Unstable Ventricular Tachycardia Research Articles

The arrhythmic substrate of hypertrophic cardiomyopathy using ECG imaging.

Introduction: Patients with hypertrophic cardiomyopathy (HCM) are at risk for lethal ventricular arrhythmia, but the electrophysiological substrate behind this is not well-understood. We used non-invasive electrocardiographic imaging to characterize patients with HCM, including cardiac arrest survivors. Methods: HCM patients surviving ventricular fibrillation or hemodynamically unstable ventricular tachycardia (n = 17) were compared to HCM patients without a personal history of potentially lethal arrhythmia (n = 20) and a pooled control group with structurally normal hearts. Subjects underwent exercise testing by non-invasive electrocardiographic imaging to estimate epicardial electrophysiology. Results: Visual inspection of reconstructed epicardial HCM maps revealed isolated patches of late activation time (AT), prolonged activation-recovery intervals (ARIs), as well as reversal of apico-basal trends in T-wave inversion and ARI compared to controls (p < 0.005 for all). AT and ARI were compared between groups. The pooled HCM group had longer mean AT (60.1ms vs. 52.2ms, p < 0.001), activation dispersion (55.2ms vs. 48.6ms, p = 0.026), and mean ARI (227ms vs. 217ms, p = 0.016) than structurally normal heart controls. HCM ventricular arrhythmia survivors could be differentiated from HCM patients without a personal history of life-threatening arrhythmia by longer mean AT (63.2ms vs. 57.4ms, p = 0.007), steeper activation gradients (0.45ms/mm vs. 0.36ms/mm, p = 0.011), and longer mean ARI (234.0ms vs. 221.4ms, p = 0.026). A logistic regression model including whole heart mean activation time and activation recovery interval could identify ventricular arrhythmia survivors from the HCM cohort, producing a C statistic of 0.76 (95% confidence interval 0.72-0.81), with an optimal sensitivity of 78.6% and a specificity of 79.8%. Discussion: The HCM epicardial electrotype is characterized by delayed, dispersed conduction and prolonged, dispersed activation-recovery intervals. Combination of electrophysiologic measures with logistic regression can improve differentiation over single variables. Future studies could test such models prospectively for risk stratification of sudden death due to HCM.

Early experience with mechanical hemodynamic support for catheter ablation of malignant ventricular tachycardia

Objective: To explore the role of mechanical hemodynamic support (MHS) in mapping and catheter ablation of patients with hemodynamically unstable ventricular tachycardia (VT), report single-center experience in a cohort of consecutive patients receiving VT ablation during MHS therapy, and provide evidence-based medical evidence for clinical practice. Methods: This was a retrospective cohort study. Patients with hemodynamically unstable VT who underwent catheter ablation with MHS at Beijing Anzhen Hospital, Capital Medical University between August 2021 and December 2023 were included. Patients were divided into rescue group and preventive group according to the purpose of treatment. Their demographic data, periprocedural details, and clinical outcomes were collected and analyzed. Results: A total of 15 patients with hemodynamically unstable VT were included (8 patients in the rescue group and 7 patients in the preventive group). The acute procedure was successful in all patients. One patient in the rescue group had surgical left ventricular assist device (LVAD) implantation, remaining 14 patients received extracorporeal membrane oxygenation (ECMO) for circulation support. ECMO decannulation was performed in 12 patients due to clinical and hemodynamic stability, of which 6 patients were decannulation immediately after surgery and the remaining patients were decannulation at 2.0 (2.5) d after surgery. Two patients in the rescue group died during the index admission due to refractory heart failure and cerebral hemorrhage. During a median follow-up of 30 d (1 d to 12 months), one patient with LVAD had one episode of ventricular fibrillation at 6 months after discharge, and no further episodes of ventricular fibrillation and/or VT occurred after treatment with antiarrhythmic drugs. No malignant ventricular arrhythmia occurred in the remaining 12 patients who were followed up. Conclusions: MHS contributes to the successful completion of mapping and catheter ablation in patients with hemodynamically unstable VT, providing desirable hemodynamic status for emergency and elective conditions.

