Episodes Of Sustained Ventricular Tachycardia Research Articles

The use of left bundle branch pacing as a bail-out in case of CRT pacing failure: a case series

Abstract Introduction LBBB pacing has emerged as a novel alternative to CS pacing for cardiac resynchronization therapy in patients with heart failure. Purpose We hereby present a series of four cases wherein the use of LBB pacing, although not initially planned as first choice, was able to overcome a variety of different limitations of traditional CRT pacing. Presentation Patient #1 was an 81-year old man with a history of ischemic HF and AF who was admitted with recurring episodes of sustained ventricular tachycardia (VT) below the detection zone of the CRT-D that had been implanted 11 years ago. Interrogation of the device revealed fracture in the RV lead, intact values of the RV defibrillation coil and inability to capture from an LV lead in an anterior vein. Following initial stabilization the patient underwent successful LBB lead implantation combined with a new RV pace-sense lead as backup due to acceptable but non-optimal LBB lead values attributed to ischemic septal scarring. We were able to retain the previous CRT-D device by relegating the LBB lead to the atrial port and with the use of DDDR programming with custom AV delay values in order to achieve LBB pacing with RV pacing as backup. Patient #2 was a 51-year old man with a history of ischemic HF and permanent AF with a previously implanted CRT-D who was also admitted due to episodes of VT. Device interrogation revealed high threshold of an LV lead located in an anterior vein. The patient underwent supplementary LBB lead implantation which was then connected to the atrial port of the pre-existing CRT-D device, providing primarily LBB pacing with RV pacing backup through the use of custom DDDR programming same as in the previous case. Patient #3 was a 71–year old man with newly-diagnosed ischemic cardiomyopathy and multiple episodes of hemodynamically unstable VT that persisted even after successful reperfusion, necessitating VT ablation. The patient had narrow QRS at baseline and was not eligible for CRT-D, however after medical therapy to suppress ventricular arrhythmias the patient seemed prone to developing LBBB-like QRS widening. The decision was made to proceed with standard ICD implantation and combine a standard defibrillation lead with an LBB lead through the use of a DF1 port, so as to be able to provide LBB pacing as needed in the future. Patient #4 was a 62-year old man with a history of hypertrophic cardiomyopathy and HF with extensive apical scar scheduled for CRT-D implantation. CS venography during implantation revealed a single lateral vein draining the apical LV, lead was implanted but with no capture. An LBB pacing lead was successfully implanted and used instead of the LV lead in the conventional CRT-D set up. Conclusion In this case series we demonstrate that LBB pacing is a viable option as a bail-out in various cases of CRT pacing failure, including both septal scar and hypertrophy, as well as different anatomical substrates and CRT status.LBB pacing characteristics summary

Left and right ventricular function measured by strain analysis predicts one-year mortality in ventricular tachycardia ablation patients with structural heart disease

Abstract Introduction Radiofrequency catheter ablation has become increasingly important in the management of scar-related ventricular tachycardia (VT). Wide range of clinical and procedural predictors of VT recurrence and mortality are described by previous studies. However, currently known echocardiographic predictors are mainly limited to conventional echo parameters. Speckle tracking echocardiography (STE) is a novel and promising method to evaluate systolic and diastolic function. STE derived parameters, such as global longitudinal strain (GLS), are proven predictors of mortality and arrhythmic events in heart diseases. Aims The aim of the present study was to assess whether STE derived parameters could be considered predictors of VT recurrence and mortality after catheter ablation of ventricular tachycardia in patients with structural heart disease. Methods We measured pre-ablation strain and strain rate parameters with speckle tracking. Left ventricular four-chamber longitudinal strain (LV4CLS), early diastolic strain rate (e’-sr), right ventricular free wall longitudinal strain (RVFWLS) and right ventricular four-chamber longitudinal strain (RV4CLS) were assessed in 73 cases. Patients were followed up for one year. Endpoints were VT recurrence, which was defined as either ICD recording of a sustained VT episode requiring therapy or an episode of sustained VT recorded on 12-lead ECG or CIED, and all-cause mortality. Results Univariate analysis using the Cox proportional hazard model revealed that only lower LVEF (HR: 0.52 [0.31-0.88], p=0.02) was associated with higher VT recurrence in the first year among the echocardiographic parameters. High LVEDD (HR: 3.9 [1.31-11.65], p=0.02), low TAPSE (HR: 0.52 [0.28-0.98], p=0.04), low LV4CLS (HR: 0.4 [0.19-0.83], p=0.01) and low RV4CLS (HR: 0.31 [0.13-0.72], p<0.01) were the predictors of 1-year mortality. Conclusion Strain parameters, especially right ventricular four-chamber longitudinal strain may supplement conventional echocardiographic parameters in the prediction of one-year mortality after catheter ablation in patients with structural heart disease. Further prospective clinical studies are necessary to verify the significance of strain parameters.

Scar tissue characterization to predict arrhythmia recurrence in patients undergoing ventricular tachycardia ablation: cardiac computed tomography compared with cardiac magnetic resonance

