segmentation of the left ventricle, global and layer-specific, obtained with STE (TomTec Arena), to investigate whether echocardiography can predict the areas of scar and late potential, as identified by electroanatomic mapping (EnSite X mapping, HD Grid mapping catheter, Abbott). Strain analysis and electroanatomic mapping data were matched segment-by-segment to obtain pairs of endocardial strain and bipolar substrate maps, as well as pairs of midmyocardial/epicardial strain and unipolar substrate maps. Results Twenty-three consecutive patients with an indication for catheter ablation for recurrent VT were enrolled. All patients were being treated with beta-blockers, 52% were taking amiodarone, and only 2 patients were on mexiletine. A total of 1170 pairs of bull’s eye segments were available for analysis. A binary logistic mixed-effects model was used to predict the presence of electroanatomical scar based on strain echocardiography data, to account for interpatient variability. The study findings highlighted a close correlation between the bipolar map and endocardial strain values, and between the unipolar map and midmyocardial strain values. Progressively higher (less negative) values of endocardial strain proved predictive of bipolar electroanatomical scar, with an increase in the odds ratio of bipolar electroanatomical scar equal to 6.2% (95% confidence interval 2.5%-10%) for each unit increase in strain values. Similarly, progressively higher values of midmyocardial strain were predictive of unipolar electroanatomical scar, with an increase in the odds ratio of unipolar electroanatomical scar equal to 6.2% (95% confidence interval 1.2%-11.4%) for each unit increase in strain values. Conclusions The data from our study showed an anatomical correspondence between the areas of low potential identified by electroanatomical mapping and the areas of anomalous longitudinal strain. In particular, the endocardial strain correlates with the bipolar map, and the meso-epicardial strain correlates with the unipolar map. These data may prove useful in the appropriate planning of the procedure in patients with an indication for catheter ablation in the context of recurrent VT.

Accuracy of endocardial abnormal electrogram characterization using a 17-AHA-segmental late boundary and voltage-dependent sensitivity annotation for ventricular tachycardia ablation

Abstract Background Substrate-based catheter ablation of ventricular tachycardia (VT) has become the mainstay therapy for patients with scar-related VT. Correct identification and timing of abnormal near-field EGMs and discerning it from far-field EGMs, is key for procedural success. The novel CARTO™ Late Activation Mapping (LAM) module provides fast and accurate annotation of near-field EGMs including late abnormal ventricular activation. For the algorithm to succeed, a late boundary (LB) annotation line should be positioned immediately behind the normal near-field EGM, however, since the timing of normal local near-field activation varies greatly throughout the endocardium, there is currently no consensus for the optimal LB positioning. We hypothesized that 17-AHA segmental annotation of the endocardial LB followed by scar-dependent sensitivity settings, will improve the accuracy of the near-field EGM characterization. Purpose To evaluate the accuracy of endocardial abnormal EGM characterization using a 17-AHA-segmental late boundary and voltage-dependent sensitivity annotation as compared to conventional mid-QRS LB positioning. Methods Five high-resolution substrate voltage maps were obtained from 5 patients (80% male, 68±7 years old, 80% ischemic cardiomyopathy) that underwent a catheter-based ablation for scar-related VT. A personalized CT-derived anatomical reconstruction of the 17-segment AHA model was co-registered offline with the electroanatomic voltage map, using ADAS3D software. Per segment, individual LB timings were set at the highest sensitivity. A gold standard annotation map was created by two independent experts after manual scrutiny of individual EGMs. Next, the expert map was compared to automatic maps created from segmental LB and mid-QRS LB positions at normal, high, highest or mixed (normal/high or normal/highest) sensitivities, focusing on EGM voltage and activation accuracy. Results A mean of 2041±1028 points per map were analyzed. Correct correlation of EGM annotation was found on average in 91% (activation) and 81% (voltage) for all segmental LB positioned maps (segLB), and in 83% (activation) and 77% (voltage) for all mid-QRS LB positioned maps (mid-QRSLB). The highest correlation with expert map for both activation and voltage annotation was found in the mixed sensitivity normal/highest map with segmental LB positioning (activation 98%, voltage 88%). The correlation on activation was significantly superior in the segLB map when compared to the normal sensitivity maps (p=0.0008 for mid-QRSLB and p=0.02 for segLB). For correlation on voltage, the segLBmap with mixed sensitivity was significantly superior compared to three mid-QRSLB maps at normal (p=0.04), high and highest (p=0.01) sensitivity. Conclusion Individualized, 17-AHA-segmental late boundary and voltage-dependent sensitivity annotation provides a possible accurate and clinically-relevant framework for substrate assessment. Prospective validation is needed.

