Venoarterial Extracorporeal Membrane Oxygenation for "Protected" Percutaneous Coronary Intervention Secondary to Refractory Polymorphic Ventricular Tachycardia and Cardiac Arrest.

ABSTRACT: We present a case of cardiogenic shock secondary to refractory polymorphic ventricular tachycardia associated with coronary ischemia resulting in cardiac arrest. Following the return of spontaneous circulation, the patient was cannulated for peripheral venoarterial extracorporeal membrane oxygenation (V-A ECMO) in anticipation of high-risk "protected" percutaneous coronary intervention (PCI). Under full V-A ECMO support, inotropes and vasopressors were weaned off, and the patient underwent uneventful PCI of left circumflex and obtuse marginal lesions. After 48 hours, the patient was decannulated and could be discharged home alive 16 days after his initial cardiac arrest.

Combined Stellate Ganglion Blockade and Epidural Thoracic Anesthesia for the Management of Ventricular Storm: A Case Report.

ABSTRACT: The term "ventricular storm (VS)" is defined as the occurrence of two or more separate episodes of ventricular tachycardia or fibrillation (VT/VF) or three or more appropriate discharges of an implantable cardioverter defibrillator for VT/VF during a 24-h period. A patient in his early 40s was observed in the emergency department of our hospital and was admitted to the cardiac intensive care unit due to multiple episodes of VT. This led to the need for deep sedation with orotracheal intubation and mechanical ventilation. Intravenous lidocaine treatment was started; however, the patient had a recurrence of the episodes of VT. We decided to combine stellate ganglion block with epidural thoracic anesthesia. After the sympathetic block, there was no recurrence of the arrhythmic episodes. The patient was then transferred for ablation treatment. We demonstrated the efficacy of both techniques in managing a patient with multiple episodes of ventricular storm.

Extracorporeal Membrane Oxygenation for Protected Catheter Ablation in A Post-Cardiotomy Patient With Electrical Storm.

ABSTRACT: An electrical storm (ES) refers to multiple occurrences of ventricular arrhythmias within a short time. Catheter ablation is a treatment option for ES but can be challenging in unstable cardiovascular patients. We present the case of a 50-year-old patient with poor left ventricular function who experienced ES after emergency coronary artery bypass grafting (CABG). Despite maximal antiarrhythmic therapy, the patient had recurrent ventricular tachycardia and fibrillation (VT/VF), hindering catheter ablation. Elective venoarterial extracorporeal membrane oxygenation (ECMO) support was established, allowing a successful second catheter ablation attempt without complications. The patient was weaned off ECMO the following day and remained in normal sinus rhythm.

Oral amiodarone and propranolol in maintenance therapy of postimplantation tachycardia: An observational study.

Left ventricular assist devices (LVADs) are widely used as end-stage therapy in patients with advanced heart failure, whereas implantation increases the risks of development of sustained ventricular tachycardia at the later postimplantation stage. Therefore, this study aimed to evaluate the clinical efficacy of orally administered amiodarone and propranolol in 3 patients with ventricular tachycardia (VT) after LVAD implantation who were resistant to initial anti-antiarrhythmic drugs. This retrospective cohort study consisted of the initial evaluation of the clinical data of 14 adult patients who underwent implantation of LVAD between January 2019 and March 2021. A total of 3 patients with resistant VT were finally included. In all cases, the patients were initially administered amiodarone in the different doses intravenously to stabilize the critical condition, whereas its oral form along with that of propranolol was used as maintenance therapy in the first 2 cases. In the third case, amiodarone was withdrawn because of the risk of development of hyperthyroidism, while oral propranolol was used in the treatment. The assessment in the 16-month follow-up period after discharge did not show presence of non-sustained and sustained VT in all 3 cases. In the ventricular arrhythmia-free group, the total mortality rate within the follow-up period was 11.1 ±â€…7.78 months in the 3 patients. We suggest that maintenance oral therapy of propranolol and amiodarone can significantly decrease the risks of complications in patients with VT after implantation of ventricular assist device in the long term.

[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.

Transmural APD heterogeneity determines ventricular arrhythmogenesis in LQT8 syndrome: Insights from Bidomain computational modeling.

