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Introduction: The most common clinical presentation of neuroblastoma is an abdominal mass, but it can present with uncommon symptoms, such as adrenergic storm due to catecholamine release., Objective: To describe an unusual presentation of neuroblastoma and the wide differential diagnosis that exists in an infant with adrenergic symptoms., Clinical Case: A 7-week old female infant was evaluated due to a 3-week history of sweating and irritability associated with a 24-hour fever and respiratory distress. At admission, she presented poor general condition, irritability, sweating, facial redness, tachypnea and skin paleness, extreme sinus tachycardia, and high blood pressure (HBP), interpreted as adrenergic symptoms. The study was completed with abdominal ultrasound and magnetic reso nance imaging that showed a large retroperitoneal mass compatible with neuroblastoma. Plasma and urinary catecholamines tests showed high levels of dopamine, adrenaline, and noradrenaline, probably of tumor origin. We started antihypertensive treatment with alpha-blocker drugs, showing a good blood pressure control. The tumor was surgically resected without incidents and adequate subsequent recovery. The patient presented a favorable evolution after three years of follow-up. Con clusions: In an infant with adrenergic symptoms such as irritability, redness, sweating associated with HBP, it should be ruled out pathology heart or metabolic (hypoglycemia) pathology, intoxications, and/or adrenal pathology. Within this last one, neuroblastoma is the first diagnostic possibility, since it is one of the main tumors in childhood and, although this presentation is not usual, it can produce these symptoms.

Objective: To determine the diagnostic accuracy measures of defining characteristics of respiratory nursing diagnoses "impaired gas exchange" and "impaired spontaneous ventilation" in asmathics children in emergency department., Methods: Observational, descriptive transversal study developed between April and September 2013 in a hospital in northeastern Brazil with a sample of 205 children. Diagnoses were established by nurses trained experts in this field. Measures of sensitivity, specificity, positive and negative value prediction right positive and negative likelihood ratio and diagnostic odds for the defining characteristics identified were calculated., Results: 28.8% of the evaluated children had "impaired gas exchange". Dyspnea, abnormal breathing, tachycardia and hypoxemia had higher frequencies. Hypoxemia presented as clinical feature high sensitivity and specificity. 5.9% of the evaluated children had "impaired spontaneous ventilation" and their most frequent defining characteristics were dyspnea, increased heart rate and decreased SaO2. The increasing use of accessory muscles to breathe presented the best measures of validity for this diagnosis., Conclusion: The hypoxemia and increased use of accessory muscles presented the best measures of the validity respectively to "deterioration in gas exchange" and "impairment of spontaneous ventilation". These characteristics is necessary to provide for adequate definition and use of diagnostics in clinical practice., (Copyright © 2015 Elsevier España, S.L.U. All rights reserved.)

A proper characterization of frequency-dependent bundle branch blocks can provide useful prognostic information in some clinical situations. Often, this physiological event may be due to an extensive damage of infrahisian system, which poses a high risk of developing advanced atrioventricular block requiring pacemaker implantation. We describe the case of a 62 year-old man with chronic ischemic heart disease who exhibited alternating tachycardia-dependent bundle branch block during stress test. We discuss the main prognostic implications of this unusual event in the context of systolic dysfunction.

The differential diagnosis and therapeutic management of wide QRS tachycardia preceded by pacemaker spike is presented. The pacemaker-mediated tachycardia, tachycardia fibrillo-flutter in patients with pacemakers, and runaway pacemakers, have a similar surface electrocardiogram, but respond to different therapeutic measures. The tachycardia response to the application of a magnet over the pacemaker could help in the differential diagnosis, and in some cases will be therapeutic, as in the case of a tachycardia-mediated pacemaker. Although these conditions are diagnosed and treated in hospitals with catheterization laboratories using the application programmer over the pacemaker, patients presenting in primary care clinic and emergency forced us to make a diagnosis and treat the haemodynamically unstable patient prior to referral., (Copyright © 2012 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España. All rights reserved.)

Arrythmias in the pediatric patient usually are considered rare; nonetheless, their number is increasing. The paroxistic supraventricular tachycardia is the most frequent symptomatic arrhythmia. The diagnosis is based on electrocardiographic register. There are few diagnostic tools including the Hotter monitoring and loop recorders. Once the tachychardia is detected, a deductive electrocardiographic diagnosis and specific treatment are established.

