Malignant Arrhythmias Research Articles

The Role of Extracorporeal Membrane Oxygenation in Cyanide Poisoning

Siyanür, mitokondriyal bozulmayla organları etkiler. Son zamanlarda, zehirlenmelerde hayati organ fonksiyonunu korumak ve antidot tedavisi için zaman kazanmak için ekstrakorporeal membran oksijenizasyonu (EKMO) kullanılmaktadır. Siyanür zehirlenmesinde, EKMO uygulanan ve beyin ölümü gerçekleşen olguyu sunduk. Yirmi sekiz yaşında hasta, 30 dakika önce ağızdan siyanür alımıyla getirildi. Hipotansif, taşikardik ve komadaydı. Laktik asidozu mevcuttu. Ekokardiyografide kalpte global hipokinezi izlendi. Perfüzyonun devamlılığı için venoarteriyel EKMO planlandı. EKMO uygulamasına hazırlanırken ventriküler fibrilasyon gelişti, defibrilasyon uygulandı ve ritm atriyal fibrilasyona döndü. EKMO uygulamasından önce, siyanür alımının 4. saatinde hidroksikobalamin verildi. Antidottan sonra kan basıncı yükseldi. Kan basıncı düzelse de yüksek laktat düzeyleri ve malign aritmi nedeniyle perfüzyonun tekrar bozulabileceği öngörülerek 4. saatte venoarteriyel EKMO uygulandı. İkinci gün beyin ölümü tanısı kondu. Organ nakli komitesi siyanürle ilgili komplikasyonlardan endişe duyduğu için organ naklini iptal edildi. Hasta üçüncü gün öldü. Siyanürün intrasellüler metabolizmayı bozduğu ve perfüzyondan bağımsız olarak beyin hasarına neden olduğu bilinmektedir. Bu nedenle, EKMO’nun siyanür zehirlenmesinde kalıcı beyin hasarını önleyememiştir.

ECG as a risk stratification tool in patients with wearable cardioverter-defibrillator

BackgroundThe wearable cardioverter defibrillator (WCD) is increasingly used in patients at elevated risk for ventricular arrhythmias but not fulfilling the indications for an implantable cardioverter defibrillator (ICD). Currently, there is an insufficient risk prediction of fatal arrhythmias in patients at risk. In this study, we assessed the prognostic role of baseline electrocardiogram (ECG) in WCD patients. MethodsWCD patients from diverse clinical institutions in Germany (n = 227) were retrospectively enrolled and investigated for the incidences of death or ventricular arrhythmias during WCD wearing. In addition, the widely accepted ECG predictors of adverse outcome were analyzed in patients with arrhythmic events. ResultsLife-threatening arrhythmias occurred in 22 (9.7 %) patients, mostly in subjects with ischemic heart disease (15 of 22). There was no difference in baseline left ventricular ejection fraction (LVEF) in subjects with and without arrhythmic events (31.3 ± 7.9 % vs. 32.6 ± 8.3 %; p = 0,24). Patients with arrhythmia exhibited significantly longer QRS duration (109.5 ± 23.1 ms vs. 100.6 ± 22.3 ms, p = 0,04), Tpeak-Tend (Tp-e) (103.1 ± 15.6 ms vs. 93.2 ± 19.2 ms, p = 0,01) and QTc (475.0 ± 60.0 ms vs. 429.6 ± 59.4 ms, p < 0,001) intervals. In contrast, no significant differences were found for incidences of fragmented QRS (27.3 % vs. 24 %, p = 0.79) and inverted/biphasic T-waves (16.6 % vs. 22.7 %, p = 0,55). In multivariate regression analysis both Tp-e (HR 1.03; 95 % CI 1.001–1.057; p = 0.02) and QTc (HR 1.02; 95 % CI 1.006–1.026; p < 0.001) were identified as independent predictors of ventricular arrhythmias.After WCD use, the prophylactic ICD was indicated in 76 patients (33 %) with uneventful clinical course but persistent LVEF ≤35 %. The ECG analysis in these subjects did not reveal any relevant changes in arrhythmogenesis markers. ConclusionsECG repolarization markers Tp-e and QTc are associated with malignant arrhythmias in WCD patients and may be used - in addition to other established risk markers - to identify appropriate patients for ICD implantation.

