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Introduction and Objectives: Our aim was to assess the impact of prosthetic pulmonary valve replacement (PVR) in patients with repaired tetralogy of Fallot (rTOF) on changes in biventricular volumes and function and on adverse cardiac events., Methods: Adults with rTOF were identified from the SACHER-registry. Data from serial cardiac magnetic resonance imaging, echocardiography, exercise capacity and n-terminal pro b-type natriuretic peptide (NT-proBNP) were collected. The primary endpoint was right ventricular ejection fraction (RVEF) as measured by cardiac magnetic resonance. Secondary endpoints were biventricular volumes, left ventricular ejection fraction, exercise capacity and NT-proBNP levels, and time to adverse cardiac outcomes (atrial and ventricular arrhythmia, endocarditis). Associations between previous PVR and longitudinal changes in functional outcomes and time to adverse cardiac outcomes were analyzed using linear mixed-effects models and Cox proportional hazards models, respectively., Results: A total of 308 patients (153 with and 155 without PVR) with 887 study visits were analyzed. Previous PVR was not significantly associated with changes in RVEF (CE, -1.33; 95%CI, -5.87 to 3.21; P=.566). Previous PVR was associated with lower right ventricular end-diastolic volume but had no significant effect on left ventricular ejection fraction, exercise capacity, or NT-proBNP-levels. Previous PVR was associated with an increased hazard of atrial arrhythmias (HR, 2.09; 95%CI, 1.17-3.72; P=.012) and infective endocarditis (HR, 12.72; 95%CI, 4.69-34.49; P<.0001) but not with an increased hazard of sustained ventricular arrhythmias (HR, 0.64; 95%CI, 0.18-2.27; P=.490)., Conclusions: Previous PVR was not significantly associated with changes in RVEF but was associated with an increased risk of atrial arrhythmias and infective endocarditis., (Copyright © 2023 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.)

Introduction: Epileptic seizures can be associated with peri-ictal heart rhythm disorders and even sudden death (SUDEP). Few paediatric studies have been conducted on the subject., Aim: To determine heart rhythm disorders in paediatric patients with epilepsy who were studied with video-electroencephalogram (video-EEG)., Methods: Prospective, observational study in patients under 18 years of age admitted for video-EEG at the Hospital Clinico Red de Salud UC-Christus, Santiago, Chile. A neurological and cardiological evaluation and electrocardiogram (ECG) were performed, in addition to a Holter ECG simultaneously with the video-EEG., Results: Twenty-five patients were studied, 12 with refractory epilepsies, 23/25 focal and 20 on polytherapy. Altogether 768 hours of video-EEG were recorded, including 281 seizures in 15 patients: 157 clinical and 103 generalised. There were no serious arrhythmias, only non-specific or probably benign disorders, mainly incomplete right bundle branch block in 11 patients, which were more frequent in refractory epilepsies (p<0.036). Heart rate variation occurred mainly in seizures >30 seconds. No patient presented SUDEP., Conclusions: This is the first prospective study, with a new technique, using video-EEG and Holter ECG simultaneously in paediatrics. Despite the high number of seizures and refractory patients, we found no serious heart rhythm disorders, consistent with the clinical evaluation. Right bundle branch block is considered a non-pathological cardiological finding, but was highly prevalent in our sample compared to the normal population, especially in refractory epilepsy. Given that this is a serious event in epilepsy, it is important to further investigate such studies to assess preventive measures.

Antecedentes: El corazón pulmonar crónico (CPC) muestra un incremento en habitantes que viven en grandes altitudes., Objetivo: Investigar la frecuencia de arritmias cardíacas y factores de riesgo para su desarrollo., Métodos: Estudio descriptivo y transversal; se revisó el registro de pacientes internados del Departamento de Cardiología del Instituto Nacional de Tórax, La Paz, Bolivia, entre enero de 2017 y junio de 2018; se incorporó a todos los individuos con diagnóstico de CPC, definido por criterios clínicos, electrocardiográficos y ecocardiográficos; se incluyó a 162 pacientes que cumplieron los criterios en el análisis; se utilizaron la t de Student y ANOVA., Resultados: Arritmias: fibrilación auricular (FA), 125 (75%); aleteo auricular (AA), 17 (10.5%); taquicardia auricular (TA), 17 (10.5%); extrasístoles, 3 (1.9%). Según el análisis univariado, los factores relacionados con el desarrollo de arritmias fueron: eritrocitosis: FA, RR: 1.33, otras arritmias (RR: 1.67), p = 0.0001; hipertensión arterial pulmonar: FA, RR: 3.10, otras arritmias (RR: 3.21), p = 0.0001; dilatación de aurícula derecha (AD): FA, RR: 1.92, otras arritmias (RR: 2.13), p = 0.0001; obesidad: FA, RR: 3.47, p = 0.001, otras arritmias (RR: 3.70), p = 0.001; hipertensión arterial sistémica: FA, RR: 3.10, p = 0.001, otras arritmias (RR: 3.21), p = 0.001. Según el análisis multivariado: eritrocitosis (RR: 2.2), dilatación de AD (RR: 1.2), p = 0.0001., Conclusiones: Se encontró FA con mayor frecuencia en los pacientes con CPC; los factores de riesgo con mayor significancia estadística para su presentación fueron la eritrocitosis y la dilatación de la AD., Background: Chronic cor pulmonale (CPC), with increased presentation in high-altitude inhabitants., Objectives: Investigating the frequency of cardiac arrhythmias, and risk factors for its development., Methods: Descriptive, cross-sectional study, the inpatient registry of the Department of Cardiology of the National Institute of Torax, La Paz-Bolivia, from January 2017 to June 2018 was reviewed, all were incorporated with the diagnosis of CPC, defined by clinical criteria, electrocardiographic and echocardiographic, 162 patients who met the criteria were taken, the student’s t-test and ANOVA were used for the analysis., Results: Arrhythmias: atrial fibrillation (AF) 125 (75%), atrial flutter (AA) 17 (10.5%), atrial tachycardia (AT) 17 (10.5%), extrasystoles 3 (1.9%). Univariate analysis of factors related to the development of arrhythmias: erythrocytosis: FA, RR: 1.33, other arrhythmias RR: 1.67, p = 0.0001, pulmonary arterial hypertension: FA, RR: 3.10, other arrhythmias RR: 3.21, p = 0.0001, right atrial dilation (AD): FA, RR: 1.92, other arrhythmias RR: 2.13, p = 0.0001, obesity: FA, RR: 3.47, p = 0.001, other arrhythmias RR: 3.70, p = 0.001, systemic arterial hypertension: FA: RR: 3.10, p = 0.001, other arrhythmias RR: 3.21, p = 0.001. Multivariate analysis: erythrocytosis (RR: 2.2), AD dilation (RR: 1.2), p = 0.0001., Conclusions: AF was found more frequently in patients with CPC, the risk factors with the greatest statistical significance for presentation were: erythrocytosis and AD dilation., (Copyright: © 2020 Permanyer.)