Abstract Background The role of imaging in evaluating patients undergoing ventricular tachycardia (VT) ablation is crucial for planning, procedural success, and clinical outcomes. In daily practice, cardiac computed tomography (CCT) assessing wall thinning and late iodine uptake (LI) and cardiac magnetic resonance (CMR) assessing late-gadolinium enhancement (LGE) are most commonly implemented. However, data comparing the two imaging modalities for scar tissue characterization is scarce. Aims To compare the performance of both imaging modalities for scar tissue characterization in ischemic (ICM) and non-ischemic (NICM) patients undergoing VT ablation and predict procedural outcomes. Methods In a retrospective analysis, consecutive patients undergoing both CCT and LGE-CMR before scheduled VT ablation were included. The presence and extent of scar was assessed by means of each imaging modality using dedicated softwares (MUSIC and ADAS). To compare scar distribution and agreement between the two modalities, a scar classification scheme was used for all 17 AHA segments: 0 points (no scar present), 1 point (scar <50% of total segment area), 2 points (scar representing 50-99% of total segment area) or 3 points (scar present in 100% of the segment area).<scar<100%)><scar<100%> Results 36 patients (67±10 years; 97% male; LVEF 39±10%; 72% ischemic) undergoing CCT and LGE-CMR before scheduled VT ablation were included. In the ICM group, mean detected scar burden was higher than in the NICM group on LGE-CMR (total volume: 62.3±32.9g vs. 32.8±9.5g, p<0.001), using wall thinning model (WT)(mean scar area 69.0±45.6 cm2 vs. 23.4±23.6cm2, p=0.005) as well as LI (dense scar area: 39.2±28.1 cm2 vs. 11.0±6.3 cm2 , p=0.005). The absolute score difference per segment and patient between CCT and LGE-CMR was calculated and summed for all patients divided by the number of patients. Differences were more pronounced for NICM compared to ICM and LGE-CMR showed better concordance to LI than WT in both NICMP and ICM (Figure). Total procedure time was 205±68 min (ablation time 28±16 min; fluoroscopy time 15 ± 12 min). During a follow-up period of 19±7 months, 87 sustained VT episodes in 12 patients (33%) were documented. Three patients (8%) underwent a second VT ablation and one patient (3%) died during follow-up. In ICM, total scar volume on LGE-CMR and scar area on LI showed numerically higher predictive value for VT recurrence than total scar area by means of WT (AUC: LGE 0.76, LI 0.78 and WT 0.65 respectively), while in NICM scar characterization by means of WT yielded higher performance to predict VT recurrence than LI or LGE-CMR (AUC: LGE 0.67, LI 0.58, WT 0.83 respectively). Conclusions In patients undergoing VT ablation, both LGE-CMR and CCT are valuable for scar tissue characterization. Late iodine uptake on CCT showed a high concordance with LGE-CMR in both NICM and ICM.</scar<100%></scar<100%)>

Electrical storm after left ventricular assist device (LVAD) implantation.

Ventricular tachycardia storm or electrical storm (ES) is a common complication following left ventricular assist device (LVAD) implantation. The factors contributing to ES and outcomes are less studied. The study aimed to determine the factors associated with ES and the probability of survival in patients undergoing LVAD in three tertiary centers over a span of 15 years. We performed a retrospective cohort study on all patients who underwent LVAD implantation at the Mayo Clinic (Rochester, Phoenix, and Jacksonville) from January 1, 2006to December 31, 2020. ES was defined as ≥3 episodes of sustained ventricular tachycardia over a period of 24 h with no identifiable reversible cause. Detailed chart reviews of the electronic health records within the Mayo Clinic and outside medical records were performed. A total of 883 patients who underwent LVAD implantation were included in our study. ES occurred in 7% (n = 61) of patients with a median of 13 days (interquartile range [IQR]: 5-297 days) following surgery. We found 57% of patients (n = 35) developed ES within 30 days, while 43% (n = 26) patients developed ES at a median of 545 (IQR 152-1032) days after surgery. Following ES, 26% of patients died within 1 year. Patients with ES had a significant association with a history of ventricular arrhythmias and implantable cardioverter defibrillator(ICD) shocks before the procedure. ES was significantly associated with reduced survival compared to patients without ES(hazards ratio [HR]: 1.92, 95% CI: 1.39-2.64, p < .001). Following LVAD implantation, the rate of ES was 7% with majority of ES occurring within 30 days of LVAD. Risk factors for ES included pre-implant history of ventricular arrhythmias and ICD shock. ES was significantly associated with reduced survival compared to patients without ES.

Electrical Storm/Refractory Ventricular Tachycardia.