Preprocedural imaging with cardiac computed tomography for endo-epicardial ventricular tachycardia ablation

BackgroundStudies evaluating the systematic use of cardiac computed tomography (CCT) for the preprocedural assessment of myocardial fibrosis are limited. Their implementation in the electrophysiology workflow has not been extensively described. ObjectiveThis study aimed to explore the degree of concordance between CCT and electroanatomic mapping (EAM) for the evaluation of cardiac fibrosis in patients undergoing endo-epicardial ventricular tachycardia (VT) ablation. MethodsFrom November 2017 to December 2021, patients undergoing endo-epicardial VT catheter ablation with CCT as the only source of preprocedural scar assessment were prospectively enrolled. After image integration, myocardial fibrosis detected with CCT was compared with low-voltage areas identified by endo-epicardial EAM. Postprocedural VT recurrences of this approach were evaluated after at least 1 year of follow-up. ResultsThe study enrolled 35 patients (mean age, 60.7 ± 13.2 years; 94.2% male). The most common underlying arrhythmic substrate was dilated cardiomyopathy (48.6%). CCT was employed for contraindications to cardiac magnetic resonance, such as unstable VTs (31.4%) or nonconditional implantable cardioverter-defibrillators (28.6%), but also for patients’ and operators’ preferences (14.3%–25.7%). Myocardial fibrosis was correctly identified by CCT and EAM, with strong agreement between these techniques both overall (Cohen κ for agreement, 0.933) and in per-segment analysis (κ ranging from 0.796 to 1.0). Ischemic patients showed the best correlation (κ = 1.000), whereas myocarditis showed the worst (κ = 0.750). After a median follow-up of 14 (12–24) months, 1-year freedom from recurrences was achieved in 74.3% patients; overall freedom from recurrences was 60.0%. ConclusionA CCT-based preprocedural assessment before VT ablation is feasible, showing high diagnostic concordance with EAM in detecting myocardial fibrosis.

An Uncommon Presentation of Unstable Ventricular Tachycardia: Raising Awareness for Early Recognition of Chagas Disease

An Uncommon Presentation of Unstable Ventricular Tachycardia: Raising Awareness for Early Recognition of Chagas Disease

Ablation of hemodynamically unstable ventricular tachycardia guided by ultra-high density pacemapping and PASO correlation map, a multi-center clinical trial

Abstract Background Due to hemodynamic instability during ventricular tachycardia (VT), obtaining a complete electroanatomic map is often difficult if not impossible. Pace-mapping has progressed but still lacks precision and may not reveal sufficient details for complete ablation of the potential critical isthmus. Purpose We hypothesized that a novel strategy of combining ultra-high density (HD) pace-mapping using the PASO algorithm and Carto system to match the induced/clinical VT may aid in the reconstruction of the VT critical isthmus and effective VT ablation leading to reduce the risks of VT recurrence. Methods This was a prospective, multi-center trial conducted between January 2021 and July 2023. We enrolled 30 patients with ischemic heart disease and scar mediated recurrent VT clinically indicated for ablation. Following induction of clinical VT, we performed ultra-HD pace-mapping (5-10 mm distance between pacing points) of the identified ventricular substrate. Using PASO Module, a pacing correlation map (PCM) was constructed based on the percentage match to the induced VT. Using the PCM and the measured stimulation to electrogram intervals, the potential VT critical isthmus was reconstructed. Radiofrequency ablation was carried out to completely transect the delineated isthmus. Post ablation, repeat HD mapping and ablation was performed, until the PASO % correlation dropped from &amp;gt;93% to &amp;lt;70%, indicating at least uni-directional (orthodromic to the perceived VT circuit) conduction block through the ablation line. Follow-up data, including ICD interrogations were collected via chart review. Outcomes were compared to 60 propensity-score matched patients with an ICD who were enrolled in the Ranolazine in High-Risk Patients with Implanted Cardioverter-Defibrillators (RAID) trial who did not undergo VT ablation and served as the control group. The primary endpoint was the first occurrence of any VT at 1-year of follow-up. Results Patients enrolled had a mean age of 69 ± 9 years and 13% were women. Propensity matched patients from the RAID trial had similar baseline clinical characteristics to patients who underwent VT ablation (Table). At 1 year follow up, there was a significantly lower cumulative probability of VT/VF recurrent events in the patients who underwent PCM guided ablation as compared with the control group (17% vs 69%, respectively; log-rank p&amp;lt;0.001 Figure). There were no serious procedure related complications with all patients remaining free of adverse events or death at 30 days. Conclusion Our findings suggest that ablation for unstable or unmappable VT is enhanced by ultra-high density pace-mapping to reconstruct the potential VT circuit and is associated with a significantly lower rate of recurrent VT as compared with patients managed with aggressive and escalating medical therapy.Cumulative probability of ICD therapyBaseline clinical characteristics