Introduction and Objectives: This report presents the findings of the 2018 Spanish Catheter Ablation Registry., Methods: Data collection was retrospective. A standardized questionnaire was completed by each of the participating centers., Results: Data sent by 100 centers were analyzed, with a total number of 16566 ablation procedures performed (the highest historically reported in this registry) for a mean of 165.5±127.9 and a median of 119 procedures per center. The ablation targets most frequently treated were atrial fibrillation (n=4234; 25.6%), atrioventricular nodal re-entrant tachycardia (n=3525; 21.3%) and cavotricuspid isthmus (n=3425; 20.7%). A new peak was observed in the ablation of atrial fibrillation, increasing the distance from the other substrates. The overall success rate was 91%. The rate of major complications was 2.2%, and the mortality rate was 0.04%. A total of 2.1% of the ablations were performed in pediatric patients., Conclusions: The Spanish Catheter Ablation Registry enrolls systematically and continuously enrolls the ablation procedures performed in Spain, showing a progressive increasing in the number of ablations over the years, with a high success rate and low percentage of complications., (Copyright © 2019 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.)

Introduction and Objectives: To assess the diagnostic yield and cost-effectiveness of a diagnostic protocol based on the systematic use of latest-generation external loop recorders (ELRs) compared with the classic diagnostic strategy for patients with recurrent unexplained palpitations., Methods: Two cohorts of consecutive patients referred for diagnosis of unexplained palpitations to the outpatient clinic of the arrhythmia unit were compared: a prospective cohort after the implementation of a new diagnostic protocol based on the systematic use of ELRs, and another, retrospective, cohort before the implementation of the protocol. The cost of diagnosis was calculated based on the number of complementary examinations, visits to outpatient clinics, or emergency department visits required to reach a diagnosis, and its costs according the prices published for the local health system., Results: One hundred and forty-nine patients were included (91 in the ELR group, 58 in the control group). The diagnostic yield was higher in the ELR group (79 [86.8%] definitive diagnoses in the ELR group vs 12 [20.7%] in the control group, P < .001). The cost per diagnosis was €375.13 in the ELR group and €5184.75 in the control group (P < .001). The cost-effectiveness study revealed that the systematic use of ELR resulted in a cost reduction of €11.30 for each percentage point of increase in diagnosis yield., Conclusions: In patients with recurrent unexplained palpitations, evaluation by means of a study protocol that considers the systematic use of a latest-generation ELR increases diagnostic yield while reducing the cost per diagnosis., (Copyright © 2018 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.)

Introduction and Objectives: Catheter ablation has become the treatment of choice in an increasing number of arrhythmias in children and adolescents. There is still limited evidence of its use at a national level in Spain. The aim was to describe the characteristics and results of a modern monocentric series form a referral tertiary care centre., Methods: Retrospective register of invasive procedures between 2004 and 2016 performed in patients under 17 years and recorded clinical characteristic, ablation methodology and acute and chronic results of the procedure., Results: A total of 291 procedures in 224 patients were included. Median age was 12.2 years, 60% male. Overall, 46% patients were referred from other autonomous communities. The most frequent substrates were accessory pathways (AP) (70.2%,>50% septal AP localization) and atrioventricular nodal reentrant tachycardia (AVNRT) (15.8%). Congenital and acquired heart disease was frequent (16.8%). Cryoablation was used in 35.5% of the cases. Overall acute success of the primary procedure was 93.5% (AP 93.8%; AVNRT 100%). Redo procedures after recurrence were performed in 18.9% of all substrates, with a long-term cumulative efficacy of 98.4% (AP 99.3%; AVNRT 100%). One (0.37%) serious complication occurred, a case of complete atrioventricular block., Conclusions: Our study replicated previous international reports of high success rates with scarce complications in a high complexity series, confirming the safety and efficacy of pediatric catheter ablation in our environment performed at highly experienced referral centers., (Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.)

