RESUMO
Background There is limited information regarding the clinical use and effectiveness of IV sotalol in pediatric patients and patients with congenital heart disease, including those with severe myocardial dysfunction. A multicenter registry study was designed to evaluate the safety, efficacy, and dosing of IV sotalol. Methods and Results A total of 85 patients (age 1 day-36 years) received IV sotalol, of whom 45 (53%) had additional congenital cardiac diagnoses and 4 (5%) were greater than 18 years of age. In 79 patients (93%), IV sotalol was used to treat supraventricular tachycardia and 4 (5%) received it to treat ventricular arrhythmias. Severely decreased cardiac function by echocardiography was seen before IV sotalol in 7 (9%). The average dose was 1 mg/kg (range 0.5-1.8 mg/kg/dose) over a median of 60 minutes (range 30-300 minutes). Successful arrhythmia termination occurred in 31 patients (49%, 95% CI [37%-62%]) with improvement in rhythm control defined as rate reduction permitting overdrive pacing in an additional 18 patients (30%, 95% CI [19%-41%]). Eleven patients (16%) had significant QTc prolongation to >465 milliseconds after the infusion, with 3 (4%) to >500 milliseconds. There were 2 patients (2%) for whom the infusion was terminated early. Conclusions IV sotalol was safe and effective for termination or improvement of tachyarrhythmias in 79% of pediatric patients and patients with congenital heart disease, including those with severely depressed cardiac function. The most common dose, for both acute and maintenance dosing, was 1 mg/kg over ~60 minutes with rare serious complications.
Assuntos
Cardiopatias Congênitas , Taquicardia Supraventricular , Arritmias Cardíacas/complicações , Arritmias Cardíacas/diagnóstico , Arritmias Cardíacas/tratamento farmacológico , Criança , Cardiopatias Congênitas/complicações , Humanos , Lactente , Sistema de Registros , Sotalol/efeitos adversos , Taquicardia Supraventricular/complicaçõesRESUMO
OBJECTIVE: We evaluated the safety of maximal cardiopulmonary exercise testing (CPET) in individuals with sickle cell disease (SCD). Maximal CPET using gas exchange analysis is the gold standard for measuring cardiopulmonary fitness in the laboratory, yet its safety in the SCD population is unclear. DESIGN: Systematic review. DATA SOURCES: Systematic search of Medline (PubMed), EMBASE, Cochrane, ClinicalTrials.gov and professional society websites for all published studies and abstracts through December 2020. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Two reviewers independently extracted data of interest from studies that assessed safety outcomes of maximal CPET in children and adults with SCD. A modified version of the Newcastle-Ottawa Scale was used to assess for risk of bias in studies included. RESULTS: In total, 24 studies met inclusion/exclusion criteria. Adverse events were reported separately or as part of study results in 36 (3.8%) of 939 participants with SCD undergoing maximal CPET in studies included. Most adverse events were related to transient ischaemic changes on ECG monitoring or oxygen desaturation during testing, which did not result in arrhythmias or other complications. Only 4 (0.43%) of 939 participants experienced pain events due to maximal CPET. CONCLUSION: Maximal CPET appears to be a safe testing modality in children and adults with SCD and can be used to better understand the physiological basis of reduced exercise capacity and guide exercise prescription in this population. Some studies did not focus on reporting adverse events related to exercise testing or failed to mention safety monitoring, which contributed to risk of bias.
Assuntos
Anemia Falciforme , Teste de Esforço , Adulto , Anemia Falciforme/complicações , Criança , Exercício Físico , Teste de Esforço/métodos , Terapia por Exercício , HumanosRESUMO
BACKGROUND: Despite safety concerns, many young patients with implantable cardioverter-defibrillators (ICDs) participate in sports. We undertook a prospective, multinational registry to determine the incidence of serious adverse events because of sports participation. The primary end points were death or resuscitated arrest during sports or injury during sports because of arrhythmia or shock. Secondary end points included system malfunction and incidence of ventricular arrhythmias requiring multiple shocks for termination. METHODS: Athletes with ICDs aged ≤21 years were included in this post hoc subanalysis of the ICD Sports Registry. Data on sports and clinical outcomes were obtained by phone interview and medical records review. ICD shocks and clinical details of lead malfunction were classified by 2 electrophysiologists. RESULTS: A total of 129 young athletes participating in competitive (n=117) or dangerous (n=12) sports were enrolled. The mean age was 16 years (range, 10-21; 40% female; 92% white). The most common diagnoses were long QT syndrome (n=49), hypertrophic cardiomyopathy (n=30), and congenital heart disease (n=16). The most common sports were basketball and soccer, including 79 varsity/junior varsity high school and college athletes. During a median follow-up of 42 months, 35 athletes (27%) received 38 shocks. There were no occurrences of death, arrest, or injury related to arrhythmia, during sports. There was 1 ventricular tachycardia/ventricular fibrillation storm during competition. Freedom from lead malfunction was 92.3% at 5 years and 79.6% at 10 years. CONCLUSIONS: Although shocks related to competition/practice are not uncommon, there were no serious adverse sequelae. Lead malfunction rates were similar to previously reported in unselected pediatric ICD populations. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT00637754.
