Ventricular Tachycardia Morphologies Research Articles

Novel systematic processing of cardiac magnetic resonance imaging identifies target regions associated with infarct-related ventricular tachycardia

Abstract Introduction In the clinic, complete characterization of reentrant ventricular tachycardia (VT) circuits using classical electrophysiological criteria and state-of-the-art high density mapping during VT is complex, and often cannot be completed because of hemodynamic instability. This common limitation has motivated the implementation of mapping strategies during sinus rhythm or ventricular pacing aiming to identify scar regions associated with VT isthmuses or potential arrhythmogenicity. Complementary imaging-based strategies including advanced analyses of scar tissue characteristics have been also proposed for procedure planning and identification of potential arrhythmogenic regions. However, the most recent expert consensus report on catheter ablation of ventricular arrhythmia highlights the lack of agreement on the preferable signal intensity (SI) cut-off values for assessment of tissue heterogeneity and scar areas on late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) images. The latter makes LGE-CMR imaging processing highly operator-dependent and potentially sensitive to selection bias. Purpose We aimed at developing and validating a systematic processing approach on LGE-CMR images to identify potential VT corridors that may include protected isthmuses associated with VT maintenance. Methods Translational study including 18 pigs with established myocardial infarction and inducible VT undergoing in vivo characterization of the anatomical and functional myocardial substrate associated with VT maintenance. Clinical validation was conducted in a multicenter series of 33 patients with ischemic cardiomyopathy undergoing VT ablation. Three-dimensional CMR-LGE images were processed using systematic scanning of 15 signal intensity cut-off ranges to obtain surface visualization of all potential VT corridors. Analysis and comparisons of imaging and electrophysiological data were performed in individuals with full electrophysiological characterization of the isthmus sites of at least one VT morphology. Results In both the experimental pig model and patients undergoing VT ablation, all the electrophysiologically-defined isthmus sites (n=11 and n=19, respectively) showed overlapping regions with CMR-based potential VT corridors. Such imaging-based VT corridors were less specific than electrophysiologically-guided ablation lesions at functionally relevant isthmus sites (Figure). However, in patients, decreasing from 15 to 7 the number of signal intensity cut-off ranges for systematic imaging processing significantly reduced the area of imaging-based potential VT corridors, without diminishing the capability to detect functionally relevant VT isthmus sites. Conclusions Systematic processing of 3D LGE-CMR images provides unbiased identification of imaging based potential VT corridors that contain functionally relevant protected isthmus sites.

Ventricular tachycardia mapping and ablation using MIXture of well-established approaches. The MIX-VT study

Abstract Introduction Ablation for ventricular tachycardia (VT) is still challenging despite impressive technology development, especially in mid- or low-volume centers. The most frequently used approach is homogenization of scar area responsible for VT, combined with standard electrophysiological (EP) approaches such as VT inducibility and mapping. However, in real life long-term efficacy of VT ablation in such centers does not exceed 50%. We hypothesized that an approach consisting of the mixture of various well-established parameters would be more effective than scar homogenization and VT non-inducibility as the endpoints. Purpose To compare the outcome of VT ablation using the standard approach (scar homogenization) and a more complex approach, called the MIX-VT protocol, using late potential mapping + pace mapping with rapid change of VT morphology to localize the critical isthmus + core isolation. All procedures were performed using the 3D mapping system, Pentaray mapping catheter, Smart-Touch ablation catheter and intracardiac echocardiography (ICE). Methods 48 consecutive patients (41 male, mean age 71.5 years) with ischemic cardiopathy referred for urgent VT ablation were included: 23 patients underwent "standard" VT ablation between December 2018 and December 2019, whereas the next 25 patients underwent ablation using the MIX-VT protocol between January 2020 and December 2020. First step in the MIX-VT group was to perform ICE imaging of the scar area from the right ventricle. Next, left ventricular maps were created during rhythm at which spontaneous VT occurred (sinus or paced). Areas of late potentials were identified to localize the critical isthmus where the abrupt change in the paced-QRS axis was seen. Finally, areas delineated by these two above-mentioned maneuvers where ablated in order to achieve core isolation (Figure 1). The patients were followed for 12 months in the outpatient clinic during ICD examination. The composite end-point for follow-up was VT recurrences terminated by anty-tachycardia pacing (ATP) or shock, or death. Results Clinical and demographic variables were similar between the two groups (Figure 2), except for a higher prevalence of diabetes mellites and number of previous ablations in the standard group (4/25 [16%] vs 10/23 [43%], p=0.03 and 2/24 vs 8/23 [34.8], p=0.03, respectively). Three patients from the MixVT group and one patient from the standard group were lost to follow-up. During follow-up, VT recurrences were significantly less frequent in the MIX-VT group (3/22 [13.6] vs 10/22 [45.4]. p=0.02. It was mostly driven by less ATP therapy. (Figure 2). One patient from the standard approach groups died. Conclusion Ablation for VT in low- or medium volume centers using the combination of well-established various EP approaches resulted in the improvement in overall survival and arrythmia-free survival. The presented approach does not involve additional resource utilization.

