Paediatric radiofrequency ablation experience at a Venezuelan cardiology facility

Radiofrequency (RF) ablation is a curative treatment for many different types of cardiac arrhythmias but its application has been more limited in the paediatric population. We here describe RF paediatric ablation experience at a 400-bed University Hospital in a western Venezuelan province and compare it with the results reported in other countries. METHODS: One hundred and fifty five patients under 18 years of age who where submitted to RF ablation between 1994 and 2007 were included. The patients were 12.8+/-3.4 year-old (rank: 3-17 years); 59% were female. Nine patients were submitted to more than one procedure. AV nodal re-entrant tachycardia and atrio-ventricular re-entrant tachycardias mediated by accessory pathways made up 83% of the ablations. The overall success rate was 91.5%. In the AV nodal re-entrant tachycardia and atrial flutter, success rate almost reached 100%. Ablation was successful in 93% of the patients with the Wolff-Parkinson-White syndrome. The overall complication rate was 5% with 0.6% of major complications and 0% death rate. The results were comparable to those recently reported by the cooperative paediatric ablation registry in the United States of America and by a large hospital in Taiwan. CONCLUSION: RF ablation is a curative therapy with a high success rate and very low complication rates in the paediatric population at the Cardiovascular Research Institute of the University Hospital of The Andes in Venezuela.     

Changes in blood pressure in children undergoing psychological treatment before dental procedures

Different dental procedures in children undergoing treatment can induce changes in blood pressure. These changes will be minimized if psychological treatment is applied prior to any procedure. The objective of this study was to determine changes in blood pressure (systolic-diastolic) in children undergoing psychological treatment before dental procedures. The population studied consisted of 100 children and adolescents, ages 6 to 15 years. The patients were assigned to two groups at random, i.e. with or without psychological treatment before dental procedures. Behavior management was carried out applying the tell-show-do technique of conduct handling. The systolic and diastolic blood pressures were measured prior to the initiation of the treatment, during drilling, restoring, and before dismissing the patient. The no-psychological treatment group exhibited significant differences in diastolic and systolic blood pressures during the dental procedure whereas the psychological treatment group evidenced no significant differences in blood pressure. No correlation was found between the alterations of blood pressure and the type of dental treatment performed. The application of the tell-show-do method would have an effect on the blood pressure in patients undergoing dental procedures.     

Ebstein's anomaly in association with anomalous nodoventricular conduction. Pre-operative and intra-operative electrophysiological studies.

A 13 year old girl with Ebstein's anomaly was investigated for refractory paroxysmal tachycardias and ventricular pre-excitation. Intracardiac electrophysiological studies demonstrated that ventricular pre-excitation was due to conduction in an anomalous nodo-ventricular pathway. Tachycardia occurred as a result of re-entry within the A-V node with pre-excitation during tachycardia due to conduction in the nodo-ventricular pathway. These tachycardias were controlled initially by medical therapy but because of increasing frequency of attacks, occasionally requiring D.C. conversion, further electrophysiological studies and epicardial mapping were undertaken. The epicardial surface of the right ventricle and right atrium were mapped during tachycardia. The results of the studies confirmed that a direct anomalous atrio-ventricular pathway was not present and that re-entrant tachycardia did not involve an accessory pathway of this type. A rapid atrial pacing system was implanted and paroxysmal tachycardias have been successfully controlled.     

Organ and tissue procurement system: a novel intervention to increase organ donation rates in Venezuela

The limited number of organs and tissues available for transplantation in Venezuela and the need to improve outcomes for patients with life-threatening end-stage organ failure or inadequate quality of life resulted in the development and implementation of an organ and tissue procurement system by the Venezuelan National Transplant Organization. This procurement system, a 24-hour, nationwide, free phone service for detection of potential organ donors, connects callers with transplant coordinators. The on-call coordinator supervises family approach as well as maintenance, transport, and allocation of the organs and tissues. During a period of 21 months, the phone service received 1191 calls (713 requesting information to become a voluntary donor, 207 requesting information about donation and transplantation, and 271 reporting potential donors). Of the potential donors, 74% were men and 67% were aged between 11 and 40 years, and most came from hospital intensive care units, emergency departments, and trauma shock units. The main causes of death were trauma and stroke. Reasons why donation was not accomplished included early cardiorespiratory arrest and denied consent. In conclusion, establishing the procurement system resulted in an increase in the detection, referral, and maintenance of potential donors; doubling of the number of donors per million population; and an increase in the number of cadaveric transplants.     

