Activated 4-Factor Prothrombin Complex Concentrate as a Hemostatic Adjunct for Neonatal Cardiac Surgery: A Propensity Score-Matched Cohort Study.

BACKGROUND: Prothrombin complex concentrates are an emerging "off-label" therapy to augment hemostasis after cardiopulmonary bypass (CPB), but data supporting their use for neonatal cardiac surgery are limited. METHODS: We retrospectively reviewed neonates undergoing open heart surgery with first-time sternotomy between May 2014 and December 2018 from a hospital electronic health record database. Neonates who received activated 4-factor prothrombin complex concentrate (a4FPCC) after CPB were propensity score matched (PSM) to neonates who did not receive a4FPCC (control group). The primary efficacy outcome was total volume (mL/kg) of blood products transfused after CPB, including the first 24 hours on the cardiovascular intensive care unit (CVICU). The primary safety outcome was the incidence of 7- and 30-day postoperative thromboembolism. Secondary outcomes included 24 hours postoperative chest tube output, time to extubation, duration of CVICU stay, duration of hospital stay, 30-day mortality, and incidence of acute kidney injury on postoperative day 3. We used linear regression modeling on PSM data for the primary efficacy outcome. For the primary safety outcome, we tested for differences using McNemar test on PSM data. For secondary outcomes, we used linear regression, Fisher exact test, or survival analyses as appropriate, with false discovery rate-adjusted P values. RESULTS: A total of 165 neonates were included in the final data analysis: 86 in the control group and 79 in the a4FPCC group. After PSM, there were 43 patients in the control group and 43 in the a4FPCC group. We found a statistically significant difference in mean total blood products transfused for the a4FPCC group (47.5 mL/kg) compared with the control group (63.7 mL/kg) for PSM patients (adjusted difference, 15.3; 95% CI, 29.4-1.3; P = .032). We did not find a statistically significant difference in 7- or 30-day thromboembolic rate, postoperative chest tube output, time to extubation, incidence of postoperative acute kidney injury (AKI), or 30-day mortality between the groups. The a4FPCC group had a significantly longer length of intensive care unit stay (32.9 vs 13.3 days; adjusted P = .049) and hospital stay (44.6 vs 24.1 days; adjusted P = .049) compared with the control group. CONCLUSIONS: We found that the use of a4FPCC as a hemostatic adjunct for post-CPB bleeding in neonatal cardiac surgery was associated with a decrease in mean total blood products transfused after CPB without an increased rate of 7- or 30-day postoperative thromboembolism. Our findings suggest that a4FPCCs can be considered as part of a hemostasis pathway for refractory bleeding in neonatal cardiac surgery.

The use of prothrombin complex concentrate as a warfarin reversal agent in pediatric patients undergoing orthotopic heart transplantation.

BACKGROUND: Patients supported with a ventricular assist device are predisposed to severe bleeding at the time of orthotopic heart transplant due to several risk factors including anticoagulation with vitamin K antagonists. Kcentra, a four-factor prothrombin complex concentrate, has been approved by the FDA for warfarin reversal in adults prior to urgent surgery. There is a lack of published data on the preoperative use of four-factor prothrombin complex concentrates in pediatric patients undergoing cardiacsurgery. METHODS: This is a single-center retrospective analysis of pediatric patients with a continuous-flow ventricular assist device who underwent heart transplant, comparing patients who received Kcentra for anticoagulation reversal with a historical patient cohort who did not. Consecutive patients from January 2013 to December 2017 were analyzed. The primary outcome was volume of blood product transfusion prior to cardiopulmonary bypass initiation. Secondary outcomes include blood product transfusion after cardiopulmonary bypass intraoperatively and up to 24 hours postoperatively, chest tube output within 24 hours of surgery, time to extubation, incidence of thromboembolism, and post-transplant length ofstay. RESULTS: From 2013 to 2017, 31 patients with continuous-flow ventricular assist devices underwent heart transplant, with 27 patients included in the analysis. Fifteen patients received Kcentra compared with 12 patients who received fresh-frozen plasma for anticoagulation reversal. Compared with the control group, patients who received Kcentra had less packed red blood cells, fresh-frozen plasma, and platelets transfused prior to cardiopulmonary bypass initiation. The Kcentra group also received less packed red blood cells on bypass and less packed red blood cells after cardiopulmonary bypass termination. There were no differences in chest tube output, time to extubation, intensive care unit length of stay, or overall hospital length of stay. Neither group had thromboembolic complications detected during the first seven postoperative days. CONCLUSION: This small retrospective study indicates that preoperative warfarin reversal with Kcentra reduces blood product exposure in pediatric patients with ventricular assist devices undergoing heart transplant.