Dynamic voltage mapping of the ventricular tachycardia substrate

Abstract Background Substrate mapping techniques that predict ventricular tachycardia (VT) isthmus components in sinus or paced rhythm are necessary as mapping during VT is often not possible. Voltage maps lack accuracy in differentiating scar, traditionally displayed as tissue <0.50mV, from bordering arrhythmogenic substrate. We developed a practical technique aiming to improve the utility of a voltage map during VT ablation, termed ‘Dynamic Voltage Mapping’ (DVM). Methods Consecutive patients with post-infarct VT at our centre underwent left ventricle (LV) voltage mapping (mean 4762 points) with Carto3 v.7® and a PentaRay®, or Ensite X® and a HD Grid mapping catheter. Both mapping systems offer algorithms that allow substrate activation maps to be superimposed and analysed on the surface of a voltage display (i.e. Carto Ripple Maps, or Ensite X activation vectors). DVM is a process that sequentially adjusts the voltage display to highlight scar tissue in areas devoid of Ripple bars, or in areas where activation vectors point in multiple unfathomable directions (‘vector disarray’). This approach is summarised in Figures 1 & 2 and was retrospectively performed in all cases. This alternative scar voltage limit was termed the ‘DVM scar threshold’ (mV). Tissue below this threshold was termed ‘DVM-scar’, and tissue immediately surrounding (up to 0.5mV) was termed "DVM-Borderzone (BZ)". Results Twenty-five patients (mean age 64.4±11.0 years, 88% male, LV ejection fraction 31.8±6.9%, 16.4±8.5 years since infarct) were studied (n=15 Carto; n=10 EnSite). Across all cases, the mean shell area with voltage <0.50 mV was 36.8±20.3 cm2. The mean DVM scar threshold was 0.24±0.07 mV (Carto: 0.22±0.07 mV [range 0.12–0.35 mV]; EnSite: 0.26±0.08 [range 0.18–0.50 mV]). The mean DVM-scar area was 18.4±14.3 cm2, significantly smaller than the traditional 0.50mV value (p=0.0002). In the 8 patients where stable VT was mapped, the VT isthmus sites co-located within the DVM-BZ in all cases, exemplified in the figures. Pace-mapping at the DVM-BZ matched the remaining unmappable VT morphologies. Ablation lesions were retrospectively superimposed onto the DVM map and generally co-located within the DVM-BZ. No ablation was delivered in tissues >0.5mV. At median follow-up of 8.8 months, VT burden significantly reduced (median 3 episodes in 3-months pre vs. 0 post; p<0.001), with 76% of patients VT-free. Conclusion DVM appears to improve the delineation of the post-infarct VT substrate, and is feasible using two commercially-available mapping systems. The mean voltage threshold that differentiated DVM-Scar from BZ tissue was significantly lower than the traditional 0.50 mV scar definition, at 0.24mV, though ranged widely, suggesting that scar thresholds require individualised substrate definition. Targeted ablation of DVM-BZ may be effective at reducing future VT, though requires prospective validation.Figure 1Figure 2