Background: Based on the theory of probability and not equiprobable entropy ratios in the context of dynamical systems theory, a methodology for cardiac dynamic evaluation was developed., Objectives: To confirm the clinical applicability of the diagnostic methodology based on probability and entropy for patients with different types of arrhythmia assessing the degree of intensification in the ICU through its characteristic proportions., Methods: 80 Holter records from ICU diagnosed with arrhythmia and 20 normal were analyzed. Holter clinical findings were masked and were taken from them the maximum and minimum values of heart rate and total number of beats per minute to build the numerical attractor for each dynamics. Probability, entropy, S/k ratio, and proportions of entropy were evaluated, establishing its mathematical diagnosis and quantifying its severity level., Results: It was shown that the methodology difference in all cases normal of abnormal dynamics, obtaining a sensitivity and specificity of 100 % and Kappa coefficient of 1, showing that it is also possible to establish quantitatively the degree of exacerbation., Conclusions: The methodology developed is useful in clinical practice to correlate the severity of arrhythmias with physical and mathematical predictions of exacerbation.

Introduction: an exponential law has been found for chaotic dynamic cardiac systems, making it possible to quantify the differences between normal and pathological cardiac dynamics., Methodology: 120 electrocardiographic records were analyzed, 40 corresponded to subjects within the limits of normality and 80 with different pathologies. For each holter the attractors generated with the data during 18 hours and throughout the dynamics were analyzed. The fractal dimension of the attractor and its spatial occupation were calculated. To these measures was applied the diagnosis mathematical evaluation previously developed, comparing the evaluation for 18 hours and for the whole registry; sensitivity, specificity and Kappa coefficient were finally calculated., Results: For the normal dynamics, the occupancy spaces in the Kp grid were between 200 and 381 for the evaluation of the whole holter, and between 201 and 384 in the evaluation during 18 hours, showing the closeness in the measurements, which allows that the decrease in the time of the evaluation is consistent, this same proximity was observed for the diseased and acute dynamics., Conclusion: It was evidenced the clinical applicability in 18 hours of the exponential law in the chaotic cardiac dynamics associated with arrhythmias showing to be useful for the prediction of the evolution towards acute states of the dynamics

Introduction and Objectives: To report the findings of the Spanish Implantable Cardioverter-defibrillator Registry for 2016 compiled by the Electrophysiology and Arrhythmias Section of the Spanish Society of Cardiology., Methods: Prospective data were voluntarily recorded on a data collection form and send to the Spanish Society of Cardiology by each implantation team., Results: Overall, 5673 device implantations were reported, representing 85% of the estimated total number of implantations. The reported implantation rate was 122 per million population and the estimated total implantation rate was 143 per million. The proportion of first implantations was 66.8%. Data were received from 177 hospitals (8 more than in 2015). Most implantable cardioverter-defibrillator recipients were men (81.9%). The mean age was 62.7 ± 13.4 years. Most patients had severe or moderate-to-severe ventricular dysfunction and were in New York Heart Association functional class II. The most frequent underlying cardiac condition was ischemic heart disease, followed by dilated cardiomyopathy. Indications for primary prevention accounted for 62% of first implantations. Overall, 81.2% of devices were implanted by cardiac electrophysiologists., Conclusions: The 2016 Spanish Implantable Cardioverter-defibrillator Registry includes information on 85% of the devices implanted in Spain. The total number of device implantations increased in comparison with the last few years. The percentage of implantations for primary prevention also increased in comparison with the previous year., (Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.)

Objective: To determine the relationship between QRS duration and dispersion and the occurrence of ventricular arrhythmias in early stages of acute myocardial infarction (AMI)., Design: A retrospective, longitudinal descriptive study was carried out., Setting: Hospital General Universitario "Camilo Cienfuegos", Sancti Spíritus, Cuba. Secondary health care., Patients or Participants: A total of 209 patients diagnosed with ST-segment elevation AMI from January 2012 to June 2014., Main Variables of Interest: The duration and dispersion of the QT interval, corrected QT interval, and QRS complex were measured in the first electrocardiogram performed at the hospital. The presence of ventricular tachycardia/fibrillation was assessed during follow-up (length of hospital stay)., Results: Arrhythmias were found in 46 patients (22%); in 25 of them (15.9%), arrhythmias originated in ventricles, and were more common in those subjects with extensive anterior wall AMI, which was responsible for 81.8% of the ventricular fibrillations and more than half (57.1%) of the ventricular tachycardias. The widest QRS complexes (77.3±13.3 vs. 71.5±6.4ms; P=.029) and their greatest dispersion (24.1±16.2 vs. 16.5±4.8ms; P=.019) were found on those leads that explore the regions affected by ischemia. The highest values of all measurements were found in extensive anterior wall AMI, with significant differences: QRS 92.3±18.8ms, QRS dispersion 37.9±23.9ms, corrected QT 518.5±72.2ms, and corrected QT interval dispersion 94.9±26.8ms. Patients with higher QRS dispersion values were more likely to have ventricular arrhythmias, with cutoff points at 23.5ms and 24.5ms for tachycardia and ventricular fibrillation, respectively., Conclusions: Increased QRS duration and dispersion implied a greater likelihood of ventricular arrhythmias in early stages of AMI than increased duration and dispersion of the corrected QT interval., (Copyright © 2016 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.)