A 56-year-old man came to the Pacemaker Clinic for his regular pacemaker control. He had experienced a syncopal episode in the previous week. He had a previous diagnosis of non-obstructive hypertrophic cardiomyopathy. Due to a previous syncope and documented 2:1 infrahisian block, a dual-chamber permanent pacemaker had been implanted a few years before. The device was interrogated, showing several ventricular high rate episodes. A careful analysis of the stored intracardiac electrograms showed ventricular tachycardia (VT) with 2:1 ventriculoatrial conduction. The following presentation discusses the alternative diagnosis and clinical management in an unusual diagnosis of VT in the presence of non-obstructive hypertrophic cardiomyopathy.

Objective: To determine whether an algorythm designed at our Electrophysiology Unit could facilitate the electrocardiographic diagnosis of tachyarrhythmias., Methods: Twenty two first-year cardiology residents, general practitioners and last-year medical students attended an electrophysiology course. One hundred ECG of tachyarrhythmic patients were distributed to the participants who were then randomly divided into 2 groups. Group A analyzed the ECG with the help of the algorythm, whereas Group B analyzed them without it. Results were compared to those obtained by an electrophysiologist., Results: Group A diagnosis coincided with that of the electrophysiologist in 41% of the cases. In Group B the concordance reached 64% (p = 0.0000013). There was no between-group difference regarding the type and number of uninterpreted ECG., Conclusions: The decision tree increases diagnostic accuracy in less expert hands. This could in turn entail an improvement in the therapeutic measures applied to the study of arrhythmias.

The surface ECG constitutes an invaluable tool for the differential diagnosis in those cases in which the QRS complex exceeds the normal duration (120 mseg or more) and a heart rate of 100 bpm or more. Most of the arrhythmias with wide QRS complexes are ventricular in origin, and frequently related to heart disease; nevertheless, in those patients with hemodynamic stability it is frequently misdiagnosed as supraventricular tachycardia. The importance of the surface ECG resides in the fact that the correct diagnosis can be done with high probability when the analysis is orderly made. To be able to perform such an analysis it is necessary to count upon a good quality ECG, besides it is very important if, in addition, a transesophageal record is available to establish the precise relation between the "p" wave and the ventricular activation. There are the traditional morphologic criteria, with their limited usefulness, but the observations of Brugada et al. increased the sensitivity, which can reach up to 98% with a high degree of specificity (96%). The clinical data plus an adequate ECG analysis can lead to the differential diagnosis with a high grade of certainty.

In patients with an orthostatic intolerance, the hemodynamic response to standing, may identify an abnormality know as postural orthostatic tachycardia syndrome or orthostatic hypotension, that can often be treated without further testing. When the response to standing is normal, tilt-table testing may be useful in making the diagnosis of vasovagal syncope or postural orthostatic tachycardia syndrome and guiding treatment. In evaluating the results of tilt-table testing, an important consideration is the distinction between vasovagal syncope, and the dysautonomic response to tilt characterized by a gradual and progressive decrease in blood pressure that leads to syncope. Current practice patterns suggest that beta blockers, fludrocortisone, and midodrine are commonly used to treat patients with vasovagal syncope. These also suggest that patients with the postural orthostatic tachycardia syndrome, and with the dysautonomic response, are better treated with fludrocortisone and midodrine.

Introduction and Objectives: Radiofrequency ablation has shown to be an effective treatment for supraventricular tachycardias including flutter and atrial tachycardia, however the clinical information available on atrial tachycardia is limited. The aim of this study was to evaluate the immediate and long term effectiveness of radiofrequency ablation in patients with atrial tachycardia and to establish predictors of effectiveness and arrhythmia recurrence., Methods: We analyzed a series of 126 procedures of atrial tachycardia ablation in 117 patients (69% women) with a mean age of 50 +/- 19 years., Results: Ninety-one percent of the foci were located in the right atrium. A mean of 6 applications were necessary to achieve an efficacy of 74% during the first procedure with a total of 80%. The only predictor of ablation success was the number of foci being smaller in multifocal compared to unifocal (p < 0.01) whereas for recurrences a less premature electrogram at the application point (p = 0.02) was predictive of ablation success. Over a follow-up of 34 +/- 19 months 7.4% of patients had recurrent atrial tachycardia. The probability of recurrence at one year calculated by the Kaplan-Meier method was 12%. Seventy-one percent of the recurrences occurred during the first 3 months after ablation., Conclusions: Ablation is an effective, safe procedure for short and long term treatment of patients with atrial tachycardia. Effectiveness depends on the number of foci while the recurrence rate is related to the prematurity of atrial electrogram at the application point.

