Super-refractory status epilepticus, rhabdomyolysis, central hyperthermia and cardiomyopathy attributable to spinal anesthesia: a case report and review of literature.

BACKGROUND: There are only six past reports of super-refractory status epilepticus induced by spinal anesthesia. None of those patients have died. Only < 15 mg of bupivacaine was administered to all six of them and to our case. Pathophysiology ensuing such cases remains unclear. CASE PRESENTATION: A 27 year old gravida 2, para 1, mother at 37 weeks of gestation came to the operating theater for an elective cesarean section. She had no significant medical history other than controlled hypothyroidism and one episode of food allergy. Her current pregnancy was uneventful. Her American Society of Anesthesiologists (ASA) grade was 2. She underwent spinal anesthesia and adequate anesthesia was achieved. After 5-7 min she developed a progressive myoclonus. After delivery of a healthy baby, she developed generalized tonic clonic seizures that continued despite the induction of general anesthesia. She had rhabdomyolysis, one brief cardiac arrest and resuscitation, followed by stress cardiomyopathy and central hyperthermia. She died on day four. There were no significant macroscopic or histopathological changes in her brain that explain her super refractory status epilepticus. Heavy bupivacaine samples of the same batch used for this patient were analyzed by two specialized laboratories. National Medicines Quality Assurance Laboratory of Sri Lanka reported that samples failed to confirm United States Pharmacopeia (USP) dextrose specifications and passed other tests. Subsequently, Therapeutic Goods Administration of Australia reported that the drug passed all standard USP quality tests applied to it. Nonetheless, they have detected an unidentified impurity in the medicine. CONCLUSIONS: After reviewing relevant literature, we believe that direct neurotoxicity by bupivacaine is the most probable cause of super-refractory status epilepticus. Super-refractory status epilepticus would have led to her other complications and death. We discuss probable patient factors that would have made her susceptible to neurotoxicity. The impurity in the drug detected by one laboratory also would have contributed to her status epilepticus. We propose several possible mechanisms that would have led to status epilepticus and her death. We discuss the factors that shall guide investigators on future such cases. We suggest ways to minimize similar future incidents. This is an idiosyncratic reaction as well.

Peripartum Cardiomyopathy: A Review Article.

Peripartum cardiomyopathy (PPCM) is an important cause of heart failure (HF) in northern Nigeria and many other regions of the world. Although the aetiology is unknown, several aetiopathogenic mechanisms have been proposed, including myocarditis, vasculo-hormonal (16-kDa prolactin and Cathepsin D), genetic susceptibility and selenium deficiency hypotheses. The peripartum cardiomyopathy in Nigeria (PEACE) registry has revealed that three socioeconomic factors (lack of formal education, unemployment, underweight status), pre-eclampsia and selenium deficiency were independently associated with higher risk for PPCM. However the customary postpartum practices previously implicated in the aetio-pathogenesis of postpartum cardiac failure, comprising regular hot baths and pap enriched with dried lake salt, were not associated with PPCM. Maternal age <20 years, tachycardia, hypotension and ejection fraction <25% independently increased the risk for mortality. Regular use of beta-blockers and obesity were independently associated with higher survival, and selenium supplementation is a promising treatment strategy for PPCM.

La cardiomyopathie du péripartum (PPCM) est une cause importante d'insuffisance cardiaque (IC) dans le nord du Nigeria et dans de nombreuses autres régions du monde. Bien que l 'ét iol ogi e soi t i nconnue, pl usi eurs mécani smes éti opat hogéni ques ont ét é proposés, not amment les hypothèses de myocardite, vasculo-hormonale (prolactine 16kDa et cathepsine D), de susceptibilité génétique et de carence en sélénium. Le registre PEACE (peripartum cardiomyopathy in Nigeria) a révélé que trois facteurs socio-économiques (absence d'éducation formelle, chômage, insuffisance pondérale), la pré-éclampsie et la carence en sélénium étaient indépendamment associés à un risque plus élevé de PPCM. Cependant , l es prat iques post-part um habit uel l es, précédemment i mpl iquées dans l'éti opat hogéni e de l'insuffisance cardiaque post-partum, comprenant des bains chauds réguliers et des bouillies enrichies de sel de lac séché, n'étaient pas associées au PPCM. L'âge maternel <20 ans, la tachycardie, l'hypotension et la fraction d'éjection <25% augmentaient indépendamment le risque de mortalité. L'utilisation régulière de bêta-bloquants et l'obésité étaient indépendamment associées à une survie plus élevée, et la supplémentation en sélénium est une stratégie de traitement prometteuse pour le PPCM. . Mots clés: Cardiomyopathie du péripartum; Facteurs de risque; Étiologie; résultats.