Effects of renal denervation therapy on cardiac function and malignant arrhythmia in patients with reduced left ventricular ejection fraction and narrow QRS complexes treated with implantable cardioverter defibrillator.

Objective : The purpose of this study was to explore the effects of renal denervation (RDN) on cardiac function and malignant arrhythmia in patients with reduced left ventricular ejection fraction (HFrEF) and narrow QRS treated with an implantable cardioverter defibrillator (ICD). Methods: A total of 20 eligible HFrEF patients [left ventricular ejection fraction (LVEF) <40%] and narrow QRS complexes (QRS duration <120 ms) were randomized into either the ICD plus RDN group or the ICD only group during 17 April 2014 to 22 November 2016. Clinical data, including clinical characteristics, blood biochemistry, B-type natriuretic peptide, echocardiographic indexes, 6-min walk distance (6MWD), New York Heart Association (NYHA) classification, and count of ICD discharge events before and after the operation were analyzed. Patients were followed up for up to 3 years post ICD or ICD plus RDN. Results: Baseline clinical data were comparable between the two groups. Higher LVEF (%) (mixed model repeated measure, p = 0.0306) (39.50% ± 9.63% vs. 31.20% ± 4.52% at 1 year; 41.57% ± 9.62% vs. 31.40% ± 8.14% at 3 years), systolic blood pressure (p = 0.0356), and longer 6MWD (p < 0.0001) as well as reduction of NYHA classification (p < 0.0001) were evidenced in the ICD plus RDN group compared to ICD only group during follow-up. Patients in the ICD plus RDN group experienced fewer ICD discharge events (2 vs. 40) and decreased diuretic use; rehospitalization rate (30% vs. 100%, p = 0.0031) and cardiogenic mortality rate (0% vs. 50%, p = 0.0325) were also significantly lower in the ICD plus RDN group than in the ICD only group during follow-up. Conclusion: ICD implantation plus RDN could significantly improve cardiac function and cardiac outcome as well as increase exercise capacity compared to ICD only for HFrEF patients with narrow QRS complexes.

Use of torsades de pointes risk drugs among patients with out-of-hospital cardiac arrest and likelihood of shockable rhythm and return of spontaneous circulation: A nationwide study

AimTreatment with certain drugs can augment the risk of developing malignant arrhythmias (e.g. torsades de pointes [TdP]). Hence, we examined the overall TdP risk drug use before out-of-hospital cardiac arrest (OHCA) and possible association with shockable rhythm and return of spontaneous circulation (ROSC). MethodsPatients ≥18 years with an OHCA of cardiac origin from the Danish Cardiac Arrest Registry (2001–2014) and TdP risk drug use according to www.CredibleMeds.org were identified. Factors associated with TdP risk drug use and secondly how use may affect shockable rhythm and ROSC were determined by multivariable logistic regression. ResultsWe identified 27,481 patients with an OHCA of cardiac origin (median age: 72 years [interquartile range 62.0, 80.0 years]). A total of 37% were in treatment with TdP risk drugs 0–30 days before OHCA compared with 33% 61–90 days before OHCA (p < 0.001). Most commonly used TdP risk drugs were citalopram (36.1%) and roxithromycin (10.7%). Patients in TdP risk drug treatment were older (75 vs 70 years) and more comorbid compared with those not in treatment. Subsequently, TdP risk drug use was associated with less likelihood of the presenting rhythm being shockable (odds ratio [OR] = 0.63, 95% confidence interval [CI]:0.58–0.69) and ROSC (OR = 0.73, 95% CI:0.66–0.80). ConclusionTdP risk drug use increased in the time leading up to OHCA and was associated with reduced likelihood of presenting with a shockable rhythm and ROSC in an all-comer OHCA setting. However, patients in TdP risk drug treatment were older and more comorbid than patients not in treatment.

