Congenital Cardiac Anesthesia Society
A Section of the the Society for Pediatric Anesthesia

{“questions”:{“odzkd”:{“id”:”odzkd”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Michael A. Evans, MD \u2013 Ann & Robert H. Lurie Children\u2019s Hospital of Chicago, Northwestern Feinberg School of Medicine \r\n\r\nA 17-year-old child with an automated implantable cardioverter defibrillator (AICD) placed for congenital long QT syndrome presents to the operating room emergently for fixation of a right-sided open radial fracture. The surgeon plans to use electrocautery for the procedure. Device reprogramming by the electrophysiology service is not possible due to the emergent nature of the procedure. Which of the following strategies is MOST EFFECTIVE to minimize the source of electromagnetic interference with the AICD?\r\n”,”desc”:””,”hint”:””,”answers”:{“bl8vu”:{“id”:”bl8vu”,”image”:””,”imageId”:””,”title”:”A. Placement of the electrocautery current return pad next to the device”},”s47l9″:{“id”:”s47l9″,”image”:””,”imageId”:””,”title”:”B. Use of monopolar electrocautery”},”vyap3″:{“id”:”vyap3″,”image”:””,”imageId”:””,”title”:”C. Use of bipolar electrocautery”,”isCorrect”:”1″},”rdd91″:{“id”:”rdd91″,”image”:””,”imageId”:””,”title”:”D. Placement of a magnet over the AICD”}}}},”results”:{“3j1n5”:{“id”:”3j1n5″,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:””,”redirect_url”:”https:\/\/ccasociety.org\/wp-content\/uploads\/2022\/01\/Question-of-the-Week-January-17-2022-CIED.pdf”}}}

{“questions”:{“axizs”:{“id”:”axizs”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Michael A. Evans, MD \u2013 Ann & Robert H. Lurie Children\u2019s Hospital of Chicago, Northwestern Feinberg School of Medicine \r\n\r\nA 6-month-old infant with a history of perimembranous ventricular septal defect (VSD) undergoes VSD closure on cardiopulmonary bypass (CPB). After separating from CPB, additional residual muscular VSDs are demonstrated on transesophageal echocardiography (TEE). \r\n\r\nIn order to ascertain the hemodynamic significance of the residual VSDs, calculation of the ratio of pulmonary flow to systemic flow (Q_{p<\/sub>:Qs<\/sub>) is necessary. The table below demonstrates data from a venous and arterial blood gases. The surgeon also obtains pulmonary arterial blood from the field, which yields a saturation of 85% on blood gas analysis. \r\n\r\n\r\n\r\n\r\nAssuming no pulmonary venous desaturation, which of the following BEST represents the Qp<\/sub>:Qs<\/sub> in this patient?”,”desc”:””,”hint”:””,”answers”:{“yxq38”:{“id”:”yxq38″,”image”:””,”imageId”:””,”title”:”A. 1:1″},”wlbub”:{“id”:”wlbub”,”image”:””,”imageId”:””,”title”:”B. 1.5:1″},”e41ji”:{“id”:”e41ji”,”image”:””,”imageId”:””,”title”:”C. 2.0:1″,”isCorrect”:”1″},”m8phv”:{“id”:”m8phv”,”image”:””,”imageId”:””,”title”:”D. 2.5:1″}}}},”results”:{“k5pp0”:{“id”:”k5pp0″,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:””,”redirect_url”:”https:\/\/ccasociety.org\/wp-content\/uploads\/2022\/01\/CCAS-Question-of-the-Week-January-12-2022.pdf”}}}}

{“questions”:{“gvdza”:{“id”:”gvdza”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Author: Michael A. Evans, MD \u2013 Ann & Robert H. Lurie Children\u2019s Hospital of Chicago, Northwestern Feinberg School of Medicine \r\n\r\nA 5-year-old male child with a history of Mucopolysaccharidosis Type I-H (Hurler Syndrome) presents for an elective MRI. Upon exam, the anesthesiologist auscultates a previously undiagnosed murmur. A preprocedural transthoracic echocardiogram is ordered prior to the MRI. Which lesion is MOST LIKELY to be found on echocardiogram in a patient with Mucopolysaccharidosis Type I-H?\r\n”,”desc”:””,”hint”:””,”answers”:{“zk19v”:{“id”:”zk19v”,”image”:””,”imageId”:””,”title”:”A. Atrial Septal Defect”},”1omj9″:{“id”:”1omj9″,”image”:””,”imageId”:””,”title”:”B. Ventricular Septal Defect”},”ji188″:{“id”:”ji188″,”image”:””,”imageId”:””,”title”:”C. Patent Ductus Arteriosus”},”66ngm”:{“id”:”66ngm”,”image”:””,”imageId”:””,”title”:”D. Mitral regurgitation”,”isCorrect”:”1″}}}},”results”:{“64t9g”:{“id”:”64t9g”,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:””,”redirect_url”:”https:\/\/ccasociety.org\/wp-content\/uploads\/2022\/01\/CCAS-Question-of-the-Week-January-6-2022.pdf”}}}