Assuntos
Atletas , Morte Súbita Cardíaca/prevenção & controle , Desfibriladores Implantáveis/efeitos adversos , Cardiopatias/fisiopatologia , Cardiopatias/terapia , Segurança do Paciente , Esportes , Adolescente , Criança , Falha de Equipamento , Feminino , Humanos , Masculino , Estudos Prospectivos , Sistema de Registros , Prevenção Secundária , Adulto JovemRESUMO
Although ß-blockers can be used to eliminate stress-induced ventricular arrhythmias in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), this treatment is unsuccessful in â¼25% of cases. Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) generated from these patients have potential for use in investigating the phenomenon, but it remains unknown whether they can recapitulate patient-specific drug responses to ß-blockers. This study assessed whether the inadequacy of ß-blocker therapy in an individual can be observed in vitro using patient-derived CPVT iPSC-CMs. An individual with CPVT harboring a novel mutation in the type 2 cardiac ryanodine receptor (RyR2) was identified whose persistent ventricular arrhythmias during ß-blockade with nadolol were abolished during flecainide treatment. iPSC-CMs generated from this patient and two control individuals expressed comparable levels of excitation-contraction genes, but assessment of the sarcoplasmic reticulum Ca(2+) leak and load relationship revealed intracellular Ca(2+) homeostasis was altered in the CPVT iPSC-CMs. ß-adrenergic stimulation potentiated spontaneous Ca(2+) waves and unduly frequent, large and prolonged Ca(2+) sparks in CPVT compared with control iPSC-CMs, validating the disease phenotype. Pursuant to the patient's in vivo responses, nadolol treatment during ß-adrenergic stimulation achieved negligible reduction of Ca(2+) wave frequency and failed to rescue Ca(2+) spark defects in CPVT iPSC-CMs. In contrast, flecainide reduced both frequency and amplitude of Ca(2+) waves and restored the frequency, width and duration of Ca(2+) sparks to baseline levels. By recapitulating the improved response of an individual with CPVT to flecainide compared with ß-blocker therapy in vitro, these data provide new evidence that iPSC-CMs can capture basic components of patient-specific drug responses.
Assuntos
Catecolaminas/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Modelos Biológicos , Taquicardia Ventricular/tratamento farmacológico , Taquicardia Ventricular/patologia , Antagonistas Adrenérgicos beta/farmacologia , Antagonistas Adrenérgicos beta/uso terapêutico , Arritmias Cardíacas/tratamento farmacológico , Arritmias Cardíacas/fisiopatologia , Biomarcadores/metabolismo , Cálcio/metabolismo , Sinalização do Cálcio/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Linhagem da Célula/efeitos dos fármacos , Fenômenos Eletrofisiológicos/efeitos dos fármacos , Feminino , Flecainida/farmacologia , Flecainida/uso terapêutico , Homeostase/efeitos dos fármacos , Humanos , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Linhagem , Receptores Adrenérgicos beta/metabolismo , Taquicardia Ventricular/fisiopatologiaRESUMO
OBJECTIVE: To determine whether implementation of a standardized clinical practice guideline (CPG) for the evaluation of syncope would decrease practice variability and resource utilization. DESIGN: A retrospective review of medical records of patients presenting to our practice for outpatient evaluation of syncope before and after implementation of the CPG. The guideline included elements of history, physical exam, electrocardiogram, and "red flags" for further testing. SETTING: Outpatient pediatric cardiology offices of a large pediatric cardiology practice. PATIENTS: All new patients between 3 and 21 years old, who presented to cardiology clinic with a chief complaint of syncope. INTERVENTIONS: The CPG for the evaluation of pediatric syncope was presented to the providers. OUTCOME MEASURES: Resource utilization was determined by the tests ordered by individual physicians before and after initiation of the CPG. Patient final diagnoses were recorded and the medical records were subsequently reviewed to determine if any patients, who presented again to the system, were ultimately diagnosed with cardiac disease. RESULTS: Of the 1496 patients with an initial visit for syncope, there was no significant difference in the diagnosis of cardiac disease before or after initiation of the CPG: (0.6% vs. 0.4%, P = .55). Electrocardiography provides the highest yield in the evaluation of pediatric syncope. Despite high compliance (86.9%), there were no overall changes in costs ($346.31 vs. $348.53, P = .85) or in resource utilization. There was, however, a decrease in the variability of ordering of echocardiograms among physicians, particularly among those at the extremes of utilization. CONCLUSIONS: Although the CPG did not decrease already low costs, it did decrease the wide variability in echo utilization. Evaluation beyond detailed history, physical exam, and electrocardiography provides no additional benefit in the evaluations of pediatric patients presenting with syncope.