CONTINUOUS LEFT STELLATE GANGLION BLOCK DURING VT ABLATION TO SLOW VT AND IMPROVE ABLATION OUTCOME

Abstract Introduction Perioperative management of advanced patients with indication to ventricular tachycardia (VT) ablation is complex. A PAINESD score ≥ 15 was proposed to identify those who might benefit from pre–emptive mechanical cardiopulmonary support (MCS). We present a case successfully managed with continuous percutaneous left stellate ganglion block (C–PLSGB). Case A 71–year–old diabetic man with severe post–ischemic cardiomyopathy (LVEF 24%, NYHA Class III) and chronic pulmonary disease was admitted for electrical storm with multiple ICD shocks due to poorly tolerated monomorphic VT (MMVT) at 176 bpm resistant to anti–tachycardia pacing (ATP), despite ongoing chronic oral therapy with amiodarone and carvedilol. Poorly tolerated and ATP–resistant MMVTs at 170–180 bpm recurred despite intravenous (iv) amiodarone and lidocaine (20 mcg/kg/min) and oral propranolol. Ultrasound guided C–PLSGB was therefore started; lidocaine was chosen for the continuous infusion due to the short half–life, at the initial dose of 10 mg/h; 6 hours later, his poorly tolerated MMVT recurred at 167 bpm. Therefore, at first we increased iv lidocaine to 30 mcg/kg/min, without benefit, then we increased C–PLSGB at 37.5 mg/h and decreased iv lidocaine to 20 mcg/kg/min due to neurological symptoms. With this regimen, the patient stayed VT free for 2 hours, then the clinical VT recurred at 130 bpm, with good hemodynamic tolerability and ATP–response. C–PLSGB infusion was than increased to 75 mg/h, with no more VT. Endocardial VT ablation was planned. Despite a very high PAINESD score (31) we decided to avoid pre–emptive MCS. We stopped lidocaine (both iv and as C–PLSGB) 2 hours before ablation. As soon as the patient came in the EP room (before instrumentation), the clinical MMVT recurred at 133 bpm. C–PLSGB was then resumed (initially at 100 mg/h for 30 minutes, then at 37.5 mg/h). The MMVT then spontaneously recurred at 133 bpm: it was mapped and ablated in the medio–apical anterior wall, with acute VT interruption. A second VT morphology then appeared, that was mapped and ablated at a more basal site, despite a partial epicardial component of the circuit was identified. C–PLSGB was then stopped and no more VT occurred nor were induced 1 hour later. At 8 months the patient is still alive with no more VT. Conclusion C–PLSGB with individually tailored infusion rates could be used during VT ablation as a mean to reduce VT cycle length and allow for mapping without MCS.

A VENTRICULAR TACHYCARDIA CASE NOT TREATABLE WITH TRANSCATHETER ABLATION DUE TO APICAL THROMBOSIS OF THE LEFT VENTRICLE RESOLVED WITH RADIOTHERAPY BASED ON THE NON–INVASIVE MAPPING SYSTE

Abstract The clinical case focuses on a 52–year–old man smoker, heavy alcohol consumer. In 2017 he began with sustained ventricular tachycardia (VT) effectively treated with DC–shock. The following ECG showed signs of anterior necrosis. Severe left ventricular (LV) dilatation, apical thrombosis and severe impairment of LV function were found on echocardiogram. Angiography was performed and LAD occlusion was found. Since of 68% necrosis of the LV at myocardial scintigraphy, no revascularization was performed. He underwent to a dual chamber ICD implantation and started oral anticoagulation therapy. In the following years recurrence of arrhythmic episodes, despite the optimization of antiarrhythmic therapy, led the patient to numerous hospitalizations. Unfortunately the persistence of the apical thrombosis, made transcatheter ablation NOT possible. The only chance for the patient remained stereotactic arrhythmia radioablation. But which area of the LV to highlight as responsible for the arrhythmia and how to program the radiotherapy treatment plan was a challenging problem. We proposed in March 2023 non–invasive mapping of arrhythmia using Cardioinsight. The patient performed heart high–resolution computed tomography (CT) for the anatomical reconstruction with precise spatial resolution of all LV aereas and surrounding structures. A 252–electrode vest is applied to the patient’s torso and connected to the system Cardioinsight. A programmed ventricular stimulation was performed using ICD inducing two VT morphologies. Through electroanatomical mapping we identified the mid LV antero–septal and infero–septal sites as target areas. Thanks to multidisciplinary team a personalized treatment plan was created to deliver an effective lesion in the target area and minimize exposure to nearby organs at risk. The treatment was generated, optimized and delivered by TrueBeam, lasted 3 minutes and no complications arose. The patient was quickly discharged in good clinical condition. After 3 months of clinical well–being he was hospitalized for a single episode of VT. Up to now no hospitalizations occurred. This treatment may represent a "bail–out" choice in patients with advanced heart failure with arrhythmic storm who have exhausted all other therapeutic options.