Supraventricular arrhythmias are one of the main causes of medical consultation. They may also be the clinical presentation of various cardiovascular diseases and a marker of sudden death. The correct diagnosis of these arrhythmias could be a challenge. The purpose of this narrative review is to update succinctly on the topic.

Background: Anorexia nervosa is an eating disorder in which cardiac arrhythmias and sudden death are frequent causes of mortality, which makes electrocardiographic monitoring indispensable in these patients. There are many suggestive findings but results are contradictory, making a critical review of the scientific literature is necessary., Methods: The most relevant studies on electrocardiographic (EKG) changes in patients with AN, found in PubMed from 1974 to February 2014, were reviewed using the MeSH terms: eating disorders, nervosa anorexia, sinus bradycardia, QT prolongation, QT dispersion, electrocardiography, EKG, and electrocardiogram., Findings and Discussion: The two most common EKG findings reported in the literature are sinus bradycardia and changes in depolarization, as shown by prolongation and increased dispersion of the QT interval. Electrolyte disturbances seem to be the cause of these disturbances in some patients, but other reasons are also discussed in detail, such as QRS right axis deviation, disturbances of heart rate variability, low R wave voltage in V6, amplitude decrease of the QRS and T wave, and QRS prolongation. The majority of authors report that these changes are reversible after treatment of AN., Conclusions: These findings support the need for initial and follow-up EKGs in patients with AN and for early diagnosis and treatment of cardiovascular disturbances that are associated with morbidity and mortality. They also support the need for the rational use of psychopharmacology, and that does not increase the risk of arrhythmias and sudden death in these patients., (Copyright © 2014 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.)

A properly interpreted electrocardiogram (ECG) provides important information and is an inexpensive and easy test to perform. It continues to be the method of choice for the diagnosis of arrhythmias. Although the principles of cardiac electrophysiology are the same, there are anatomical and physiological age-dependent changes which produce specific alterations in the paediatric ECG, and which may be misinterpreted as pathological. The intention of this article is to address in a systematic way the most relevant aspects of the paediatric ECG, to propose a possible reading scheme of the ECG and to review the electrocardiograph tracings most frequently found in the paediatric age group., (Copyright © 2013 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España. All rights reserved.)

Clinical echocardiography is a fast, non-invasive and safe diagnostic method carried out at the patient's bedside by clinicians, not necessarily cardiologists, and can provide useful information about cardiac anatomy, with estimates of volumes, diameters, the presence or absence pericardial effusion, and visualization of ventricular wall motion and valve function. The most practical measure of ventricular function to distinguish between patients with systolic dysfunction and those with preserved systolic function is ejection fraction, which can be estimated approximately. The new small pocket echocardiography devices that have become available in recent years offer major advantages in terms of availability and their cost can be considered accessible compared with that of other devices. An undisputed practical advantage is their portability and ease of use. Clinical echocardiography is perfectly compatible with the subsequent performance of echocardiography by a highly qualified expert., (Copyright © 2014 Elsevier España, S.L. All rights reserved.)

In this article we aimed to establish that interatrial block exists as an anatomical-electrical entity, which should be considered a true block. Interatrial block presents with different degrees as other blocks in the conduction system. It shows a correlation with the left atrium size, however, it can be seen in patients with normal atrial size too. Interatrial block is strongly associated with atrial arrhythmias and it could be considered a predictor of cardioembolic stroke. Interatrial block is an expression of atrial electrical remodeling and dysfunction. IAB can be transient and in certain clinical circumstances, may be reversible. The contribution of endocardial mapping has increased our knowledge of the anatomy and pathophysiology of interatrial block. Magnetocardiography could be a possible non-invasive procedure to further investigate this entity. The interatrial block classification should include first, second and third degree or alternatively, in order to simplify the terminology: partial or advanced. The P wave morphology should always be taking into consideration when diagnosing this condition. Finally, without the initial description of interatrial block made by Dr. Bayés de Luna, it would be impossible to understand interatrial block as an anatomical and electrical substrate for atrial arrhythmias. It is our opinion that this represents a major contribution to the knowledge of electrocardiography and electrophysiology, and makes commendable that this arrhythmic syndrome should be called «Bayés' syndrome», (Copyright © 2013 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.)