[Research advance of the mechanism and treatment of septic cardiomyopathy].

Sepsis is a life-threatening organ dysfunction caused by dysregulation of the body's response to infection. It is one of the common and serious complications in clinically critical patients with trauma, burn, shock, infection, etc., with high morbidity and mortality. Although the treatment of sepsis has made great achievements in clinical practice, the mortality of patients with sepsis is still increasing due to its secondary complications. Septic cardiomyopathy (SCM) is one of the major complications that threaten septic patient's life. SCM refers to myocardial dysfunction with the aggravation of the primary disease, which is manifested by biventricular dilatation accompanied by a decrease in left ventricular ejection fraction (LVEF). It is one of the major complications that threaten the life of patients with sepsis. The existing research shows that the mechanism of SCM includes myocardial mitochondrial dysfunction, myocardial cell apoptosis, calcium circulation disorder and its treatment including conventional treatment, ß1 receptor blocker treatment and traditional Chinese medicine treatment,etc. This paper reviewed the pathogenesis of SCM and its related, in order to provide references for the rational diagnosis and treatment of SCM.

Ventricular assist device support for children with chemotherapy-induced cardiomyopathy and advanced heart failure: Perspectives gained from a single-center experience.

BACKGROUND: Guidance and data on ventricular assist device (VAD) support for children with chemotherapy-induced cardiomyopathy, particularly within the first 2 years after chemotherapy, are limited. METHODS: We performed a single-center retrospective case series, reviewing medical records of children <18 years of age with chemotherapy-induced cardiomyopathy and advanced heart failure (HF) who received durable VAD support. RESULTS: Six patients met inclusion criteria-5 HeartWare™ HVAD, 1 Berlin Heart EXCOR® . Median age at cancer diagnosis was 6 years (IQR 4.5-10 years). Median dose of anthracycline received was 540 mg/m2 (IQR 450-630 mg/m2 ). All patients developed HF within 1 year after initiation of cancer treatment (median 8 months, IQR 6-11.5 months) and were initiated on durable VAD support at a median of 8 months after completion of cancer treatment (IQR 3.3-43.5 months). Four patients had significant right ventricular dysfunction needing oral pulmonary vasodilator therapy, one patient had a major bleeding complication, and two patients had thromboembolic strokes while on VAD support. Median duration of VAD support was 7.5 months (IQR 3-11.3 months). Two patients underwent VAD explant due to recovery of LV function, one died due to cancer progression, and three underwent heart transplantation. CONCLUSIONS: Durable VAD support should be considered as a therapeutic option for children who have advanced HF due to chemotherapy-induced cardiomyopathy, even within 2 years of completing cancer treatment. A multi-disciplinary approach is essential for appropriate patient selection prior to implant and to ensure comprehensive care throughout the duration of VAD support.

Comparison of efficacy and safety of His-Purkinje system pacing versus cardiac resynchronisation therapy in patients with pacing-induced cardiomyopathy: protocol for a randomised controlled trial.