Fibrinogen Concentrate as an Alternative to Cryoprecipitate in a Postcardiopulmonary Transfusion Algorithm in Infants Undergoing Cardiac Surgery: A Prospective Randomized Controlled Trial.

BACKGROUND: Infants undergoing cardiac surgery are at risk for bleeding and massive transfusion due to an immature coagulation system, complex surgeries, and cardiopulmonary bypass (CPB) effects. Hemodilution from CPB promotes an acquired hypofibrinogenemia that results in impaired fibrin formation, inadequate clot formation, and increased bleeding. In North America, the current standard of care to supplement fibrinogen is cryoprecipitate. An alternative option is the off-label use of fibrinogen concentrate (FC; RiaSTAP; CSL Behring, Marburg, Germany), a purified fibrinogen. Because perioperative allogenic transfusions are associated with increased morbidity and mortality, we sought to determine whether FC would be an acceptable alternative to cryoprecipitate in a post-CPB transfusion algorithm in infants undergoing open-heart surgery. METHODS: We randomized 60 infants (<12 months) undergoing nonemergent cardiac surgery with CPB at 2 tertiary care children's hospitals to receive either cryoprecipitate or FC in a post-CPB transfusion algorithm. Infants underwent a stratified randomization based on institution and surgical complexity. The primary outcome was the difference in number of intraoperative allogenic blood product transfusions. Secondary outcomes included 24-hour chest tube output (CTO), mechanical ventilation time, adverse events (AEs), intensive care unit (ICU) length of stay (LOS), hospital LOS, postoperative thrombosis, and death within 30 days of surgery. The primary analysis followed the intent-to-treat (ITT) principle and was performed using linear regression adjusted for institution and complexity of surgery. A per-protocol (PP) analysis was also performed. RESULTS: Between June 2016 and January 2018, we enrolled 60 patients with complete data available for 25 patients who received cryoprecipitate and 29 patients who received FC. Patients in the cryoprecipitate group (median age: 4 months [2-6 months]) received 5.5 (4.0-7.0) allogeneic blood units in the ITT analysis and 6.0 units (5.0-7.0 units) in the PP analysis. Patients in the FC group (median age: 4 months [2-5]) received 4 units (3.0-5.0 units) in the ITT analysis and 4.0 units (3.0-5.0 units) in the PP analysis. In the adjusted ITT analysis, the FC group received 1.79 units (95% confidence interval [CI], 0.64-2.93; P = .003) less than the cryoprecipitate group. In the adjusted PP analysis, the FC group received 2.67 units (95% CI, 1.75-3.59; P < .001) less than the cryoprecipitate group. There were no significant differences in secondary outcomes or AEs. CONCLUSIONS: Our findings suggest that FC may be considered as an alternative to cryoprecipitate for the treatment of hypofibrinogenemia in infants with bleeding after CPB. Although we found no significant differences between secondary outcomes or AEs, further studies are needed to assess safety.

Epoprostenol Therapy for a Pediatric Patient With Subacute Heparin-Induced Thrombocytopenia and a Ventricular Assist Device Undergoing Heart Transplant: A Case Report.

Concerns remain regarding the use of direct thrombin inhibitors for cardiopulmonary bypass anticoagulation in pediatric patients with heparin-induced thrombocytopenia undergoing complex cardiac surgery. We describe the safe and effective use of epoprostenol sodium as an alternative therapy before heparin exposure for a pediatric patient with subacute heparin-induced thrombocytopenia and a ventricular assist device undergoing heart transplant.

Reporting of Perioperative Adverse Events by Pediatric Anesthesiologists at a Tertiary Children's Hospital: Targeted Interventions to Increase the Rate of Reporting.