Initial and terminal T wave angle as hyperkalemia indicator in chronic kidney disease

ABSTRACT Background Hyperkalemia is one prevalent complication in chronic kidney disease and is considered fatal since it potentially causes malignant arrhythmias and mortality. It is associated with electrocardiography (ECG) changes, such as peaked T wave in all ECG leads. However, the universal definition of the peaked T wave is still unclear, with low sensitivity and specificity. Aim This study aims to determine the predictive value of initial and terminal T wave angle in detecting hyperkalemia among CKD patients. Methods A cross-sectional study was conducted at Dr. Soetomo General Hospital, including all adult hospitalized CKD patients. A caliper was used to measure T wave morphology. The initial deflection angle (Tia) and terminal deflection angle (Tta) were calculated from an arctan of T peak amplitude and the respective initial or terminal length. The receiver operating characteristics (ROC) curve was analyzed to determine the area under the curve (AUC) and optimal cutoff. Results A total of 220 CKD patients were enrolled in this study, with 98 patients with hyperkalemia (potassium >5.0). The majority of the patients were male, with a mean age of 51.12 ± 12.58 years. Ti-Tp duration, Tp-Tt duration, Tia, Tta, and Tp amplitude were significantly higher in the hyperkalemia group (all p < 0.05). A Spearman correlation analysis demonstrated a significant positive correlation of Tia (r = 0.346 and p < 0.001) and Tta (r = 0.445 and p < 0.001) with potassium levels in the participants. The optimal cutoff angle for Tta was 66.20° (sensitivity = 67.3% and specificity = 73.8%) and Tia was 61.07° (sensitivity = 66.3% and specificity = 69.7%). Conclusion The terminal T wave angle outperformed the initial angle in predicting hyperkalemia in CKD patients.

Pharmacokinetics, systemic toxicity, thermoregulation and acute behavioural effects of 25CN-NBOMe.

N-(2-methoxybenzyl)phenethylamines (NBOMes) are a family of potent 5-HT2A agonists containing substances emerging on the illicit drug market as a replacement for N,N-diethyllysergamide (LSD). Despite the increasing use of NBOMes for diagnostic, research and recreational purposes, only a limited number of studies have focussed on their in vivo effect. Here, we investigated pharmacokinetics, systemic toxicity, thermoregulation in individually and group-housed animals, and acute behavioural effects after subcutaneous administration of 2,5-dimethoxy-4-(2-((2-methoxybenzyl)amino)ethyl)benzonitrile (25CN-NBOMe; 0.2, 1, and 5 mg/kg) in Wistar rats. Drug concentration peaked 1 h after the administration of 5 mg/kg in both blood serum and brain tissue with a half-life of 1.88 and 2.28 h, respectively. According to Organisation for Economic Co-operation and Development 423 toxicity assay, the drug is classified into category 3 with a lethal dose of 300 mg/kg and an estimated LD50 value of 200 mg/kg. Histological examination of organs collected from rats injected with the lethal dose revealed subtle pathological changes, highly suggestive of acute cardiovascular arrest due to malignant arrhythmia. Altered thermoregulation after 5 mg/kg was demonstrated by reduced body temperature in individually housed rats (p < 0.01). Behavioural effects assessed by the Open Field test and Prepulse Inhibition of Startle Response revealed that the two lower doses (0.2 and 1 mg/kg) caused a reduction in locomotor activity (p < 0.01), increased anxiety (p < 0.05) and 5 mg/kg additionally impaired sensorimotor gating (p < 0.001). In summary, 25CN-NBOMe readily passes the blood-brain barrier and exhibits a moderate level of toxicity and behavioural effect comparable with other NBOMes.

Incidence of ventricular arrhythmias after biventricular defibrillator replacement: impact on safety of downgrading from CRT-D to CRT-P.