{“questions”:{“2gab8”:{“id”:”2gab8″,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Authors: Pascual Sanabria, MD –Hospital Universitario Infantil La Paz. Madrid, Espa\u00f1a and Destiny F Chau, MD –Arkansas Children\u2019s Hospital\/University of Arkansas for Medical Sciences, Little Rock, AR \r\n\r\nThis Question of the Week was written by Dr. Sanabria from Madrid, Spain and Dr. Chau. English translation by Destiny Chau, MD. \r\n\r\nUn reci\u00e9n nacido de 2,9 kg con estenosis de la v\u00e1lvula pulmonar (EP) fue sometido a cateterismo card\u00edaco y dilataci\u00f3n con bal\u00f3n de la v\u00e1lvula pulmonar. El paciente estaba recibiendo una infusi\u00f3n de prostaglandina E1 (PGE1). El ecocardiograma previo al cateterismo mostr\u00f3 EP grave, insuficiencia valvular tric\u00faspide (IT) grave, shunt bidireccional tanto en el ductus arterioso persistente (DAP) como en el foramen oval persistente (FOP). La valvuloplastia pulmonar con bal\u00f3n se consider\u00f3 satisfactoria y se detuvo la PGE1. En el posoperatorio, el paciente mostr\u00f3 signos de hipoperfusi\u00f3n sist\u00e9mica con desarrollo de acidosis metab\u00f3lica grave. El ecocardiograma repetido mostr\u00f3 insuficiencia pulmonar severa, IT severa, shunt de derecha a izquierda en el FOP y de izquierda a derecha en el DAP. \u00bfQu\u00e9 intervenci\u00f3n considera como la M\u00c1S adecuada para estabilizar y mejorar la hemodin\u00e1mica de este paciente?\r\n\r\n\r\nA 2.9 kg neonate with pulmonary valve stenosis (PS) underwent cardiac catheterization and balloon dilation of the pulmonary valve. The patient was on a prostaglandin E1(PGE1) infusion. Pre-catheterization echocardiogram showed severe PS, severe tricuspid valve regurgitation (TR), bi-directional shunting at both the patent ductus arteriosus (PDA) and patent foramen ovale (PFO) levels. The pulmonary balloon valvuloplasty was deemed successful and the PGE1 was stopped. Postoperatively, the patient showed signs of hypoperfusion with development of severe metabolic acidosis. Repeat echocardiogram showed severe pulmonary insufficiency (PI), severe TR, right to left shunting at the PFO and left to right shunting at the PDA. What next intervention would be the MOST effective to stabilize and improve this patient\u2019s hemodynamics?\r\n\r\n”,”desc”:””,”hint”:””,”answers”:{“gez7j”:{“id”:”gez7j”,”image”:””,”imageId”:””,”title”:”A)\tReinicio del PGE1 \/ Restarting the PGE1″},”v0dvh”:{“id”:”v0dvh”,”image”:””,”imageId”:””,”title”:”B)\tOclusi\u00f3n de DAP \/ PDA occlusion “,”isCorrect”:”1″},”vad98″:{“id”:”vad98″,”image”:””,”imageId”:””,”title”:”C)\tSeptostom\u00eda auricular con bal\u00f3n \/ Balloon atrial septostomy “},”f1za0”:{“id”:”f1za0″,”image”:””,”imageId”:””,”title”:”D)\tAdministraci\u00f3n de paracetamol \/ Acetaminophen administration”}}}},”results”:{“belhq”:{“id”:”belhq”,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:”Explicaci\u00f3n: \r\n\r\nEste paciente desarroll\u00f3 un shunt circular despu\u00e9s del inicio de un insuficiencia pulmonar (IP) grave por la valvuloplastia pulmonar con bal\u00f3n. Un shunt circular (CS) ocurre cuando la sangre fluye a trav\u00e9s de cada una de las cuatro c\u00e1maras card\u00edacas y regresa a su c\u00e1mara original sin pasar por un lecho capilar. La implicaci\u00f3n hemodin\u00e1mica es que