Efecto de los fármacos en la prolongación del QT y la aparición de muerte súbita en la COVID-19 / Effect of Drugs on QT Prolongation and Sudden Death in COVID-19

Introducción: Las evidencias científicas han demostrado que durante el período pandémico por la COVID-19 ha existido un incremento de la incidencia de muerte súbita cardiovascular, proporcional al incremento de los casos y a la letalidad por la enfermedad. Objetivos: Compilar información sobre los fármacos empleados en el tratamiento de la COVID-19 y sus posibles efectos en la prolongación del intervalo QT y la aparición de muerte súbita. Métodos: Se realizó una búsqueda de información a partir de las bases de datos PubMed, Medline y SciELO, en los idiomas español e inglés en el período de enero de 2020 a enero de 2023. Resultados: Los hallazgos más recientes sugieren que los factores relacionados con el tratamiento médico del paciente para sus enfermedades cardiovasculares previas, el empleo concomitante de drogas para otras comorbilidades, el ensayo de nuevas drogas que se investigan en la actualidad para el tratamiento de la enfermedad y el uso inadecuado de fármacos en complicaciones graves por la COVID-19, pueden ocasionar prolongación del intervalo QT y arritmias ventriculares tipo torsades de pointes, lo que puede conllevar a la aparición de muerte súbita. Conclusiones: Ha sido demostrado el efecto deletéreo de los fármacos en el tratamiento de la COVID-19 y sus posibles asociaciones a la terapéutica del paciente, en la prolongación del tiempo de repolarización ventricular cardíaca, cuya traducción eléctrica es un intervalo QT prolongado y su contribución a la génesis de arritmias malignas potencialmente fatales capaces de desencadenar un paro cardíaco y evolucionar a la muerte súbita(AU)

Scientific evidence has shown an increase in the incidence of sudden cardiovascular death during the COVID-19 pandemic period. This has been proportional to the increase in cases and mortality from the disease. Direct and indirect injury to the myocardium and vascular system allow to partially explain the statistics. Among the factors related to the medical treatment of the patient for previous cardiovascular diseases, it is the concomitant use of drugs for other comorbidities. The trial of new drugs for the treatment of this condition and the inappropriate use of drugs in serious complications from COVID-19 are currently being investigated. These can cause QT prolongation and torsades de pointes ventricular arrhythmias, which can lead to sudden death. Monitoring the QT interval is recommended, before and during treatment, in patients who come to the emergency room with a clinical condition suggestive of COVID-19. Additionally, modifiable factors favoring its prolongation should be evaluated. Decision-making in the application of therapeutic protocols in patients with COVID-19 with prolonged QTc at baseline, or with increased QTc after starting treatment, must go through the analysis of the risk/benefit ratio defined by a multi- and interdisciplinary team(AU)

Cardioverter-defibrillator reduces mortality risk in eligible ischemic and non-ischemic cardiomyopathy patients: Sub-analysis of the multi-center Improve SCA study

Background & Objective: Despite the burden of sudden cardiac arrest (SCA) worldwide, implantable cardioverter-defibrillators (ICDs) are underutilized, particularly in Asia, Latin America, Eastern Europe, the Middle East, and Africa. The Improve SCA trial demonstrated that primary prevention (PP) patients in these regions benefit from an ICD or a cardiac resynchronization therapy defibrillator (CRT-D). We aimed to compare the rate of device therapy and mortality among ischemic and non-ischemic cardiomyopathy (ICM and NICM) PP patients who met guideline indications for ICD therapy and had an ICD/CRT-D implanted. Methods: Improve SCA was a prospective, non-randomized, non-blinded multicenter trial that enrolled patients from the above-mentioned regions. All-cause mortality and device therapy were examined by cardiomyopathy (ICM vs NICM) and implantation status. Cox proportional hazards methods were used, adjusting for factors affecting mortality risk. Results: Of 1848 PP NICM patients, 1007 (54.5%) received ICD/CRT-D, while 303 of 581 (52.1%) PP ICM patients received an ICD/CRT-D. The all-cause mortality rate at 3 years for NICM patients with and without an ICD/CRT-D was 13.1% and 18.3%, respectively (HR 0.51, 95% CI 0.38e0.68, p < 0.001). Similarly, all-cause mortality at 3 years in ICM patients was 13.8% in those with a device and 19.9% in those without an ICD/CRT-D (HR 0.54, 95% CI 0.33e.0.88, p ¼ 0.011). The time to first device therapy, time to first shock, and time to first antitachycardia pacing (ATP) therapy were not significantly different between groups (p 0.263). Conclusions: In this large data set of patients with a guideline-based PP ICD indication, defibrillator device implantation conferred a significant mortality benefit in both NICM and ICM patients. The rate of appropriate device therapy was also similar in both groups.