Cardiac resynchronization therapy (CRT) reduces mortality and hospitalizations. It is debated whether CRT alone (CRT-P) or CRT plus defibrillator (CRT-D) is preferable, and still guidelines are not exhaustive. The aim of the study was to investigate whether to implant CRT-P or CRT-D in CRT-D patients who did not experience malignant arrhythmias at the moment of replacement. Out of 451 heart failure patients undergoing CRT-D according to guidelines, 103 (67±10 years, 80% men) underwent device replacement with CRT-D. Every 6 months patients underwent to clinical evaluation and device interrogation and episodes of ventricular arrhythmias (VA) stored. At baseline and before replacement echocardiogram was performed. Patients were defined responders if left ventricular (LV) end-systolic volume decreased ≥15% and super-responders if LV ejection fraction increased ≥40% or ≥50%. Mean follow-up was 75±24 months after implantation and 26±10 months after replacement. First VAs incidence per year did not decrease over time (P=0.619). Before replacement, 27 patients (26.2%, 15 responders/12 non-responders) experienced VA. After replacement, 8 patients (7.7%, 4 responders/4 non-responders) experienced VA for the first time. Super-responder condition was not associated with lower VA incidence before (0.499) and after (P=0.339) replacement. At multivariate analysis, age was the only independent predictor of electrical appropriate therapy after substitution (OR<inf>per year</inf>=1.17; 95% CI: 1.03-1.34; P=0.003). Freedom from VA before device replacement does not correlate with freedom from VA after replacement, so downgrade from CRT-D to CRT-P is not feasible at replacement, in particular in the elderlies, independently of responder and super-responder condition.

Prognostic value of the PDW/HDL-C ratio in patients with chest pain symptoms and coronary artery calcification

BackgroundPlatelet-related parameters and HDL-C have been regarded as reliable and alternative markers of coronary heart disease (CHD) and the independent predictors of cardiovascular outcomes. PDW is a simple platelet index, which increases during platelet activation. Whether the PDW/HDL-C ratio predicts major adverse cardiovascular and cerebrovascular events (MACCEs) in patients who complained of chest pain and confirmed coronary artery calcification remains to be investigated. This study aimed to investigate the prognostic value of the PDW/HDL-C ratio in patients with chest pain symptoms and coronary artery calcification.MethodsA total of 5,647 patients with chest pain who underwent coronary computer tomography angiography (CTA) were enrolled in this study. Patients were divided into two groups according to their PDW/HDL-C ratio or whether the MACCE occurs. The primary outcomes were new-onset MACCEs, defined as the composite of all-cause death, non-fatal MI, non-fatal stroke, revascularization, malignant arrhythmia, and severe heart failure.ResultsAll patients had varying degrees of coronary calcification, with a mean CACS of 97.60 (22.60, 942.75), and the level of CACS in the MACCEs group was significantly higher than that in non-MACCE (P<0.001). During the 89-month follow-up, 304 (5.38%) MACCEs were recorded. The incidence of MACCEs was significantly higher in patients with the PDW/HDL-C ratio > 13.33. The K–M survival curves showed that patients in the high PDW/HDL-C ratio group had significantly lower survival rates than patients in the low PDW/HDL-C ratio group (log-rank test: P < 0.001). Multivariate Cox hazard regression analysis reveals that the PDW/HDL ratio was an independent predictor of MACCEs (HR: 1.604, 95% CI: 1.263–2.035; P < 0.001). Cox regression analysis showed that participants with a lower PDW/HDL-C ratio had a higher risk of MACCEs than those in the higher ratio group. The incidence of MACCEs was also more common in the PDW/HDL-C ratio > 13.33 group among different severities of coronary artery calcification. Furthermore, adding the PDW/HDL-C ratio to the traditional prognostic model for MACCEs improved C-statistic (P < 0.001), the NRI value (11.3% improvement, 95% CI: 0.018–0.196, P = 0.01), and the IDI value (0.7% improvement, 95% CI: 0.003–0.010, P < 0.001).ConclusionThe higher PDW/HDL-C ratio was independently associated with the increasing risk of MACCEs in patients with chest pain symptoms and coronary artery calcification. In patients with moderate calcification, mild coronary artery stenosis, and CAD verified by CTA, the incidence of MACCEs increased significantly in the PDW/HDL-C ratio > 13.33 group. Adding the PDW/HDL-C ratio to the traditional model provided had an incremental prognostic value for MACCEs.