Assuntos
Cardiologia/normas , Ecocardiografia/normas , Eletrocardiografia/normas , Fidelidade a Diretrizes/normas , Guias de Prática Clínica como Assunto/normas , Avaliação de Processos em Cuidados de Saúde/normas , Melhoria de Qualidade/normas , Indicadores de Qualidade em Assistência à Saúde/normas , Síncope/diagnóstico , Adolescente , Cardiologia/economia , Criança , Pré-Escolar , Ecocardiografia/economia , Eletrocardiografia/economia , Feminino , Fidelidade a Diretrizes/economia , Custos de Cuidados de Saúde/normas , Recursos em Saúde/normas , Recursos em Saúde/estatística & dados numéricos , Disparidades em Assistência à Saúde/normas , Humanos , Masculino , Prontuários Médicos , Padrões de Prática Médica/normas , Valor Preditivo dos Testes , Avaliação de Processos em Cuidados de Saúde/economia , Avaliação de Programas e Projetos de Saúde , Melhoria de Qualidade/economia , Indicadores de Qualidade em Assistência à Saúde/economia , Estudos Retrospectivos , Inquéritos e Questionários/normas , Síncope/economia , Síncope/etiologia , Síncope/terapia , Resultado do Tratamento , Adulto JovemAssuntos
Cardiologia/educação , Bolsas de Estudo/normas , Pediatria/educação , Adolescente , Criança , Pré-Escolar , Competência Clínica , Educação Baseada em Competências/normas , Currículo/normas , Dislipidemias/diagnóstico , Dislipidemias/terapia , Avaliação Educacional , Objetivos , Cardiopatias Congênitas/diagnóstico , Cardiopatias Congênitas/terapia , Cardiopatias/diagnóstico , Cardiopatias/genética , Cardiopatias/terapia , Humanos , Lactente , Recém-Nascido , EnsinoRESUMO
Atrioventricular nodal reentrant tachycardia (AVNRT), a common tachycardia in children, is routinely treated by catheter ablation using radiofrequency or cryothermal energy. Acute success rates of 95-97 % are reported for cryoablation, similar to those achieved with radiofrequency ablation (RFA). However, early studies reported higher recurrence rates after cryoablation for treatment of AVNRT than those reported for RFA. This study evaluated the success and recurrence rates for cryoablation in a current cohort of pediatric patients across several institutions. Patients 21 years old or younger with AVNRT who underwent cryoablation at five participating centers between 2004 and 2009 were retrospectively reviewed. Patient demographics and procedural data were extracted from patient records and analyzed. A total of 434 patients with AVNRT who underwent cryoablation were identified. Cryoablation was used as the exclusive ablation method for 379 patients. For 97 % (368/379) of these patients, cryoablation was acutely successful. A higher acute success rate was found with the 6-mm-tip catheter (99 %) than with the 4-mm-tip catheter (91 %) (p < 0.01). Recurrence was experienced by 7.3 % of the patients. Recurrence was more likely for those treated with the 4-mm-tip catheter (6/42, 14 %) than for those who had the larger catheters (12/204, 6 %) No patient experienced permanent heart block. Success and recurrence rates for this cohort of patients were similar to those reported for RFA used to treat AVNRT in pediatric patients. The findings show a higher success rate and a lower recurrence rate after cryoablation with a 6-mm-tip catheter than after use of the 4-mm-tip catheter, with an associated excellent safety profile.
Assuntos
Criocirurgia/métodos , Taquicardia por Reentrada no Nó Atrioventricular/cirurgia , Adolescente , Análise de Variância , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Modelos Logísticos , Masculino , Recidiva , Estudos Retrospectivos , Taquicardia por Reentrada no Nó Atrioventricular/fisiopatologia , Resultado do Tratamento , Adulto JovemRESUMO
Implantable cardioverter defibrillators (ICDs) are being used with increasing frequency in children and young adults. Our aim was to examine the appropriateness and frequency of ICD discharges in children and young adults, to compare the effectiveness of ICDs when placed for primary or secondary prevention, and to provide time-dependent analysis of ICD discharges. Data were collected from seven institutions on 210 patients <30 years of age who underwent ICD implantation from October 1992 to January 2007. Median age at implant was 15.4 years with a follow-up average of 3.3 years. Heart disease was categorized as electrical (n = 90, 42%), cardiomyopathic (n = 62, 30%), or congenital heart disease (n = 58, 28%). ICDs are increasingly placed for primary prevention. There are increased appropriate ICD discharges for ICDs placed for secondary prevention (52%) versus primary prevention (14%) at 5 years. There is no difference in the risk of inappropriate discharges between primary and secondary prevention indications. There is an increased risk for inappropriate therapy in the congenital heart disease population. An increasing number of ICDs are being placed for primary prevention in young patients, a marked shift in practice during the last two decades. The benefits of ICDs remain greater in secondary than in primary-prevention patients. In both groups, approximately 25% of patients received inappropriate discharges within 5 years of implant. Patients with congenital heart disease are the most affected by inappropriate discharges.