BACKGROUND: Incident reporting systems (IRSs) are important patient safety tools for identifying risks and opportunities for improvement. A major IRS limitation is underreporting of incidents. Perioperative anesthesia IRSs have been established at multiple pediatric institutions and a national pediatric anesthesia IRS for perioperative serious adverse events (SAEs) is maintained by Wake Up Safe (WUS), a patient safety organization dedicated to pediatric anesthesia quality improvement. A confidential, electronic, perioperative IRS was instituted at our tertiary children's hospital, which is a WUS member. The primary study aim was to increase the rate of incident reporting by anesthesiologists at our institution through a series of interventions. The secondary aim was to characterize our reporting behavior relative to national practice by referencing SAE data from WUS. METHODS: Perioperative adverse events reported over a 71-month period (November 2010 to September 2016) were categorized and the monthly reporting rates determined. Effects of 6 interventions targeted to increase the reporting rate were analyzed using control charts. Intervention 5 involved interviewing pediatric anesthesiologists to ascertain incident reporting barriers and motivators. A key driver diagram was developed and used to guide an improvement initiative. Incidents that fulfilled WUS criteria for SAEs were identified and categorized. SAE reporting rates over a 27-month period for 12 WUS member institutions were determined. RESULTS: 2689 perioperative adverse events were noted in 1980 of 72,384 anesthetics. Mean monthly adverse event case rate was 273 (95% confidence interval, 250-297) per 10,000 anesthetics. A subgroup involving 54,469 cases had 529 SAEs in 440 anesthetics; a mean monthly SAE case rate of 80 (95% confidence interval, 69-91) per 10,000 anesthetics. Cardiac, respiratory, and airway events predominated. Relative to WUS peer members, our institution is a high-reporting outlier. The rate of incident reporting per 10,000 anesthetics was sustainably increased from 149 ± 35 to 387 ± 73 (mean ± SD) after implementing mandatory IRS data entry and Intervention 5 quality improvement initiative. Barriers to reporting included concern for punitive repercussions, feelings of incompetence, poor education about what constitutes an event, lack of feedback, and the perception that reporting had no value. These were addressed by IRS education, cultivation of a culture of safety where reporting is encouraged, reporter feedback, and better inclusion of anesthesiologists in patient safety work. CONCLUSIONS: Electronic mandatory IRS data entry and an initiative to understand and address reporting barriers and motivators were associated with sustained increases in the adverse event reporting rate. These strategies to minimize underreporting enhance IRS value for learning and may be generalizable.

Current use of factor concentrates in pediatric cardiac anesthesia.

Excessive bleeding following pediatric cardiopulmonary bypass is associated with increased morbidity and mortality, both from the effects of hemorrhage and the therapies employed to achieve hemostasis. Neonates and infants are especially at risk because their coagulation systems are immature, surgeries are often complex, and cardiopulmonary bypass technologies are inappropriately matched to patient size and physiology. Consequently, these young children receive substantial amounts of adult-derived blood products to restore adequate hemostasis. Adult and pediatric data demonstrate associations between blood product transfusions and adverse patient outcomes. Thus, efforts to limit bleeding after pediatric cardiopulmonary bypass and minimize allogeneic blood product exposure are warranted. The off-label use of factor concentrates, such as fibrinogen concentrate, recombinant activated factor VII, and prothrombin complex concentrates, is increasing as these hemostatic agents appear to offer several advantages over conventional blood products. However, recognizing that these agents have the potential for both benefit and harm, well-designed studies are needed to enhance our knowledge and to determine the optimal use of these agents. In this review, our primary objective was to examine the evidence regarding the use of factor concentrates to treat bleeding after pediatric CPB and identify where further research is required. PubMed, MEDLINE/OVID, The Cochrane Library and the Cochrane Central Register of Controlled Trials (CENTRAL) were systematically searched to identify existing studies.

Perioperative management of pediatric en-bloc combined heart-liver transplants: a case series review.