Introduction: Implantable loop recorders (ILR) may allow detection of occult paroxysmal atrial fibrillation (PAF) in patients with cryptogenic ischemic stroke. However, optimal selection algorithm and ideal duration of monitoring remain unclear. AIM. To determine the incidence and time-profile of PAF in patients with cryptogenic ischemic stroke studied with Reveal XT ILR, who were selected based on a high suspicion of cerebral embolism., Selection Criteria: absence of stroke etiology after complete study including vascular imaging, transesophageal echocardiography and at least 24 hours of cardiac rhythm monitoring, and confirmation of acute embolic occlusion of intracranial artery by transcranial duplex or characteristics of acute ischemic lesion on neuroimaging suggesting embolic mechanism of ischemia. After implanting Reveal XT ILR, patients were trained to perform transmissions monthly or when symptoms occurred. We reviewed the information online each month and patients underwent clinical visits at 3rd and 6th month and then every six months., Results: We included 101 patients with cryptogenic ischemic stroke and at least one month of follow-up after ILR implant. Mean age was 67 years, 54 women (53.5%). Mean follow-up after implantation was 281 ± 212 days. Occult PAF was detected in 34 patients (33.7%). Frequency of false positives: 22.8%. Median time from implant to arrhythmia detection was 102 days (range: 26-240 days). 24 (70%) patients with PAF had several arrhythmic episodes detected with ILR. The majority of events (75%) were detected during the first six months of monitoring., Conclusions: In our patients with probably embolic cryptogenic ischemic stroke, PAF was detected by Reveal XT ILR in 33.7%. One in four events occurred after the first six months of monitoring.

Electrical shock can cause a direct myocardial damage and different types of arrhythmias, which are uncommon and occur more often when there is a high voltage exposure. We report a 19-year-old male that received a high voltage shock, falling thereafter from an altitude of four meters. On admission to the emergency room, he had second and third degree burns in the right hand and the left thigh. The electrocardiogram showed a nodal rhythm of 72 beats per minute. After four hours of monitoring, sinus rhythm returned spontaneously.

Bradyarrhythmias are a common clinical finding and comprise a number of rhythm disorders including sinus node dysfunction and atrioventricular conduction disturbances. Clinical presentation varies from asymptomatic electrocardiogram findings (eg, during a routine examination) to a wide range of symptoms such as heart failure symptoms, near syncope or syncope, central nervous symptoms, or nonspecific and chronic symptoms such as dizziness or fatigue. Conditions resulting in bradyarrhythmic disorders are divided into intrinsic and extrinsic conditions causing damage to the conduction system. Furthermore bradyarrhythmias can be a normal physiologic reaction under certain circumstances. A proper diagnosis including a symptom-rhythm correlation is extremely important and is generally established by noninvasive diagnostic studies (12-lead electrocardiogram, Holter electrocardiogram, exercise testing, event recorder, implantable loop recorder). Invasive electrophysiologic testing is rarely required. If reversible extrinsic causes of bradyarrhythmias such as drugs (most often beta-blockers, glycosides and/or calcium channel blockers) or underlying treatable diseases are ruled out, cardiac pacing is usually the therapy of choice in symptomatic bradyarrhythmias. In this article of the current series on arrhythmias we will review the pathophysiology, diagnosis and treatment options of bradyarrhythmias, especially sinus node dysfunction and atrioventricular conduction blocks., (Copyright © 2012 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.)

Cardiac arrhythmias are prevalent among humans across all age ranges and may occur in the setting of underlying heart disease as well as in structurally normal hearts. While arrhythmias are widely varied in their clinical presentations, they possess shared electrophysiologic properties at the cellular level. The 3 main mechanisms responsible for cardiac arrhythmias are automaticity, triggered activity, and reentry. Although identifying the specific mechanism may at times be challenging for the clinician and require invasive electrophysiologic study, differentiating and understanding the underlying mechanism may be critical to the development of an appropriate diagnosis and treatment strategy., (Copyright © 2011 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.)

Background: Sarcoidosis is a multisystem granulomatous disease of unknown origin that can cause sudden death., Objective: Electrophysiological evaluation of patients with suspected sarcoidosis with cardiac involvement., Methods: We studied 22 patients with mean age of 55.32 ± 13.13 years, diagnosed with sarcoidosis and suspected cardiac involvement. These patients underwent clinical evaluation, laboratory tests, electrocardiogram, echocardiogram, 24-hour Holter, technetium or gallium scintigraphy and electrophysiological study. In selected cases, we performed positron emission tomography or magnetic resonance imaging. Patients were followed up in the outpatient care service with quarterly visits., Results: Cardiac involvement was confirmed in four (18.2%) patients. Ventricular extrasystoles with density > 100/24 h were documented in 24-Holter monitoring in 12 (54.5%) patients. Electrophysiological studies revealed an increased HV interval in seven patients (31.8%) and increased Wenckebach point in four (18.2%) patients. There was induction of atrial fibrillation in seven patients (31.8%) and sustained ventricular tachycardia in one patient (4.5%). Four patients with confirmed cardiac sarcoidosis had documented ventricular extrasystoles with density > 100/24 h. Out of these, two had prolonged HV interval and atrial fibrillation was induced in two of them. Sustained ventricular tachycardia was not induced in any of these patients. After mean follow-up period of 20.9 ± 15.7 months, one patient with cardiac sarcoidosis had sudden death., Conclusion: Patients with sarcoidosis and suspected cardiac involvement have a high prevalence of ventricular extrasystoles (VEs) and conduction system disorders.

This article provides a commentary on some of the most significant research on cardiac arrhythmias published during the last year. Publications were selected for their clinical importance or because they report on improvements in the invasive techniques used in cardiac electrophysiology., (Copyright © 2011 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.)