Background: There is poor information for isolated clinical tachycardia (ICT), that is to say, office tachycardia but normal ambulatory heart rate (HR). Our objective was to describe it and to know differences between hypertensive subjects with and without ICT., Patients and Method: Comparative study after a diagnostic intervention (ambulatory blood pressure monitoring, ABPM, SpaceLabs 90202-90207), with convenience sampling of non-treated hypertensive patients attended in primary care. We excluded subjects with heart, thyroid or lung disease. ICT were defined on the basis of office and daytime HR percentile 90 of the whole sample., Results: A total of 256 subjects were included, 128 (50%) women, age 49.1 (16.1) years, with mean office blood pressure (BP) 151 (17.1)/92 (11.9) mmHg. The prevalence of ICT was 7.03% (CI 95%, 4.03-11.07) (n = 18). We didn't find any association between isolated clinical hypertension and ICT (p = 0.87). Patients with ICT have lower office and systolic night time BP, lower night time variability, higher night time BP fall, although higher 24 hours-HR and daytime-HR in comparison with non ICT hypertensive patients. In the multivariate analysis only office diastolic BP (OR, 0.93 [CI 95%, 0.87-0.98], for each mmHg increment) and office HR (OR, 1.2 [CI 95%, 1.11-1.28], for each beat for minute increment) were predictive of ICT., Conclusions: In this study 7.03% of non treated hypertensive patients present ICT, which suggest a profile of more favorable cardiovascular risk than that without ICT. Only office diastolic BP and office HR were predictive variables of ICT.

Even though the 12-lead electrocardiogram is the most helpful tool in the diagnosis of tachycardia, a careful history and physical examination can be useful in both differentiating between ventricular and supraventricular tachycardia and elucidating the electrophysiological mechanism of supraventricular tachycardia. This article will focus on the most relevant clinical aspects of tachyarrhythmias as well as on the electrocardiographic differential diagnosis of regular broad complex tachycardia.

The differential diagnosis of tachycardias with a widened QRS complex is a frequent problem that cardiologists and emergency room physicians must face. Ventricular tachycardias, supraventrical tachycardias with aberration of ventricular conduction and supraventricular tachycardias conducted by accessory routes (pre-exited or antidromic) are the three mechanisms that cause tachycardias with a widened QRS complex, whose clinical significance and treatments are different. Recently, intracardiac electrophysiological studies allowed the identification of efficient electrocardiographic criteria to distinguish each of these mechanisms. Several reports have indicated these criteria based on the careful analysis of the surface electrocardiogram.

Background: The permanent form of junctional reciprocating tachycardia occurs predominantly in childhood and is frequently refractory to pharmacologic treatment. These patients are at high risk for developing tachycardia-induced cardiomyopathy. Radiofrequency transcatheter ablation appears promising as safe and effective therapy in children., Patients, Methods and Results: Six patients ranged in age from 3 months to 20 years who had the permanent form of junctional reciprocating tachycardia underwent radiofrequency catheter ablation. Five patients had been treated with 3.4 +/- 1.1 antiarrhythmic drugs and one patient did not receive treatment before ablation. Three accessory pathways were located in the right posteroseptal area, two in the left posteroseptal area and one in the left posterior free wall. The six patients had seven successful procedures performed including one after tachycardia recurrence in one patient six weeks after the first ablation session. Five ablation procedures were performed with temperature-guided catheter ablation. The temperature reached during successful radiofrequency applications was 55-60 degrees C at a power output from 24 to 47 W. In the other two procedures 25 W were given. No complications were observed. After a mean follow up of 11.6 months all patients are asymptomatic including a 3 months old patient with tachycardia-induced cardiomyopathy., Conclusions: Radiofrequency transcatheter ablation is an important option of therapy in children with the permanent form of junctional reciprocating tachycardia, including patients with tachycardia-induced cardiomyopathy.