KCNH2 mutation c.3099_3112del causes congenital long QT syndrome type 2 with gender differences

Abstract Introduction: Long QT Syndrome (LQTS) is an inherited disease with an abnormal electrical conduction system in the heart that can cause sudden death as a result of QT prolongation. LQT2 is the second most common subtype of LQTS caused by loss of function mutations in the potassium voltage-gated channel subfamily H member 2 (KCNH2) gene. Although more than 900 mutations are associated with the LQTS, many of these mutations are not validated or characterized. Methods and results: Sequencing analyses of genomic DNA of a family with LQT2 identified a putative mutation. i.e., KCNH2(NM_000238.3): c.3099_3112del, in KCNH2 gene which appeared to be a definite pathogenic mutation. The family pedigree information showed a gender difference in clinical features and T-wave morphology between male and female patients. The female with mutation exhibited recurring ventricular arrhythmia and syncope, while two male carriers did not show any symptoms. In addition, T-wave in females was much flatter than in males. The female proband showed a positive reaction to the lidocaine test. Lidocaine injection almost completely blocked ventricular arrhythmia and shortened the QT interval by ≥30 ms. Treatment with propranolol, mexiletine, and implantation of cardioverter-defibrillators prevented the sustained ventricular tachycardia, ventricular fibrillation, and syncope, as assessed by a 3-year follow-up evaluation. Conclusions: A putative mutation c.3099_3112del in the KCNH2 gene causes LQT2 syndrome, and the pathogenic mutation mainly causes symptoms in female progeny.

Radiofrequency ablation of ventricular arrhythmias from the pulmonary sinus cusp in pediatric patients and the follow-up / 中华实用儿科临床杂志

Objective:To evaluate the strategy and safety of the radiofrequency ablation (RFA) on ventricular arrhythmias (VAs) originating from the pulmonary sinus cusp (PSC) in pediatric patients.Methods:Retrospective study.Fifteen patients with VAs originating from the PSC who were intervened by RFA in the Department of Pediatric Cardiology, Guangdong Provincial People′s Hospital between March 2014 to July 2020 were enrolled.All the patients met the indication criteria for RFA in pediatric patients.The electrocardiogram, ablation method of ablation were analyzed.Different curved catheters were selected for RFA according to the age and weight of the patients.The catheter was then inserted in a " U" or inverted " P" shape to the PSC.The long-term effect of ablation were reviewed.Results:The mean age and body weight of 15 patients with VAs originating from the PSC were (11.6±2.6) (6-15) years and (39.9±12.2) (19-65) kg, respectively.The electrocardiogram recorded during VAs originating from the PSC showed left bundle branch block and inferior axis with monomorphic R pattern, as well as a QS-wave in aVR and aVL.The electrocardiogram characteristics varied in patients with VAs originating from the PSC.The ideal excitation point was not found in the right ventricular outflow tract or the ablation was unsuccessful in all patients, and the earliest target was mapped and RFA was successful.Among the 15 patients, the successful ablation site was in the lower regions of the PSC, involving the right cusp in 11 patients(73.3%), the anterior cusp in 3 patients(20.0%), and the left cusp in 1 patient(6.7%). The earliest potential recorded at the PSC ablation site preceded the QRS complex onset by (27.3±6.0) ms.During the follow-up period for (2.7±2.0) years, no recurrence of VAs or complications were recorded.Conclusions:Under the premise of gentle catheterization procedure and appropriate radiofrequency energy, ablation was effective, safe and with low recurrence rate to eradicate VAs originating from the PSC in children.