P 023: Idiopathic left fascicular ventricular tachycardia in pregnancy

Ventricular tachycardia (VT) can occasionally cause complications in pregnancy. In structurally normal heart, VT that arises in the left ventricle is uncommon and is termed as idiopathic left fascicular VT (ILVT). We report a case of 32-year-old lady, gravida 4 para 3 who presented to us at 34 weeks of pregnancy with symptomatic stable cardiac arrythmia with heart rate of 160 beats per minute. Electrocardiogram showed wide complex tachycardia with positive initial R wave at aVR and capture beats suggestive of ILVT. Echocardiogram was normal. She received IV verapamil 25 mg in total which failed to revert to sinus rhythm and hence, she underwent emergency Caesarean section followed by synchronized cardioversion urgently in operation theatre. Post cardioversion ECG showed sinus rhythm with memory T waves at chest leads. She was scheduled radiofrequency ablation later. This case highlights the importance of attaining the diagnosis of ILVT with distinctive ECG changes. Left ventricular outflow tract (LVOT) VT morphology depends on the site of origin, with either LBBB or early precordial transition in leads V1 to V2 or RBBB pattern in V1 with broad monophasic R in the precordial leads. In addition, there will be an R:S amplitude ratio of 30% or more or an R:QRS duration ratio of 50% in leads V1–2 with other features like capture beats and fusion beats. ILVT responds well with verapamil and can be cured with cardiac ablation, with success rates of more than 90%. ILVT though difficult to diagnose, it has distinctive ECG features which can lead to its diagnosis for appropriate treatment to be given accordingly. ILVT in pregnant patients generally has a good prognosis.

Significant delayed conduction and characteristic ventricular tachycardias in patients with cardiac sarcoidosis and electrical storm.

Electrical storm (ES) of ventricular tachyarrhythmias (VTAs) is an important cause of sudden death in patients with cardiac sarcoidosis (CS). VTAs in CS are associated with myocardial scarring and inflammation. However, little is known about the risk factors of ES in patients with CS and VTAs. The objective of this study is to clarify the characteristics and risk factors for the development of ES in patients with CS. The study population included consecutive 52 patients with CS and sustained VTA. Twenty-five out of 52 patients experienced ES. We evaluated clinical characteristics, imaging modalities, and electrocardiogram (ECG) parameters to determine the risk factors associated with ES. Half of the patients experienced VTAs as the initial symptom of sarcoidosis, and eight patients had ES as the initial VTA episode. There were no differences in cardiac imaging abnormalities between patients with and without ES. Among ECG markers, significant QRS fragmentation (odds ratio [OR]: 7.9, p = .01) and epsilon waves (OR: 12.24, p = .02) were associated with ES. Among the ventricular tachycardia (VT) characteristics, multiple morphologies of monomorphic VTs (OR: 10.9, p < .01), short VT cycle lengths (OR: 12.5, p < .01), and polymorphic VT (OR: 13.5, p < .01) were associated with ES. Bidirectional VTs were detected in 10 patients with ES and one patient without ES. Immunosuppressive therapy relieved ES in some patients. ES was common in patients with CS and VTAs. Significant depolarization abnormalities that appeared as QRS fragmentation, epsilon waves, and specific VT characteristics were associated with ES.

Machine-Learning-Based Prediction of 1-Year Arrhythmia Recurrence after Ventricular Tachycardia Ablation in Patients with Structural Heart Disease.

Ventricular tachycardia (VT) recurrence after catheter ablation remains a concern, emphasizing the need for precise risk assessment. We aimed to use machine learning (ML) to predict 1-month and 1-year VT recurrence following VT ablation. For 337 patients undergoing VT ablation, we collected 31 parameters including medical history, echocardiography, and procedural data. 17 relevant features were included in the ML-based feature selection, which yielded six and five optimal features for 1-month and 1-year recurrence, respectively. We trained several supervised machine learning models using 10-fold cross-validation for each endpoint. We observed 1-month VT recurrence was observed in 60 (18%) cases and accurately predicted using our model with an area under the receiver operating curve (AUC) of 0.73. Input features used were hemodynamic instability, incessant VT, ICD shock, left ventricular ejection fraction, TAPSE, and non-inducibility of the clinical VT at the end of the procedure. A separate model was trained for 1-year VT recurrence (observed in 117 (35%) cases) with a mean AUC of 0.71. Selected features were hemodynamic instability, the number of inducible VT morphologies, left ventricular systolic diameter, mitral regurgitation, and ICD shock. For both endpoints, a random forest model displayed the highest performance. Our ML models effectively predict VT recurrence post-ablation, aiding in identifying high-risk patients and tailoring follow-up strategies.