Introduction: Radiofrequency ablation has been extensively used in adults to treat supraventricular and ventricular tachycardia. In children and adolescents few data are available on its safety and efficacy., Methods: 28 patients (mean age 12.8) with symptomatic tachyarrhythmias underwent catheter ablation; 21 children had atrioventricular accessory pathways (11 right connections, 9 lef connections and one midseptal pathway), 3 had intranodal tachycardia, 2 had ventricular tachycardia and 2 had atrial tachycardia. Only four patients had associated structural anomalies., Results: Success rate was 71.4% (20 patients). The success per cents in each group were: in intranodal tachycardias 100%; we failed in the two patients with ventricular tachycardias; in accessory pathways 76.1% and 50% in atrial tachycardia. There were no recurrences of arrhythmia in a mean chase period of 24 months (12-46). Major complications were only observed in one patient who developed a Wallenberg syndrome after ablation., Conclusions: Radiofrequency catheter ablation appears to be a safe and effective method to treat arrhythmias in children and adolescents, which in most cases can supersede surgery. Alow incidence of complications is reported, although long term damage on endocardial structures remains yet to be determined.

The case of a gestant diagnosed fetal arrhythmia in the 35th week of gestation is presented. A fetal echocardiography indicates an aneurysm of the interauricular septum and a fetal supraventricular tachycardia. Also is obtained an ambulatory 24-hour Holter electrocardiograph of the gestant and fetus rhythm. The register makes evident a gestant supraventricular tachycardia and as well a fetal supraventricular tachycardia, occurring in both without clinical company. Following the birth, the tachycardia in the newborn is identified to be automatic and incessant, requiring digital for its control. In postpartum registers of the mother no significant arrhythmia of any type is observed. We conclude that the ambulatory monitoring with a Holter electrocardiograph could be a good method of diagnosis and follow-up of fetal and gestant arrhythmias.

We comment the results with non pharmacological treatment in 23 patients (mean age 11 +/- 4 years) with multiple episodes of palpitations, most of them required intravenous drugs for interrupting it. Twenty-eight procedures were performed, 17 catheter ablation and 11 surgical interventions. The energy source employed for fulguration until 1990 was DC and since 1991 radiofrequency. The best results with catheter ablation were obtained with accessory pathways. Interruption was achieved in all patients after a mean of 1.2 sessions per patient, but it was definitive in only 72%. Most of the patients (81%) remained asymptomatic without antiarrhythmic drugs. Nine patients with accessory pathways underwent surgery interruption, it was achieved in all; only one patient had arrhythmia recurrence, due to a second pathway in a different localization. We could not ablate a ectopic atrial tachycardia, that underwent surgery. There was only one indication for surgery in a patient with ventricular tachycardia. Catheter ablation does not present technical problem in children and teenagers, different from adults. The presented results lead us to suppose that the indications for non pharmacological treatment in the young will become more common.

Clinical and electrophysiological characteristics in 20 patients with clinical ventricular tachycardia and normal hearts documented by physical examination, echocardiography, and angiocardiography were analysed. There were 11 males and 9 females. All patients had sustained ventricular tachycardia without hemodynamic instability during tachycardia. A right bundle branch block morphology of ventricular tachycardia was present in 14 patients and left bundle branch block morphology in six patients. During electrophysiologic studies, ventricular tachycardia was induced in 10/15 (66%) patients. Intravenous verapamil terminated the ventricular tachycardia in 9/10 (90%) of cases. However oral verapamil not prevented recurrences. Among 14 patients on whom exercise tests were performed, only two had exercise-induced ventricular/tachycardia. Late potentials were positive in 3/14 (21%) cases and one patient died suddenly during exercise without antiarrhythmic drugs.