Arritmias ventriculares en el posoperatorio de cirugía cardíaca / Ventricular arrhythmias in the postoperative period of cardiac surgery / Arritmias ventriculares no pós-operatório de cirurgia cardíaca

Resumen: Las arritmias representan unas de las complicaciones más frecuentes en el posoperatorio de cirugía cardíaca (POCC). Pueden alterar la evolución del paciente, su tiempo de internación, la conducta terapéutica y aumentan los costos en salud. Su diagnóstico y manejo adecuados, mejoran el pronóstico de los pacientes a largo plazo. La fibrilación auricular (FA) es la arritmia más frecuente del POCC, siendo menos frecuentes otras arritmias supraventriculares. Las arritmias ventriculares son causa de aumento de morbi-mortalidad y sobre sus principales características se centrará esta revisión.

Summary: Arrhythmias represent one of the most frequent complications during the postoperative period of cardiac surgery. They may worsen patient evolution, increase the in-hospital length of stay, modify therapeutics and increase health costs. Its proper diagnosis and management improves the long-term prognosis of patients. Atrial fibrillation is the most common arrhythmia in the postoperative period of cardiac surgery, with other supraventricular arrhythmias being less common. Ventricular arrhythmias are cause of increases in morbidity and mortality. Their main characteristics will be discussed in this review.

Resumo: As arritmias representam uma das complicações mais frequentes no pós-operatório de cirurgia cardíaca. Eles podem modificar a evolução do paciente, o tempo de internação, o comportamento terapêutico e aumentam os gastos de saúde. Seu diagnóstico e manejo adequados melhoram o prognóstico dos pacientes a longo prazo. A fibrilação atrial é a arritmia mais comum no pós-operatório de cirurgia cardíaca, com outras arritmias supraventriculares sendo menos comuns. As arritmias ventriculares são causa do aumento de morbimortalidade. Suas principais características serão analisadas nesta revisão.

Taquicardia incesante del tracto de salida del ventrículo derecho - ¿Taquimiocardiopatía?: El enigma / Incessant right ventricular outflow tract tachycardia - Tachycardiomyopathy? The enigma

RESUMEN Las taquicardias ventriculares de larga duración o incesantes pueden causar insuficiencia cardíaca, disfunción del ventrículo izquierdo y cardiomiopatía, cuadros que revierten una vez resueltas las arritmias. Se trata de un diagnóstico de exclusión: puede existir una cardiopatía de base que empeora con la taquicardia y debe precisarse si la arritmia lleva a la cardiomiopatía (puede existir un subregistro) o viceversa. Se presenta un paciente con taquicardia incesante del tracto de salida del ventrículo derecho, de larga evolución, con repercusión hemodinámica, cardiomiopatía dilatada y disfunción grave del ventrículo izquierdo, rebelde a fármacos antiarrítmicos y con dos ablaciones fallidas, pendiente de biopsia endomiocárdica y nueva ablación de su taquicardia. Se discuten algunas pistas para diferenciar las arritmias del tracto de salida del ventrículo derecho, en sus variantes benignas (las más frecuentes) y malignas. Algunas pistas para diferenciarlas son: la duración del complejo QRS, el intervalo de acoplamiento de la extrasístole y la frecuencia de la taquicardia.

ABSTRACT Long-lasting or incessant ventricular tachycardias may cause heart failure, left ventricular dysfunction, and cardiomyopathy; conditions that reverse once the arrhythmias have been solved. This is a diagnosis of exclusion: there may be a basic heart disease that worsens with the tachycardia and it must be clarified whether the arrhythmia leads to cardiomyopathy (there may be an underregistration) or vice versa. A patient with incessant right ventricular outflow tract tachycardia, with long evolution, hemodynamic repercussion, dilated cardiomyopathy and severe dysfunction of the left ventricle, refractory to antiarrhythmic drugs and with two failed ablations, pending endomyocardial biopsy and new ablation of his tachycardia is presented. Some clues to differentiate right ventricular outflow tract arrhythmias, in their benign (most frequent) and malignant variants, are discussed. Some clues to differentiate them are: the duration of the QRS complex, the coupling interval of premature contractions and the heart rate of the tachycardia.