Objective: To study the efficacy of induced hypothermia (IH) in children, its effect on hemodynamic, hematological, and biochemical parameters and its side effects., Design: Retrospective, observational study., Setting: Pediatric intensive care unit., Patients: Pediatric patients requiring induced hypothermia., Interventions: None., Data Collected: The following variables were recorded prior to the initiation of IH and after 4, 24, 48, 72, and 120 hours: heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), diuresis, dose of inotropic, sedative, and muscle relaxant drugs, fluid balance, hematocrit, white cell count, white cell differential percentages, platelet count, blood levels of glucose, sodium, and potassium, C reactive protein, lactate, coagulation times, pressure ulcers, shivering, infections and death., Results: Thirty-one patients with a mean age of 20 months (SD: 39.8) were included in the study. The mean duration of IH was 3.97 days (range: 1 to 11 days). Among the IH effects, there was a significant fall in heart rate, with no changes in SBP, DBP, or diuresis. The blood tests revealed a progressive and significant fall in platelet count and an increase in C reactive protein levels. The fall in hematocrit and glucose and lactate levels was not significant. Positive cultures were detected in 25.8% of the patients during IH, most commonly from the bronchial aspirate (65%)., Conclusions: Induced hypothermia can be useful in some critically ill children. Tolerance is generally good and there are usually few side effects, which can be controlled through appropriate monitoring., (Copyright © 2009 Elsevier España, S.L. y SEMICYUC. All rights reserved.)

Background and Objectives: One third of patients with a coronary event show kidney failure. Our aim is to establish the relationship between kidney failure and mortality in patients diagnosed of acute coronary syndrome (ACS) through Cockcroft Index (C-G) and MDRD-4 equation, analyzing which of them is better for prognostic stratification., Patients and Method: Prospective study of 445 patients admitted consecutively between 2006 and 2007 with a high risk of ACS, dividing the sample depending on his kidney function at admission in < 60 mL/min/1.73 m(2) and > or =60 mL/min/1.73 m(2) through C-G and Modification of Diet in Renal Disease study group 4 (MDRD-4) and other variables. We performed a multivariate logistic regression for both of them, analysing the relationship with mortality in the following six months after admission., Results: Renal failure was present in 27.9% (creatinine < 1.1mg/dl); 30.5% (C-G) and 22.6% (MDRD-4). Glomerular filtration (GF) was 81.6+/-35.2 mL/min (C-G) and 77.2+/-26.1 mL/min/1.73 m(2) (MDRD-4). Patients with GF < 60 mL/min showed high mortality, Odds ratio 2.652; p=0.024 (IC 95%, 1.140-6.166) for C-G and 3.372; p=0.001 (IC 95%, 1.637-6.954) for MDRD-4., Conclusion: Renal failure increases the risk to die in the following six months after an ACS. The estimation through Cockcroft Index and/or MDRD-4 equation depends on the population characteristics and is indifferent with GF between 60 and 80 mL/min., (2009 Elsevier España, S.L. All rights reserved.)

This article contains a review of some of the most important studies in the field of arrhythmias and cardiac electrophysiology that have been reported in publications during the last year. They were selected because of their clinical relevance and because they made a positive contribution to the continuing technological development of the invasive procedures used in cardiac electrophysiology.

The remarkable advances that have taken place in biomedicine over the past 50 years have resulted in dramatic improvements in the prevention, diagnosis and treatment of many diseases. Although cardiology has adopted these advances at a relatively slow pace, today it is fully immersed in this revolution and has become one of the most innovative medical specialties. Research is continuing to give rise to new developments in genetics and molecular biology that lead, almost daily, to innovative ways of preventing, diagnosing and treating the most severe forms of heart disease. Consequently, it is essential that clinical cardiologists have some basic knowledge of genetics and molecular biology as these disciplines are having an increasing influence on clinical practice.

Introduction: Chagas disease is the main cause of chronic myocardiopathy in Central America. The mechanisms proposed for this cardiac pathology during the chronic phase remain controversial. Several studies have detected the presence of circulating autoantibodies against beta-adrenergic and cholinergic muscarinic receptors of the myocardium in patients with Chagas disease. These autoantibodies can trigger intracellular signals and modify the cardiac function during the progression of the disease., Objectives: The serological frequency of these autoantibodies was compared among patients with chronic Chagas disease, patients with other cardiopathies and healthy controls., Materials and Methods: The prevalence of autoantibodies against beta-adrenergic and cholinergic muscarinic receptors was determined in four groups of Panamenian patients: 53 chagasic patients, 25 serologically negative patients with cardiac insufficiency, 25 patients with cardiac arrhythmia and 25 healthy individuals., Results: The antibodies against autonomic receptors were more frequently observed in patients with chronic chagasic cardiomyopathy (24.5%) compared to the cardiac insufficiency group (20.0%) and the cardiac arrhythmia group (16.0%). The proportion of autoantibodies was significantly different between the groups with chronic chagasic cardiomyopathy and healthy controls (24.5% versus 0%; p = 0.015). Of the 53 chronically infected chagasic patients, 48 (90%) showed some degree of cardiac dysfunction., Conclusions: The frequency of autoantibodies against autonomic receptors is significantly increased in patients with chronic Chagas disease and in patients with other cardiopathies.

This article contains a review of the most important developments in clinical arrhythmology and interventional cardiac electrophysiology that have been reported during the past year. Special emphasis has been placed on clinical conditions that are most prevalent in the general population as well as on progress that has been achieved using the main therapeutic approaches, whether pharmacologic or interventional.