Sixteen consecutive patients (5 males and 11 females) aged 40 +/- 22 years suffering for spontaneous symptomatic arrhythmias underwent attempted transcatheter ablation of an atrioventricular accessory pathway using radiofrequency current. Five patients had the WPW syndrome. The Kent bundle was located in the left free wall in 14 patients, in the right anteroseptal region in one patient and in the posteroseptal zone in one patient. A 7F catheter (Polaris, Mansfield) with a 4 mm2 distal electrode, was used for ablation positioned on the left atrioventricular annulus in the 13 patients with left free wall accessory pathways or at the right atrium in the two patients with right accessory pathways. Without general anesthesia, a mean of 12 +/- 9 applications of radiofrequency current were delivered between the large tip electrode and a large skin patch positioned on the left posterior chest. By using radiofrequency current, a successful clinical outcome was achieved in 14 of 16 patients (87%). In patients with concealed accessory pathways, accessory conduction was abolished in 10 of 11 patients, in 8 patients in the first radiofrequency session and in two other patients in a successful second procedure. In the 5 patients with the WPW syndrome, the anterograde conduction disappeared after the procedure but the retrograde conduction remained, although deteriorated, in 2 patients. One patient developed uncomplicated tibioperoneal thrombophlebitis and in 2 cases an elevated concentration of creatine kinase value was found. In one female patient with a concealed accessory pathway, the Kent bundle conduction reappeared 3 months after the procedure and was ablated in a second session.(ABSTRACT TRUNCATED AT 250 WORDS)

We describe a 9-year old patient with arrhythmogenic right ventricular dysplasia. The patient presented with sustained ventricular tachycardia in an apparently normal heart. The diagnosis was suspected by the electrocardiographic morphology of the tachycardia and definitive diagnosis was made by right ventricular angiogram, echocardiogram and the ventricular endomyocardial biopsy findings (replacement of myocardial by adipose tissue and fibrosis). We believe that this condition may be a common etiology of ventricular tachycardia with left bundle branch block conduction pattern in children with otherwise normal hearts.

We describe a case of a 46 years old female with chagasic heart disease. In one year she presented six episodes of sustained ventricular tachycardia, heart rate 230 beats per minute, morphology of RBBB AQRS -60 degrees, with hemodynamic deterioration that needed electrical cardioversion. She was treated with several antiarrhythmic drugs but not good response was obtained. Programmed electrical stimulation was done and it show three different types of ventricular tachycardia, trough pace-mapping the site of the clinical tachycardia was located in the portion inferior and inferior-posterior of the left ventricle that was confirmed by entrainment. Epicardial mapping was performed in 38 ventricular sites following the modified Harken sketch and the location of the site of outlet was confirmed in the posterior base of the left ventricle, at this point the surgical resection was done with no complication. The results were satisfactory. Eight days later programmed electrical stimulation was done and the ventricular tachycardia could not be induced. Six months afterwards the patient is asymptomatic without medical treatment.

Active ventricular arrhythmias were provoked in damaged dog myocardium to study their response to some antiarrhythmic agents of Vaughan-Williams' class I. Dogs anesthetized with intravenous sodium pentobarbital (30 mg/Kg) were intubated and submitted to artificial ventilation using a Palmer pump. An infarction was produced near the apex of the left ventricle by intramural injection of 1-1.5 ml of phenol, and 30 to 60 min later, minute crystals of aconitine were introduced into the periphery of the infarcted area. Once ventricular tachycardia appeared and became stable, corresponding records were obtained and the antiarrhythmic agent to be studied was administered through the superior vena cava over a period of 5 to 15 min. Electrocardiographic tracings were registered at constant intervals in order to detect the recovery and duration of sinus rhythm. The reappearance of arrhythmia was always required in order to consider the action of the medication administered positive. High doses of lidocaine (6 mg/Kg) reestablished transient sinus rhythm in 23% of 35 treated dogs. Fifteen mg/Kg of mexiletine reestablished it in 45% of 22 animals and 2.5 mg/Kg of propafenone restored it in 39% of 18 animals receiving this drug. The positive effect of these antiarrhythmic agents of groups I B and I C consisted essentially in controlling no-rapid tachycardias with the "wave jumping" phenomenon and fusion beats, which may be due to activity of ectopic foci. Very rapid ventricular tachycardia with "wave jumping" generally did not respond to the antiarrhythmic agents tested. These tachycardias may be maintained by reentry or by the intervention of calcium-dependent potentials. Rapid ventricular tachycardias without extensive "wave jumping" also occurred. These were never controlled by the group I B antiarrhythmic agents, although they were sometimes suppressed with propafenone. These tachycardias probably originated near the intraseptal barrier. In few animals, amiodarone of class III was employed with a marked hypotensive effect.