INTRODUCTION: Recent studies have shown that the His-Purkinje system pacing (HPSP) can achieve electrocardiomechanical synchronisation, and thus improve cardiac function. For patients with pacing-induced cardiomyopathy (PICM) who should be treated with pacemaker upgrade, the HPSP is a viable alternative to cardiac resynchronisation therapy (CRT). However, no randomised controlled trial has been performed to evaluate the efficacy and safety of HPSP in patients with PICM. The present study compared the efficacy and safety of HPSP with that of traditional CRT in the treatment of patients with PICM. METHODS AND ANALYSIS: This study is a single-centre, randomised controlled non-inferiority trial. This trial was carried out at the cardiac centre of Beijing Anzhen Hospital. A total of 46 patients with PICM who needed pacemaker upgrade treatment between January 2022 and December 2023 will be enrolled in this study. Patients will be randomised into an investigational group (HPSP) and a control group (CRT) at a 1:1 ratio. The primary outcome is the duration of QRS complex (QRS width), and the secondary outcomes are NT-proBNP (N terminal pro B type natriuretic peptide), C reactive protein, the number of antibiotics used, left ventricular ejection fraction, end systolic volume, end diastolic volume, the hospitalisation duration, the incidence of postoperative infection, pacemaker parameters (threshold, sensing and impedance), the 6-minute walking test, and quality of life (36-Item Short Form Survey scale), all-cause mortality, cardiovascular death, heart failure-related rehospitalisation rate, other rehospitalisation rates, major complication rates and procedure costs. ETHICS AND DISSEMINATION: This study has been approved by the Beijing Anzhen Hospital Medical Ethics Committee (No. 2020043X). TRIAL REGISTRATION NUMBER: Chinese Clinical Trial Registry (ChiCTR2000034265).

Transthyretin Amyloid Cardiomyopathy-Current and Future Therapies.

OBJECTIVE: To describe the clinical presentation of transthyretin amyloid cardiomyopathy (ATTR-CM) and discuss current treatments and investigational products and their effect on patient outcomes. DATA SOURCES: A literature search was performed in PubMed (September 2018 to December 2020) using the following keywords: transthyretin amyloidosis, cardiomyopathy, polyneuropathy and transthyretin amyloid cardiomyopathy, monoclonal light-chain, tafamidis, cardiac amyloidosis, ATTR cardiomyopathy, green tea and inhibition of cardiac amyloidosis, AG10, tolcapone, tolcapone and leptomeningeal ATTR, PRX004, NI006, patisiran, inotersen, vutrisiran, AKCEA-TTR-LRx, and NTLA-2001. STUDY SELECTION AND DATA EXTRACTION: Clinical trials were evaluated for evidence supporting pharmacology, safety, efficacy, and measured outcomes. DATA SYNTHESIS: Until 2019, there were no approved treatments for ATTR-CM. Treatment consisted of symptom management and organ transplant. Nonpharmacological and pharmacological treatments focused on the symptoms of heart failure (HF) associated with ATTR-CM. However, there are several emerging therapies recently approved or in development to address the underlying pathophysiology. Treatment classes for ATTR-CM include transthyretin stabilizers, human monoclonal antibodies, gene silencers, and CRISPR/Cas9 gene editing. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: ATTR-CM is a complex disease in which amyloidosis causes cardiomyopathy. Underdiagnosis is attributed to the clinical presentation being heterogeneous, indistinguishable from HF caused by other etiologies, and the need for invasive testing modalities, including endomyocardial biopsy. Improved diagnostic approaches along with targeted therapies can slow disease progression and enhance patient quality of life. CONCLUSION: Diagnostic modalities along with biomarker and genetic testing could detect disease earlier and target therapy more accurately. Novel therapies demonstrate potential treatment benefits and can help shape the standard of care for these patients.

Machine learning and network medicine: a novel approach for precision medicine and personalized therapy in cardiomyopathies.