Association of ventricular tachycardia morphology induced on electrophysiology study after myocardial infarction: long-term survival and ventricular tachyarrhythmia recurrence

Abstract Background Electrophysiology study (EPS) presents a valuable risk stratification tool to facilitate the implantation of implantable cardioverter-defibrillators (ICDs) to prevent sudden cardiac death from ventricular tachyarrhythmia early after myocardial infarction. Purpose To investigate long-term survival of patients with inducible ventricular tachycardia (VT) at electrophysiology study (EPS) early after ST elevation myocardial infarction (MI) and possible association with site of origin of the induced VT. Methods Consecutive patients with LVEF ≤40% on day 3–5 after MI who underwent EPS were prospectively recruited. Positive EPS was defined as sustained monomorphic VT cycle length ≥200ms for &amp;gt;10 seconds, or shorter duration if hemodynamic compromise occurred. The primary outcome was time to death from any cause. The secondary outcome was time to the composite endpoint of first activation of ICD for ventricular tachyarrhythmia or death. Results A total of 126 patients with inducible VT on EPS early after MI were included with median follow up 6.7 years. 54% had LBBB and 46% had RBBB morphologies during induced VT. The distributions of age, sex, left ventricle ejection fraction, cardiovascular risk factors, infarct artery and EPS characteristics did not differ significantly by induced VT morphology. The estimated risk of death was independently associated with RBBB morphology of VT induced at EPS (adjusted HR 3.2, 95%CI 1.0-10.0, p=0.044). The estimated risk of the composite end-point of spontaneous ventricular tachyarrhythmia recurrence or death was also independently associated with RBBB morphology of VT induced at EPS (HR 1.8, 95%CI 1.0-3.2, p=0.043). Conclusion There is an increased risk of death and spontaneous ventricular tachyarrhythmia recurrence at median follow up of 6.7 years, associated with RBBB morphology of VT (likely origin from left ventricle) induced at EPS early after MI, in those with LVEF &amp;lt;40%. This study is the first to characterise the association between site of origin of VT induced at EPS after myocardial infarction, indicated by RBBB or LBBB morphology, and overall survival as well as activation free survival. The results could help to identify a group of patients that could benefit from closer monitoring post MI and more intense preventative management to improve long-term outcomes.

Abstract 17014: Differences in the Outcomes of Catheter Ablation for Ventricular Tachycardia in Patients With Ischemic versus Non-Ischemic Cardiomyopathy

Background: Catheter ablation is an effective tool to reduce ventricular tachycardia (VT) burden. There is a lack of robust data studying the characteristics and outcomes of VT ablation in patients with ischemic (ICM) versus non-ischemic cardiomyopathy (NICM). Aims: The aim of this study was to assess the impact of ICM vs NICM on outcomes of VT ablation. Methods: A single-center, retrospective study of patients undergoing catheter ablation for VT was conducted. Results: A total of 168 patients, undergoing 200 VT ablation procedures, were included in this study. NICM group (112 procedures) was compared to ICM group (88 procedures). Patients in the ICM group were older (66.6 ± 13.4 vs 58.9 ± 14.4 years) and had higher rates of prior myocardial infarction (65.9% vs 3.6) and coronary artery bypass graft surgery (40.9% vs 1.8%). Overall, ICM group had more comorbidities like hypertension (80.7% vs 52.7%), diabetes mellitus (23.9% vs 12.5%), chronic kidney disease (45.5% vs 35.7%), stroke (17% vs 7.1%), and lower left ventricular ejection fraction (36.8 ± 13.2% vs 43.1 ± 14.7%). The ICM group had lower incidence of prior cardiac valvular surgery (9.1% vs 29.5%). The inducibility of VT (93% vs 93.5%; p= 1.0) and the number of different VT morphologies induced during the case (1.9 ± 1.5 vs 2.3 ± 2.5; p=0.19) was similar between the two groups. There was no acute mortality in either group. There was a non-significant trend towards greater VT recurrence in the NICM group (43.2% vs 33.3%, p= 0.19). However, patients with NICM had a lower VT-free survival as determined by Kaplan-Meier analysis (p=0.05) [Figure]. Long term mortality was higher in ICM group when compared to NICM group (18.2% vs 8.9%, p&lt;0.01). Conclusion: Patients undergoing VT ablation in the NICM group when compared to the ICM group were noted to be younger, had fewer comorbidities, and lower long-term mortality. However, they had significantly less VT-free survival, likely owing to more challenging substrate responsible for VT.

EASI Monitoring: An Alternative to Conventional Electrocardiography in the Recording of Ventricular Tachycardia

This study compares the EASI monitoring setting with the conventional 12-lead electrocardiogram (ECG) in patients experiencing ventricular tachycardia (VT) episodes. The results revealed that the EASI monitoring setting demonstrated a VT morphology that closely resembled that of the conventional ECG in the majority of cases. This finding suggests that EASI monitoring could serve as a valuable alternative in situations where obtaining a conventional ECG is either risky or not feasible.