Papel del sistema Purkinje y del tracto de salida del ventrículo derecho en las arritmias ventriculares malignas y la muerte súbita / Role of the Purkinje system and right ventricular outflow tract in malignant ventricular arrhythmias and sudden death

RESUMEN El sistema Purkinje y el tracto de salida del ventrículo derecho tienen un papel trascendente en relación con las arritmias ventriculares malignas (taquicardia y fibrilación ventriculares, torsión de puntas) y con la muerte súbita cardíaca. Se discuten su fisiopatología, participación en el origen (extrasístoles desencadenantes) y mantenimiento de estas arritmias, y las posibilidades ablativas para disminuir las recurrencias y los episodios de tormenta eléctrica. Se expone el diagnóstico diferencial entre variantes benignas y malignas de la taquicardia ventricular relacionada con el tracto de salida del ventrículo derecho y la relación entre factores genéticos, estructurales, electroanatómicos y funcionales (inflamación, fibrosis), con los eventos clínicos y la vulnerabilidad a las arritmias. Se necesita reclasificar algunas de estas enfermedades, vistas ahora en su carácter orgánico-funcional (síndrome de Brugada, por ejemplo), lo cual implica cambios revolucionarios en algunos conceptos clásicos y una nueva visión en cuanto a la estratificación de riesgo y la conducta terapéutica.

ABSTRACT The Purkinje system and the right ventricular outflow tract play a pivotal role in relation to malignant ventricular arrhythmias (ventricular tachycardia and fibrillation, torsades de pointes) and sudden cardiac death. Details such as their pathophysiology, origin involvement (triggering extrasystoles) maintenance of such arrhythmias, and ablative possibilities to reduce recurrences and electrical storm events are discussed herein. The differential diagnosis between benign and malignant ventricular tachycardia related to the right ventricular outflow tract, and the relationship between genetic, structural, electroanatomical and functional factors (inflammation, fibrosis) with clinical events and vulnerability to arrhythmias are presented. Some of these diseases need to be reclassified as they are now seen in their organic-functional character (Brugada syndrome, for example), and this implies radical changes in some classical concepts as well as a new perspective on risk stratification and therapeutic management.

Study of Acid Base and Electrolyte Disturbances in Patients of Acute Myocardial Infarction

Introduction: Myocardial infarction is the main cause of deathin Western countries, with in hospital mortality of 6-13%. Acidbase and electrolyte status in AMI patients at the time ofadmission that can be help in risk stratification and it can helpfor further planning of management strategy for managementof patient with AMI.Aim of Study: To Study of Acid base and electrolytedisturbances in patients of acute myocardial infarction andrelation of Hypokalemia and hypomagnesemia with ventricularArrhythmias in AMI.Materials and Methods: This Observational study wasconducted in the department of Medicine at R.N.T. MedicalCollege and Govt. MB Hospital, Udaipur. Study subjects were50 patients of acute ST segment elevated Myocardial Infarctionpresenting within 24 hrs of onset of chest pain. We estimatedtheir acid base status, serum sodium, serum potassium, serummagnesium.Results: The definite correlation was found between metabolicacidosis and mortality (p=0.03). There was also increasedmortality in patients with hyponatremia, but p value was notstatistically significant (p=0.15). In our study definite correlationfound between hypokalemia and ventricular arrhythmias andalso between hypomagnesemia and ventricular arrhythmiasthere was increased tendency towards developing ventriculararrhythmias in patients with hypokalemia andhypomagnesemias. There was no correlation found betweenhypernatremia and mortality and between increased potassiumlevel and ventricular Arrhythmias in our study

Influence of the Right Ventricular Lead Location on Ventricular Arrhythmias in Cardiac Resynchronization Therapy / 中华医学杂志(英文版)

<p><b>Background</b>The influence of different right ventricular lead locations on ventricular arrhythmias (VTA) in patients with a cardiac resynchronization therapy (CRT) is not clear. This study aimed to evaluate the influence on VTA in patients with a CRT when right ventricular lead was positioned at the right ventricular middle septum (RVMS) and the right ventricular apical (RVA).</p><p><b>Methods</b>A total of 352 patients implanted with a CRT-defibrillator (CRT-D) between May 2012 and July 2016 in the Department of Cardiology of Anhui Provincial Hospital were included. Two-year clinical and pacemaker follow-up data were collected to evaluate the influence of the right ventricular lead location on VTA. Patients were divided into the RVMS group (n = 155) and the RVA group (n = 197) based on the right ventricular lead position. The VTA were compared between these two groups using a Kaplan-Meier curve and Cox multivariate analysis.</p><p><b>Results</b>When the left ventricular lead location was not considered, RVMS and RVA locations did not affect VTA. However, the subgroup analysis results showed that when the left ventricular lead was positioned at the anterolateral cardiac vein (ALCV), the RVMS group had an increased risk of ventricular arrhythmias and appropriate defibrillation (hazard ratio [HR] = 3.29, P = 0.01 and HR = 4.33, P < 0.01, respectively); when the left ventricular lead was at the posterolateral cardiac vein (PLCV), these risks in the RVMS group decreased (HR = 0.45, P = 0.02 and HR = 0.33, P < 0.01, respectively), and when the left ventricular lead was at the lateral cardiac vein, there was no difference between the two groups. In regard to inappropriate defibrillation, there was no significant difference among all these groups.</p><p><b>Conclusions</b>When the left ventricular lead was positioned at ALCV or PLCV, the right ventricular lead location was associated with VTA and appropriate defibrillation after CRT. Greater distances between leads not only improved cardiac function but also may reduce the risk of VTA.</p>