Introduction and Objectives: This article reports the findings of the 2007 Spanish Catheter Ablation Registry, as compiled by the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias., Methods: As in previous years, data were collected in two ways: retrospectively using a standard questionnaire sent to electrophysiology laboratories by the Working Group on Electrophysiology and Arrhythmias, and prospectively from a central database. Each participating center selected its own preferred method of data collection., Results: Fifty Spanish centers contributed data voluntarily. In total, 7062 ablations were analyzed, averaging 141 (82) per center. The three most frequently treated conditions were atrioventricular nodal reentrant tachycardia (n=2068, 30%), typical atrial flutter (n=1701, 24%) and accessory pathways (n=1624, 23%). A steady increase in both the absolute number of cavotricuspid isthmus ablations for typical atrial flutter and in the relative frequency of this procedure was observed, such that it has overtaken accessory pathway ablation to became the second most common form of treatment. The fourth most common condition was atrial fibrillation (n=659, 9%), which accounted for 22% more procedures than in 2006. Overall, the success rate was 92%, major complications occurred in 1.7%, and the mortality rate was 0.04%., Conclusions: Registry data for 2007 show that the number of ablations carried out continues to increase, and has exceeded 7000 for the first time. In general, the success rate was high and there were few complications. Typical atrial flutter, requiring cavotricuspid isthmus ablation, has become the second most frequently treated condition. A moderate steady increase in the number of ablations for atrial fibrillation was also observed.

This article contains a review of some of the most significant advances in cardiac arrhythmias that have taken place in the last year, particularly those concerning the most common clinical conditions associated with the risk of arrhythmia, such as sudden cardiac death, atrial fibrillation and syncope, and genetically determined and hereditary heart disease, as well as advances concerning the principal nonpharmacologic treatments, such as catheter ablation, and the use of implantable defibrillators and cardiac resynchronization therapy.

The hereditary disease known as polymorphic catecholaminergic ventricular tachycardia (PCVT) is highly lethal. Almost 30% of the affected patients die before 40 years old, mainly due to sudden cardiac death. We have used isolated hearts from mutant mice (type 2 ryanodine receptors, RyR2/RyR2(R4496C)) to investigate arrhythmia mechanisms that are adrenergic- and intracellular calcium ([Ca2+]o) levels-dependent. Our results corroborate that polymorphic and bidirectional ventricular arrhythmias, as well as ventricular fibrillation, occurs in 50% of RyR2/ RyR2(R4496C) mice, and in less than 12% of the non-affected mice. Our hypothesis suggests that the origin of catecholaminergic arrhythmias in animals, and possibly in humans, is conditioned by the focal activity that begins by late post-potentials in the Purkinje fibers.

Unlabelled: Patients with surgical correction of congenital cardiopathies have a high incidence of macro-reentrant arrhythmias. In previous reports the incidence of atrial fibrillation or flutter is around 20% preoperatively and increases to 10% more after surgery. In Mustard and Senning procedures the incidence could be as high as 30%. The physiopathology of these arrhythmias is due to conduction block and heterogeneity of refractory periods due to scaring and fibrosis left by the surgical procedure. Radiofrequency ablation is a good treatment option in this patients, but with conventional approaches the percentage of success is lower and with higher recurrence. In our institution out of 39 patients with macro-reentrant atrial tachycardia, acute success was 77% in patients with isthmus dependent flutter and 44% if the Isthmus was not part of the circuit. Recurrence in both groups was 42%. New mappings systems like Localisa, CARTO an NavX, are useful to localize areas of scar and block, that produce multiple conduction channels that can participate in reentrant arrhythmias. Radiofrequency ablation of these channels is up to day the ideal approach for these patients., Conclusions: Arrhythmias in patients with congenital cardiopathies are frequent and complicate the evolutions of these patients. Radiofrequency ablation is the treatment of choice in centers with experience. The use of non fluoroscopic electroanatomic mapping systems is of great help in this setting.

Cardiac arrhythmias can develop during pregnancy. The risk of arrhythmias is relatively higher during labor and delivery. Potential factors that can promote arrhythmias in pregnancy or during labor and delivery, include the direct cardiac electrophysiological effects of hormones, changes in autonomic tone, hemodynamic perturbations, hypokalemia, and underlying heart disease. In this review, the basis for treatment of supraventricular and ventricular tachycardias are described. No drug therapy is usually needed for the management of supraventricular or ventricular premature beats, but potential stimulants, such as smoking, caffeine, and alcohol should be eliminated. In paroxysmal supraventricular tachycardia, vagal stimulation maneuvers should be attempted first. In pregnant women with atrial fibrillation, the goal of treatment is conversion to sinus rhythm by electrical cardioversion. Rate control can be achieved by a cardioselective beta-adrenergic blocker drug and/ or digoxin. Ventricular arrhythmias may occur in the pregnant women, specially when cardiomyopathy, congenital heart disease, valvular heart disease, or mitral valve prolapse exists. Electrical cardioversion or treatment with sotalol may be used (amiodarone is not safe for the fetus). Finally, in women with congenital long QT syndrome, beta-blocker therapy must be continued during pregnancy and postpartum period.