Long QT Syndrome type 8 (LQT8) is a cardiac arrhythmic disorder associated with Timothy Syndrome, stemming from mutations in the CACNA1C gene, particularly the G406R mutation. While prior studies hint at CACNA1C mutations' role in ventricular arrhythmia genesis, the mechanisms, especially in G406R presence, are not fully understood. This computational study explores how the G406R mutation, causing increased transmural dispersion of repolarization, induces and sustains reentrant ventricular arrhythmias. Using three-dimensional numerical simulations on an idealized left-ventricular model, integrating the Bidomain equations with the ten Tusscher-Panfilov ionic model, we observe that G406R mutation with 11% and 50% heterozygosis significantly increases transmural dispersion of repolarization. During S1-S4 stimulation protocols, these gradients facilitate conduction blocks, triggering reentrant ventricular tachycardia. Sustained reentry pathways occur only with G406R mutation at 50% heterozygosis, while neglecting transmural heterogeneities of action potential duration prevents stable reentry, regardless of G406R mutation presence.

An Unusual Case of Takotsubo Cardiomyopathy with Cardiac Arrest: The Importance of Clinical Context in Implanted Cardioverter Defibrillator Candidacy.

Takotsubo syndrome (TTS), also known as stress-induced cardiomyopathy, is characterized by acute heart failure, reversible left ventricular dysfunction, and other complications such as life-threatening arrhythmias. The management of TTS is challenging due to its unpredictable clinical course and the lack of evidence-based treatment recommendations. In this case report, we present a 71-year-old female who developed TTS with ventricular tachycardia (VT) cardiac arrest following septic shock and an exploratory laparotomy for appendicitis. Despite the presence of VT cardiac arrest and a left ventricular ejection fraction of 30-35%, an implanted cardioverter-defibrillator (ICD) was not indicated due to the rapid and satisfactory recovery of the patient's ventricular function. This case highlights the importance of considering the clinical context and the transient nature of TTS in the decision-making process for ICD candidacy.

Respiratory Function of Mitochondria in Patients with Coronary Heart Disease with Implantable Cardioverter-Defibrillator.

We studied the respiratory activity of mitochondria in peripheral blood leukocytes from 36 patients with coronary heart disease (CHD) and a history of ventricular tachyarrhythmias required cardioverter-defibrillator implantation. The measurements were carried out in incubation buffers with different oxidation substrates (succinate and pyruvate-malate mixture). In pyruvate-malate incubation buffer, oxygen consumption rate and respiratory control coefficients in patients with triggered device did not differ significantly from those in patients without cardioverter-defibrillator triggering. At the same time, respiratory control coefficients were below the reference values. In succinate buffer, values of mitochondrial parameters were significantly lower in patients with triggered devices. Our findings indicate that mitochondria of patients with non-triggered cardioverters-defibrillators have better functional and metabolic plasticity. It was concluded that activity of respiratory processes in mitochondria could be an indicator that should be taken into the account when assessing the risk of developing ventricular tachyarrhythmias.

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

AIMS: Patients with structural heart disease (SHD) undergoing catheter ablation (CA) for ventricular tachycardia (VT) are at considerable risk of periprocedural complications, including acute haemodynamic decompensation (AHD). The PAINESD score was proposed to predict the risk of AHD. The goal of this study was to validate the PAINESD score using the retrospective analysis of data from a large-volume heart centre. METHODS AND RESULTS: Patients who had their first radiofrequency CA for SHD-related VT between August 2006 and December 2020 were included in the study. Procedures were mainly performed under conscious sedation. Substrate mapping/ablation was performed primarily during spontaneous rhythm or right ventricular pacing. A purposely established institutional registry for complications of invasive procedures was used to collect all periprocedural complications that were subsequently adjudicated using the source medical records. Acute haemodynamic decompensation triggered by CA procedure was defined as intraprocedural or early post-procedural (<12 h) development of acute pulmonary oedema or refractory hypotension requiring urgent intervention. The study cohort consisted of 1124 patients (age, 63 ± 13 years; males, 87%; ischaemic cardiomyopathy, 67%; electrical storm, 25%; New York Heart Association Class, 2.0 ± 1.0; left ventricular ejection fraction, 34 ± 12%; diabetes mellitus, 31%; chronic obstructive pulmonary disease, 12%). Their PAINESD score was 11.4 ± 6.6 (median, 12; interquartile range, 6-17). Acute haemodynamic decompensation complicated the CA procedure in 13/1124 = 1.2% patients and was not predicted by PAINESD score with AHD rates of 0.3, 1.8, and 1.1% in subgroups by previously published PAINESD terciles (<9, 9-14, and >14). However, the PAINESD score strongly predicted mortality during the follow-up. CONCLUSION: Primarily substrate-based CA of SHD-related VT performed under conscious sedation is associated with a substantially lower rate of AHD than previously reported. The PAINESD score did not predict these events. The application of the PAINESD score to the selection of patients for pre-emptive mechanical circulatory support should be reconsidered.