PO-04-190 LONG TERM OUTCOMES OF VENTRICULAR TACHYCARDIA ABLATION IN DESMOPLAKIN ARRHYTHMOGENIC CARDIOMYOPATHY – A MULTICENTER STUDY

Desmoplakin (DSP) pathogenic/likely pathogenic (P/LP) variants have been associated with the development of highly arrhyhtmogenic phenotypes of the spectrum of the arrhythmogenic cardiomyopathy (DSP-ACM). Data addressing arrhythmic outcomes after ventricular tachycardia (VT) ablation in patients (pts) with DSP-ACM are scarce. To report on long-term outcomes of pts with DSP-ACM undergoing VT-ablation All pts with P/LP DSP variant at 8 tertiary academic institutions in North America and Europe undergoing VT ablation were included in the study. Demographic, clinical, and instrumental data, as well as all arrhythmic events including per patient rates of VA episodes/year were collected. Sustained ventricular arrhythmia (VA) episodes (defined as a combination of sustained VT, proper implantable cardioverter defibrillator (ICD) intervention, and ventricular fibrillation episodes) after index procedure were the primary outcome of the study and reported with Kaplan Meyer curves. A per-pt pre- and post- VT ablation paired comparison of VA episodes/year rates was performed as well. Nineteen DSP-ACM pts (29 [25–36] y.o.; 68.4% male; 94.7% probands) referred for VT ablation were included. At the time of index procedures, all patients had a highly arrhythmic profile with a high PVC burden and over 30 different VT morphologies (56.6% right bundle branch block (BBBB); 26.6% left BBB; 16.8% unknown)(Table1). VT ablation targets were located in the LV in 7/19 pts, the RV in 7/19 pts, and both ventricles in 5/19 pts. An epicardial ablation was needed in 14/19 pts. Over a median follow-up of 27 [20–72] months, 10/19 (52.6%) pts experienced recurrent VA episodes (Figure1-PanelA). A significant reduction in per-patient event/year pre- and post- VT ablation was observed (0.50 0.25–0.94] vs 0.14 [0–0.40]; Matched Pair Wilcoxon p=0.009) (Figure1-Panel B). VT ablation in DSP-ACM is effective in significantly reducing the VA burden of the disease. However, it is not uncommon for pts to experience VA recurrences during follow up.

Radiofrequency catheter ablation of ventricular tachycardia using combined endocardial techniques in patients with structural heart disease improves procedural effectiveness and reduces arrhythmia episodes.

Evidence indicates that radiofrequency catheter ablation (RFCA) of ventricular tachycardia (VT) in patients with structural heart disease (SHD) is safe and effective. However, arrhythmia recurrence is still relatively high, and the optimal procedural strategy is unclear. In clinical practice, several combinations of mapping and ablation techniques are used to improve VT ablation efficacy. The study aimed to evaluate and provide evidence on the efficiency and safety of a systematized combination of VT ablation (mapping) techniques in patients with SHD. From 2016 to 2019, 47 patients (54 procedures) with SHD (89% heart failure, 94% ischemic heart disease, 37% VT storm) who underwent RFCA of VT were retrospectively analyzed from a group of 58 consecutive patients. During RFCA of VT, different combinations of three techniques, activation mapping (AM), pace mapping (PM), and substrate-based mapping (SbM), were used. The procedures were performed using the CARTO® 3 (Biosense Webster Inc., Diamond Bar, CA, US) electro-anatomical mapping system. During a median (interquartile range [IQR]) follow-up of 25.5 months (11.75-52.25), VT-free survival after ablation was 68.5% (n = 37/54 procedures). Acute procedural success was achieved in 85% (n = 46/54 procedures). The number of induced VT morphologies, induction of non-clinical or non-sustained VT after ablation, and fewer VT mapping techniques used during the procedure were related to decreasing VT-free survival. VT ablation strategy based on systemic use of combined techniques is effective and safe in long-term follow-up of patients with SHD.

Antitachycardic Therapy of ICD in Patients with Multiple Morphologies of Monomorphous Ventricular Tachycardia Refractory to Therapy