Hypoglycemia Is Associated With Worse Outcomes in Patients With Cholangitis Despite Undergoing Endoscopic Retrograde Cholangiopancreatography

BackgroundHypoglycemia has been associated with poorer outcomes in hospitalized patients undergoing surgical interventions. In cholangitis, endoscopic retrograde cholangiopancreatography (ERCP) is often a critical adjunct to surgery, capable of diagnosing and treating various biliary and pancreatic pathologies. While technically less invasive than surgery, the effect of hypoglycemia on clinical outcomes of patients with cholangitis undergoing ERCP has not been elucidated.MethodologyData were extracted from the National Inpatient Sample (NIS) database from 2016 to 2019. Using the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes, patients diagnosed with cholangitis and underwent ERCP were identified. Baseline demographic data, comorbidities, in-hospital mortality, hospital charges, and hospital length of stay (LOS) were extracted and compared based on the presence or absence of hypoglycemia. Statistical analysis was done using t-test and chi-square analyses. A multivariate analysis for the mortality odds ratio (OR) was calculated to adjust for possible confounders.ResultsA total of 256,540 patients with cholangitis who underwent ERCP were identified, and 2,810 of them had hypoglycemia during their hospitalization. The mean age of the hypoglycemia group was 64.41 years. Most patients were females (54%) and whites (57%). More patients in the hypoglycemia group had a history of alcoholism and congestive heart failure (CHF). Hypoglycemia was associated with higher odds of in-hospital mortality (OR = 6.71, confidence interval (CI) = 5.49-8.2; p < 0.0001). In addition to hypoglycemia, age >65 years, non-white race, and CHF were independently associated with higher mortality. Moreover, patients with hypoglycemia had higher total hospital charges ($87,147 vs. $133,400; p < 0.0001) and a significant increase in the LOS (9.7 vs. 6.7 days; p < 0.0001).ConclusionsPrevious studies in the surgical literature have linked hypoglycemia to increased incidence of atrial fibrillation, usage of mechanical ventilation, and application of circulatory support. Hypoglycemia may also affect the metabolism of the heart, leading to myocardial ischemia and malignant arrhythmias. However, it is unclear if hypoglycemia represents a proxy for the severity of patient illness as septic shock and renal insufficiency are common etiologies that may strongly impact mortality. Therefore, careful glycemic control during hospitalization should be practiced as hypoglycemia serves as a poor prognostic indicator that should not be overlooked.

Neglected Tropical Diseases and Sudden Cardiac Death: The NET-Heart Project.

Sudden cardiac death (SCD) is responsible for approximately 6% of global mortality and 25% of cardiovascular (CV) deaths. SCD has been traditionally linked to coronary artery disease, valvular heart disease, cardiomyopathies, and genetic arrhythmia disorders. However, advancements in care for these diseases have not translated to a proportional reduction in SCD. This suggests an important role of underrecognized contributing pathologies. Neglected tropical diseases (NTDs) are a group of illnesses prevalent in tropical and sub-tropical regions which have been understudied partially due to their high prevalence in marginalized populations. The relationship between SCD and Chagas disease has been well-established, though emerging literature suggests that other NTDs with CV involvement may lead to fatal arrhythmias. Additionally, specific therapies for a subset of NTDs put patients at increased risk of malignant arrhythmias and other cardiac complications. This review aims to summarize the association between a group of selected NTDs and SCD.

Cardiac Cx43 Signaling Is Enhanced and TGF-β1/SMAD2/3 Suppressed in Response to Cold Acclimation and Modulated by Thyroid Status in Hairless SHRM.