In-hospital outcomes of ventricular tachycardia catheter ablation in the presence of intra-cardiac thrombus

Abstract Background Ventricular tachycardia (VT) catheter ablation in the presence of intracardiac thrombi was evaluated in very few studies. Objectives To investigate in-hospital outcomes of VT ablation in the presence of an intracardiac thrombus, in a large inpatient US registry. Methods Using the National Inpatient Sample (NIS) database, patients who underwent non-elective VT catheter ablations in the US between 2016 and 2019 were identified using ICD-10 codes. Sociodemographic, clinical data, in-hospital procedures and outcomes as well as in-hospital mortality were collected. In-hospital outcomes were compared using propensity score (PS) matching analysis with a 1:3 ratio between patients with and without intracardiac thrombus. Results A weighted total of 15,725 admissions for non-elective VT ablation were included in the study, of which 190 (1.2%) had a discharge diagnosis of intracardiac thrombus. Patients with intracardiac thrombus had a higher comorbidity burden and were more likely to have ischemic cardiomyopathy and a diagnosis of cardiac aneurysm. In PS analysis, the presence of intracardiac thrombus was significantly associated with higher rates of any in-hospital complications (42.1% vs 19.3%, P&amp;lt;0.009), driven by higher periprocedural cerebrovascular accident and vascular injury events. In-hospital mortality rates were not significantly different between the groups. Conclusions In patients undergoing non-elective VT ablation, intracardiac thrombus was associated with higher rates of in-hospital complications, but not higher in-hospital mortality. These findings suggest that intracardiac thrombus should not contraindicate VT ablation when deemed necessary, while efforts should be made to decrease potential complications.

Machine-learning models to predict the risk of recurrent VT following catheter ablation in patients with structural heart disease

Abstract Background Ventricular tachycardia (VT) is a life-threatening arrhythmia that can complicate structural heart disease. While catheter ablation is effective in treating this condition, the recurrence of VT after the procedure continues to be a concern. Consequently, there is a need for a reliable system to evaluate the likelihood of arrhythmia recurrence following an ablation. Objective To predict recurrence or repeat ablation after a VT catheter ablation procedure using machine learning (ML) models. Methods We conducted a single-center, retrospective study of all patients undergoing catheter ablation for scar-related VT between 2012 and 2022. Data collected included demographics, comorbidities, medications, relevant laboratory abnormalities, electrocardiograms, echocardiograms, detailed procedural characteristics, and outcomes. Python version 3.8.5 for exploratory data analysis (EDA) and visualization. Using six different ML models from the training set (90:10 split), we used 34 variables to predict the primary outcome, including VT recurrence or repeat catheter ablation. The accuracy of these models was compared using ROC curves based on their performance on the test set. Results Out of 508 VT ablation procedures, 261 experienced a recurrence. Support Vector Classifier (SVM) performed the best, having an AUC of 0.73, followed by logistic regression at 0.69 (Figure A). SVM yielded sensitivity, specificity, positive and negative predictive values of 0.73, 0.73, 0.79, and 0.67, respectively. The F1 score was 0.70. Among the factors with the highest feature importance in the model, the most influential variable was the proceduralist’s experience level, followed by QRS width at baseline, LVEF, and patient’s age (Figure B). Conclusion Our model can predict recurrent VT after ablation with reasonable accuracy, outperforming the existing clinical risk scores significantly. Larger training sample sizes will help achieve more robust ML models and improve predictive accuracy further.Figure A: ROC curve depicting the AUROCB. Feature importance graph

Stereotactic arrhythmia radioablation - A systematic review and meta-analysis of the prospective clinical studies