BACKGROUND: Combined heart and liver transplantation (CHLT) in the pediatric population involves a complex group of patients, many of whom have palliated congenital heart disease (CHD) involving single ventricle physiology. OBJECTIVE: The purpose of this study was to describe the perioperative management of pediatric patients undergoing CHLT at a single institution and to identify management strategies that may be used to optimize perioperative care. METHODS: We did a retrospective database review of all patients receiving CHLT at a children's hospital between 2006 and 2014. Information collected included preoperative characteristics, intraoperative management, blood transfusions, and postoperative morbidity and mortality. RESULTS: Five pediatric CHLTs were performed over an 8-year period. All patients had a history of complex CHD with multiple sternotomies, three of whom had failing Fontan physiology. Patient age ranged from 7 to 23 years and weight from 29.5 to 68.5 kg. All CHLTs were performed using an en-bloc technique where both the donor heart and liver were implanted together on cardiopulmonary bypass (CPB). The median operating room time was 14.25 h, median CPB time was 3.58 h, and median donor ischemia time was 4.13 h. Patients separated from CPB on dopamine, epinephrine, and milrinone infusions and two required inhaled nitric oxide. All patients received a massive intraoperative blood transfusion post CPB with amounts ranging from one to three times the patient's estimated blood volume. The patient who required the most transfusions was in decompensated heart and liver failure preoperatively. Four of the five patients received an antifibrinolytic agent as well as a procoagulant (prothrombin complex concentrate or recombinant activated Factor VII) to assist with hemostasis. There were no 30-day thromboembolic events detected. Postoperatively the median length of mechanical ventilation, ICU stay and stay to hospital discharge was 4, 8, and 37 days, respectively. All patients are alive and free from allograft rejection at this time. CONCLUSION: Combined heart and liver transplantation in the pediatric population involves a complex group of patients with unique perioperative challenges. Successful management starts with thorough preoperative planning and communication and involves strategies to deal with massive intraoperative hemorrhage and coagulopathy in addition to protecting and supporting the transplanted heart and liver and meticulous surgical technique. An integrated multidisciplinary team approach is the cornerstone for successful outcomes.

Development and implementation of a new data registry in congenital cardiac anesthesia.

A new multisite registry for congenital cardiac anesthesia patients has now been incorporated into The Society of Thoracic Surgeons Congenital Heart Surgery Database. This new registry, "The Joint Congenital Cardiac Anesthesia Society-Society of Thoracic Surgeons Congenital Cardiac Anesthesia Database," is part of the Congenital Cardiac Anesthesia Society's commitment to patient care and research on outcomes improvement. This report will review the planning and funding of the initial start-up as well as the data elements being used in the registry. Patients in the registry include not only cardiac surgical patients but also those with congenital heart disease undergoing procedures in locations other than the operating room, including in the cardiac catheterization laboratory, intensive care unit, general operating room, and radiology suite. Initial results from the first data harvests are reported, including site participation, patient population submitted, and adverse outcomes observed. These initial results validate the concept and serve as a benchmark for further development and implementation of the registry. Because of the relative infrequency of anesthesia-related events in this low-volume procedure, a multisite data harvest is the most reasonable approach to capture a sufficient number of patient encounters in a timely manner to support outcomes analysis, quality assessment, and quality improvement.

Case report: airway and concurrent hemodynamic management in a neonate with oculo-auriculo-vertebral (Goldenhar) syndrome, severe cervical scoliosis, interrupted aortic arch, multiple ventricular septal defects, and an unstable cervical spine.

We report the challenging case of a 1-week-old, term, 2.4 kg neonate with Goldenhar syndrome (including microcephaly, left microtia, left facial palsy, dextro-scoliosis of the cervical spine, and cervico-thoracic levoscoliosis), multiple ventricular septal defects, a type B interrupted aortic arch, a large patent ductus arteriosis, and radiographic and clinical signs concerning for an unstable cervical spine. Our anesthesia team was consulted for perioperative management of this patient during her surgical repair. This case report describes the use of the Air-Q size 1 laryngeal airway (LA) to assist fiberoptic intubation in an ASA 4 neonate with cardiac disease, an anticipated difficult airway with the addition of an unstable cervical spine, as well as the anesthetic techniques used to maintain hemodynamic stability while the airway was secured.

Review of the off-label use of recombinant activated factor VII in pediatric cardiac surgery patients.