Assuntos
Desfibriladores Implantáveis , Cardiopatias/terapia , Adolescente , Adulto , Criança , Pré-Escolar , Morte Súbita Cardíaca/epidemiologia , Morte Súbita Cardíaca/prevenção & controle , Feminino , Seguimentos , Alemanha/epidemiologia , Cardiopatias/epidemiologia , Cardiopatias/fisiopatologia , Humanos , Incidência , Lactente , Masculino , Estudos Retrospectivos , Taxa de Sobrevida/tendências , Fatores de Tempo , Resultado do Tratamento , Estados Unidos/epidemiologia , Adulto JovemRESUMO
OBJECTIVES: Patients undergoing surgical closure of ventricular septal defects are at risk for immediate or delayed atrioventricular conduction block. Our goal was to better define the incidence of delayed atrioventricular conduction block. METHODS: A retrospective review was conducted of hospital records and pacemaker database for ventricular septal defect, atrioventricular canal, and tetralogy of Fallot repairs between 1999 and 2004. A total of 922 patients were identified (atrioventricular canal in 197, tetralogy of Fallot in 222, and ventricular septal defect in 503). Median follow-up was 4.1 years. RESULTS: There were 472 male and 450 female patients, median age 6 months (0-444 months) and median weight 5.8 kg (1.3-116 kg) at surgery. Postoperative atrioventricular conduction block developed in 21 (2.3%) of the 922, being transient, with return of conduction 3 days (1-14 days) after surgery, in 13 (1.4%) and permanent, with pacemakers implanted 10 days (6-20 days) after surgery, in 8 (0.9%). Of the 905 patients at risk for delayed atrioventricular conduction block, 3 (0.3%) had second- or third-degree block at 2, 8, and 16 months after surgery. Two of these 3 had transient postoperative block. For isolated ventricular septal defects, the incidence was 1 (0.2%) of 496. There were 8 late deaths at 31 months (7-45 months) after surgery. Five had normal conduction at death, but for 3 patients the conduction status at death could not be determined. Including these 3 patients as possible cases of delayed atrioventricular block yields an incidence of 0.3% to 0.7%. CONCLUSIONS: The incidence of early atrioventricular conduction block requiring a pacemaker was 0.9% and that of delayed atrioventricular conduction block was 0.3% to 0.7%. Transient atrioventricular conduction block may be a marker for increased risk of delayed block. These data may be useful for evaluation of new techniques.
Assuntos
Bloqueio Atrioventricular/etiologia , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Comunicação Interventricular/cirurgia , Tetralogia de Fallot/cirurgia , Adolescente , Adulto , Bloqueio Atrioventricular/fisiopatologia , Bloqueio Atrioventricular/terapia , Estimulação Cardíaca Artificial , Criança , Pré-Escolar , Feminino , Comunicação Interventricular/mortalidade , Comunicação Interventricular/fisiopatologia , Humanos , Lactente , Recém-Nascido , Masculino , Marca-Passo Artificial , Estudos Retrospectivos , Tetralogia de Fallot/fisiopatologia , Fatores de Tempo , Resultado do Tratamento , Adulto JovemRESUMO
Short QT syndrome (SQTS) is a recently described genetic syndrome characterized by abnormally brisk ventricular repolarization. Similar to long QT syndrome, SQTS might result in ventricular arrhythmias, syncope, and sudden death. The clinical diagnosis of SQTS is supported by the finding of an abnormally short QT interval on the resting electrocardiogram in combination with a suggestive clinical or family history. To date, few pediatric cases have been reported and the ideal therapy is unknown. We report a teenage boy who suffered a witnessed ventricular fibrillation arrest and was subsequently diagnosed with SQTS. Additional data from nine other pediatric patients diagnosed with SQTS are presented.