Manifestation of conduction block zones by substrate mapping evaluated under multidirectional pacing during ventricular tachycardia ablation

Abstract Introduction Catheter ablation (CA) has proven to be effective therapy for ventricular tachycardia (VT) in patients with structural heart disease. However, activation mapping during VT is often limited in case of non-inducible, non-sustained or hemodynamically tolerable. It has been reported that a substrate-based approach for identifying conduction block and slow-conducting sites during sinus rhythm and ventricular pacing is promising strategies for CA. However, detailed analysis on the effectiveness of substrate mapping with multidirectional pacing to identify critical isthmus in unmappable VT have been lacking. Purpose The purpose of the present study was to evaluate the effectiveness of substrate mapping with multidirectional pacing in VT ablation. Methods From April 2022 to July 2023, 7 consecutive patients (4 men, age 62±9years) who underwent CA of VTs at our institute were enrolled. Isochronal late activation mapping (ILAM) was performed during sinus rhythm, right ventricular (RV) and left ventricular (LV) pacing. Cardiovascular magnetic resonance were performed in 3 of 7 cases to assess the distribution of myocardial late gadolinium enhancement. For catheter ablation, 2Fr electrode catheter was inserted into the anterior interventricular vein (AIV) at the distal site of the coronary sinus. LV pacing was performed using an electrode catheter placed in the AIV. ILAM were constructed by annotating the last deflection of each electrogram. Results In the 7 patients, 5 had ischemic cardiomyopathy and 2 had non-ischemic cardiomyopathy (Figure 1). During sinus rhythm, a deceleration zone (DZ) was identified in only 1 of 7 cases, consistent with linear conduction block. RV pacing demonstrated DZ in 3 of 7 cases. LV pacing revealed DZ in 6 of 7 cases, all of which had conduction blocks. U-shaped conduction blocks, which was not detectable in activation mapping during sinus rhythm, was newly identified in 29% of RV pacing, 71% of LV pacing. Combined RV and LV pacing unmasked the U-shaped conduction block in 86% of the cases. Only in case 7, activation mapping of VT with a cycle length of 470ms could be performed, and VT isthmus activation was observed in the area surrounded by the U-shaped conduction block (Figure 2). In other cases, the clinical VTs were unmappable because of the hemodynamic instability with tachycardia cycle length of approximately 300 milliseconds. Eventually, VTs became non-inducible in 3 of 5 cases in which induction was performed after the CA. During the follow-up period of 7±5 months, 6 of 7 cases remained free from any VT episodes. One patient showed small amount of pericardial effusion after CA. However, there were no life-threatening complications in any patients. Conclusion Substrate mapping using several different wavefront vectors in unstable VTs unveiled conduction block zones that might be potential ablation target sites for VT.Figure 1Figure 2

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

Epicardial ablation of hemodynamically unstable ventricular tachycardia supported by a percutaneous assist device, limited by a left ventricular aneurysm and adhesions after cardiac surgery.

Epicardial ablation of hemodynamically unstable ventricular tachycardia supported by a percutaneous assist device, limited by a left ventricular aneurysm and adhesions after cardiac surgery.

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.

Early Onset Severe Aortic Stenosis Presenting with Recurrent Ventricular and Supraventricular Arrhythmia and Postoperative Stroke in a 44-year-old Man with Uncontrolled Rheumatoid Arthritis

Calcific aortic stenosis is the most common aetiology of aortic stenosis and is mostly seen in older people. Systemic inflammatory diseases, such as rheumatoid arthritis (RA), are rarely associated with aortic stenosis in the literature. Uncontrolled systemic inflammation related to RA may lead to postoperative complications but this is not well documented. The patient in this case report was a 44-year-old man who had been diagnosed with RA that had been poorly controlled. He had a 7-month history of heart failure symptoms attributed to severe calcific aortic stenosis. He underwent surgical aortic valve replacement, but developed an acute cerebrovascular infarct 2 hours after surgery and recurrent unstable ventricular tachycardia on the first postoperative day warranting 15 synchronised cardioversions. RA is a rare antecedent cause of severe calcific aortic stenosis especially in younger people. Such a valvular complication associated with acute ischaemic stroke and ventricular arrhythmia warrants further study to provide optimal medical management, especially for patients with RA and early cardiovascular complications.

