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Congenit Heart Dis ; 4(5): 356-61, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19740190


OBJECTIVE: We studied, as a physiological benchmark, acute effects of right ventricular (RV) apical, RV outflow, and left ventricular (LV) pacing in children with normal cardiac function on LV and RV function and ventricular-ventricular interactions. DESIGN: The design of the study was a prospective, acute intervention. SETTING: The study was conducted in a tertiary care electrophysiology laboratory. Population and Methods. Seven children (mean +/- SD, 12 +/- 4 years) were paced after accessory pathway ablation, at baseline (AOO), and with atrioventricular pacing (DOO) from the RV apex, RV outflow, and left ventricle. OUTCOME MEASURES: Right ventricular dP/dT(max) and RV dP/dT(neg) (high-fidelity transducer-tipped catheters, Millar Instruments, Houston, TX, USA), cardiac index (Fick), blood pressure, and QRS duration were measured at each pacing condition. Intra- and interventricular mechanical dyssynchrony, systolic- and diastolic peak tissue velocities, and isovolumic acceleration were recorded by tissue Doppler imaging at the lateral mitral, septal, and tricuspid annuli at each condition. Results at each pacing condition were compared by repeated-measures analysis of variance. Results. Pacing prolonged QRS duration, causing electrical dyssynchrony (86 +/- 19 ms [baseline], 141 +/- 44 ms [RV apex], 121 +/- 18 ms [RV outflow], and 136 +/- 34 ms [LV], P < .01). Right ventricular outflow pacing caused LV intraventricular delay (63 +/- 52 vs. 12 +/- 7 ms, P < .05). Right ventricular apical pacing caused interventricular delay (61 +/- 29 vs. 25 +/- 18 ms, P < .05). There were no significant changes in blood pressure, cardiac index, RV dp/dT(max), RV dP/dT(neg), regional tissue velocities, or isovolumic acceleration during any of the pacing conditions, indicating preserved ventricular function and hemodynamics. No important ventricular-ventricular interactions were seen. CONCLUSIONS: In children with normal cardiac anatomy and function, single-site RV apical, RV outflow, and LV pacing induce electromechanical dyssynchrony without significantly changing ventricular function or hemodynamics, or adversely affecting ventricular-ventricular interactions.

Estimulación Cardíaca Artificial/métodos , Hemodinámica , Taquicardia Supraventricular/fisiopatología , Función Ventricular Izquierda , Función Ventricular Derecha , Adolescente , Presión Sanguínea , Ablación por Catéter , Niño , Criocirugía , Ecocardiografía Doppler de Pulso , Técnicas Electrofisiológicas Cardíacas , Femenino , Humanos , Masculino , Contracción Miocárdica , Estudios Prospectivos , Taquicardia Supraventricular/diagnóstico por imagen , Taquicardia Supraventricular/cirugía
Anesth Analg ; 106(1): 79-83, table of contents, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18165557


BACKGROUND: Dexmedetomidine (DEX) is an alpha2-adrenergic agonist that is approved by the Food and Drug Administration for short-term (<24 h) sedation in adults. It is not approved for use in children. Nevertheless, the use of DEX for sedation and anesthesia in infants and children appears to be increasing. There are some concerns regarding the hemodynamic effects of the drug, including bradycardia, hypertension, and hypotension. No data regarding the effects of DEX on the cardiac conduction system are available. We therefore aimed to characterize the effects of DEX on cardiac conduction in pediatric patients. METHODS: Twelve children between the ages of 5 and 17 yr undergoing electrophysiology study and ablation of supraventricular accessory pathways had hemodynamic and cardiac electrophysiologic variables measured before and during administration of DEX (1 microg/kg IV over 10 min followed by a 10-min continuous infusion of 0.7 microg x kg(-1) x h(-1)). RESULTS: Heart rate decreased while arterial blood pressure increased significantly after DEX administration. Sinus node function was significantly affected, as evidenced by an increase in sinus cycle length and sinus node recovery time. Atrioventricular nodal function was also depressed, as evidenced by Wenckeback cycle length prolongation and prolongation of PR interval. CONCLUSION: DEX significantly depressed sinus and atrioventricular nodal function in pediatric patients. Heart rate decreased and arterial blood pressure increased during administration of DEX. The use of DEX may not be desirable during electrophysiology study and may be associated with adverse effects in patients at risk for bradycardia or atrioventricular nodal block.

Agonistas alfa-Adrenérgicos/efectos adversos , Dexmedetomidina/efectos adversos , Electrocardiografía , Técnicas Electrofisiológicas Cardíacas , Sistema de Conducción Cardíaco/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Hipnóticos y Sedantes/efectos adversos , Taquicardia Supraventricular/fisiopatología , Adolescente , Agonistas alfa-Adrenérgicos/administración & dosificación , Nodo Atrioventricular/efectos de los fármacos , Nodo Atrioventricular/fisiopatología , Nodo Atrioventricular/cirugía , Presión Sanguínea/efectos de los fármacos , Ablación por Catéter , Niño , Dexmedetomidina/administración & dosificación , Femenino , Sistema de Conducción Cardíaco/fisiopatología , Sistema de Conducción Cardíaco/cirugía , Humanos , Hipnóticos y Sedantes/administración & dosificación , Infusiones Intravenosas , Masculino , Mecánica Respiratoria/efectos de los fármacos , Nodo Sinoatrial/efectos de los fármacos , Nodo Sinoatrial/fisiopatología , Nodo Sinoatrial/cirugía , Taquicardia Supraventricular/diagnóstico , Taquicardia Supraventricular/cirugía , Resultado del Tratamiento
Curr Opin Cardiol ; 21(3): 205-7, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-16601458


PURPOSE OF REVIEW: As the safety and efficacy of invasive electrophysiologic studies and ablation therapy in pediatrics improves, there has been a greater interest in developing adequate risk stratification criteria for the asymptomatic pediatric patient with Wolff-Parkinson-White syndrome. This review will discuss the recent literature regarding this debate. RECENT FINDINGS: Recent retrospective and prospective studies of Wolff-Parkinson-White syndrome in asymptomatic pediatric patients have shown that the well established adult criteria for risk stratification may not be applicable in children. Both symptomatic and asymptomatic children had similar accessory pathway effective refractory periods and supraventricular tachycardia inducibility in recent invasive electrophysiologic studies. The first attempt at prospective evaluation of the use of ablation therapy in asymptomatic adult and pediatric patients with the condition has sparked a debate as to the definition of a high-risk patient and the utility of ablation in the asymptomatic patient. SUMMARY: It is still controversial whether the established criteria for risk stratification in adults can be confidently applied to the pediatric patient. The majority of pediatric electrophysiologists use invasive electrophysiologic studies for risk stratification and selection of appropriate therapy. This clinical practice reflects the increasing prevalence and safety of electrophysiologic study and ablation. Further studies to better define indications for study and ablation are still necessary, however, to define accurate criteria for risk stratification in this difficult pediatric problem.

Ablación por Catéter/métodos , Técnicas Electrofisiológicas Cardíacas/métodos , Síndrome de Wolff-Parkinson-White/terapia , Factores de Edad , Niño , Humanos , Modelos de Riesgos Proporcionales , Medición de Riesgo , Factores de Riesgo , Síndrome de Wolff-Parkinson-White/diagnóstico , Síndrome de Wolff-Parkinson-White/prevención & control