The early identification of pathogenic mechanisms is essential to predict the incidence and progression of cardiomyopathies and to plan appropriate preventive interventions. Noninvasive cardiac imaging such as cardiac computed tomography, cardiac magnetic resonance, and nuclear imaging plays an important role in diagnosis and management of cardiomyopathies and provides useful prognostic information. Most molecular factors exert their functions by interacting with other cellular components, thus many diseases reflect perturbations of intracellular networks. Indeed, complex diseases and traits such as cardiomyopathies are caused by perturbations of biological networks. The network medicine approach, by integrating systems biology, aims to identify pathological interacting genes and proteins, revolutionizing the way to know cardiomyopathies and shifting the understanding of their pathogenic phenomena from a reductionist to a holistic approach. In addition, artificial intelligence tools, applied to morphological and functional imaging, could allow imaging scans to be automatically analyzed to extract new parameters and features for cardiomyopathy evaluation. The aim of this review is to discuss the tools of network medicine in cardiomyopathies that could reveal new candidate genes and artificial intelligence imaging-based features with the aim to translate into clinical practice as diagnostic, prognostic, and predictive biomarkers and shed new light on the clinical setting of cardiomyopathies. The integration and elaboration of clinical habits, molecular big data, and imaging into machine learning models could provide better disease phenotyping, outcome prediction, and novel drug targets, thus opening a new scenario for the implementation of precision medicine for cardiomyopathies.

[Astragalus injection mediates autophagy and myocardial remodeling in rats with ischemic cardiomyopathy through calumenin].

OBJECTIVE: To study the effects of astragalus injection on myocardial remodeling, calumenin and autophagy in rats with ischemic cardiomyopathy. METHODS: Thirty-six male SD rats were divided into normal control group, ischemic cardiomyopathy group and astragalus injection group, 12 in each group. Electrocardiogram (ECG) and echocardiography were performed before operation in three groups. Rats in ischemic cardiomyopathy group and astragalus injection group underwent thoracotomy and ligation of coronary artery for 20 minutes, then thoracic cavity was closed after reperfusion. In the astragalus injection group,10 g/kg body weight of Astragalus injection was injected once a week, four times in total. Four weeks after operation, rats in three groups were executed by echocardiography and their hearts were collected for Hematoxylin-Eosin (HE) staining and Van Gieson (VG) staining to observe myocardial pathological changes. Calumenin, LC3-I, LC3-II expressions and LC3-I/LC3-II ratio were detected by Western blot. RESULTS: Compared with ischemic cardiomyopathy group, the echocardiography and myocardial pathology of rats in astragalus injection group changed obviously, and the expressions of calumenin, LC3-I, LC3-II and LC3-I/LC3-II ratio changed significantly (P＜0.01). CONCLUSION: Astragalus injection has apparent inhibitory effect on ventricular remodeling and autophagy of myocardial cells in rats with ischemic cardiomyopathy, which may be mediated by calumenin.

Effects of L-Carnitine Supplementation in Patients Receiving Hemodialysis or Peritoneal Dialysis.

L-carnitine is an important factor in fatty acid metabolism, and carnitine deficiency is common in dialysis patients. This study evaluated whether L-carnitine supplementation improved muscle spasm, cardiac function, and renal anemia in dialysis patients. Eighty Japanese outpatients (62 hemodialysis (HD) patients and 18 peritoneal dialysis (PD) patients) received oral L-carnitine (600 mg/day) for 12 months; the HD patients further received intravenous L-carnitine injections (1000 mg three times/week) for 12 months, amounting to 24 months of treatment. Muscle spasm incidence was assessed using a questionnaire, and cardiac function was assessed using echocardiography. Baseline free carnitine concentrations were relatively low in patients who underwent dialysis for >4 years. Total carnitine serum concentration, free carnitine, and acylcarnitine significantly increased after oral L-carnitine treatment for 12 months, and after intravenous L-carnitine injection. There was no significant improvement in muscle spasms, although decreased muscle cramping after L-carnitine treatment was reported by 31% of patients who had undergone HD for >4 years. Hemoglobin concentrations increased significantly at 12 and 24 months in the HD group. Therefore, L-carnitine may be effective for reducing muscle cramping and improving hemoglobin levels in dialysis patients, especially those who have been undergoing dialysis for >4 years.

Updates in Sepsis Resuscitation.

Sepsis care has evolved significantly since the initial early goal-directed therapy (EGDT) trials. Early fluid resuscitation, source control, and antibiotic therapy remain cornerstones of care but overall understanding is more nuanced, particularly regarding fluid selection, vasopressors, and inotropic support. Timely nutrition therapy and ventilatory support tend to receive less attention but also are important. Recent research has explored immunomodulation, ß-blockade, and vitamin supplementation. A renewed emphasis on early, aggressive resuscitation reaffirms the importance of emergency medicine providers knowledgeable and skilled in sepsis management.