Treatment of lidocaine-refractory ventricular tachycardia using procainamide in an anesthetized horse.

To highlight the use of procainamide as a potential alternative treatment modality in cases of ventricular tachycardia that are refractory to lidocaine and magnesium sulfate. 1 adult horse weighing 380 kg. A 25-year-old Arabian gelding presented with severe colic signs. Due to persistent pain, it was elected to carry out an exploratory laparotomy. During the procedure a diagnosis of severe, unstable ventricular tachycardia was made based on the ECG findings, with an initial heart rate of 195 beats per minute and severe hypotension. Initial treatment consisted of discontinuing dobutamine and the administration of a 2 mg/kg IV lidocaine bolus followed by a continuous rate infusion at 50 μg/kg/min. Twenty grams magnesium sulfate (5 mg/kg) was administered IV in 1 L of lactated Ringer solution as a slow bolus over 30 minutes. Ventricular tachycardia persisted with poor peripheral pulses, a severely dampened arterial waveform, and a MAP of 30 to 45 mm Hg. Two milligrams/kg IV procainamide was administered over 3 minutes, 3 separate times, at 5-minute intervals. Immediately following the third dose sinus rhythm was detected on the ECG, the arterial waveform improved, and MAP increased to 85 mm Hg. Ventricular tachycardia is a rare but potentially life-threatening complication in horses undergoing general anesthesia. The potential of this arrhythmia to progress to ventricular fibrillation is of grave concern, as the option to attempt to externally defibrillate horses back to normal sinus rhythm does not exist. This case highlights procainamide as a potential option for cases of ventricular tachycardia that are refractory to more standard treatment modalities.

Arrhythmias in patients with acute ST-elevation myocardial infarction induced by various risk factors during the first day after myocardial reperfusion by primary percutaneous coronary intervention

Introduction. Acute coronary syndrome, in particular acute ST-elevation myocardial infarction (STEMI), is often accompanied by complex hemodynamically significant arrhythmias and conduction disorders. Such patients have a worse prognosis compared to patients with sinus rhythm. Arrhythmias in patients with STEMI are facilitated by the presence of comorbidities such as arterial hypertension, diabetes mellitus, obesity, and post-COVID-19 syndrome. The aim of the study. To elucidate the nature of arrhythmias in patients with acute STEMI induced by various risk factors during the first day after myocardial reperfusion by primary percutaneous coronary intervention. Materials and methods. The study involved 50 patients aged 45 to 83 years (average age – 63,4 ± 9,6 years; men – 70,97 %, women – 29,03 %), who were treated during 2021-2023 at the cardiology and reperfusion therapy department of Cardio-vascular center of ʺSaint Panteleimon Hospital in Lvivʺ and the infarction department of ʺLviv Regional Clinical Cardiological Centerʺ. The patients under investigation were subjected to daily electrocardiogram (ECG) monitoring for 24 hours after stenting of the infarct-related coronary artery, using a 7-channel ECG recorder Solvaig 06000.7 with computer processing of the recording using the DiaCard2 software. The obtained material was further subjected to software packages Microsoft Excel 2022, Statistica 10. Results. It was established that among supraventricular rhythm disturbances the most common were premature contractions, the average number of which per patient was significantly higher in the presence of obesity. Similarly high it was in post COVID-19 patients, as well as in those with hypertension. In post-coronavirus infection and in hypertension cases, extrasystoles were often in the form of pairs, triplets, bigemia, and trigemia; paroxysms of supraventricular tachycardia were also recorded in these patients. Among the ventricular arrhythmias also the most frequent were premature cardiac contractions, significantly more oftenly recorded in patients with hypertension and those experienced COVID-19; only in these patients were documented extrasystoles in the form of pairs, triplets, bigeminy, trigeminy, runs of ʺR to Tʺ, which are currently considered as harbingers of life-threatening ventricular arrhythmias. In the presence of hypertension and post-COVID-19, episodes of unstable ventricular tachycardia were also observed. Conclusions. In patients with STEMI, both supraventricular and ventricular premature contractions and episodes of supraventricular and unstable ventricular tachycardia are quite common during the first day after primary percutaneous coronary intervention with infarct-related coronary artery stenting, which is evidence of myocardial electrical instability. The nature of rhythm disturbances in the presence of hypertension and post-COVID-19 is prognostically unfavorable and indicates a higher risk of lifethreatening arrhythmias in these patients. Myocardial revascularization should be supplemented with optimal medical treatment in order to prevent the adverse cardiovascular events in post-STEMI patients. Further research should be directed toward elucidation of predictive value of detected arrhythmias with respect to the occurrence of unfavorable cardiovascular events in the early and long-term post-infarction period.