Prevalence and electrocardiographic and electrophysiological characteristics of idiopathic ventricular arrhythmias originating from the septal left ventricular summit.

INTRODUCTION: The left ventricular summit (LVS) is the highest point on the epicardial surface of the left ventricle. A part of the LVS that is located between the left coronary arteries (lateral-LVS) is one of the major sites of idiopathic ventricular arrhythmia (VA) origins. Some idiopathic epicardial VAs can be ablated at endocardial sites adjacent to the epicardial area septal to the lateral-LVS (septal-LVS). This study examined the prevalence and electrocardiographic and electrophysiological characteristics of septal-LVS VAs. METHODS: We studied consecutive patients with idiopathic VAs originating from the LVS (67 patients) and aortic root (93 patients). RESULTS: Based on the ablation results, among 67 LVS VAs, 54 were classified as lateral and 13 as septal-LVS VAs. As compared with the lateral-LVS VAs, the septal-LVS VAs were characterized by a greater prevalence of left bundle branch block with left inferior-axis QRS pattern, later precordial transition, lower R-wave amplitude ratio in leads III to II, lower Q-wave amplitude ratio in leads aVL to aVR, and later local ventricular activation time relative to the QRS onset during VAs (V-QRS) in the great cardiac vein. The electrocardiographic and electrophysiological characteristics of the septal-LVS VAs were similar to those of the aortic root VAs. However, the V-QRS at the successful ablation site was significantly later during the septal-LVS VAs than aortic root VAs (p < .0001). The precordial transition was significantly later during the septal-LVS VAs than aortic root VAs (p < .05). CONCLUSIONS: Septal-LVS VAs are considered a distinct subgroup of idiopathic VAs originating from the left ventricular outflow tract.

Ibrutinib, a Bruton's tyrosine kinase inhibitor, regulates ventricular electromechanical activities and enhances arrhythmogenesis.

BACKGROUND: Ibrutinib, a Bruton's tyrosine kinase inhibitor used in cancer therapy, exerts ventricular proarrhythmic effects; however, the underlying mechanisms remain unclear. Excitation-contraction coupling (E-C) disorders are pivotal for the genesis of ventricular arrhythmias (VAs), which arise mainly from the right ventricular outflow tract (RVOT). In this study, we aimed to comprehensively investigate whether ibrutinib regulates the electromechanical activities of the RVOT, leading to enhanced arrhythmogenesis, and explore the underlying mechanisms. METHODS: We utilized conventional microelectrodes to synchronously record electrical and mechanical responses in rabbit RVOT tissue preparations before and after treatment with ibrutinib (10, 50, and 100 nM) and investigated their electromechanical interactions and arrhythmogenesis during programmed electrical stimulation. The fluorometric ratio technique was used to measure intracellular calcium concentration in isolated RVOT myocytes. RESULTS: Ibrutinib (10-100 nM) shortened the action potential duration. Ibrutinib at 100 nM significantly increased pacing-induced ventricular tachycardia (VT) (from 0% to 62.5%, n = 8, p = 0.025). Comparisons between pacing-induced VT and non-VT episodes demonstrated that VT episodes had a greater increase in contractility than that of non-VT episodes (402.1 ± 41.4% vs. 232.4 ± 29.2%, p = 0.003). The pretreatment of ranolazine (10 µM, a late sodium current blocker) prevented the occurrence of ibrutinib-induced VAs. Ibrutinib (100 nM) increased late sodium current, reduced intracellular calcium transients, and enhanced calcium leakage in RVOT myocytes. CONCLUSION: Ibrutinib increased the risk of VAs in the RVOT due to dysregulated electromechanical responses, which can be attenuated by ranolazine or apamin.

[VT ablation - a technically complex procedure]. / Ablationsbehandling hos patienter med strukturell hjärtsjukdom.