Specific Therapy for Transthyretin Cardiac Amyloidosis: A Systematic Literature Review and Evidence-Based Recommendations.

Background The emergence of specific therapies for transthyretin cardiac amyloidosis (CA) warrants the need for a systematic review of the literature. Methods and Results A systematic review of the literature was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A systematic search was performed on MEDLINE, PubMed, and Embase databases on November 29, 2019. Studies were selected based on the following predefined eligibility criteria: English-language randomized controlled trials (RCTs), non-RCTs, or observational studies, which included adult patients with variant/wild-type transthyretin-CA, assessed specific therapies for transthyretin-CA, and reported cardiovascular outcomes. Relevant data were extracted to a predefined template. Quality assessment was based on National Institute for Health and Care Excellence recommendations (RCTs) or a checklist by Downs and Black (non-RCTs). From 1203 records, 24 publications were selected, describing 4 RCTs (6 publications) and 16 non-RCTs (18 publications). Tafamidis was shown to significantly improve all-cause mortality and cardiovascular hospitalizations and reduce worsening in 6-minute walk test, Kansas City Cardiomyopathy Questionnaire-Overall Summary score, and NT-proBNP (N-terminal pro-B-type natriuretic peptide) in variant/wild-type transthyretin-CA. Patisiran showed promising results in a subgroup analysis of patients with variant transthyretin-CA, which have to be confirmed in RCTs. Inotersen showed conflicting results on cardiac imaging parameters. The one study on AG10 had only a 1-month duration and cardiovascular end points were exploratory and limited to cardiac biomarkers. Limited evidence from noncomparative single-arm small non-RCTs existed for diflunisal, epigallocatechin-3-gallate (green tea extract), and doxycycline+tauroursodeoxycholic acid/ursodeoxycholic acid. Conclusions This systematic review of the literature supports the use of tafamidis in wild-type and variant transthyretin-CA. Novel therapeutic targets including transthyretin gene silencers are currently under investigation.

Usefulness of Carnitine Supplementation for the Complications of Liver Cirrhosis.

Carnitine is a vitamin-like substance that regulates lipid metabolism and energy production. Carnitine homeostasis is mainly regulated by dietary intake and biosynthesis in the organs, including the skeletal muscle and the liver. Therefore, liver cirrhotic patients with reduced food intake, malnutrition, biosynthetic disorder, and poor storage capacity of carnitine in the skeletal muscle and liver are more likely to experience carnitine deficiency. In particular, liver cirrhotic patients with sarcopenia are at a high risk for developing carnitine deficiency. Carnitine deficiency impairs the important metabolic processes of the liver, such as gluconeogenesis, fatty acid metabolism, albumin biosynthesis, and ammonia detoxification by the urea cycle, and causes hypoalbuminemia and hyperammonemia. Carnitine deficiency should be suspected in liver cirrhotic patients with severe malaise, hepatic encephalopathy, sarcopenia, muscle cramps, and so on. Importantly, the blood carnitine level does not always decrease in patients with liver cirrhosis, and it sometimes exceeds the normal level. Therefore, patients with liver cirrhosis should be treated as if they are in a state of relative carnitine deficiency at the liver, skeletal muscle, and mitochondrial levels, even if the blood carnitine level is not decreased. Recent clinical trials have revealed the effectiveness of carnitine supplementation for the complications of liver cirrhosis, such as hepatic encephalopathy, sarcopenia, and muscle cramps. In conclusion, carnitine deficiency is not always rare in liver cirrhosis, and it requires constant attention in the daily medical care of this disease. Carnitine supplementation might be an important strategy for improving the quality of life of patients with liver cirrhosis.

Absorbable antibiotic beads as an adjuvant therapy in treating ventricular assist devices driveline infection: A case report.