Assuntos
Arritmias Cardíacas/diagnóstico , Eletrocardiografia Ambulatorial , Sistema de Condução Cardíaco/fisiopatologia , Frequência Cardíaca/fisiologia , Adolescente , Arritmias Cardíacas/complicações , Arritmias Cardíacas/fisiopatologia , Morte Súbita Cardíaca/etiologia , Diagnóstico Diferencial , Humanos , Masculino , SíndromeRESUMO
BACKGROUND: Implantable cardioverter defibrillator (ICD) use is increasing in young patients and is frequently complicated by inappropriate device discharges (IDs), leading to discomfort, anxiety and, potentially, proarrhythmia. Dual-chamber (DC) ICDs may decrease IDs by improving rhythm discrimination, but are associated with increased size, expense, and implant complications. We examined whether the frequency of IDs was the same in dual- and single-chamber (SC) ICDs in young patients. METHODS: A multicenter review of patients Assuntos
Arritmias Cardíacas/epidemiologia
, Arritmias Cardíacas/prevenção & controle
, Desfibriladores Implantáveis/estatística & dados numéricos
, Falha de Equipamento/estatística & dados numéricos
, Cardiopatias Congênitas/epidemiologia
, Cardiopatias Congênitas/terapia
, Adolescente
, Criança
, Pré-Escolar
, Análise de Falha de Equipamento
, Feminino
, Humanos
, Incidência
, Lactente
, Recém-Nascido
, Masculino
, Pediatria/métodos
, Estudos Retrospectivos
, Estados Unidos/epidemiologia
, Adulto Jovem
RESUMO
BACKGROUND: During catheter ablation procedures, non-radiologic navigation systems may reduce fluoroscopic exposure and energy applications, as well as improve procedural success rates. OBJECTIVE: To examine the impact of a non-radiologic navigation system on ablation procedures in pediatric patients, the procedural characteristics and success rates prior to and following incorporation of the LocaLisa (LL) navigation system into a pediatric electrophysiology laboratory were compared. METHODS: Between January 2000 and April 2005, 246 consecutive patients underwent catheter ablation for either Atrioventricular Reentry Tachycardia AVRT (168) or Atrioventricular Nodal Reentry Tachycardia AVNRT (78). Ablation procedures performed prior to LL (108) were compared to ablation procedures performed using LL (113). The first 25 patients using LL were censored to remove the bias of a learning curve. RESULTS: There was no difference in demographic features between the two groups. Statistically significant decreases were found in the diagnostic (11.4 +/- 6.1 min v 18.8 +/- 9.8 min w/o LL), ablation (5.7 +/- 10.3 vs 18.5 +/- 20.1 min w/o LL) and total (17.2 +/- 12.6 vs 37.3 +/- 21.3 min w/o LL) fluoroscopy times for the LL group, as well as in the total number of energy applications (9.0 +/- 8.5 vs 12.3 +/- 12.2 w/o LL). Success rates were 99.1% w/ LL v 97.2% w/o LL (p = NS). No major complications were observed in either group. CONCLUSIONS: The use of a computer assisted navigation system significantly decreased the diagnostic, ablation, and total fluoroscopy times, as well as the number of energy applications, without affecting procedural success or complication rates. Non-radiologic navigation systems reduce radiation exposure during transcatheter electrophysiologic procedures and thus lower the lifetime radiation cumulative risk, a goal particularly important in children.
Assuntos
Ablação por Cateter/métodos , Exposição Ambiental/prevenção & controle , Cirurgia Assistida por Computador/métodos , Raios X/efeitos adversos , Adolescente , Mapeamento Potencial de Superfície Corporal/métodos , Ablação por Cateter/efeitos adversos , Criança , Técnicas Eletrofisiológicas Cardíacas/efeitos adversos , Técnicas Eletrofisiológicas Cardíacas/métodos , Exposição Ambiental/efeitos adversos , Feminino , Fluoroscopia/efeitos adversos , Humanos , Masculino , Taquicardia por Reentrada no Nó Atrioventricular/diagnóstico , Taquicardia por Reentrada no Nó Atrioventricular/cirurgiaRESUMO
Complete heart block, either congenital or acquired, in children and patients with congenital heart disease is a relatively frequent occurrence requiring therapy. The natural history of this condition has been distorted by the advent of new diagnostic and therapeutic modalities. The therapy of complete heart block is evolving with new data suggesting that traditional treatment strategies utilizing right ventricular apical pacing may have inadvertent deleterious effects on cardiac function. In the following manuscript, the natural history of complete heart block is reviewed and the current therapy examined.