A research on predictive value of plane QRS-T angle for postoperative malignant ventricular arrhythmia of patients with AMI undergoing PCI and the correlation analysis between the predictive value and prognostic effect / 中国医学装备

Objective: To analyze predictive value of plane QRS-T angle for postoperative malignant ventricular arrhythmia (MVA) of patients with acute myocardial infarction (AMI) who underwent PCI and the correlation between the predictive value and prognostic effect. Methods: The clinical data of 100 patients with AMI who underwent the treatment of percutaneous coronary intervention(PCI) were researched by using retrospective analysis. All of patients were divided into observation group (24 cases) and control group (76 cases) according to the angle of plane QRS-T after PCI. The plane QRS-T angle of observation group was more than 90°, and it was less than or equal to 90° in control group. The occurrence of MVA and clinical outcome of MVA between the two group were compared. Results: The age of observation group was significantly higher than that of control group (t=3.516, P<0.05). The interval of QTc of observation group was significantly higher than that of control group (t=2.131, P<0.05). And the percentage of left ventricular ejection fraction (LVEF) less than 45%, the occurrence rate of high blood pressure and the occurrence rate of MVA of observation group were significantly higher than those of control group (x2=3.922, x2=3.950, x2=5.942, P<0.05), respectively. The results of multi-factor Logistic regression analysis indicated that the angle of plane QRS-T of patients with AMI after PCI above 90° was the independent risk factor of MVA after PCI (OR=9.640, P<0.05). Conclusion: After the PCI of patients with AMI, the QRS-T angle> 90 ° was an independent risk factor of MVA.

Effect of down-regulation of IKs repolarization-reserve on ventricular arrhythmogenesis in a guinea pig model of cardiac hypertrophy / 中南大学学报(医学版)

Objective:To observe the changes of rapidly activated delayed rectifier potassium channel (IKs) and slowly activated delayed rectifier potassium channel (IKs) in cardiac hypertrophy and to evaluate the effects of IKs and IKs blocker on the incidence ofventricular arrhythmias in guinea pigs with left ventricular hypertrophy (LVH).Methods:Guinea pigs were divided into a sham operation group and a left ventricular hypertrophy (LVH) group.LVH model was prepared.Whole cell patch-clamp technique was used to record IKr and IKs tail currents in a guinea pig model with LVH.The changes of QTc and the incidence rate of ventricular arrhythmias in LVH guinea pigs were observed by using the IKr and IKs blockers.Results:Compared with cardiac cells in the control group,the interventricular septal thickness at end systole (IVSs),left ventricular posterior wall thickness at end systole (LVPWs),QTc interval and cell capacitance in guinea pigs with LVH were significantly increased (P＜0.05);while IKs densities were significantly reduced [+60 mV:(0.36±0.03) pA/pF vs (0.58±0.05) pA/pF,P＜0.01].However,LVH exerted no significant effect on IKr densities.IKr blocker markedly prolonged the QTc interval (P＜0.01) and increased the incidence of ventricular arrhythmias in guinea pigs with LVH compared with the control guinea pigs.In contrast,IKs blocker produced modest increase in QTc interval in guinea pigs of control group with no increase in LVH animals.IKs blocker did not induce ventricular arrhythmias incidence in either control or LVH animals.Conclusion:The cardiac hypertrophy-induced arrhythmogenesis is due to the down-regulation of IKs.