The hearts of spontaneously hypertensive rats (SHR) are prone to malignant arrhythmias, mainly due to disorders of electrical coupling protein Cx43 and the extracellular matrix. Cold acclimation may induce cardio-protection, but the underlying mechanisms remain to be elucidated. We aimed to explore whether the adaptation of 9-month-old hairless SHRM to cold impacts the fundamental cardiac pro-arrhythmia factors, as well as the response to the thyroid status. There were no significant differences in the registered biometric, redox and blood lipids parameters between hairless (SHRM) and wild type SHR. Prominent findings revealed that myocardial Cx43 and its variant phosphorylated at serine 368 were increased, while an abnormal cardiomyocyte Cx43 distribution was attenuated in hairless SHRM vs. wild type SHR males and females. Moreover, the level of β-catenin, ensuring mechanoelectrical coupling, was increased as well, while extracellular matrix collagen-1 and hydroxyproline were lower and the TGF-β1 and SMAD2/3 pathway was suppressed in hairless SHRM males compared to the wild type strain. Of interest, the extracellular matrix remodeling was less pronounced in females of both hypertensive strains. There were no apparent differences in response to the hypothyroid or hyperthyroid status between SHR strains concerning the examined markers. Our findings imply that hairless SHRM benefit from cold acclimation due to the attenuation of the hypertension-induced adverse downregulation of Cx43 and upregulation of extracellular matrix proteins.

Targeted potassium levels to decrease arrhythmia burden in high risk patients with cardiovascular diseases (POTCAST): Study protocol for a randomized controlled trial

Low plasma potassium (p-K) is associated with increased risk of malignant arrhythmia and observational studies indicate protective effects of p-K in the upper reference level. However, randomized clinical studies are needed to document whether actively increasing p-K to high-normal levels is possible and safe and improves cardiovascular outcomes. To investigate if increased p-K reduces the risk of malignant arrhythmia and all-cause death in high-risk patients with a cardiovascular disease treated with an implantable cardioverter defibrillator (ICD) for primary or secondary preventive causes. Secondly, to investigate whether high-normal p-K levels can be safely reached and maintained using already available medications and potassium-rich dietary guidance. This is a prospective, randomized, and open-labelled study enrolling patient at high-risk of malignant arrhythmias. According to sample size calculations, 1,000 patients will be randomized 1:1 to either an investigational regiment that aims to increase and maintain p-K at high-normal levels (4.5-5.0 mmol/L) or to usual standard of care and followed for an expected four years. The trial will run until a total of 291 events have occurred providing an α=0.05 and 1-β=0.80. The composite primary endpoint includes ventricular tachycardia >125 bpm lasting >30 seconds, any appropriate ICD-therapy, and all-cause mortality. At present, 739 patients have been randomized. We present the rationale for the design of the POTCAST trial. The inclusion was initiated 2019 and is expected to be finished 2022. The study will show if easily available treatments to increase p-K may be a new treatment modality to protect against malignant arrythmias.

Short-Coupled Idiopathic Ventricular Fibrillation: A Literature Review With ExtendedFollow-Up.

Idiopathic ventricular fibrillation is responsible for approximately 5%-7% of cases of aborted cardiac arrest. Recent studies have shown that short-coupled ventricular premature complexes are present at the onset of idiopathic ventricular fibrillation in 6.6%-17% of patients. The present review provided information on 86 patients with short-coupled malignant ventricular arrhythmias that were reported as case reports or small patient series during the last 70 years. In 75% of the 81 cases published during the last 40 years, extended information and follow-up (from 2.63 ± 4.5 years to 10.67±7.8 years; P< 0.001, between the original publication to the latest update) could be obtained from the authors. The review shows that short-coupled malignant ventricular arrhythmias occurred almost equally in males and females, at the mean age of 40 years. A tendency for later occurrence of the arrhythmia by 4 years was observed in females. A prior history of syncope was noted in 45.3% of the patients, whereas arrhythmic storm occurred in 42% at presentation. The most common mode of revelation of short-coupled malignant ventricular arrhythmias was syncope (53.5%), followed by aborted cardiac arrest (26.7%) and recurrent arrhythmic event after prior implantable-cardioverter defibrillator implantation for idiopathic ventricular fibrillation (17.4%). For the first time, short-coupled malignant arrhythmias exhibiting "not-so-short" coupling intervals (≥350milliseconds) were found in a significant proportion of patients (17.4%). Duringlong-term follow-up, quinidine yielded a slightly higher success rate in arrhythmia control than ablation. Largerstudies are necessary to assess the best strategy for the management of this potentially lethal arrhythmia.