BACKGROUND: Ventricular assist devices driveline infections are common, recalcitrant, and carry high morbidity and mortality. Herein, we reported a patient with driveline infection that was successfully treated with a combination of systemic antibiotics, surgical debridement, and instillation of absorbable antibiotic beads to the wound bed. METHODS AND RESULTS: A 39-year-old man with nonischemic cardiomyopathy underwent insertion of a continuous flow left ventricular assist device. Four years postoperatively, the patient presented with clinical, laboratory, and radiologic signs of driveline tract infection. He underwent extensive surgical debridement, installation of absorbable antibiotic beads that consisted of calcium sulfate, vancomycin, and tobramycin, into the wound bed, and systemic antibiotics. The patient was free of infection 9 month postoperatively. CONCLUSION: Absorbable calcium sulfate antibiotic beads may serve as a beneficial adjunct to surgical debridement and systemic antibiotics for the treatment of ventricular assist device driveline infection, and merit further investigation.

Cardiomyopathy in Thalassemia: Quick Review from Cellular Aspects to Diagnosis and Current Treatments.

BACKGROUND: Cardiomyopathic manifestations induced by continuous blood transfusion are the leading cause of death among patients with thalassemia major (TM). Despite introduction of chelation therapy, heart failure after cardiomyopathic manifestations is still a major threat to patients. METHODS: We performed a search of relevant English-language literature, retrieving publications from the PubMed database and the Google Scholar search engine (2005-2018). We used "thalassemia major", "cardiomyopathy", "iron overload", "cardiac magnetic resonance T2" "chelation therapy", and "iron burden" as keywords. RESULTS: The results of the studies we found suggest that cardiac hepcidin is a major regulator of iron homeostasis in cardiac tissue. Unlike previous assumptions, the heart appears to have a limited regeneration capability, originating from a small population of hypoxic cardiomyocytes. CONCLUSIONS: Oxygen levels determine cardiomyocyte gene-expression patterns. Upregulation of cardiac hepcidin in hypoxia preserves cardiomyocytes from forming out of reactive oxygen species catalyzed by free cellular iron in cardiomyocytes. Using the limited regeneration capacity of cardiac cells and gaining further understanding of the cellular aspects of cardiomyopathic manifestations may help health care professionals to develop new therapeutic strategies.

The role of atrial sensing for new-onset atrial arrhythmias diagnosis and management in single-chamber implantable cardioverter-defibrillator recipients: Results from the THINGS registry.

INTRODUCTION: Atrial tachycardia/fibrillation (AT/AF) episodes are common in implantable cardioverter-defibrillator (ICD) recipients and can be undetected by standard single-chamber devices. This study aims to explore whether a single-lead ICD with an atrial dipole (ICD DX; BIOTRONIK SE & Co, Berlin, Germany) could improve the AT/AF diagnosis and management as compared to standard ICD (ICD VR). METHODS AND RESULTS: We selected patients without AT/AF history from the THINGS registry which included consecutive patients implanted with ICD for standard indications. The ICD VR and the ICD DX groups included 236 (62.8%) and 140 (37.2%) patients, respectively, and had no significant differences in baseline characteristics. During a median follow-up of 27 months, there were 7 AT/AF diagnoses in the ICD VR and 18 in the ICD DX group. The 2-year incidence of AT/AF diagnosis was 3.6% (95% confidence interval [CI]: 1.6%-9.6%) for the ICD VR and 11.4% (95% CI: 6.8%-18.9%) for the ICD DX group (adjusted hazard ratio [HR]: 3.85 [95% CI: 1.58-9.41]; P = .003). Initiation of oral anticoagulation (OAC) due to AT/AF diagnosis was reported in 15 patients. The 2-year incidence of OAC onset was 3.6% (95% CI: 1.6%-7.8%) for the ICD VR and 6.3% (95% CI: 3.0%-12.7%) for ICD DX group (adjusted HR: 1.99 [95% CI: 0.72-5.56]; P = .184). CONCLUSION: We observed that atrial sensing capability in single-chamber ICD patients without evidence of atrial arrhythmias at implant is associated with a greater likelihood of detecting AT/AF episodes. The management of these diagnosed arrhythmias often led to clinical interventions, mainly represented by initiation of OAC therapy.