Assuntos
Cardiologia/tendências , Bloqueio Cardíaco/fisiopatologia , Bloqueio Cardíaco/terapia , Cardiopatias Congênitas/complicações , Pediatria/tendências , Bloqueio Atrioventricular/congênito , Bloqueio Atrioventricular/etiologia , Bloqueio Atrioventricular/terapia , Estimulação Cardíaca Artificial/efeitos adversos , Estimulação Cardíaca Artificial/métodos , Procedimentos Cirúrgicos Cardíacos/efeitos adversos , Bloqueio Cardíaco/congênito , Bloqueio Cardíaco/epidemiologia , Bloqueio Cardíaco/etiologia , Humanos , IncidênciaRESUMO
This study examines the cardioprotective effects of Na+/H+ exchange inhibition with BIIB-722 or ischemic preconditioning after occlusive thrombus formation and subsequent thrombolysis for reperfusion. Coronary artery thrombosis was induced by vessel wall electrolytic injury. Thrombotic occlusion was maintained for 60 or 90 min in 4 different groups: (1) control; (2) Na+/H+ exchange inhibitor, BIIB-722 (3 mg/kg) before occlusion; (3) BIIB-722 (0.75 mg/kg) before reperfusion; (4) ischemic preconditioning (4 x 5 min). Thrombolysis with intracoronary recombinant tissue plasminogen activator produced reperfusion in 6.3 +/- 1.4 min (average for 68 dogs). After restoration of blood flow, vessel patency was maintained for 4 h with the glycoprotein IIb/IIIa receptor antagonist, BIBU 52ZW. BIIB-722, administered before (26.9 +/- 3.6%) or after (22.0 +/- 2.3%) 60-min ischemia or preconditioning (18.4 +/- 2.8%), produced comparable and significant reductions in infarct size (percent of area at risk) compared to controls (47.2 +/- 2.0%). After 90 min of ischemia, BIIB-722 administered before occlusion (37.3 +/- 1.1%) and ischemic preconditioning (35.0 +/- 4.8%) provided significant cardioprotection compared to control (45.9 +/- 1.8%). BIIB-722 was not cardioprotective when administered during occlusion (48.0 +/- 2.4%). The results indicate that Na+/H+ exchange inhibition and preconditioning provide a comparable degree of cardioprotection against 60 min of regional ischemia. However, when the regional ischemic period is extended to 90 min, the degree of cardioprotection is markedly reduced. Further studies incorporating clinically relevant events such as thrombosis and thrombolysis are required before one can conclude that Na+/H+ exchange inhibition is effective against more prolonged myocardial ischemia.
Assuntos
Vasos Coronários/patologia , Infarto do Miocárdio/patologia , Trocadores de Sódio-Hidrogênio/antagonistas & inibidores , Terapia Trombolítica , Trombose/patologia , Animais , CãesRESUMO
BACKGROUND: Junctional ectopic tachycardia in the normal heart is rare and often is resistant to pharmacologic management. Transcatheter ablation using radiofrequency energy places the AV node at risk. OBJECTIVES: The purpose of this study was to report our experience with transcatheter cryothermal ablation using three-dimensional mapping in six patients with junctional ectopic tachycardia. METHODS: A review of clinical and electrophysiologic data was performed on all patients with structurally normal hearts who underwent cryothermal ablation for treatment of junctional ectopic tachycardia at two institutions. RESULTS: Six patients (age 7.7-36.5 years) underwent attempted transcatheter cryothermal ablation using three-dimensional mapping. Only one patient had achieved arrhythmia suppression on medical management. Cryothermal mapping (-30 degrees C) localized the junctional focus while normal conduction was monitored. The junctional focus was high in the triangle of Koch in four patients and was low in one patient. The sixth patient had only one run of junctional ectopic tachycardia during the procedure and therefore received an empiric cryoablation (-70 degrees C) lesion. Subsequent cryoablation lesions were delivered at and around the junctional focus. In one patient, cryomapping eliminated the junctional focus but resulted in transient complete AV block; therefore, cryoablation was not performed. All patients who received the cryoablation lesions had elimination of their junctional ectopic tachycardia at 6-week follow-up. The patient who did not receive a cryoablation lesion remained in a slower junctional rhythm at follow-up. CONCLUSION: Cryoablation of junctional ectopic tachycardia is safe and effective. Nonetheless, proximity to the His-Purkinje system may preclude success. Empiric cryoablation can be effective; cryotherapy may not yield immediate success, but a delayed salutary effect can follow.