The article presents a description of a clinical case of a patient with structural myocardial pathology (postinfarction cardiosclerosis) with recurrent paroxysmal sustained monomorphic ventricular tachycardia (VT) refractory to the nominal recommended ICD (implantable cardioverter defibrillator) settings; as well as discusses the shortcomings of existing standard algorithms for antitachycardia pacing (ATP) of implantable cardioverter defibrillators and potential ways to increase its efficiency. The refractoriness of recurrent paroxysms of ventricular tachycardia to ATP therapy increases the risk of repeated ICD shocks.&#x0D; Despite the existence of universal recommendations for ICD programming and ATP therapy, there is a need in clinical practice for individualized ATP programming in patients refractory to nominal settings. Increasing the number of ATP series and changing algorithms enables to increase the efficiency of ATP up to 8089%. Refractoriness to standard ATP settings may be also overcome by using alternative ATP pacing algorithms (Ramp, Burst-plus, or Ramp-plus instead of Burst), changing the pacing interval, ATP sequence duration, pacing type, and even adding 12 extra stimuli, as well as using data from the previous intracardiac electrophysiological heart test.&#x0D; The presented clinical case of a patient with postinfarction cardiosclerosis and paroxysmal stable monomorphic VT (SM-VT) of several morphologies demonstrates that the arrhythmogenic substrate after myocardial infarction changes for a long time without new stenoses in large coronary arteries and without new episodes of acute coronary syndrome, as well as generates several different morphologies of VT from one scar (with different heart rates) and the effect on hemodynamics. The efficiency of early ATP pacing may differ for VT of various morphologies, which makes it reasonable to use alternative pacing algorithms (in addition to the standard Burst sequences recommended by the 2019 Consensus on ICD programming) and testing possible ATP algorithms during ablation of monomorphic VT, including during preventive VT ablation before ICD implantation.

A rapid wide complex tachycardia

A rapid wide complex tachycardia

Fascicular ventricular tachycardia arising from the left side His and its adjacent region: a subset of upper septal idiopathic left ventricular tachycardia.

Fascicular ventricle tachycardia (FVT) arising from the proximal aspect of left His-Purkinje system (HPS) has not been specially addressed. Current study was to investigate its clinical, electrocardiographic, and electrophysiological characteristics. Eighteen patients who were identified as this rare FVT were consecutively enrolled, and their scalar electrocardiogram and electrophysiological data were collected and analysed. The ventricular tachycardia (VT) morphology was similar to sinus rhythm (SR) in eight patients, left bundle branch block type in one patient, right bundle branch block type in seven patients, and both narrow and wide QRS type in two patients. During VT, right-sided His potential preceded the QRS with His-ventricle (H-V) interval of 36.3 ± 12.4 ms, which was shorter than that during SR (-51.4 ± 8.6 ms) (P = 0.002). The earliest Purkinje potentials (PPs) were recorded within 7 ± 3 mm of left-side His and preceded the QRS by 49.1 ± 14.0 ms. Mapping along the left anterior fascicle and left posterior fascicle revealed an antegrade activation sequence in all with no P1 potentials recorded. In the two patients with two VT morphologies, the earliest PP was documented at the same site, and the activation sequence of HPS remained antegrade. Ablation at the earliest PP successfully eliminated the tachycardia, except one patient who developed complete atrial-ventricular block and two patients who abandoned ablations. After at least 12 months follow-up, 15 patients were free from any recurrences. Fascicular ventricle tachycardia arising from the proximal aspect of left HPS was featured by recording slightly shorter H-V interval and absence of P1 potentials. Termination of VT requires ablation at the left-sided His or its adjacent region.

Long-Term Outcomes after Catheter Ablation of Ventricular Tachycardia in Dilated vs. Ischemic Cardiomyopathy.

Ischemic (ICM) and dilated cardiomyopathy (DCM) represent the two main underlying heart diseases in patients referred for catheter ablation of ventricular tachycardia (VT). While VT ablation in ischemic cardiomyopathy is relatively well-studied, data in patients with DCM are still scarce. The study aimed to compare the acute and long-term outcomes in patients with ICM and DCM who underwent VT ablation at a high-volume center. Consecutive patients who underwent VT ablation from April 2018 to April 2021 were included retrospectively. Patients with ischemic cardiomyopathy were compared to those with dilated cardiomyopathy. The primary endpoint was rate of VT recurrences, the secondary endpoints included overall mortality, rehospitalization because of cardiac condition (VT, acute heart failure, acute myocardial infarction, heart transplantation or implantation of left ventricular assisting device), and major adverse cardiac events (MACE) at long-term follow-up. A total of 225 patients admitted for first VT ablation were included. A total of 156 patients (69%) revealed ICM and 69 (31%) DCM. After a mean follow-up of 22 months, the primary endpoint of VT recurrence occurred significantly more often in the patients with dilated cardiomyopathy (ICM n = 47; 37% vs. DCM n = 34; 64%; p = 0.001). In regard to the secondary endpoint of overall mortality, there was no difference between the two patient cohorts (DCM n = 9; 15% vs. ICM n = 22; 16%; p = 0.677); the patients with DCM showed significantly higher rehospitalization rates due to cardiac conditions (75% vs. 59%; p = 0.038) and more frequent MACE (68% vs. 52%; p= 0.036). In a Cox regression model, electrical storm at admission was shown to be a predictor for VT recurrence after successful catheter ablation (HR = 1.942: 95% CI 1.237–3.050; p = 0.004), while the ablation of every induced VT morphology during the procedure (HR = 0.522; 95% CI = 0.307–0.885; p = 0.016) contributed to a positive long-term outcome. DCM is associated with a higher risk of VT recurrence after catheter ablation compared to ICM. Furthermore, patients with DCM are more frequent re-hospitalized in the majority of cases due the VT recurrence. There is no difference in the long-term mortality between the two cohorts.