Effects of Mitral Valve Surgery on Ventricular Arrhythmia in Mitral Valve Prolapse Patients: Five-Year Eollow-up.

Aim To evaluate the effect of mitral valve (MV) repair and replacement on the incidence of ventricular arrhythmias (VA) and to identify risk factors for the persistence of VA in patients with MV prolapse and severe mitral regurgitation (MR) during a mid-term follow-up.Material and methods A single-site observational, prospective study successively enrolled 30 patients (mean age, 55.2±9.9 years, 60% men) who underwent MV repair or replacement for severe MR due to MV prolapse or chordal avulsion. Transthoracic echocardiography and Holter monitoring were performed in all patients before and annually after surgery. A pathomorphological study of MV fragments excised during surgery was performed.Results During the five-year follow-up period (144 person-years), one case of sudden cardiac death outside a health care facility was recorded. MR severity progressed in three patients after MV repair. The total number of all VAs decreased during the follow-up period, with a significant decrease in the number of paroxysms of unstable ventricular tachycardia during the first two years after surgery. The presence of VA in the postoperative period was correlated with the severity of postoperative left ventricular (LV) remodeling: end-diastolic volume (EDV) (rs=0.69; p=0.005), LV ejection fraction (EF) (rs = -0.55; p=0.004) and severity of MV myxomatous alterations according to histological study data (rτ=0.58; p=0.045). The beta-blocker treatment did not influence the VA frequency and severity (rs= -0.18; p=0.69). According to a univariate regression analysis only EDV (p = 0.001), LVEF &lt;50% (p = 0.003), and myxomatous MV degeneration (p = 0.02) were risk factors for persistent ventricular tachycardia in the postoperative period.Conclusion Surgical intervention on MV in patients with MV prolapse and severe MR decreased the number of cases of malignant VAs and was correlated with the postoperative changes in LV volume and function, as well as the severity of MV myxomatous alterations.

Arrhythmogenic Right Ventricular Dysplasia Presenting with Sustained Ventricular Tachycardia: A Case Report

Arrhythmogenic right ventricular dysplasia (ARVD) is a cardiomyopathy characterized pathologically by fibrofatty tissue replacement of the myocyte of the right ventricle (RV) and clinically by life-threatening ventricular arrhythmias in young people. It is a major cause of sudden death. We present the case of a 60-year-old man with cardiovascular risk factors, was admitted for unstable ventricular tachycardia (VT) treated immediately with synchronized cardioversion. After the stabilization of the patient, Electrocardiogram demonstrated an epsilon wave in precordial leads and diffuse T-wave inversions. Transthoracic echocardiography revealed a dilated, hypokinetic right ventricle with moderately reduced function and a focal area of dyskinesia. The diagnosis of arrhythmogenic right ventricular dysplasia (ARVD) was made and an implantable cardioverter defibrillator (ICD) was indicated for secondary prevention. This case report will present the clinical presentation, diagnosis and management of this rare disease.