Assuntos
Ablação por Cateter , Criocirurgia , Taquicardia Ectópica de Junção/cirurgia , Adolescente , Adulto , Mapeamento Potencial de Superfície Corporal , Criança , Eletrocardiografia Ambulatorial , Técnicas Eletrofisiológicas Cardíacas , Feminino , Seguimentos , Sistema de Condução Cardíaco/patologia , Sistema de Condução Cardíaco/cirurgia , Humanos , Imageamento Tridimensional , Iowa , Masculino , Michigan , Estudos Retrospectivos , Taquicardia Ectópica de Junção/fisiopatologia , Resultado do TratamentoRESUMO
INTRODUCTION: Transcatheter cryotherapy is an emerging technology for the treatment of children with supraventricular tachyarrhythmias. Limited data exist regarding the use of cryoablation therapy in children. We report a single center's experience with transcatheter cryoablation in the pediatric population. METHODS AND RESULTS: A retrospective review of demographic, procedural and outcome data was performed for patients undergoing cryoablation for treatment of supraventricular tachycardia (SVT). A historical control group was taken from the 3 years preceding the introduction of cryoablation. Between August 2003 and November 2005, 83 cryoablation procedures were performed in 81 patients (age: 4 to 21 years, mean: 13.4 years) for AV nodal reentrant tachycardia (AVNRT--53), AV reentrant tachycardia (AVRT--20), ectopic atrial tachycardia (EAT--9), and junctional ectopic tachycardia (JET--1). The acute success rate for all procedures was 88% (AVNRT: 96%, AVRT: 85%, EAT: 55%, and JET: 100%). Of 72 patients that underwent successful cryoablation, nine experienced recurrence of SVT (12.5%). The control group consisted of 73 patients (AVNRT--60, AVRT--13). There were no differences in demographic data between the two groups. The overall success rate for the RFA group (96%) was identical to that for patients with AVNRT and AVRT undergoing cryoablation. The recurrence rate for RFA (10%) was less but not significantly different than that for cryoablation (12%). There were no complications in either group. CONCLUSIONS: Cryoablation is a safe and effective alternative for the treatment of SVT in children.
Assuntos
Cateterismo Cardíaco/métodos , Ablação por Cateter , Crioterapia/métodos , Taquicardia Supraventricular/terapia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Resultado do TratamentoRESUMO
Exposure to stressors that elicit fear and feelings of hopelessness can cause severe vagal activation leading to bradycardia, syncope, and sudden death. These phenomena though documented, are difficult to diagnose, treat clinically, and prevent. Therefore, an animal model incorporating these cardiovascular conditions could be useful. The present study examined 'sinking' during a 2-h swim stress, a phenomenon that occurs in 50% of rats during 25 degrees C water exposure. Concurrent measurements of body temperature, immobility, heart rate (HR), and PR interval (a measure of vagal activity) were made. Neither decreases in immobility nor variations in hypothermia during swim were correlated with sinking. Bradycardia was more severe in sinking rats (average minimum HR+/-SEM; 143+/-13 vs 247+/-14; p<0.01), and PR interval was elevated (p<0.0001). To examine potential modulation of vagal activity during stress, corticotropin-relasing factor (CRF) receptor antagonists (antalarmin, R121919 and astressin B), a glucocorticoid receptor antagonist (RU486), and a peripherally acting cholinergic antagonist (methylatropine nitrate) were administered. The centrally acting CRF antagonist, antalarmin (32 mg/kg), produced elongation of the PR interval (p<0.0001), robust bradycardia (135+/-18; p<0.001), and increased sinking (92%; p<0.05), and methylatropine nitrate (3.2 mg/kg) blocked these effects. Corroborating these data, two different CRF antagonists, R121919 (30 mg/kg) and astressin B (intracerebroventricular (i.c.v.), 0.03 mug/rat) increased sinking to 100%. RU486 (20 mg/kg) blocked HPA axis negative feedback and decreased percent sinking to 25%. From these studies, we concluded that sinking during a 2-h water exposure was a result of extreme vagal hyperactivity. Furthermore, stress-induced CRF release may serve to protect against elevated cardiac vagal activity.
Assuntos
Bradicardia/induzido quimicamente , Bradicardia/fisiopatologia , Tolerância ao Exercício/efeitos dos fármacos , Receptores de Hormônio Liberador da Corticotropina/antagonistas & inibidores , Estresse Psicológico/complicações , Doenças do Nervo Vago/induzido quimicamente , Animais , Bradicardia/metabolismo , Antagonistas Colinérgicos/farmacologia , Hormônio Liberador da Corticotropina/metabolismo , Hormônio Liberador da Corticotropina/farmacologia , Morte Súbita Cardíaca , Modelos Animais de Doenças , Tolerância ao Exercício/fisiologia , Fadiga/induzido quimicamente , Fadiga/metabolismo , Fadiga/fisiopatologia , Frequência Cardíaca/efeitos dos fármacos , Frequência Cardíaca/fisiologia , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Sistema Hipotálamo-Hipofisário/metabolismo , Sistema Hipotálamo-Hipofisário/fisiopatologia , Hipotermia Induzida , Masculino , Mifepristona/farmacologia , Fragmentos de Peptídeos/farmacologia , Agitação Psicomotora/fisiopatologia , Pirimidinas/farmacologia , Pirróis/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores de Hormônio Liberador da Corticotropina/metabolismo , Estresse Psicológico/fisiopatologia , Natação/fisiologia , Nervo Vago/efeitos dos fármacos , Nervo Vago/fisiopatologia , Doenças do Nervo Vago/metabolismo , Doenças do Nervo Vago/fisiopatologiaRESUMO
INTRODUCTION: A multicenter prospective study was designed and implemented to assess the short- and longer-term results and risks associated with radiofrequency (RF) ablation in children. METHODS AND RESULTS: Patients recruited for the study were aged 0 to 16 years with supraventricular tachycardia due to accessory pathways or AV nodal reentrant tachycardia (AVNRT), excluding patients with nontrivial congenital heart disease. A national registry also was established, and contributing centers were encouraged to enroll all pediatric patients, aged 0 to 21 years, undergoing ablation at their center. This report summarizes acute results of these procedures. For analysis, subjects were divided into three groups: the prospective cohort (n = 481), cohort-eligible registry participants (n = 504), and not cohort eligible registry participants (n = 1,776). Prospectively enrolled cohort patients were similar to cohort-eligible patients in terms of demographic and other patient characteristics. Overall success rates for RF ablation were high (95.7%), with higher success rates for left-sided and particularly left free-wall pathways (97.8%) than right free-wall pathways (90.8%). Complications of both electrophysiologic study and RF ablation were infrequent (4.2% and 4.0%, respectively), and there were no deaths. AV block was uncommon overall (1.2%) and was limited to ablation in AVNRT (2.1%) and septal accessory pathways (3.0%). CONCLUSION: Despite the multicenter and prospective design, the study demonstrates high success rates and low complication rates, which are comparable to prior single-center retrospective studies. These results may serve as the current best benchmark for expected results in the pediatric population, aged 0 to 16 years, both in terms of acute success rates and the occurrence of complications.