This simulation case was created for emergency medicine (EM) residents at all levels of training. Cardiac electrical storm (ES) is commonly defined as three or more episodes of sustained ventricular tachycardia, ventricular fibrillation, or three shocks from an implantable defibrillator within a 24 hour period.1 This can occur in up to 30-40% of patients with implantable defibrillators; however, it may also present in a wide variety of patients, including those with structural heart disease, myocardial infarction, electrolyte disturbances, and channelopathies.2,3 With each subsequent episode of ventricular arrhythmia, the arrhythmogenic potential of the heart may increase secondary to increased intracellular calcium dysregulation, myocardial injury, and increased endogenous release of catecholamines. The increased pain and catecholamine release from cardioversion/defibrillation and exogenous epinephrine during cardiac arrest further exacerbates ES.2 This carries a significant mortality risk of up to 12% in the first 48 hours.3This case involves a basic knowledge of the Advanced Cardiac Life Support (ACLS) for ventricular tachycardia, both with and without a pulse, and the application of Sgarbossa criteria in a patient with an ST elevation myocardial infarction (STEMI) which makes it ideal for the PGY-1. However, the case quickly becomes refractory to the basic management prescribed in ACLS, requiring trouble shooting and quick thinking about deeper pathophysiology, a skill that is crucial for all emergency medicine physicians. There are multiple ways to troubleshoot this case, making for a good variety of discussion and recent literature review on the complexities of a relatively common arrhythmia, ventricular tachycardia. By the end of this simulation, learners should be able to: 1) recognize unstable ventricular tachycardia and initiate ACLS protocol, 2) practice dynamic decision making by switching between various ACLS algorithms, 3) create a thoughtful approach for further management of refractory ventricular tachycardia, 4) interpret electrocardiogram (ECG) with ST-segment elevation (STE) and left bundle branch block (LBBB), 5) appropriately disposition the patient and provide care after return of spontaneous circulation (ROSC), 6) navigate a difficult conversation with the patient's husband when she reveals that the patient's wishes were to not be resuscitated. This simulation was performed using high-fidelity simulation followed by an immediate debriefing with nine learners who directly participated in the SIM and twenty-three residents, who were online observers via Zoom. This case was done during our conference day, and there were a total of approximately forty total learners comprised of medical students, PGY-1, PGY-2 and PGY-3 residents. There were several medical students who also observed via Zoom but were not surveyed, and the survey was sent to 32 learners. The case was run three separate times with each session consisting of three-four learners at the same level of training, with other learners in the same level of training observing via Zoom™ video platform. Since we can only have a team of three-four learners participate per group during simulation, the rest of the learners were observing the case and the debrief. There was one simulation instructor and one technician. We sent an online survey to all the participants and the observers after the debrief via surveymonkey.com. The survey collected responses to the following statements: (1) the case was believable, (2) the case had right amount of complexity, (3) the case helped in improving medical knowledge and patient care, (4) the simulation environment gave me a real-life experience and, (5) the debriefing session after simulation helped improve my knowledge. Likert scale was used to collect the responses. A total of thirteen participants responded to the survey. One hundred percent of them either strongly agreed or agreed that the case was believable and that it helped in improving medical knowledge and patient care. Fifty-four percent strongly agreed, 38 percent agreed, and eight percent were neutral about the case having the right amount of complexity. Thirty one percent strongly agreed, 61 percent agreed, and eight percent were neutral about the case giving them real-life experience. All of them agreed that the debriefing session helped them improve their knowledge. The high-fidelity simulation case was helpful with educating learners with ventricular tachycardia and fibrillation. Learners learned how to switch between various ACLS algorithms and how to manage a patient with refractory ventricular fibrillation. Learners enforced their knowledge in how to communicate with patient's family members when the patient does not want resuscitation. Stable ventricular tachycardia, unstable ventricular tachycardia, refractory ventricular tachycardia, electrical storm, STEMI equivalents, medical simulation.

Machine learning-derived cycle length variability metrics predict spontaneously terminating ventricular tachycardia in implantable cardioverter defibrillator recipients.

Implantable cardioverter defibrillator (ICD) therapies have been associated with increased mortality and should be minimized when safe to do so. We hypothesized that machine learning-derived ventricular tachycardia (VT) cycle length (CL) variability metrics could be used to discriminate between sustained and spontaneously terminating VT. In this single-centre retrospective study, we analysed data from 69 VT episodes stored on ICDs from 27 patients (36 spontaneously terminating VT, 33 sustained VT). Several VT CL parameters including heart rate variability metrics were calculated. Additionally, a first order auto-regression model was fitted using the first 10 CLs. Using features derived from the first 10 CLs, a random forest classifier was used to predict VT termination. Sustained VT episodes had more stable CLs. Using data from the first 10 CLs only, there was greater CL variability in the spontaneously terminating episodes (mean of standard deviation of first 10 CLs: 20.1 ± 8.9 vs. 11.5 ± 7.8 ms, P < 0.0001). The auto-regression coefficient was significantly greater in spontaneously terminating episodes (mean auto-regression coefficient 0.39 ± 0.32 vs. 0.14 ± 0.39, P < 0.005). A random forest classifier with six features yielded an accuracy of 0.77 (95% confidence interval 0.67 to 0.87) for prediction of VT termination. Ventricular tachycardia CL variability and instability are associated with spontaneously terminating VT and can be used to predict spontaneous VT termination. Given the harmful effects of unnecessary ICD shocks, this machine learning model could be incorporated into ICD algorithms to defer therapies for episodes of VT that are likely to self-terminate.

Ventricular Tachycardia.

This scenario was developed to educate emergency medicine residents on the diagnosis and management of ventricular tachycardia (VT) that is refractory to single dose anti-arrhythmic management. Electrical storm, defined as three or more episodes of sustained VT, ventricular fibrillation, or appropriate shocks from an implantable cardioverter defibrillator within 24 hours,1 has a mortality rate up to 14% in the first 48 hours.2 Ventricular tachycardia may present in a heterogenous fashion, not only with stable versus unstable clinical presentations, but also with different electrocardiographic morphologies and etiologies.1 Understanding how to rapidly diagnose, treat, and utilize second or third-line treatments is vital in the setting of refractory ventricular tachycardia rather than relying on the success of first-line agents. Appreciation for what medications are readily available in your crash cart and medication dispensing cabinet is critical for timely management for refractory ventricular tachycardia. At the conclusion of the simulation session, learners will be able to: 1) identify the different etiologies of VT, including structural heart disease, acute ischemia, and acquired or congenital QT syndrome; 2) describe confounding factors of VT, such as electrolyte abnormalities and sympathetic surge; 3) describe how to troubleshoot an unsuccessful synchronized cardioversion, including checking equipment connections, increasing delivered energy, and changing pad placement; 4) compare and contrast treatments of VT based on suspected underlying etiology; 5) describe reasons to activate the cardiac catheterization lab other than occlusive myocardial infarction; and 6) identify appropriate disposition of the patient to the cardiac catheterization lab. This session was conducted using high-fidelity simulation, followed by a debriefing session and lecture on the diagnosis, differential diagnosis, and management of VT. Debriefing methods may be left to the discretion of participants, but the authors have utilized advocacy-inquiry techniques. This scenario may also be run as an oral board case. Our residents are provided a survey at the completion of the debriefing session so they may rate different aspects of the simulation, as well as provide qualitative feedback on the scenario. The local institution's simulation center's electronic feedback form is based on the Center of Medical Simulation's Debriefing Assessment for Simulation in Healthcare (DASH) Student Version Short Form3 with the inclusion of required qualitative feedback if an element was scored less than a 6 or 7. Twelve learners completed a feedback form. This session received 6 and 7 scores (consistently effective/very good and extremely effective/outstanding, respectively) other than three isolated 5 scores. The lowest average score was 6.67 for "Before the simulation, the instructor set the stage for an engaging learning experience." The highest average score was 7 for "The instructor helped me see how to improve or how to sustain good performance." The form also includes an area for general feedback about the case at the end. Illustrative examples of feedback include: "Excellent care and debrief." Specific scores are available upon request. This is a cost-effective method for reviewing VT diagnosis and management. The case may be modified for appropriate audiences, such as describing what medications may be readily available in a free-standing emergency department or pre-hospital setting. Medical simulation, ventricular tachycardia, cardiac emergencies, dysrhythmias, cardiology, emergency medicine.