una gran parte del gasto cardiaco ventricular recircula de forma ineficaz entre ambos ventr\u00edculos sin contribuir a la perfusi\u00f3n sist\u00e9mica, lo que da lugar a un s\u00edndrome de bajo gasto card\u00edaco sist\u00e9mico y riesgo de fallo multiorg\u00e1nico. La sangre recirculada tambi\u00e9n causa una sobrecarga de volumen ventricular e insuficiencia card\u00edaca. En este caso, el shunt circular se gener\u00f3 en presencia de insuficiencia pulmonar grave que permiti\u00f3 que la sangre fluyera hacia atr\u00e1s volviendo al ventr\u00edculo derecho, retrocediendo por la v\u00e1lvula tric\u00faspide incompetente hacia la aur\u00edcula derecha, pasando a trav\u00e9s del FOP al coraz\u00f3n izquierdo, luego bombeada hacia la aorta por donde ingresa al DAP a la arteria pulmonar y, en lugar de proseguir por la circulaci\u00f3n pulmonar, vuelve de regreso a trav\u00e9s de la v\u00e1lvula pulmonar incompetente, al ventr\u00edculo derecho. Otras combinaciones anat\u00f3micas descritas de anomal\u00edas card\u00edacas que predisponen a shunt circulares incluyen: \r\n1. Defecto del tabique ventricular, EP grave, IT y FOP \r\n2. Atresia pulmonar con tabique ventricular intacto, posvalvotom\u00eda IP, IT y FOP \r\n3. Anomal\u00eda de Ebstein (IT), IP, DAP y FOP \r\n\r\nLa interrupci\u00f3n del shunt circular es esencial para revertir el bajo gasto cardiaco. En este caso cl\u00ednico, la oclusi\u00f3n ductal mediante el cierre con dispositivo transcat\u00e9ter o la ligadura quir\u00fargica, o el cierre espont\u00e1neo final despu\u00e9s de la interrupci\u00f3n de la PGE1 romper\u00eda el shunt circular, aumentar\u00eda la perfusi\u00f3n sist\u00e9mica y disminuir\u00eda la insuficiencia card\u00edaca. En el contexto de un flujo pulmonar sangu\u00edneo adecuado a trav\u00e9s de la arteria pulmonar principal, se restablecer\u00eda el gasto card\u00edaco sist\u00e9mico y se restablecer\u00eda la estabilidad hemodin\u00e1mica. Otros m\u00e9todos de tratamiento quir\u00fargico descritos para la reducci\u00f3n del shunt circular incluye el banding de DAP o banding de arterias pulmonares. \r\n\r\nLa combinaci\u00f3n de lesiones card\u00edacas cong\u00e9nitas coloc\u00f3 a este beb\u00e9 a riesgo de un shunt circular despu\u00e9s de la valvuloplastia pulmonar. La anticipaci\u00f3n y el seguimiento cercano por los primeros signos de hipoperfusi\u00f3n sist\u00e9mica posoperatorio son fundamentales para una intervenci\u00f3n oportuna. La monitorizaci\u00f3n por espectroscopia de infrarrojo cercano (NIRS) parece un indicador \u00fatil para detectar cambios tempranos en la tendencia de la perfusi\u00f3n sist\u00e9mica relacionados con la direccionalidad del flujo sangu\u00ednea a trav\u00e9s del DAP; la disminuci\u00f3n de los valores de NIRS despu\u00e9s de la valvuloplastia puede reflejar un shunt importante de izquierda a derecha y un robo de perfusi\u00f3n sist\u00e9mico, mientras que aumentos en los valores de NIRS despu\u00e9s de la ligadura del DAP ayudan a determinar la efectividad de la intervenci\u00f3n de un modo inmediato. \r\n\r\nLas otras opciones de respuesta del cuestionario, sobre reiniciar la PGE1 o realizar una septostom\u00eda auricular con bal\u00f3n, aumentar\u00edan y empeorar\u00edan el shunt circular. Aunque se ha descrito que la administraci\u00f3n de paracetamol promueve el cierre del DAP en reci\u00e9n nacidos prematuros, su efectividad, confiabilidad y tiempo oportuno en el cierre ductal son altamente cuestionables en este escenario urgente.