Analysis on the factors related to the immediate success rate of radiofrequency catheter ablation on patients with idiopathic right ventricular outflow tract ventricular arrhythmia / 中华心血管病杂志

Objective@#To analyze the clinical characteristics of patients with idiopathic right ventricular outflow tract (RVOT) ventricular arrhythmias (VA) and factors related to the immediate success rate of radiofrequency ablation.@*Methods@#Patients diagnosed as idiopathic RVOT arrhythmia in Fuwai Hospital from February 2009 to January 2013 were retrospectively screened. Patients with structural heart disease or inherited arrhythmia were excluded. All patients underwent endocardial electrophysiological study and radiofrequency catheter ablation. Baseline clinical and operation records were collected and analyzed. Immediate success rate was defined as no inducible ventricular arrhythmia by isoprinosine and electrophysiological induction at the end of ablation. The origins of idiopathic RVOT were classified as septal, anterior, posterior, free wall site, epicardial and RVOT-aorta root site.@*Results@#A total of 468 patients were finally included, and the age was (40.4±13.3) years old and 60.5%(283/468) patients were female. Immediate radiofrequency success rate was 89.3%(418/468). Patients were divided into ablation success group (n=418) and ablation failure group (n=50). Percent of female patients and patients with interventricular septal origin was significantly higher in the ablation success group than in ablation failure group (261(62.4%) vs. 22 (44.0%) , P=0.01, and 233(55.7%) vs. 18(36.0%), P=0.005), while percent of patients with epicardial origin was significantly lower in the ablation success group than in ablation failure group (17(4.1%) vs. 11(22.0%), P<0.001). Immediate success rate was the highest for patients with the septal origin and the lowest for patients with epicardial origin (92.8%(233/251) vs. 60.7%(17/28), P<0.05). Multivariate analysis showed that the origin site of VAs was the most important independent factor related to the success rate of ablation. Compared with the septal origin patients, patients with RVOT-aorta root and epicardial origin VAs faced with 1.82-fold and 8.26-fold increased risk of failed ablation, respectively (OR=2.82, 95%CI 1.05-7.57, and OR=9.26, 95%CI 3.60-23.86). Sex category was not the independent risk factor for failed ablation(OR=1.76, 95%CI 0.93-3.33, P=0.08) .@*Conclusions@#The immediate success rate of radiofrequency catheter ablation for idiopathic RVOT ventricular arrhythmia is relative high, however, immediate success rate of radiofrequency catheter ablation is relatively low for patients with epicardial and RVOT-aorta root origin arrhythmia and VAs origin is an independent risk factor of immediate ablation success rate.

Ventricular arrhythmias originating from left ventricle posterior papillary muscle:electrocardiographic characteristics and catheter ablation / 中国介入心脏病学杂志

Objective To investigate the clinical characteristics, electrocardiography, electrophysiological features and the eff ectiveness of catheter ablation of ventricular arrhythmias originating from left ventricle posterior papillary muscles. Methods Clinical features and electrocardiography of 16 patients with ventricular arrhythmias arising from left ventricular posterior papillary muscles underwent catheter ablation were retrospectively analyzed. Activation mapping and/or pace mapping were performed to identify the site of origin and transthoracic echocardiography were used to demonstrate ablation catheter position and contact. The immediate success and recurrence rates were evaluated. Results During arrhythmias, QRS wave duration of 16 patients [5 men, mean age (45.0±18.2) years] was (155.1±9.0)ms. The prevalence of R>r' and r<R' of V1QRS morphology was 6/16 and 9/16, respectively. Earliest local ventricular electrogram preceded QRS wave by (30.8±8.4)ms at successful ablation site. Immediate success were achieved in 14 patients (14/16) ,11 patients(11/16) had full clinical follow-up and recurrences occurred in 5 patients (5/11). Conclusions Electrocardiography of ventricular arrhythmias originating from left ventricular posterior papillary muscles has its specifi c features. Earliest focal electrogram indicates successful ablation site and transthoracic echocardiography can demonstrate ablation catheter position and increase success rate but recurrence rate is still high.