Targeted Ablation of Ventricular Tachycardia Guided by Wavefront Discontinuities During Sinus Rhythm: A New Functional Substrate Mapping Strategy.

BACKGROUND: Accurate and expedited identification of scar regions most prone to reentry is needed to guide ventricular tachycardia (VT) ablation. We aimed to prospectively assess outcomes of VT ablation guided primarily by the targeting of deceleration zones (DZ) identified by propagational analysis of ventricular activation during sinus rhythm. METHODS: Patients with scar-related VT were prospectively enrolled in the University of Chicago VT Ablation Registry between 2016 and 2018. Isochronal late activation maps annotated to the latest local electrogram deflection were created with high-density multielectrode mapping catheters. Targeted ablation of DZ (>3 isochrones within 1cm radius) was performed, prioritizing later activated regions with maximal isochronal crowding. When possible, activation mapping of VT was performed, and successful ablation sites were compared with DZ locations for mechanistic correlation. Patients were prospectively followed for VT recurrence and mortality. RESULTS: One hundred twenty patients (median age 65 years [59-71], 15% female, 50% nonischemic, median ejection fraction 31%) underwent 144 ablation procedures for scar-related VT. 57% of patients had previous ablation and epicardial access was employed in 59% of cases. High-density mapping during baseline rhythm was performed (2518 points [1615-3752] endocardial, 5049±2580 points epicardial) and identified an average of 2±1 DZ, which colocalized to successful termination sites in 95% of cases. The median total radiofrequency application duration was 29 min (21-38 min) to target DZ, representing ablation of 18% of the low-voltage area. At 12±10 months, 70% freedom from VT recurrence (80% in ischemic cardiomyopathy and 63% in nonischemic cardiomyopathy) was achieved. The overall survival rate was 87%. CONCLUSIONS: A novel voltage-independent high-density mapping display can identify the functional substrate for VT during sinus rhythm and guide targeted ablation, obviating the need for extensive radiofrequency delivery. Regions with isochronal crowding during the baseline rhythm were predictive of VT termination sites, providing mechanistic evidence that deceleration zones are highly arrhythmogenic, functioning as niduses for reentry.

Ventricular tachycardia in nonischemic cardiomyopathy: Anteroseptal vs inferolateral origin based on ICD ventricular electrogram timing.

INTRODUCTION: The majority of patients with nonischemic cardiomyopathy (NICM) present a perivalvular substrate that is either predominantly antero-septal (AS) or infero-lateral (IL), corresponding to specific ventricular tachycardia (VT) morphologies. The relative timing of far-field and near-field ventricular electrograms (EGMs) from stored implantable cardioverter-defibrillator (ICD) events of VT may be used to distinguish AS from IL VT in NICM. METHODS AND RESULTS: We analyzed 48 patients with NICM with either a primarily AS (54%) or IL (56%) VT source undergoing catheter ablation between 2003 and 2018. Only patients with retrievable ICD-EGMs of spontaneous VT events which could be matched with VTs induced during the ablation procedure were included. A total of 56 VT events (52% AS origin and 48% IL origin) were analyzed, yielding a mean far-field to near-field interval of 31 ± 13 milliseconds for AS VTs and 47 ± 19 milliseconds for IL VTs (P = .001). At receiver operating characteristic analysis (AUC = 0.734), a far-field to near-field interval of ≥ 60 milliseconds ruled out AS VTs in 29 (100%) cases and diagnosed IL VTs with a positive predictive value (PPV) of 100% and a negative predictive value (NPV) of 63%. An interval of ≤ 20 milliseconds ruled out IL VTs in 25 (93%) cases and diagnosed AS VTs with a PPV of 83% and NPV of 57%. Significant overlap between the two groups was observed among far-field to near-field intervals in between 20 milliseconds and 60 milliseconds. CONCLUSIONS: The relative timing of far-field and near-field EGMs from stored clinical ICD events of VT can be helpful to differentiate AS vs IL origin of VT in NICM.