Prevalence of Dyslipidemia in Children with Congenital Heart Disease

Dyslipidemia is one of the main risk factors associated with cardiovascular diseases. Few data on the impacts of congenital heart diseases are available with regard to the prevalence of dyslipidemia in children. Our study evaluated the lipid profile in children with congenital heart disease at a referral center. From January 2011 to July 2012, 52 pediatric patients had their lipid, metabolic and clinical profiles traced. The mean age was 10.4 ± 2.8 years and male/female rate of 1.38:1. Our population had 53.8% patients with high levels of total cholesterol and 13.4% (CI 95 %, from 6.6 to 25.2%) of them also presenting LDL levels ≥ 130 mg/dL, which characterizes dyslipidemia. The group of dyslipidemic patients presented only two obese individuals. Our data show that the presence of congenital heart disease does not lead to higher risk associated with the prevalence of dyslipidemia. Therefore, the screening of this specific population should follow the regular pediatric guidelines, which are also independent of the nutritional status of the children tested.     

Valsalva maneuver: a test of the functional state of cardiac innervation in Chagasic myocarditis

The ratio between maximal and minimal R-R intervals measured during the Valsalva maneuver is an adequate means of studying the functional state of the cardiac parasympathetic nervous system. We studied the changes in heart rate evoked during the Valsalva maneuver in 49 asymptomatic Chagasic patients with different degrees of myocardial involvement. The Chagasic patients were divided in three groups. Twelve patients had no evidence of heart disease except for an abnormal myocardial biopsy. Sixteen patients had a normal electrocardiogram but revealed evidence of localized myocardial damage as shown by left ventricular cineangiography. Twenty-one patients had abnormal electrocardiograms and revealed multiple areas of abnormal left ventricular wall motion. The Valsalva ratio (mean +/- standard error) was 1.62 +/- 0.12 for controls, 1.52 +/- 0.10 for those with an abnormal biopsy, 1.48 +/- 0.06 for those with localized myocardial damage, and 1.31 +/- 0.04 for those with an abnormal electrocardiogram. There were no statistically significant differences between the control group (normal sero-negative subjects) and those patients with normal electrocardiograms. Results in those with an abnormal electrocardiogram, however, were statistically different (P less than 0.05) from the other groups. These results are in discordance with the commonly accepted hypothesis that cardiac parasympathetic denervation causes a dilated myocardiopathy in patients with chronic Chagasic myocarditis.     

The effects of cardioversion and defibrillation on left ventricular systolic function.

The purpose of this research was to evaluate the left ventricular systolic function behavior after cardioversion and defibrillation. The study included 18 adult patients who had direct current cardioversion or defibrillation performed for conversion of spontaneous or induced arrhythmias. All patients were submitted to a careful medical evaluation and an M-mode echocardiogram before cardioversion or defibrillation. The clinical and echocardiographic evaluations were repeated immediately after, and 6 and 12 h following the countershock. Six hours after cardioversion or defibrillation a statistically significant (p = .04) decrease in contractility (circumferential fiber shortening and ejection fraction) was observed without significant changes in preload (end diastolic volume), heart rate or afterload (end systolic stress and diastolic arterial pressure). Within 12 h, the left ventricular systolic dysfunction disappeared. The impairment of systolic function was independent of the amount of energy used, the type of arrhythmia, the rhythm after cardioversion or defibrillation and the etiologic cardiac diagnoses. There was a significant (p = .03) direct, negative and linear correlation between left ventricular systolic indices (ejection fraction and circumferential fiber shortening) before the countershock and the amount of decrease in systolic function after the countershock. In spite of the fact that most patients had a low ejection fraction, none of them presented clinical signs of heart failure. Defibrillation and cardioversion produce a transient decrease in cardiac contractility which is independent of the amount of energy used and does not produce clinical signs of heart failure.