Bipolar radiofrequency ablation in the treatment of left ventricular aneurysm with ventricular arrhythmias guided by CARTO mapping system: A randomized controlled trial / 中国胸心血管外科临床杂志

@#Objective    To evaluate the efficacy and clinical significance of bipolar radiofrequency ablation in the treatment of left ventricular aneurysm with ventricular arrhythmias guided by CARTO mapping system. Methods    From September 2009 to December 2015, 56 patients with ventricular aneurysm following myocardial infarction were enrolled. All patients suffered different levels of angina pectoris symptoms evaluated by Holter (the frequencies of ventricular arrhythmias more than 3 000 per day). They were divided into two groups according to random ballot and preoperative communication with patients' family members: a bipolar radiofrequency ablation group (n=28, 20 males, 8 females, mean age of 61.21±1.28 years) receiving off-pump coronary artery bypass grafting (OPCABG), ventricular aneurysm surgery combined with bipolar radiofrequency ablation, and a non-bipolar radiofrequency ablation group (n=28, 22 males, 6 females, mean age of 57.46±1.30 years) receiving OPCABG and single ventricular aneurysm surgery. The grade of cardiac function and ventricular arrhythmia was compared between the two groups during pre-operation, discharge and   follow-up. Results    All patients were discharged successfully. There was no in-hospital death in both two groups. One patient in the non-radiofrequency group had cerebral infarction. All patients were re-checked with Holter before discharge and the frequency of ventricular arrhythmias significantly decreased compared to that of pre-operation in both groups, and was more significant in bipolar radiofrequency ablation group (1 197.00±248.20 times/24 h vs. 1 961.00±232.90 times/24 h, P<0.05). There was significant difference in duration of mechanical ventilation and ICU stay between the two groups (P<0.05). The left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD) and left ventricular end-systolic diameter (LVESD) significantly improved (P<0.05) after operation in both groups. Conclusion    The clinical efficacy of bipolar radiofrequency ablation in the treatment of ventricular aneurysm with ventricular arrhythmia guided by CARTO mapping is safe and effective, but its long-term outcomes still need further follow-up.

The effect of the physical activity on polymorphic premature ventricular complexes in chronic kidney disease

BACKGROUND: Polymorphic premature ventricular complexes (PVCs) are very common, appearing most frequently in patients with hypertension, obesity, sleep apnea, and structural heart disease. Sympathetic hyperactivity plays a critical role in the development, maintenance, and aggravation of ventricular arrhythmias. Endurance exercise training clearly lowers sympathetic activity in sympatho-excitatory disease states and may be tolerated by patients with chronic kidney disease (CKD). METHODS: We assessed 40 CKD patients with hypertension with polymorphic PVCs. Patients underwent a complete medical history and physical examination. We evaluated the effectiveness of β blocker only or β blocker + exercise during 12 months of follow-up regarding the changes of the numbers of PVCs and mean heart rate (HR) by 24-hour-Holter. RESULTS: We observed in the β blocker group a significant decrease in the number of polymorphic PVCs from baseline 36,515 ± 3,518 to 3, 6, 9 and 12 months of follow-up, 28,314 ± 2,938, 23,709 ± 1,846, 22,564 ± 1,673, and 22,725 ± 1,415, respectively (P < 0.001). In the β blocker + exercise group a significant decrease in the number of polymorphic PVCs also occurred from baseline 36,091 ± 3,327 to 3, 6, 9 and 12 months of follow-up, 29,252 ± 3,211, 20,948 ± 2,386, 14,238 ± 3,338, and 6,225 ± 2,319, respectively (P < 0.001). Comparisons between the two groups at the same time point showed differences from the sixth month onwards: the 6th (Δ = −2,761, P = 0.045), 9th (Δ = −8,325, P < 0.001) and 12th (Δ = −16,500, P < 0.001) months. There was an improvement during the 12 months of follow-up vs. baseline, after the β blocker or β blocker + exercise in mean 24-hour HR Holter monitoring, creatinine values, eGFR, and ACR. CONCLUSION: Polymorphic PVCs may be modifiable by physical activity in CKD patients with hypertension without structural heart disease.