Canine Model of Ischemia-Induced Ventricular Tachycardia

IntroductionDespite advances in antiarrhythmia therapies, ventricular tachycardia (VT) is a leading cause of sudden cardiac death. Investigation into the characteristics and new treatments for this arrhythmia is required to improve outcomes and a reproducible model of VT would be useful in these endeavors. We therefore created a canine model of ischemia-induced VT. Materials and methodsA pacing lead was implanted in the right ventricle in canines (n = 13) and the left anterior descending artery was occluded in two locations for 2 h and subsequently released to create an ischemia-reperfusion injury. In the 10 dogs that survived the first 48 h following the initial study, a terminal study was conducted 4-7 d later and VT was induced using premature stimulation or burst pacing through the right ventricle lead. The arrhythmia was terminated using either antitachycardia pacing or a defibrillatory shock. Multiple inductions into sustained VT were attempted. ResultsSustained VT was induced in eight of 10 dogs with an average cycle length of 335 ± 70 bpm. Multiple episodes of VT were induced. Episodes of VT exhibited different electrocardiogram morphologies and cycle lengths in individual animals. ConclusionsThis canine model provides a consistent technique for inducing multiple episodes of sustained VT. It may be useful for investigating VT mechanisms and testing novel therapeutics and treatments for patients with VT.

Ventricular tachycardia substrate ablation in patients with slightly depressed left ventricular ejection fraction. Predictors of VT-free survival in a prospective multicentre registry

Abstract Funding Acknowledgements Type of funding sources: None. Background There is no consensus about the need for ICD implantation in patients with slightly depressed left ventricle ejection fraction (LVEF) after catheter ablation for hemodynamically tolerated ventricular tachycardia (VT). Purpose This study aims to investigate predictors of mortality VT-free survival in this population. Methods We evaluated predictors of VT-free survival in patients with LVEF&amp;gt;40% from a prospective multicenter register of patients undergoing VT substrate ablation for hemodynamically tolerated VT. Decision to protect with ICD implantation at hospital discharge was performed according to the judgment of the treating cardiologist. The patients included in the study were followed every six months. Ventricular arrhythmia-free survival was the primary endpoint. Any episode of sustained VT (&amp;gt; 30 s) or appropriate ICD therapy was considered VT recurrence. Results One-hundred thirty-two patients [67±13 years, 91% male, 50±8% mean LVEF, 85 (65%) with ischemic heart disease] with a LVEF&amp;gt;40% were identified. Twenty-one (16%) of them were non-inducible at the end of the procedure and were discharged without ICD implantation as they were considered to have a low risk of recurrences. After a mean follow-up of 26±23 months, 32 (24%) patients had VT recurrences. A complete arrhythmogenic substrate elimination [HR: 0.34 (0.16-0.7), p&amp;lt;0.01] and the use multiple ventricular extrastimuli for hidden slow conduction (HSC) identification and ablation [HR: 0.51 (0.27-1.1), p=0.09] were related with VT-free survival (Figure 1). 53 (40%) patients fulfilled both criteria, having a 8% recurrence rate during the follow-up. Compared with the clinical decision making of ICD implantation at hospital discharge, the use of these two variables better identify patients at risk for VT recurrences, with a net reclassification improvement of 23% (Figure 2). Conclusions VT recurrence after VT substrate ablation in patients with slightly depressed LVEF remains high. However, complete substrate elimination and HSC analysis and ablation are related with higher VT-free survival and identify a subgroup of patients in whom ICD might be not beneficial.

P37 MULTIMODALITY DIAGNOSTIC APPROACH TO A JUVENILE CASE OF SUSTAINED VENTRICULAR TACHYCARDIA

Abstract Clinical case 31–year–old male subject, former competitive athlete, with family history of coronary artery disease and no further cardiovascular risk factors or previous cardiac events. Previous SARS–CoV2–related paucisymptomatic infection (January 2022) and subsequent episode of fever (August 2022) with negative SARS–CoV2 nasal swab. In September 2022 he reported sudden onset of palpitations after hearty meal. Because of such symptoms, the patient underwent Holter ECG showing 90 episodes of ventricular tachycardia (VT) and one episode of sustained VT. Based on such evidence, the patient went to the emergency room (ER). During the ER stay, blood exams (blood count, high–sensitivity troponin, BNP, CRP, D–dimer) and ECG were normal and SARS–CoV2 test was negative. The patient was then hospitalized in cardiac ICU. The echocardiogram showed left ventricle with normal dimension, thickness and wall motion (EF: 65%, mean GLS: –20%), trivial mitral and aortic regurgitation, no pericardial effusion. Subsequently, a cardiac coronary CT scan was performed showing absence of atherosclerotic lesions and myocardial bridge of the middle segment of LAD artery. The diagnostic pathway went on with cardiac magnetic resonance (CMR) demonstrating focal hypokinesia and wall thickness reduction of the anteroseptal–anterior junctional wall at middle–distal level (minimum thickness: 3 mm) where a millimetric area of late gadolinium enhancement with transmural distribution was described; absence of myocardial oedema. In addition, an EPS was performed with electroanatomical high–density/definition mapping of the left ventricle showing normal volumes, signals and activation and absence of LAVA/LV. Taking into account such findings, a subcutaneous defibrillator was implanted for primary prevention and a control CMR was scheduled in the follow–up period. Conclusions This case underlines the central role of CMR in identifying areas of myocardial fibrosis that can represent the electroanatomical substrate for triggering ventricular arrhythmias. In this case, the arrhythmic events are associated with a focal area of transmural fibrosis and wall thinning, usually indicating ischaemic damage, nonetheless in the presence of normal coronary arteries.