In recent years the off-label use of recombinant activated factor VII (rFVIIa) has markedly increased, particularly in pediatric cardiac surgery patients, and practitioners differ widely in their usage of the drug. In 2009, the Congenital Cardiac Anesthesia Society (CCAS) assembled a task force to review the literature on rFVIIa administration to pediatric cardiac surgery patients. The goal of the CCAS Task Force was to assess current practices and make recommendations about rFVIIa therapy to enhance quality of care, improve patient outcomes, reduce costs, and develop future research. In this review we summarized the important topics on current administration of rFVIIa to pediatric cardiac surgery patients including indications for use, efficacy, safety, dosing, and monitoring. All pediatric and pertinent adult literature regarding the administration of rFVIIa to cardiac surgical patients and published since 2000 were selected and studied. Of the 40 pediatric publications reviewed for this report, only 1 was a prospective randomized controlled trial thus making determinations of efficacy difficult. There is no substantive evidence to support the efficacy of rFVIIa as prophylactic or routine therapy during pediatric cardiac surgery. It may prove reasonable as rescue therapy because current observational evidence suggests that potential benefits of rFVIIa for this indication might outweigh the risks. Rescue therapy is appropriate for bleeding that is massive, potentially life-threatening, and refractory to conventional therapy. Nevertheless, extreme caution is advised when considering the administration of rFVIIa to patients who are at risk for thromboembolic complications because rates for clinical and subclinical thrombosis secondary to rFVIIa therapy are unknown at this time. This review is designed to aid practitioners in deciding when and how to administer rFVIIa to pediatric cardiac surgery patients; it is not intended to determine standard-of-care or practice guidelines. There are insufficient data to make evidence-based recommendations. Randomized controlled trials are needed to assess the efficacy of rFVIIa as prophylactic, routine, or rescue therapy and to determine the drug's safety profile particularly with regard to thrombosis. The CCAS rFVIIa Task Force will continue to monitor the literature, gather data, and make updates as more information becomes available.

Cardiomyopathy in childhood.

PURPOSE OF REVIEW: Cardiomyopathy is an important cause of heart failure and a major indication for heart transplantation in children. Unfortunately, there is a paucity of literature to guide the anesthesiologist who cares for these high-risk children. This review describes the cardiomyopathy phenotypes that occur in children and the factors that are associated with clinical outcomes and perioperative complications. Anesthesia considerations will be reviewed. RECENT FINDINGS: During the past decade, there has been a dramatic increase in knowledge related to cardiomyopathy. New genotypes and phenotypes are recognized and new therapies have been devised. Multicenter pediatric cardiomyopathy registries are obtaining data essential for enhanced understanding of the disease. SUMMARY: The diverse spectrum and complexity of pediatric cardiomyopathies mandate a thorough appreciation of the cardiac pathophysiology pertinent to an individual child's perioperative management. Important issues include multisystem disease associated with syndromic or genetic disorders, appropriate preoperative patient assessment to adequately characterize patient risk and guide therapy, and intraoperative and postoperative care plans that target optimal outcomes.

Perioperative management of low birth weight infants for open-heart surgery.

Infants of birth weight ≤2500 g are termed low birth weight (LBW). These children often have considerable morbidity from prematurity and intra-uterine growth restriction. Additionally, LBW infants have increased risk for cardiac and noncardiac congenital anomalies and may require surgery. Primary rather than palliative surgical repair of cardiac lesions has been preferred in recent years. However, LBW remains a risk factor for increased mortality and morbidity after open-heart surgery (OHS). There is a paucity of information about the anesthetic challenges presented by LBW infants undergoing OHS. This review summarizes the perioperative issues of relevance to anesthesiologists who manage these high-risk patients. Emphasis is placed on management concerns that are unique to LBW infants. Retrospective data from the authors' institution are provided for those aspects of anesthetic care that lack published studies. Successful outcome often requires substantial hospital resources and collaborative multi-disciplinary effort.

Perioperative complications in children with pulmonary hypertension undergoing general anesthesia with ketamine.