Exercise-induced ventricular arrhythmias and vagal dysfunction in Chagas disease patients with no apparent cardiac involvement

INTRODUCTION : Exercise-induced ventricular arrhythmia (EIVA) and autonomic imbalance are considered as early markers of heart disease in Chagas disease (ChD) patients. The objective of the present study was to verify the differences in the occurrence of EIVA and autonomic maneuver indexes between healthy individuals and ChD patients with no apparent cardiac involvement. METHODS : A total of 75 ChD patients with no apparent cardiac involvement, aged 44.7 (8.5) years, and 38 healthy individuals, aged 44.0 (9.2) years, were evaluated using echocardiography, symptom-limited treadmill exercise testing and autonomic function tests. RESULTS : The occurrence of EIVA was higher in the chagasic group (48%) than in the control group (23.7%) during both the effort and the recovery phases. Frequent ventricular contractions occurred only in the patient group. Additionally, the respiratory sinus arrhythmia index was significantly lower in the chagasic individuals compared with the control group. CONCLUSIONS : ChD patients with no apparent cardiac involvement had a higher frequency of EIVA as well as more vagal dysfunction by respiratory sinus arrhythmia. These results suggest that even when asymptomatic, ChD patients possess important arrhythmogenic substrates and subclinical disease. .

Brugada Syndrome: A Major Cause of Sudden Cardiac Death.

In 1992 a new syndrome was described consisting of syncopal episodes or sudden death in patients with a structurally normal heart and an electrocardiogram characteristic of right bundle branch block with ST segment elevation in leads V1 to V3. Brugada syndrome is an autosomal dominant disorder. It has been shown to be associated with mutations in the gene (SCN5A) that encodes for the sodium ion channel in cardiac myocyte. Over 160 mutations of gene SCN5A have been identifi ed. Th e incidence of the disease is diffi cult to estimate, but it causes sudden deaths of 5 per 10,000 inhabitants per year and involved much more frequently in people of Asian ancestry. Diagnosis can be easily made by means of genetic analysis and ECG. Recent data suggest that loss of the action potential dome in the right ventricular epicardium underlies ST segment elevation seen in this syndrome. Right ventricular epicardium is preferentially aff ected because of the predominance of transient outward current in this tissue. Antiarrhythmic drugs like amiodarone and beta-blockers do not prevent death in symptomatic or asymptomatic individuals. Th ough Implantation of an automatic cardioverter–defi brillator is the only recently proven eff ective therapy; Quinidine has been found to decrease Ventricular fi brillation and could prove to be a secured option of implantable cardioverter–defi brillator. However, researcher set focus on gene therapy that may off er an enduring cure in future years. Th e purpose of this brief review is to record the past highlights that have brought us to our present understanding of Brugada syndrome.

Initial experience of subcutaneous implantable cardioverter defibrillators in Singapore: a case series and review of the literature

Transvenous implantable cardioverter defibrillators are a type of implantable cardiac device. They are effective at reducing total and arrhythmic mortality in patients at risk of sudden cardiac death. Subcutaneous implantable cardioverter defibrillators (S-ICDs) are a new alternative that avoids the disadvantages of transvenous lead placement. In this case series, we report on the initial feasibility and safety of S-ICD implantation in Singapore.

Effects of tumor necrosis factor-α on MAPD between endocardium and epicardium in isolated heart tissues and study for mechanism / 中国免疫学杂志

Objective: To explore the relationship between expression of tumor necrosis factor-α( TNF-α) and electrophysiological heterogeneity in isolated heart tissues and isolated rat ventricular myocytes.The arrhythmogenic mechanisms of TNF-αwere further studied.Methods:Langendorff perfused heart tissues models were used to verify the arrhythmogenic effects of TNF-α.The monophasic action potentials( MAPs) of the endocardium and epicardium from the isolated heart tissues were recorded by elec-trophysiological experiments.The isolated rat ventricular myocytes were obtained by enzymatic dissociation.K+currents(Ito,IK1)were recorded by using whole cell patch clamp technique.Results: Compared to the control group, the difference in MAPD between endocardium and epicardium dramatically increased with TNF-α( P<0.05 ) .TNF-αcould cause MAP duration ( MAPD ) prolongation, and a single dose of TNF-αdifferentially affected the MAPs of endocardium and epicardium of isolated heart tissues.Compared to the control group,the K+currents(Ito,IK1)were dose-dependently decreased with TNF-αin rat ventricular myocytes(P<0.05).However, etanercept had no effects on the MAPD in the absence of TNF-α.Conclusion:TNF-α-induced heterogeneity of MAPD between the endo-cardium and epicardium may provide the substrate for the onset of ventricular arrhythmias during acute myocardial infarction.The effect might be associated with TNF-αcontribute to re-entrant ventricular arrhythmias which resulted from decreased K+currents(Ito,IK1).