The NLRP3 Inflammasome as a Novel Therapeutic Target for Cardiac Fibrosis.

Cardiac fibrosis often has adverse cardiovascular effects, including heart failure, sudden death, and malignant arrhythmias. However, there is no targeted therapy for cardiac fibrosis. Inflammation is known to play a crucial role in the disorder, and the NLR pyrin domain-containing-3 (NLRP3) inflammasome is closely associated with innate immunity. Therefore, further understanding the pathophysiological role of the inflammasome in cardiac fibrosis may provide novel strategies for the prevention and treatment of the disorder. The aim of this review was to summarize the present knowledge of NLRP3 inflammasome-related mechanisms underlying cardiac fibrosis and to suggest potential targeted therapy that could be used to treat the condition.

Functional Regulation of KATP Channels and Mutant Insight Into Clinical Therapeutic Strategies in Cardiovascular Diseases

ATP-sensitive potassium channels (KATP channels) play pivotal roles in excitable cells and link cellular metabolism with membrane excitability. The action potential converts electricity into dynamics by ion channel-mediated ion exchange to generate systole, involved in every heartbeat. Activation of the KATP channel repolarizes the membrane potential and decreases early afterdepolarization (EAD)-mediated arrhythmias. KATP channels in cardiomyocytes have less function under physiological conditions but they open during severe and prolonged anoxia due to a reduced ATP/ADP ratio, lessening cellular excitability and thus preventing action potential generation and cell contraction. Small active molecules activate and enhance the opening of the KATP channel, which induces the repolarization of the membrane and decreases the occurrence of malignant arrhythmia. Accumulated evidence indicates that mutation of KATP channels deteriorates the regulatory roles in mutation-related diseases. However, patients with mutations in KATP channels still have no efficient treatment. Hence, in this study, we describe the role of KATP channels and subunits in angiocardiopathy, summarize the mutations of the KATP channels and the functional regulation of small active molecules in KATP channels, elucidate the potential mechanisms of mutant KATP channels and provide insight into clinical therapeutic strategies.

Impact of synchronized left ventricular pacing rate on risk for ventricular tachyarrhythmias after cardiac resynchronization therapy in patients with heart failure.

The adaptive cardiac resynchronization therapy (aCRT) algorithm automatically produces synchronized left ventricular pacing (sLVP) with intrinsic atrioventricular conduction to improve clinical outcomes. However, relationship between sLVP percentage and risk for ventricular tachyarrhythmia (VT/VF) remains unclear. This study aimed to evaluate the clinical impact of sLVP rate on VT/VF occurrence. In total, 1,419 device interrogation data from 42 consecutive patients who underwent new aCRT device implantation were retrospectively analyzed. The primary endpoint was the first time VT/VF episode after aCRT device implantation. During a median follow-up of 34months, 15 patients had VT/VF episodes. Patients were divided into a high sLVP (the average sLVP percentage of ≥ 51.5%, n = 27) or low sLVP group (< 51.5%, n = 15). The high sLVP group had a significantly lower VT/VF incidence (22% vs. 60%; p = 0.014) and an independent predictor for VT/VF occurrence on multivariate analysis (hazard ratio 0.21; p = 0.007). LV ejection fraction improvements after 6months (12.3 ± 8.7% vs. 2.8 ± 10.3%; p = 0.004) and 12months (13.8 ± 9.3% vs. 6.2 ± 11.1%; p = 0.030) were significantly greater in the high sLVP group than in the low sLVP group. Age, PR interval, and left atrial diameter were significantly associated with the sLVP rate after aCRT. Patients with high sLVP percentage after aCRT had lower long-term risk of VT/VF incidence with a favorable response to CRT. A synchronized pacing algorithm using intrinsic conduction may prevent malignant arrhythmias, as well as recover cardiac functions.

Ischaemia-induced J waves.