Congenital heart disease is associated with arrhythmias. Not only the congenital anatomic component but also the greater arrhythmogenic substrate related to surgical procedures is associated with the increased incidence of arrhythmias in these patients. In pediatric cardiology the study of these phenomena is becoming important and one factor associated with it is the longer follow up, which varies depending on the type of heart disease and arrhythmia. With the same impact, there are daily breakthroughs in diagnostic and treatment through pharmacological and interventional means. The incidence of arrhythmias in post-surgical patients with congenital heart disease is in constant increment, and this is related to the constant increment in the procedures, variety and frequency, as well as the long-term survival.

A great percentage of patients who have suffered a myocardial infarction have ventricular left dysfunction. In agreement with the different prospective studies, many of these patients will have an event of ventricular arrhythmias that does them candidates for receiving a strategy of primary or secondary prevention with an ICD. The same studies have showed a significant reduction in mortality with the therapy of the ICD compared with the conventional therapy what demonstrates the balance cost - benefit in favor of the use of these devices in long periods of follow-up. The benefits of mortality with the use of the therapy with ICD at the primary prevention are at least so good as those of the secondary prevention of agreement to the results of different prospective studies.

In the past few months, numerous articles have been published on arrhythmias and cardiac electrophysiology. As in previous years, a substantial proportion of researchers have concentrated on atrial fibrillation, both on catheter ablation of chronic and paroxysmal atrial fibrillation and on the development of new approaches to thromboembolism prophylaxis. The feasibility of atrial fibrillation ablation by remote control has been demonstrated and a step-wise approach to ablation has been proposed, which appears to improve outcome and reduce lesion size. In addition, multicenter randomized trials have shown that the improvements in functional class and left ventricular ejection fraction achieved by ablation in patients with chronic atrial fibrillation are greater than those resulting from pharmacological treatment. New strategies are being developed to improve the selection of patients for defibrillator implantation and to decrease the number of high-energy discharges occurring during follow-up. Controlled trials continue to demonstrate that pharmacological therapy is of little value in preventing recurrence of vasovagal syncope compared with maneuvers involving isometric muscular contraction. Finally, one of the most significant events in the last year was the publication of new clinical practice guidelines by European and American societies of cardiology. These provide important recommendations on the treatment and prevention of ventricular arrhythmias and sudden death and on the management of and thromboembolic prophylaxis in atrial fibrillation.

The sarcoplasmic reticulum (SR) constitutes the main intracellular calcium store in striated muscle and plays an important role in the regulation of excitation-contraction-coupling (ECC) and of intracellular calcium concentrations during contraction and relaxation. The regulation of ECC occurs due to the interaction among the main proteins of the SR that are the calcium release channel or ryanodine receptor, the Ca2+-ATPase, phospholamban and calsequestrin. Due to the importance of ECC in the physiopathology of a number of cardiac diseases, the role of the SR and its components has been widely investigated in some pathologies, specifically cardiac hypertrophy, heart failure, and hereditary arrhythmias. Therefore, the SR proteins constitute an area of research of great interest for the development of new genetic and pharmacologic therapies; from this derives the importance of understanding the function of the SR. This review analyzes the expression, structure, and function of the main SR proteins, their role on myocardial contraction and relaxation and in the changes that occur in cardiac pathologies.

Some authors have shown a high prevalence of electric circuits localized in the epicardium in Chagasic cardiomyopathy. Other authors have found in these patients, during electric mapping, mid-diastolic potentials and earlier myocardial activation in epicardial regions than in the endocardium. In a previous study, we found electrocardiographic signs of subepicardial ischemia in 66% of seropositive Chagasic patients against 16% of seronegative Chagasic ones. In the case presented here, a Chagasic dilated cardiomyopathy, we found electrocardiographic signs of subepicardial injury in the left free ventricular wall, related with histological findings of lymphocytic inflammation in these regions. In contrast, the endocardium was completely free from inflammation foci.

The aim of this study was to review published data on gender differences in cardiac electrophysiology and in the presentation and clinical treatment of arrhythmias. The evidence from studies published to date show that women have a higher mean resting heart rate, a longer QT interval, a shorter QRS duration, and a lower QRS voltage than men. Women have a higher prevalence of sick sinus syndrome, inappropriate sinus tachycardia, atrioventricular nodal reentry tachycardia, idiopathic right ventricular tachycardia, and arrhythmic events in the long-QT syndrome. In contrast, men have a higher prevalence of atrioventricular block, carotid sinus syndrome, atrial fibrillation, supraventricular tachycardia due to accessory pathways, Wolff-Parkinson-White syndrome, reentrant ventricular tachycardia, ventricular fibrillation and sudden death, and the Brugada syndrome. With regard to implantable devices, it has been reported that defibrillators offer similar benefits in men and women. Moreover, there is no gender difference in the percentage who respond well to resynchronization therapy: survival is similar in the two sexes. However, it should be noted that few women have participated in studies of all types of therapy, including catheter ablation, resynchronization therapy, and the use of implantable defibrillators.

Cardiac arrhythmias are an important cause of complications throughout the perioperative period. Although our understanding of arrhythmias has increased considerably in recent years, they remain a source of concern for anesthesiologists. Our objective was to review steps to take when diagnosing arrhythmia. Although treatment is still largely influenced by therapies used in nonsurgical patients, we will review the approaches that are most applicable to practice situations in which anesthesiologists must manage patients with arrhythmias or at high risk of developing them.