Quiescent-yet-excitable pluripotent stem cell-derived cardiomyocytes engraft without fatal arrhythmias in minipig and primates

Abstract Background Pluripotent stem cell-derived cardiomyocyte (PSC-CM) transplantation is a promising therapy for subacute myocardial infarction (MI), but transient engraftment-related arrhythmia (EA) is major barrier to clinical development (1, 2). We hypothesize that PSC-CM genetically edited to remove automaticity but otherwise functionally intact will engraft in vivo with greater arrhythmic safety. Methods Combinatorial CRISPR/Cas9 genome editing to screen for electrically quiescent PSC-CM yielded a line deficient in the depolarization-associated genes HCN4, CACNA1H, and SLC8A1, combined with overexpression of the hyperpolarization-associated gene KCNJ2. Initially, we transplanted 150 million (n=3) and 500 million gene-edited (n=2) and 150 million wildtype (n=7) PSC-CMs into a minipig model of EA, and we monitored the animals for up to seven weeks on continuous ECG for arrythmia without anti-arrhythmic therapy. In a second study, we transplanted 750 million gene-edited (n=2) and wildtype (n=1) PSC-CMs into sub-acutely infarcted Macaca nemestrina primates. Sham transplant (n=1) was also performed, and all animals were observed for up to three months with immunosuppression and beta-blocker/amiodarone therapy. Results Gene-edited PSC-CM successfully engrafted and structurally coupled with the host myocardium of minipigs (Figure 1) and nonhuman primates (Figure 2). No significant EA occurred after transplanting edited PSC-CM at the 150 million dose, whereas brief EA (&amp;lt;24 hours) was observed and well tolerated at the higher 500 million dose. All five minipigs survived to prespecified timepoints without complication. Conversely, wildtype PSC-CM controls demonstrated uncontrolled and fatal ventricular tachycardia (VT). Of the seven WT control minipigs, only four survived (43% mortality); three expired or were euthanized due to unstable VT or ventricular fibrillation. Arrythmia burden for both 150 and 500 million doses were significantly reduced compared to the 150 million wildtype dose in the first 30-days post-transplant (p&amp;lt;0.0001 for both). We then tested edited PSC-CM in a clinically relevant nonhuman primate model of sub-acute myocardial infarction using standard medical therapy including modest antiarrhythmic therapy. No arrythmia was noted in both nonhuman primates dosed with 750 million edited PSC-CM whereas significant arrhythmia was observed with wildtype despite beta blocker and amiodarone therapy. All pig and primate grafts were structurally coupled with host myocardium. Conclusion Genetically-edited PSC-CM without pacemaker-like activity significantly reduced arrythmia burden and prevented arrhythmic death in a dose-escalation study in minipig. No arrhythmia was observed in a clinically relevant nonhuman primate model of cardiac remuscularization for sub-acute myocardial infarction. This study supports continued investigation of this novel strategy to improve safety and tolerability of PSC-CM transplantation.Edited PSC-CM transplant in minipigEdited PSC-CM transplant in primates

Abstract 18141: Outcomes of Prospective Computational 12-Lead ECG Mapping to Guide Ablation of Unstable Ventricular Tachycardia

Background: Unstable ventricular tachycardia is difficult to map and ablate, with high recurrence rates. We developed a 12-lead ECG mapping algorithm based on computational models to localize VT to help guide ablation of unstable VT. Hypothesis: We hypothesized that prospective ECG-mapping can facilitate invasive activation mapping and improve the success of unstable VT ablation. Aims: To compare the time to ICD shock + death in patients undergoing ECG-mapping guided ablation of unstable VT compared to standard ablation controls. Methods: Consecutive patients from 2 centers with unstable VT undergoing ECG-mapping guided VT ablation were prospectively enrolled. Using the ECG, computational mapping localized the VT onto a 3D model. A multielectrode catheter was placed at the predicted site and activation mapping was performed during VT reinduction. Ablation was performed per standard protocol. Time to ICD shock or death was compared using Cox regression (adjusting for age, EF and ICM) between ECG-mapping guided ablation vs standard VT ablation controls with a minimum 3 month f/u. Accuracy of ECG mapping was compared with activation mapping. Results: Out of 32 consecutive patients who underwent ECG-mapping guided VT ablation, 26 had unstable VT (age 66±10 yr, EF 34±17%). All 26 (100%) patients with unstable VT (median VT CL: 326±81ms) underwent successful activation mapping, Fig 1A. Using Cox regression adjusting for covariates, ECG-mapping guided VT ablation had a significant reduction in ICD shock or death compared to standard ablation controls (p=0.01, HR=0.23 [CI 0.07-0.70], Fig 1B). There was a 99% reduction in total ICD shocks during mean 7.5 month f/u. For all 32 patients, the mean accuracy of ECG mapping was 1.3±0.7cm when compared to invasive activation±entrainment mapping. Conclusions: Use of computational 12-lead ECG mapping to guide ablation of unstable VT significantly improved freedom from ICD shocks and death resulting in excellent accuracy.