A case of nonimmune hydrops fetalis (NIHF) secondary to fetal supraventricular tachycardia (SVT) diagnosed at 33 weeks gestation is presented. Administration of digoxin to the mother yielded normal fetal heart rhythm and frequency as well as progressive resolution of hydrops after 24 hours of initiation of therapy. Causes of NIHF and diagnostic approach are mentioned. Diagnosis and management of fetal arrhythmias are discussed. The successful perinatal outcome obtained in this case and the literature review, recommend the use of antiarrhythmic drugs therapy in cases of NIHF secondary to SVT.

Amiodarone has been used for the last 20 years, initially as antianginal and then as antiarrhythmic agent. To the collateral effects described, the optic neuropathy must be added as a complication, not so frequent, caused apparently by the prolonged ingestion of it. Two patients treated with MDD of 250 mg of amiodarone, for a mean of 17 months, are reported. They presented a decrease of the visual acuity. After proposing the possible differential diagnosis, the relation between the use of amiodarone and the optic alteration observed is briefly exposed, relating it with the demyelination neuropathy induced by this drug. This presumption is corroborated by the ultrastructural alterations registered in the optic nerve of animals in which amiodarone was used, similar to those of the peripheral nerves, as an expression of a disorder of the lipidic metabolism, which allow it to be integrated to the so called iatrogenic lipidoses.

Approximately 15% of patients with Wolff Parkinson White's syndrome who undergo electrophysiologic study have more than one accessory pathway. We describe the electrophysiologic testing and findings in 2 patients with multiple pathways. Identification of these is highly relevant since successful surgical therapy depends on section of all pathway.

Report of a healthy child with ventricular tachycardia is the reason for a review on the literature on this subject. Diagnosis can be made with usual electrocardiographic criteria and surely by electrophysiologic studies. Latter technique allows to study the origin, mechanism, efficiency of drugs and the type of pace-maker in case of drug treatment failure. Case report exemplifies all these aspects, and the essentials about etiology, symptoms, diagnosis and treatment are mentioned in the literature review.

The importance of cardiac autonomic neuropathy (CAN) derives from its remarkable frequency and its clinical impact. The clinical features are postural hypotension and resting tachycardia, these abnormalities may be overlooked in a high number of patients asymptomatic. Although rarely life threatening, CAN causes considerable morbidity, which can be ameliorated by its identification and appropriate treatment. Circulatory reflexes were studied in 48 diabetic patients and 14 normal control subjects. Twenty-six of the diabetic patients had normal response. The remaining 22 had evidence of neuropathy and abnormal cardiac response during these tests. Only one patient had postural syncope but he had severe orthostatic hypotension. The others remained asymptomatic. All the control subjects had normal reflexes. Beat-to-beat variation with deep breathing (sinus arrhythmia), carotid body massage and mental stress, were important for the detection of CAN (86, 90 and 90% sensitivity respectively). The Valsalva maneuver and sinus arrhythmia showed 82 and 92% of specificity for the diagnosis of CAN. Our findings suggest that CAN in diabetic patients can be detected by these relatively simple test. We propose a rational approach to the diagnosis. Our method is applicable as a clinical routine examination for cardiac neuropathy.

The coupling time of ventricular extrasystoles (VE) leading to 41 episodes of ventricular tachycardia (VT) in 35 patients with acute myocardial infarction (AMI) was studied regarding the measurement of the precocity index (R-R/QT) and vulnerability index (R-R x QT/R-R') described by other authors. A comparative group was studied in 50 VE of other patients with AMI but without VT. The majority of episodes (83%) of VT were originated by VE with a prematurity index of more than 1 (VE with coupling intervals longer than the QT duration of the previous cardiac cycle, R-R' > QT). The vulnerability index, with reported "dangerous" values of 1.1 to 1.4, was less than 1 in 92.6% of cases of VT and in 100% of VE without VT. A new index, delta QT, for the study of the abnormality of the QT interval respect to normal values (+/-.04") and its relation to the coupling time of the VE was also measured but did not show any difference among groups. In conclusion, none of the indexes were useful as predictor of ectopic beats that can produce VT in patients with AMI. We suggest that VE ocurring in patients with AMI should be suppressed disregarding the prematurity of diming of their appearance.