Abstract This article comments on a recently published case of ischemia-induced J waves aiming to highlight the utility of these waves in localizing the culprit artery as well as in classifying the patient among those at high risk for malignant arrhythmias.

Traditional Chinese medicine injections with activating blood circulation, equivalent effect of anticoagulation or antiplatelet, for acute myocardial infarction: A protocol for the systematic review and meta-analysis of randomized clinical trials.

BackgroundIn spite of a growing number in the use of percutaneous coronary intervention (PCI) in China, the mortality of acute myocardial infarction (AMI) has not decreased. Traditional Chinese medicine injections for Activating Blood Circulation (TCMi-ABC), equivalent effect of anticoagulation or antiplatelet, are widely used in China; however, the improvement of fatality towards AMI is unclear. Therefore, we intend to conduct a systematic review and meta-analysis to evaluate the efficacy and safety of TCMi-ABC in treatment with AMI.MethodsBased on the “National Medical Products Administration of China,” TCMi-ABC with AMI treatment indication will be selected, including Danhong injection, Sodium Tanshinone IIA Sulfonate injection, Danshen Chuanxiongqin injection, and Puerarin injection. Randomized controlled studies will be searched from as follows: PubMed, Embase, the CENTRAL in Cochrane Library, Chinese Biomedical Literature Database (SinoMed), China National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (VIP), and Wanfang Data Knowledge Service Platform. Two researchers will work independently on literature selection, data extraction, and quality assessment. The outcomes focus on the effects of TCMi-ABC on fatality of patients with AMI in hospitalization and in the long term, the incidence of malignant arrhythmia, left ventricular ejection fraction, and adverse events. RevMan 5.4.1 software was used for mate analysis.ResultsThis study will conduct a comprehensive literature search and provide a systematic synthesis of current published data to explore the efficacy and safety of TCMi-ABC for AMI.ConclusionThis study will provide high-quality evidence for treatment of AMI with TCMi-ABC in terms of efficacy and safety, which may help clinicians make a better complementary treatment schedule of patients with AMI.

Indications and utility of cardiac genetic testing in athletes.

Sports Cardiology practice commonly involves the evaluation of athletes for genetically determined cardiac conditions that may predispose to malignant arrhythmias, heart failure, and sudden cardiac death. High-level exercise can lead to electrical and structural cardiac remodelling which mimics inherited cardiac conditions (ICCs). Differentiation between 'athlete's heart' and pathology can be challenging and often requires the whole armamentarium of available investigations. Genetic studies over the last 30 years have identified many of the genetic variants that underpin ICCs and technological advances have transformed genetic testing to a more readily available and affordable clinical tool which may aid diagnosis, management, and prognosis. The role of genetic testing in the evaluation and management of athletes with suspected cardiac conditions is often unclear beyond the context of specialist cardio-genetics centres. This document is aimed at physicians, nurses, and allied health professionals involved in the athlete's care. With the expanding role and availability of genetic testing in mind, this document was created to address the needs of the broader sports cardiology community, most of whom work outside specialized cardio-genetics centres, when faced with the evaluation and management of athletes with suspected ICC. The first part of the document provides an overview of basic terminology and principles and offers guidance on the appropriate use of genetic testing in the assessment of such athletes. It outlines key considerations when contemplating genetic testing, highlighting the potential benefits and pitfalls, and offers a roadmap to genetic testing. The second part of the document presents common clinical scenarios in Sports Cardiology practice, outlining the diagnostic, prognostic, and therapeutic implications of genetic testing, including impact on exercise recommendations. The scope of this document does not extend to a comprehensive description of the genetic basis, investigation, or management of ICCs.

Case Report: An Unusual Case of Pheochromocytoma

Pheochromocytoma is a benign catecholamine secreting tumor, which is rare and originates from the adrenal gland. It has been known for a wide range of clinical manifestations and can mimic other difficult-to-diagnose diseases. Here, we report a female patient with acquired long QT syndrome, which is a rare complication of pheochromocytoma. Although relatively rare, the presence of pheochromocytoma should be considered in the case of malignant arrhythmias and electrocardiographic changes in patients.