P120 NEW MALIGNANT MUTATION IN HYPERTROPHIC CARDIOMYOPATHY

Abstract A 62–year–old man diagnosed with non–obstructive hypertrophic cardiomyopathy and dual–chamber pacemaker wearer since the age of 40, for third–degree atrioventricular block, came to our attention for atrial fibrillation (AF) episodes (one complicated by cardiogenic shock and multiorgan failure) and flutter with high ventricular response. For a progressive worsening of the systolic function, and the onset of multiple episodes of sustained ventricular tachycardia, an upgrade to the defibrillator was performed, which, in the following months, intervened appropriately for recurrences of ventricular arrhythmias. The patient was admitted to our ward for exacerbation of heart failure. The echocardiography showed moderate concentric hypertrophy with mild ventricular dilatation and ejection fraction 33%, inferior and inferoseptal wall, and apex akinesia with thrombotic apposition. Due to a sudden deterioration of the clinical conditions, the patient died. After genetic counseling the patient‘s family agreed to genetic testing in the proband. This highlighted the presence of a missense mutation, i.e. the substitution of the cysteine ​​residue with a serine, in the codon 905 of the MYH7 gene, encoding the cardiac isoform of myosin heavy chain. The mutation is probably pathogenetic as it falls in the region where most of the missense variants are clustered and statistically associated with the HCM phenotype. Only in one previous case of HCM was detected a mutation of the same codon, Cys905Phe. Several studies have reported that AF tends to be more prevalent in patients carrying MYH7 mutations and is associated with a substantial risk of heart failure–related mortality, stroke, and severe functional disability. Knowledge of the entire spectrum of MYH7 mutations, especially those related to a high arrhythmic burden or SCD, combined with an accurate clinical and molecular characterization of the patient, can improve the genotype–phenotype correlation by clarifying the mechanism of HCM and allowing a better clinical and therapeutic decision–making of patients.

CE-452777-1 INCIDENCE, PREDICTORS AND CLINICAL SIGNIFICANCE OF LATE VENTRICULAR ARRHYTHMIAS AFTER LVAD IMPLANTATION

Long-term survival after durable left ventricular assist device (LVAD) is improving. Ventricular arrhythmias are a driver of patient morbidity following implantation. Predictors of late ventricular arrhythmias (LVA) and their prognostic significance remain uncertain. We sought to determine the incidence of LVA, risk factors associated with their development and their clinical impact on patients in patients after LVAD implantation in long-term follow-up. A single-center retrospective analysis was performed including patients who underwent LVAD implantation from 2007-2022. We compared clinical characteristics and outcomes between patients who developed LVA to those patients without LVA. LVAs were defined as an episode of sustained ventricular tachycardia or ventricular fibrillation identified on ECG, telemetry and/or CIED occurring >30 days after LVAD implantation. Transplant-free survival was defined as time from index LVAD implantation to transplantation, LVAD explantation, death or most-recent follow-up. Of the 788 patients who underwent LVAD implantation during the study period, 141 patients (21.9%) had LVA >30 days after LVAD implantation. There was no significant difference between ages of patients with LVA and those without ventricular arrhythmia following LVAD implantation (LVA vs no LVA: 63.2 vs 62.3 years; p = 0.556). The majority of patients were male (78.7% vs 71.8%; p = 0.102) and self-identified as black (70.9% vs 71.8%; p = 0.875). Patients with LVAs more often had a history of preoperative presence of CRT (22.9% vs 12.5%; p = 0.002), history of ventricular tachycardia (49.3% vs 30.0%; p = <0.001), history of atrial flutter ablation (10.7% vs 3.7%; 0.001), appropriate ICD therapy prior to implantation (15.7% vs 5.5%; p = <0.001), taking amiodarone (31.8% vs 21.9%; p = 0.023), larger LVEDD (7.0 cm ± 1.0 vs 6.8 cm ± 1.0; p = 0.013) and QTc prolongation (504.8 ms ± 56.5 vs 518.2 ms ± 50.3; p = 0.017). The strongest independent predictors of LVA were a history of atrial flutter ablation (OR 3.52; CI 1.43-8.62; p = 0.006) and appropriate ICD shock in 7 days prior to implantation (OR 3.22; CI 1.49-6.99; p = 0.003). There was no difference between transplant-free survival time in patients with and without LVAs (p = 0.062, Figure 1). Despite being a common event after LVAD therapy, the development of LVA does not adversely impact transplant-free survival time. Future studies are warranted to determine the impact of LVA on quality-of-life in LVAD patients.