Ventricular tachycardia (VT) in patients with structural heart disease is potentially life threatening, and most patients have an indication for an implantable cardioverter-defibrillator (ICD). Catheter ablation is an effective therapeutic strategy to reduce the risk of VT recurrence and subsequent ICD therapies. However, VT ablation is a technically complex procedure with significant risks and should be performed in experienced centers with appropriate resources. While several reports on outcome and procedural risks have been published, there is currently no data from Sweden. In addition to this literature review, we have analyzed VT ablation outcome data from our center. In 2021 and 2022, 68 VT ablations were performed in 60 patients with structural heart disease. After a median follow-up of 20 months, 18 percent had recurrent VT and there were 2 major adverse events (stroke and complete atrioventricular block). Seven patients died from non-arrhythmia related causes during follow-up. A large proportion (68 percent) were subacute procedures which are associated with a higher periprocedural risk. Referral for VT ablation earlier in the course of disease progression may likely further improve outcomes.

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) in a Special Operations Soldier: A Case Report.

Special Operations Servicemembers presenting with palpitations, pre-syncope, or exertional syncope during rigorous physical training are often experiencing a benign condition; however, life-threatening etiologies should be considered. We describe a 43-year-old Special Operator who presented to his medics during selection physical assessment testing with palpitations and lightheadedness, with a subsequent workup revealing arrhythmogenic right ventricular cardiomyopathy (ARVC). His initial electrocardiogram was unremarkable without characteristic ARVC changes. Outpatient evaluation with ambulatory cardiac monitoring recorded numerous episodes of non-sustained ventricular tachycardia. Transthoracic echocardiography demonstrated findings concerning for ARVC, with subsequent cardiac MRI confirming the diagnosis via the 2020 Padua criteria. Management includes activity modification, class III anti-arrhythmic medications, and possible placement of an implantable cardioverter defibrillator to prevent sudden cardiac death. This case demonstrates the importance of maintaining high clinical suspicion for rare diagnoses that present with exertional palpitations, such as arrhythmogenic right ventricular cardiomyopathy, in even our fittest Special Operators.

Sudden cardiac arrest occurring in temporal proximity to consumption of energy drinks.

BACKGROUND: Energy drinks potentially can trigger life-threatening cardiac arrhythmias. It has been postulated that the highly stimulating and unregulated ingredients alter heart rate, blood pressure, cardiac contractility, and cardiac repolarization in a potentially proarrhythmic manner. OBJECTIVE: The purpose of this study was to describe our experience regarding sudden cardiac arrest (SCA) occurring in proximity to energy drink consumption in patients with underlying genetic heart diseases. METHODS: The electronic medical records of all SCA survivors with proven arrhythmias referred to the Mayo Clinic Windland Smith Rice Genetic Heart Rhythm Clinic for evaluation were reviewed to identify those who consumed an energy drink before their event. Patient demographics, clinical characteristics, documented energy drink consumption, and temporal relationship of energy drink consumption to SCA were obtained. RESULTS: Among 144 SCA survivors, 7 (5%; 6 female; mean age at SCA 29 ± 8 years) experienced an unexplained SCA associated temporally with energy drink consumption. Of these individuals, 2 had long QT syndrome and 2 had catecholaminergic polymorphic ventricular tachycardia; the remaining 3 were diagnosed with idiopathic ventricular fibrillation. Three patients (43%) consumed energy drinks regularly. Six patients (86%) required a rescue shock, and 1 (14%) was resuscitated manually. All SCA survivors have quit consuming energy drinks and have been event-free since. CONCLUSION: Overall, 5% of SCA survivors experienced SCA in proximity to consuming an energy drink. Although larger cohort studies are needed to elucidate the incidence/prevalence and quantify its precise risk, it seems prudent to sound an early warning on this potential risk.

A Clinical Diagnostic Test for Calcium Release Deficiency Syndrome.