BACKGROUND: Pulmonary arterial hypertension (PAH) is associated with significant perioperative risk for major complications in children, including pulmonary hypertensive crisis and cardiac arrest. Uncertainty remains about the safety of ketamine anesthesia in this patient population. AIM: Retrospectively review the medical records of children with PAH to ascertain the nature and frequency of peri-procedural complications and to determine whether ketamine administration was associated with peri-procedural complications. METHODS: Children with PAH (mean pulmonary artery pressure > or =25 mmHg and pulmonary vascular resistance index > or =3 Wood units) who underwent general anesthesia for procedures during a 6-year period (2002-2008) were enrolled. Details about the patient, PAH, procedure, anesthetic and postprocedural course were noted, including adverse events during or within 48 h of the procedure. Complication rates were reported per procedure. Association between ketamine and peri-procedural complications was tested. RESULTS: Sixty-eight children (median age 7.3 year, median weight 22 kg) underwent 192 procedures. Severity of PAH was mild (23%), moderate (37%), and severe (40%). Procedures undertaken were major surgery (n = 20), minor surgery (n = 27), cardiac catheterization (n = 128) and nonsurgical procedures (n = 17). Ketamine was administered during 149 procedures. Twenty minor and nine major complications were noted. Incidence of cardiac arrest was 0.78% for cardiac catheterization procedures, 10% for major surgical procedures and 1.6% for all procedures. There was no procedure-related mortality. Ketamine administration was not associated with increased complications. CONCLUSIONS: Ketamine appears to be a safe anesthetic option for children with PAH. We report rates for cardiopulmonary resuscitation and mortality that are more favorable than those previously reported.

A randomized, controlled trial of aprotinin in neonates undergoing open-heart surgery.

BACKGROUND: Neonates undergoing open-heart surgery are especially at risk for massive bleeding and pronounced inflammation. The efficacy of aprotinin, a serine protease inhibitor, at ameliorating these adverse effects of cardiopulmonary bypass has not been clearly demonstrated in neonates. METHODS: Term neonates were enrolled and randomly assigned in a blinded fashion to receive saline (group P, placebo) or high-dose aprotinin (group A). Intraoperative management was standardized: surgeon, anesthesia, cardiopulmonary bypass and hemostasis therapy. Patients were admitted postoperatively to a pediatric cardiac intensive care unit. Primary outcome measure of efficacy was duration of the postoperative mechanical ventilation. Secondary outcome measures were total volume and units of blood products transfused intraoperatively and for 24 h after surgery, duration of chest tube in situ, and intensive care and hospital stays after surgery. RESULTS: Twenty-six neonates were enrolled; 13 received aprotinin and 13 received placebo. The study was halted prematurely because of US Food and Drug Administration's concerns about aprotinin's safety. Baseline patient, surgery and cardiopulmonary bypass characteristics were similar between groups. No outcome variables differed between groups (P > 0.05). Duration of postoperative ventilation was 115 +/- 139 h (group A); 126 +/- 82 h (group P); P = 0.29, and total blood product exposure was 8.2 +/- 2.6 U (group A); 8.8 +/- 1.4 U (group P); P = 0.1. Postoperative blood creatinine values did not differ between groups. In-hospital mortality rate was 4%. CONCLUSIONS: Aprotinin was not shown to be efficacious in neonates undergoing open-heart surgery. It is unclear whether adult aprotinin safety data are relevant to neonates undergoing open-heart surgery.

Anesthetic management of children with pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is associated with significant perioperative risk for major complications, including pulmonary hypertensive crisis and cardiac arrest. Several mechanisms of hemodynamic deterioration, including acute increases in pulmonary vascular resistance (PVR), alterations of ventricular contractility and function and coronary hypoperfusion can contribute to morbidity. Anesthetic drugs exert a variety of effects on PVR, some of which are beneficial and some undesirable. The goals of balanced and cautious anesthetic management are to provide adequate anesthesia and analgesia for the surgical procedure while minimizing increases in PVR and depression of myocardial function. The development of specific pulmonary vasodilators has led to significant advances in medical therapy of PAH that can be incorporated in anesthetic management. It is important that anesthesiologists caring for children with PAH be aware of the increased risk, understand the pathophysiology of PAH, form an appropriate anesthetic management plan and be prepared to treat a pulmonary hypertensive crisis.

The effects of dexmedetomidine on cardiac electrophysiology in children.

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.