PO-05-082 ANTITACHYCARDIA PACING IS MORE EFFECTIVE WHEN DELIVERED TO THE LEFT BUNDLE BRANCH COMPARED TO THE RIGHT VENTRICLE IN A CANINE ISCHEMIC VENTRICULAR TACHYCARDIA MODEL

Implantable cardioverter-defibrillators (ICDs) can terminate ventricular tachycardia (VT) with Antitachycardia pacing (ATP) delivered to a right ventricular (RV) pacing lead, thereby avoiding painful and damaging high-energy shocks. However, ATP efficacy is limited for fast VT, and ATP can accelerate VT or convert VT to ventricular fibrillation (VF). Physiological pacing delivered to the left bundle branch (LBB) has emerged as a clinically relevant target to minimize ventricular dyssynchrony and pacing-induced heart failure. ATP efficacy and safety delivered to the LBB are yet to be investigated. Evaluate the therapeutic efficacy and safety of ATP delivered to an LBB lead compared to ATP delivered to a conventional RV lead. In 6 anesthetized dogs, pacing leads from two ICDs (CobaltTM XT DR, Medtronic, Inc) were implanted at the RV apex (6947 Sprint Quattro SecureTM, Medtronic, Inc) and the LBB (3830 SelectSecureTM, Medtronic, Inc). A lateral thoracotomy procedure was performed, and a two-hour lateral anterior descending artery ischemia-reperfusion injury was caused. The thoracotomy was closed and on post-infarct day 4, dogs were anesthetized, and sustained VT episodes were induced by programmed electrical stimulation. ATP (up to 5 trains of 8 pulses at approximately 88% of the VT cycle length) was delivered to either the LBB or RV pacing site in a randomized fashion. The success rate of ATP in terminating the VT episodes and the rate of VT acceleration and degeneration into VF from both pacing locations were evaluated. In our canine ischemic VT model, VT was induced 80 times, with a mean VT cycle length of 178±35 ms. ATP was delivered and tested for each episode. For ATP delivered to the RV, the success rate for terminating VT was 54%. The success rate for terminating VT for ATP delivered to the LBB was 73% (Fig. A, p < 0.05). ATP resulted in VT acceleration for 10% and 5% of ATP attempts delivered to the RV and LV, respectively (Fig. B, p = Not Significant, NS). Degeneration to VF occurred for 5% of all ATP attempts delivered to the RV, and there was no such incident for ATP delivered to the LBB (Fig. B). Higher efficacy and lower incidence of VT acceleration were observed with ATP delivered to LBB compared to ATP delivered to the RV in this canine ischemic VT model. Improved performance of ATP delivered to LBB compared to RV provides additional incentive for expanded use of LBB leads for pacing and therapy delivery.

Primary Squamous Cell Lung Cancer With Frequent Episodes of Sustained Ventricular Tachycardia due to Myocardial Metastasis

Myocardial metastasis from lung cancer rarely occurs. We encountered a patient with squamous cell lung cancer who was diagnosed with myocardial metastasis before death and sustained ventricular tachycardia during the course of the disease. The patient was a 56-year-old woman. A tumor was noted in the apex area of the left lung and was diagnosed as stage IVA of squamous cell lung cancer after a detailed examination. She underwent concurrent chemoradiotherapy with weekly treatment of carboplatin + paclitaxel. A 12-lead electrocardiogram performed upon admission for additional chemotherapy showed negative T waves in leads III, aVF, and V1-4. Transthoracic echocardiography and computed tomography showed a tumor lesion in the right ventricular wall, which was diagnosed as myocardial metastasis from lung cancer. During the course of the disease, the patient had frequent episodes of sustained ventricular tachycardia, which were refractory to treatment with antiarrhythmic drugs. However, the sinus rhythm was restored with cardioversion. Subsequently, the patient received palliative treatment and eventually died 4 months after the diagnosis of cardiac metastasis and 3 weeks after the diagnosis of ventricular tachycardia. Myocardial metastasis might reflect poor prognosis due to serious arrhythmia or some other complications. Therefore, the early diagnosis and appropriate treatment of cardiac metastasis by chemotherapy, cardiac radiotherapy, or surgery, are necessary prior to the development of symptoms in tolerant cases. J Med Cases. 2023;14(4):111-117 doi: https://doi.org/10.14740/jmc4066

178 ARRHYTHMIC STORM IN ATTR WILD TYPE AMYLOIDOSIS: AN UNUSUAL COMBINATION

Abstract Cardiac amyloidosis (CA) is characterized by extracellular protein fibril deposition in the myocardium leading to restrictive heart failure. Both atrial and ventricular arrhythmias are common in CA. Study have shown up to one half of patients with CA die suddenly. However, the most common cause of sudden death has been historically through to be secondary electromechanical dissociation rather than a lethal ventricular arrhythmia. We present the case of a 84 years old man, with a history of hypertension, dyslipidaemia, and prior smoking. In June 2020 the patient was admitted to the emergency room of our hospital due to an episode of hemodynamically unstable sustained ventricular tachycardia (SVT). The patient underwent electrical cardioversion with restoration of sinus rhythm. An echocardiogram that showed a slightly reduced ejection fraction (FE = 45%), severe concentric hypertrophy, grade 3 diastolic dysfunction with high pressures in the left ventricular (LV) cavity, and a reduced GLS (-13.8%) with a typical apical-sparing aspect. A cardiac magnetic resonance (Fig.1). was performed showing a diffuse area of LGE with a subepicardial pattern involving left ventricular and atrial segments, compatible with myocardial storage disease. In order to complete the diagnostic workout, we performed a bone scintigraphy (Fig.2). (Positive for CA, with Perugini score grade 2), a genetic test (negative for hATTR-CA mutations) and free light chain in serum (negative for AL-CA). The patient was discharged at home after ICD implantation in secondary prevention and prescribed appropriate heart failure therapy. In May 2022 the patient was readmitted in emergency room for dyspnea during an arrhythmic storm characterized by several SVTs and ICD interventions, and atrial fibrillation (FA). After stabilization of clinical parameters, the patient was hospitalized in our ward. We optimized medical therapy with metaprololo 100 mg 1 cp BID, cordarone 600 mg ev and mexiletina 200 mg cp BID. During the hospitalization we succeeded in reducing SVT burden. However, ventricular PVCs and slow SVT remained. For this reason, we decided to perform an electrophysiological study (EPS) followed by catheter ablation. The EPS found two low voltage areas (Fig.3). The first were found under the aortic valve; the second was an area of dense scar and fragmented potentials along the basal-posterior wall. After ablation of the first area we succeeded in removing clinical PVCs. During the ablation of the second area the procedure was complicated by ventricular fibrillation that required advanced life support and many electrical shocks. The patient was discharged at home in absence of further episodes of SVTs with optimized therapy At a three moths follow up no arrhythmic events were recorded.