Assuntos
Ablação por Cateter , Avaliação de Resultados em Cuidados de Saúde , Taquicardia Supraventricular/cirurgia , Adolescente , Criança , Ecocardiografia , Eletrocardiografia Ambulatorial , Técnicas Eletrofisiológicas Cardíacas , Feminino , Humanos , Masculino , Complicações Pós-Operatórias , Estudos Prospectivos , Sistema de Registros , Taquicardia Supraventricular/fisiopatologiaRESUMO
OBJECTIVE: Patient-activated transtelephonic electrocardiographic event monitors (TTMs) are often used for the evaluation of children and adolescents with suspected arrhythmias. Since their introduction 25 years ago, there has been little inquiry quantifying the usefulness of TTMs for pediatric patients. The objective of this study was to measure the utility of TTMs for children and adolescents with symptoms of a possible cardiac rhythm disturbance. METHODS: Medical records of all patients who received TTMs from C.S. Mott Children's Hospital Electrocardiography Laboratory between February 1, 1993, and October 31, 2000, were reviewed. Patients with pacemakers, known arrhythmias, or age older than 18 years were excluded. Indications for monitoring included palpitations with or without other symptoms (N = 420), chest discomfort (N = 43), and presyncope or syncope (N = 32). RESULTS: A total of 495 studies (patient mean age: 10.2 +/- 4.3 years; range: 0.1-17.9 years; 48% male) met inclusion criteria. Monitoring was performed for 1 to 1021 consecutive days (mean: 103 +/- 97). Fifty-two percent (N = 257) of patients failed to transmit an electrocardiogram while experiencing symptoms. Fewer boys transmitted electrocardiograms (N = 100/238). Of 238 symptomatic patients, 15% (N = 35; mean age: 11.4 +/- 4.7 years; range: 0.1-17.4 years; 51% male) had supraventricular tachycardia (SVT). No other significant arrhythmia that may warrant treatment was identified. All patients with SVT had palpitations. No patients with isolated chest discomfort, presyncope, or syncope had SVT (N = 75). SVT was documented more frequently in patients with postevent (N = 35/464) than loop recorders (N = 0/31). Of those with SVT, 71% (N = 25) and 91% (N = 33) transmitted events within 4 and 16 weeks, respectively. Follow-up for 1 to 108 months (mean: 32 +/- 25; median: 26) in 53% (243 of 460) of patients without SVT uncovered a 3% (N = 7) rate of subsequent SVT detection. The overall sensitivity of the TTM test was 83% (35 of 42) for detection of SVT. The sensitivity of studies theoretically limited to 4 and 16 weeks would be 60% (25 of 42) and 79% (33 of 42), respectively. The negative predictive value of the TTM study was 99% in our patient population. The negative predictive value of tests theoretically limited to 4 and 16 weeks would be 96% and 98%, respectively. TTM studies of 2 weeks' duration were most cost-effective in terms of total diagnostic yield. In contrast, studies of 4 weeks' duration were most cost-efficient for SVT detection. CONCLUSIONS: TTMs are useful for the evaluation of children and adolescents with palpitations but not with isolated chest pain, syncope, or presyncope. In this study, girls were more likely to transmit events. The sensitivity of TTMs for detection of SVT was 83%. The negative predictive value of the TTM test was 99%. Monitoring for longer than 16 weeks did not increase test sensitivity. Studies of 4 weeks' duration proved most cost-effective for SVT detection.