Abstract 15659: Bupropion Overdose Requiring Veno-Arterial Extracorporeal Membrane Oxygenation

Introduction: Bupropion is a monocyclic antidepressant that inhibits dopamine and norepinephrine reuptake, with significant risk cardiotoxicity in overdose cases. Case: A 32-year-old transgender man with a history of Human Immunodeficiency Virus (on anti-retroviral therapy), poly-substance use disorder, and depression presented with an intentional bupropion overdose. On arrival the patient was noted to have seizures and a decreased mental status. He was intubated and treated with anti-epileptic medication. Initial EKG was sinus tachycardia with a QTc of 456 milliseconds. Transthoracic echocardiogram (TTE) showed severely reduced left ventricular ejection fraction (LVEF) that worsened over a 6 hour period from 40% of 25%. Serial EKGs showed progressive QTc prolongation to 635 milliseconds. Cardiac catheterization demonstrated angiographically normal coronary arteries and a Cardiac Index of 2.5 L/min/m 2 . Due to the rapidly prolonging QTc and the significant risk of ventricular tachycardia (VT), the decision was to proceed with Veno-Arterial Extracorporeal Membrane Oxygenation (VA-ECMO) cannulation after a multidisciplinary shock team discussion. A few hours after cannulation, patient suffered hemodynamically unstable VT, requiring electrical cardioversion (DCCV) with brief return to sinus rhythm (SR) and with subsequent VT recurrence, that responded to lidocaine and repeat DCCV. ECG normalized and the patient was decannulated from VA ECMO on hospital day 4. Repeat TTE showed recovery of LVEF to 60%. The patient was extubated and discharged to psychiatric rehabilitation. Conclusion: Cardiogenic shock and ventricular arrhythmias are well recognized complications from bupropion toxicity likely due to gap junction inhibition. VA ECMO cannulation should be considered as part of multidisciplinary team assessment for patients at high risk for hemodynamic or electrical collapse in toxidromes with marked cardiotoxicity.

Calcium Jacket of Left Ventricle: An Aristocracy of the Monster

Extensive myocardial dystrophic calcification is rare and indicates a poor prognosis with a risk of arrhythmia and recurrent heart failure. We present a long term survivor of extensive myocardial infarction presenting as myocardial calcification related unstable ventricular tachycardia needing an implantable cardioverter defibrillator.

Cardiovascular system damage in the late-onset Pompe disease

The article presents a clinical case of metabolic hypertrophic cardiomyopathy against the background of a late-onset form of Pompe disease, illustrating the difficulties of differential diagnostic search for the cause of the disease. The clinical, laboratory and genetic aspects of the diagnosis of Pompe disease are highlighted. The features of laboratory diagnostics, the difficult path to the correct diagnosis and the appointment of enzyme replacement therapy are discussed. Much attention is paid to the clinical symptoms of the disease — the most significant damage to the cardiovascular system, there is no damage to the musculoskeletal sphere. Clinical picture of late Pompe disease is presented: cardiac rhythm and conduction disorders (ventricular preexcitation syndrome — multiple additional atrioventricular fenestrations), unstable ventricular tachycardia, supraventricular tachycardia, sinus node weakness syndrome. Considered approaches to the prevention of sudden cardiac death the patient underwent surgical treatment: radiofrequency ablation, endocardial implantation of a cardioverter defibrillator. Pathogenetic therapy for Pompe disease has been started.

CARDIAC AMYLOIDOSIS DIAGNOSIS DUE TO ICD QUALIFICATION

Amyloidosis is a chronic disease, based on abnormal protein deposition in the extracellular space. The heart may also be affected, which leads to amyloid cardiomyopathy. We present the case of a 69-year-old patient initially admitted due to symptomatic sick sinus syndrome, who developed hemodynamically unstable ventricular tachycardia during further hospitalization. In the course of diagnostics before ICD implantation qualification, the echocardiographic image suggested a storage disease with heart involvement. As a result of the intensive hematological diagnostics, the diagnosis of cardiac amyloidosis in the course of multiple myeloma was confirmed, which is a rare combination. Arrhythmia was the primary reason for implementing diagnostics leading to this diagnosis.