48 A CASE OF RECURRENT VENTRICULAR TACHYCARDIA IN A PATIENT WITH GRANULOMATOSIS WITH POLYANGIITIS WITH A CHALLEGING IDENTIFICATION OF ARRHYTHMIC SUBSTRATE: THE ROLE OF MULTIMODALITY IMAGING

Abstract Background Granulomatosis with polyangiitis (GPA), previously known as Wegener's granulomatosis, is a pulmonary-renal syndrome affecting small and medium sized blood vessels. Cardiac involvement is rare and generally includes pericarditis, myocarditis and aortic valve disease. We report a case of recurrent sustained ventricular tachycardia (VTs) in a patient with GPA. Case summary A 67-year-old man with past medical history of GPA presented palpitations, chest pain and episodes of presyncope. Electrocardiographic tracing upon ED presentation showed sustained monomorphic VT (fig.1) associated with global hypokinesia of the left ventricle and moderately reduced ejection fraction at transthoracic echocardiography (TTE). As the patient was hemodynamically stable, prompt treatment with amiodarone was adopted with successful recovery of sinus rhythm. After a few hours, TTE was normal. However, as troponin I was markedly elevated, coronarography was performed and coronary disease was ruled out. Contrast-enhanced cardiac magnetic resonance imaging (ceCMR) revealed late gadolinium enhancement in basal anteroseptal mid wall, suggestive of myocardial scar tissue with non-ischemic pattern. No sustained ventricular arrhythmias were induced during electrophysiological study (EPS), even with an aggressive protocol (up to 4 extra stimuli and ventricular refractoriness) and electro-anatomical mapping of both ventricles failed to show any arrhythmic substrate. An implantable cardioverter defibrillator (ICD) was then implanted. After 4 months the patient was admitted for multiple episodes of sustained VT (with cycle length in the ICD monitoring window) refractory to drugs and three external defibrillations. Repeated EPS failed to induce sustained arrhythmias. High-density electroanatomical mapping of the right ventricle, however, showed fragmented potentials in the mid-posterior septal wall (fig. 2-3). After myocardial biopsy of the region of interest, radiofrequency catheter ablation of the area was performed with regression of the potentials. The results of endomyocardial biopsy demonstrated fibrosis. At 5 months of follow-up, the patient didn't relapse. Discussion Multimodality imaging is of paramount importance in identifying arrhythmogenic substrate and in characterizing the specific anatomical–functional components of VT circuits. In our patient high-density electroanatomical mapping was able to identify fragmented potentials and define the ablation target area, despite the mismatch with ceCMR.

Early Experience with the Biotronik Protego ICD Lead.

Background: In the last decade, newer generation ICD leads have been developed based on mechanistic insides of priorly failing leads. The aim of our study was to assess the long-term performance and mechanisms of failure of the 2013-introduced Biotronik Protego ICD lead in a real-world population. Methods: All patients, who underwent implantation of a Protego ICD lead at the Heart Centre Lucerne (Lucerne, Switzerland) between November 2013 and March 2017, were followed up with semi-annual device-controls. The primary endpoint was defined as lead failure, secondary endpoints compromised all-cause death, (in)appropriate shocks and the need for reintervention. Results: A total of 64 patients (mean age 66.7 ± 8.7 years, 30% female) underwent implantation of a Protego ICD lead: 78% for primary prevention, 53% had underlying ischemic heart disease, and 40.6% had a dilated cardiomyopathy (DCM). Mean left ventricular ejection fraction (LVEF) was 32.6 ± 10.5%. A total of 24 patients were treated with cardiac resynchronization therapy (CRT), and their baseline LVEF improved from 27.8 ± 7.3% before to 39.8 ± 12.5 after implantation (p < 0.001). Mean time to follow-up was 5.5 ± 0.9 years. Overall, 14 patients (26.6%) suffered from at least one episode of sustained ventricular tachycardia; in total 10 patients (15.6%) died. Two patients experienced lead failure due to lead fracture after 5.5 and 5.7 years, which was clinically apparent by an abrupt rise in lead impedance (>2000 Ω) and by repetitive inappropriate shocks, respectively. Conclusions: In this retrospective observational study, the calculated annual lead failure rate of the Biotronik Protego ICD lead was 0.59% per patient—thus, the durability and long-term performance seem to be promising.