Importance: Sudden death and cardiac arrest frequently occur without explanation, even after a thorough clinical evaluation. Calcium release deficiency syndrome (CRDS), a life-threatening genetic arrhythmia syndrome, is undetectable with standard testing and leads to unexplained cardiac arrest. Objective: To explore the cardiac repolarization response on an electrocardiogram after brief tachycardia and a pause as a clinical diagnostic test for CRDS. Design, Setting, and Participants: An international, multicenter, case-control study including individual cases of CRDS, 3 patient control groups (individuals with suspected supraventricular tachycardia; survivors of unexplained cardiac arrest [UCA]; and individuals with genotype-positive catecholaminergic polymorphic ventricular tachycardia [CPVT]), and genetic mouse models (CRDS, wild type, and CPVT were used to define the cellular mechanism) conducted at 10 centers in 7 countries. Patient tracings were recorded between June 2005 and December 2023, and the analyses were performed from April 2023 to December 2023. Intervention: Brief tachycardia and a subsequent pause (either spontaneous or mediated through cardiac pacing). Main Outcomes and Measures: Change in QT interval and change in T-wave amplitude (defined as the difference between their absolute values on the postpause sinus beat and the last beat prior to tachycardia). Results: Among 10 case patients with CRDS, 45 control patients with suspected supraventricular tachycardia, 10 control patients who experienced UCA, and 3 control patients with genotype-positive CPVT, the median change in T-wave amplitude on the postpause sinus beat (after brief ventricular tachycardia at ≥150 beats/min) was higher in patients with CRDS (P < .001). The smallest change in T-wave amplitude was 0.250 mV for a CRDS case patient compared with the largest change in T-wave amplitude of 0.160 mV for a control patient, indicating 100% discrimination. Although the median change in QT interval was longer in CRDS cases (P = .002), an overlap between the cases and controls was present. The genetic mouse models recapitulated the findings observed in humans and suggested the repolarization response was secondary to a pathologically large systolic release of calcium from the sarcoplasmic reticulum. Conclusions and Relevance: There is a unique repolarization response on an electrocardiogram after provocation with brief tachycardia and a subsequent pause in CRDS cases and mouse models, which is absent from the controls. If these findings are confirmed in larger studies, this easy to perform maneuver may serve as an effective clinical diagnostic test for CRDS and become an important part of the evaluation of cardiac arrest.

Road-Map to Epicardial Approach for Catheter Ablation of Ventricular Tachycardia in Structural Heart Disease: Results From a 10-Year Tertiary-Center Experience.

BACKGROUND: Epicardial approach in ventricular tachycardia (VT) ablation is still regarded as a second-step strategy, due to the risk of complications. We evaluated the frequency that epicardial ablation targets were identified and ablation performed following pericardial access compared with unnecessary pericardial access for different VT causes and potential markers of epicardial VT. METHODS: All VT ablation procedures including epicardial approach over a 10-year period were included. First-line epicardial approach was indicated in arrhythmogenic right ventricular cardiomyopathy (ARVC) and postmyocarditis VT; in patients with idiopathic dilated cardiomyopathy (IDCM) and postmyocardial infarction, indications resulted from available imaging techniques or 12-lead VT morphology. The epicardial approach was considered useful if epicardial ablation was performed after epicardial mapping. Feasibility, complications, and long-term outcome were reported. RESULTS: Four hundred and eighty-eight subjects with a median age of 60 years (interquartile range, 47-65) and of left ventricle ejection fraction 41% (interquartile range, 30-55) underwent 626 epicardial VT ablations. Percutaneous access had a success rate of 92.2% and a complication rate of 3.6%. Overall, epicardial approach was, respectively, indicated to 11.8% of postmyocardial infarction patients, 49.5% in IDCM, 94% in myocarditis, and 90.7% in ARVC. Epicardial ablation at the first ablation attempt was performed in 9.3% of postmyocardial infarction patients, 28.8% in IDCM, 86.5% in myocarditis, and 81.3% in patients with ARVC. In first-line epicardial group, ARVC and myocarditis showed the highest odds for epicardial ablation (OR, 4.057 [95% CI, 1.299-8.937]; P=0.007; OR, 3.971 [95% CI, 1.376-11.465]; P=0.005, respectively). IDCM independently predicted unnecessary epicardial approach (OR, 2.7 [95% CI, 1.7-4.3]; P<0.001). After a follow-up of 41 months (interquartile range, 19-64), patients with IDCM experienced higher rate of recurrences and mortality compared with other causes. CONCLUSIONS: Epicardial approach is integral part of ablation armamentarium regardless of the VT cause, with high feasibility and low complication rate in experienced centers. Our data support its use at first ablation attempt in VTs related to ARVC and myocarditis.