PO-671-04 RATE OF CHANGE OF INITIAL INTRINSICOID DEFLECTION PREDICTS SITE OF ORIGIN OF ENDOCARDIAL VERSUS EPICARDIAL VENTRICULAR TACHYCARDIA

Electrophysiological mapping and ablation of ventricular tachycardia (VT) of epicardial origin requires precise definition of VT morphology to maximize successful outcomes. Several studies have published morphological characteristics derived from the 12-lead Electrocardiogram (ECG) that can be used to predict whether a VT is epicardial in origin. Unfortunately, for many of these criteria, when scaled to clinical practice the generalizability is limited.

Heart Mate 3 Pump Thrombosis After Ventricular Tachycardia Ablation: Pushing the Boundaries of Hemocompatibility

<h3>Introduction</h3> The risk for pump thrombosis (PT) following ventricular tachycardia (VT) ablation in HeartMate II and HeartWare HVAD left ventricular assist devices (LVADs) has been described previously; however, it is unknown whether Heart Mate 3 (HM3) LVADs are also at increased risk of PT following VT ablation. <h3>Case Report</h3> A 51-year-old male with non-ischemic cardiomyopathy status post HM3 LVAD as destination therapy, VT on mexiletine and quinidine with previous VT ablation, and amiodarone-induced thyrotoxicosis presented to the emergency room in VT storm after multiple defibrillator shocks. He underwent successful endocardial/epicardial VT ablation of seven VT morphologies, ethanol ablation of the coronary sinus branch, as well as coil embolization of two left circumflex branches that fed the culprit territory. Target ACT was achieved throughout the procedure and he was bridged to warfarin with a therapeutic INR upon discharge. Two weeks later, he presented with low flow LVAD alarms, a subtherapeutic INR, and an elevated lactate dehydrogenase concerning for PT. Despite volume resuscitation and pressors, he required initiation of venoarterial extracorporeal membrane oxygenation (VA-ECMO), intra-aortic balloon pump, and underwent a LV outflow tract aortogram. Thrombus was noted in the LVAD outflow graft and the LVAD flow was 0 liters per minute. Thrombolytics were not given due to the patient's tenuous status and need for emergent pump exchange, so decision was made to turn off the LVAD to prevent a cardioembolic event while he was supported by VA-ECMO. Transthoracic echocardiogram confirmed PT with a large thrombus extending out of the inflow cannula. The patient was deemed not to be a surgical candidate given a high operative mortality after worsening shock, liver failure, and bacteremia. His family proceeded with comfort care and support was withdrawn. <h3>Summary</h3> While PT is rare with HM3 LVADs even with lower intensity anticoagulation, there may be a higher risk of PT after VT ablation.

Anovel ECG finding in patients with epicardial infarct-associated ventricular tachycardia: acase series.

This study analyzes the incidence, characteristics, and ECG morphology of ventricular tachycardia (VT) in post-infarction patients undergoing epicardial VT ablation. Ablation of recurrent VTs in patients with ischemic cardiomyopathy is typically performed endocardially. In rare cases, epicardial access is required to achieve non-inducibility. The study evaluated the baseline characteristics, procedural data, and ECG morphology of clinical VT in patients undergoing epicardial VT ablation. From the initial 491patients with coronary heart disease (CHD) and recurrent VTs undergoing ablation at the Heart Center of Leipzig, Germany, between 2012 and 2020, only 39patients required an additional epicardial access. In 17 patients, the VTs were associated with infarction scar, while the remaining patients had concomitant CHD without infarction-associated scar and were excluded from the analysis. Apropensity match study was performed at a1:2 ratio for these 17 patients, with 34patients of the initial cohort as a control group to evaluate the differences in baseline characteristics, procedural data, and ECG morphology of the VTs. The specific VT morphology of negative concordance and superior axis in patients with inferior scar as well as the history of VT ablation were independent predictors of the need for epicardial access. In addition to previous endocardial ablation, VT ECG morphology with negative concordance and superior axis in post-infarction patients with inferior scar predicted the need for epicardial VT ablation.