Abstract 11589: Total Artificial Heart Placement in a Case of Recurrent Ventricular Tachycardia Storm

Background: Electrical storm is defined as three or more episodes of sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) within a 24-hour period requiring termination by cardioversion, anti-tachycardia pacing (ATP) or defibrillation. It can be a particularly challenging syndrome to treat when refractory to standard of care therapies, which include antiarrhythmics, sedation, and ablation. We present a case of refractory electrical storm requiring total artificial heart placement (TAH) as a bridge to transplant. Case: A 65-year-old male with a history of idiopathic non-ischemic cardiomyopathy presented with VF arrest. After return of spontaneous circulation, he was admitted to the cardiac intensive care unit. Implantable cardioverter defibrillator (ICD) interrogation showed 38 shocks delivered over the prior two-week period. Coronary angiography showed no obstructive coronary disease and an intraaortic balloon pump (IABP) was placed for cardiogenic shock. He was intubated and sedated on fentanyl and propofol. He continued to have episodes of VT despite treatment with lidocaine, procainamide, and amiodarone drips. Further trials of paralysis and left stellate ganglion nerve block did not suppress his VT. Since the patient was refractory to all prior interventions, was deemed too unstable for VT ablation, and had a prolonged anticipated wait time for heart transplant, he underwent TAH placement as a bridge to heart transplant. He recovered well and eventually underwent successful heart transplant. Discussion: Management of electrical storm requires a stepwise approach including administration of antiarrhythmics, sedation, mechanical hemodynamic support, and catheter ablation. Our patient had incessant VT despite exhaustive medical and supportive therapies, but was too unstable to undergo VT ablation. In cases of refractory VT storm, definitive treatment with heart transplantation must be considered, but bridging patients to transplant poses a challenge. Our patient underwent TAH placement and was successfully stabilized prior to transplant. In centers with this capability, TAH should be recognized as a legitimate option in the pathway for VT, particularly with a long anticipated wait time for heart transplant.

ODP461 Amiodarone Induced Thyrotoxicosis With Severe Cardiac Disease Refractory to Medical Therapy and Plasmapheresis

Abstract Introduction Management of amiodarone induced thyrotoxicosis (AIT) presents the clinical challenge of differentiating between the two subtypes: Type I AIT, characterized by increased hormonal biosynthesis, and Type II AIT, a destructive thyroiditis since the treatment differs. We present a case of a patient with severe cardiac disease on long-term amiodarone who presented with thyrotoxicosis who was minimally clinically symptomatic despite significant biochemical thyroid function abnormalities and refractory to all medical interventions, including plasmapheresis, ultimately requiring total thyroidectomy. Case Description An 82 year-old-male with severe cardiac disease including coronary artery disease with prior CABG, EF of 25-30% with ICD, and atrial fibrillation on amiodarone, presented to the hospital due to palpitations and multiple shocks delivered by patient's ICD. EKG revealed atrial fibrillation and the ICD demonstrated episodes of sustained ventricular tachycardia. The Burch-Wartofsky score was 25. He had palpitations, tremors, and atrial fibrillation but no thyromegaly, thyroid bruits or thyroid eye disease. Thyroid function testing was TSH &amp;lt;0. 01 ulU/mL (Normal 0.3 - 4.5 ulU/mL), FT4 5.29 ng/dL (Normal 0.5- 1.26 ng/dL). Thyroid ultrasound showed multiple sub-centimeter nodules without increased vascularity. Since patient had characteristics of both AIT subtypes, patient was started on treatments for both including hydrocortisone 100 mg TID, Lugol's Iodine 10 drops TID, methimazole 20 mg QID, propranolol 20 mg QID, cholestyramine 4g BID, and lithium 300 mg TID. Despite extensive medical management, the patient's thyroid levels remained grossly elevated with FT4 nadir of 4.37 ng/dL. Plasmapheresis was initiated every 1-2 days for a total of 6 treatments and the patient's FT4 improved to 3.52 ng/dL before increasing again. During this treatment period, the patient remained relatively asymptomatic but had severe cardiac disease which further complicated the urgency for thyroidectomy. Ultimately, he underwent a total thyroidectomy that caused the resolution of the thyrotoxicosis. He was started on levothyroxine and subsequent pathology revealed multi-nodular goiter with lymphocytic thyroiditis. Discussion This challenging case of amiodarone induced thyrotoxicosis in a patient with severe cardiac disease, refractory to extensive medical therapy including plasmapheresis and requiring total thyroidectomy, highlights the difficulty in management of AIT. Management of refractory AIT involves differentiating between the two clinical subtypes with the goal of expediently achieving a euthyroid state to avoid severe cardiac complications and mortality. This case was particularly challenging since our patient had relatively stable clinical status despite chemical thyrotoxicosis with characteristics of both subtypes of AIT. It was challenging to optimize a patient's thyroid levels prior to thyroidectomy, due to severe cardiac disease and persistent thyrotoxicosis. Ultimately, our patient was refractory to medical treatments for both AIT subtypes and plasmapheresis. The resolution of thyrotoxicosis was not achieved until he underwent total thyroidectomy Presentation: No date and time listed

RAF-1 Mutation Associated with a Risk for Ventricular Arrhythmias in a Child with Noonan Syndrome and Cardiovascular Pathology.

IntroductionNoonan syndrome (NS) is a dominant autosomal disease, caused by mutations in genes involved in cell differentiation, growth and senescence, one of them being RAF1 mutation. Congenital heart disease may influence the prognosis of the disease.Case presentationWe report a case of an 18 month-old female patient who presented to our institute at the age of 2 months when she was diagnosed with obstructive hypertrophic cardiomyopathy, pulmonary infundibular and pulmonary valve stenosis, a small atrial septal defect and extrasystolic arrhythmia. She was born from healthy parents, a non-consanguineous marriage. Due to suggestive phenotype for NS molecular genetic testing for RASopathies was performed in a center abroad, establishing the presence of RAF-1 mutation. Following rapid progression of cardiac abnormalities, the surgical correction was performed at 14 months of age. In the early postoperative period, the patient developed episodes of sustained ventricular tachycardia with hemodynamic instability, for which associated treatment was instituted with successful conversion to sinus rhythm. At 3-month follow-up, the patient was hemodynamically stable in sinus rhythm.ConclusionsThe presented case report certifies the importance of recognizing the genetic mutation in patients with NS, which allows predicting the severity of cardiac abnormalities and therefore establishing a proper therapeutic management of these patients.