Abstract Background Stereotactic arrhythmia radioablation (STAR) is increasingly being evaluated in prospective studies as a new promising treatment option for patients with therapy-refractory ventricular tachycardia (VT). In STAR, the VT substrate is noninvasively treated with a high dose of radiotherapy. Recently, several single-arm prospective studies evaluating the clinical outcomes of STAR were published. Considering that the evidence base consists mainly of retrospective case series, we conducted a systematic review and meta-analysis to synthesize the prospective data on outcomes of STAR. Purpose To perform a systematic review and meta-analysis of prospective studies evaluating clinical outcomes of STAR for VT. Methods This study was registered in PROSPERO and adhered to the PRISMA reporting guidelines. Full-text studies describing prospective studies evaluating the safety and efficacy of STAR for VT were included in this study. Records published until August 2023 were retrieved from OVID MEDLINE, OVID Embase, Web of Science Core Collection, the Cochrane Central Register of Controlled Trials, and Google Scholar search engine (top 200 hits), deduplicated, and screened for eligibility. Abstract screening, full-text screening, data extraction and quality assessment were performed by two reviewers independently. Endpoints were defined as treatment related CTCAE grade ≥3 adverse events within 90 days after treatment, overall survival (OS), time to VT recurrence, and recurrence-free survival. Rates of patients achieving pre-defined 50%, 75% and 95% VT burden reduction thresholds were summarised. Random-effects generalized linear mixed-effects models and inverse variance models were used for the meta-analysis. Results 1861 records were identified, 987 were screened, and 10 full-text manuscripts published between 2019 and 2023 describing the results of STAR in 82 patients were included in this study. The majority were male (n=72; 88%), between 45 and 85 years old, and suffered from ischaemic cardiomyopathy (n=51; 62%). Median left ventricular ejection fraction ranged from 21 to 38% between studies. 20 patients did not undergo a prior catheter ablation for VT. All patients were treated with a single dose of 25 Gy and median planned target volume ranged from 45 to 198 cc between studies. Pooled 12-month OS rate was 0.73, and the proportion of patients experiencing grade ≥3 adverse events within 90 days after STAR was 0.11 (Figure 1). Reduction in VT burden is shown in Table 1. Although these were not pooled because of large heterogeneity in VT reduction time frame definitions, it can be appreciated that most of the patients experienced a reduction in VT burden. Conclusion The increasing evidence from prospective studies on STAR shows acceptable 12-month OS in a population of patients with advanced heart failure and refractory VT. Moreover, there is a modest rate of high-grade adverse events and most patients experience a reduction in VT burden.

Dynamic Voltage Mapping of the Post-infarct Ventricular Tachycardia Substrate: A Practical Technique to Help Differentiate Scar from Borderzone Tissue.

During catheter ablation of post-infarct ventricular tachycardia (VT), substrate mapping is used when VT is non-inducible or poorly tolerated. Substrate mapping aims to identify regions of slowly conducting myocardium (borderzone) within and surrounding myocardial scar for ablation. Historically, these tissue types have been identified using bipolar voltage mapping, with areas of low bipolar voltage (<0.50 mV) defined as scar, and areas with voltages between 0.50 mV and 1.50 mV as borderzone. In the era of high-density mapping, studies have demonstrated slow conduction within areas of bipolar voltage <0.50 mV, suggesting that this historical cut-off is outdated. While electrophysiologists often adapt voltage cut-offs to account for this, the optimal scar-borderzone threshold is not known. In this review, we discuss dynamic voltage mapping, a novel substrate mapping technique we have developed, which superimposes data from both activation and voltage maps, to help delineate the post-infarct VT circuit through identification of the optimal scar-borderzone voltage threshold.

In-Hospital Outcomes of Ventricular Tachycardia Catheter Ablation in the Presence of Intra-Cardiac Thrombus.

Ventricular tachycardia (VT) catheter ablation in the presence of intracardiac thrombi was evaluated in very few studies. To investigate in-hospital outcomes of VT ablation in the presence of an intracardiac thrombus, in a large inpatient US registry. Using the National Inpatient Sample (NIS) database, patients who underwent non-elective VT catheter ablations in the United States between 2016 and 2019 were identified using ICD-10 codes. Sociodemographic, clinical data, in-hospital procedures, and outcomes as well as in-hospital mortality were collected. In-hospital outcomes were compared using propensity score (PS) matching analysis with a 1:3 ratio between patients with and without intracardiac thrombus. A weighted total of 15,725 admissions for non-elective VT ablation were included in the study, of which 190 (1.2%) had a discharge diagnosis of intracardiac thrombus. Patients with intracardiac thrombus had a higher comorbidity burden and were more likely to have ischemic cardiomyopathy and a diagnosis of cardiac aneurysm. In PS analysis, the presence of intracardiac thrombus was significantly associated with higher rates of any in-hospital complications (42.1%vs. 19.3%, p<0.009), driven by higher periprocedural cerebrovascular accident and vascular injury events. In-hospital mortality rates were not significantly different between the groups. In patients undergoing non-elective VT ablation, intracardiac thrombus was associated with higher rates of in-hospital complications, but not higher in-hospital mortality. These findings suggest that intracardiac thrombus should not contraindicate VT ablation when deemed necessary, while efforts should be made to decrease potential complications.

Ablating the Limits: Catheter Ablation of Ventricular Tachycardia in Cardiac Amyloid Patients.

Ablating the Limits: Catheter Ablation of Ventricular Tachycardia in Cardiac Amyloid Patients.

Functional Substrate Mapping and Rotational Activation Patterns in Catheter Ablation for Ventricular Tachycardia : Implications for Treatment Optimization

Functional Substrate Mapping and Rotational Activation Patterns in Catheter Ablation for Ventricular Tachycardia : Implications for Treatment Optimization