\r\n\r\n\r\n\r\nExplanation: \r\n\r\nThis patient developed a circular shunt after the onset of severe pulmonary insufficiency (PI) from the balloon pulmonary valvuloplasty. A circular shunt (CS) occurs when blood flows through each of the four cardiac chambers and returns to its original chamber without going through a capillary bed. The hemodynamic implication is that a large portion of the ventricular output recirculates ineffectively between both ventricles without contributing to systemic perfusion resulting in low systemic cardiac output and leading to the risk of multiorgan failure. The recirculated blood also causes ventricular volume load and high output cardiac failure. In this case, the circular shunt was generated in the presence of severe pulmonary insufficiency which allowed blood to flow backwards into the right ventricle. The blood flow was then regurgitated through the incompetent tricuspid valve into the right atrium and then passed through the patent foramen ovale (PFO) into the left heart. It was then pumped into the aorta where the blood flow entered the patent ductus arteriosus (PDA) into the pulmonary artery. Instead of going through the lungs, the blood flows retrograde through the incompetent pulmonary valve back into the right ventricle. Other described anatomic combinations of cardiac anomalies predisposing to circular shunts include: \r\n1.\tVentricular septal defect, severe PS, TR, and PFO \r\n2.\tPulmonary atresia with intact ventricular septum, post-valvotomy PI, TR, and PFO \r\n3.\tEbstein\u2019s anomaly (TR), PI, PDA and PFO \r\nInterruption of the circular shunt is essential for restoration of hemodynamic stability. In this case scenario, ductal occlusion via transcatheter device closure, surgical ligation, or eventual spontaneous closure after PGE1 discontinuation would break the circular shunt leading to increased systemic perfusion and decreased high output cardiac failure. In the setting of adequate forward pulmonary blood flow through the main pulmonary artery, systemic cardiac output would be restored and hemodynamic stability re-established. Other described surgical approaches for reducing the circular shunt include PDA banding or pulmonary artery banding. \r\n\r\nThe combination of congenital cardiac lesions placed this infant at risk for a circular shunt after the pulmonary valvuloplasty. Anticipation and close monitoring for early signs of postprocedural systemic hypoperfusion is critical for timely intervention. Near infrared spectroscopy (NIRS) monitoring has been reported as a useful indicator for detecting and trending early systemic perfusion changes related to blood shunt directionality through the PDA. Thus, decreasing NIRS values after the valvuloplasty may reflect significant left to right shunting through the PDA and systemic \u201csteal\u201d while increases in NIRS values after ligation of the PDA aids in determining the intervention\u2019s effectiveness. \r\n\r\nThe other answer choices of restarting the PGE1 or performing balloon atrial septostomy would only worsen the circular shunt. Although acetaminophen administration has been described to promote closure of PDA in premature infants, its effectiveness, reliability and timeliness on ductal closure are highly questionable in this emergent case scenario. \r\n\r\n\r\nReferences: \r\n\r\nSchmitz ML, Ullah S, Dasgupta R, Thompson LL. Anesthesia for right-sided obstructive lesions. In: Andropoulos D, Stayer S, Mossad E, Miller-Hance W, eds. Anesthesia for Congenital Heart Disease<\/em>. 3rd Edition. Hoboken, New Jersey: John Wiley & Sons, Inc.; 2015: 522. \r\n\r\nElzein C, Subramanian S, Ilbawi M. Surgical management of neonatal Ebstein’s anomaly associated with circular shunt. World J Pediatr Congenit Heart Surg<\/em>. 2019; 10(1): 116-120. \r\n\r\nHasegawa M, Iwai S, Yamauchi S, et al. Bilateral pulmonary artery banding in Ebstein’s anomaly with circular shunting. Ann Thorac Surg<\/em>. 2019; 107(5): e317-e319. \r\n\r\nBautista-Rodriguez C, Rodriguez-Fanjul J, Moreno Hernando J, Mayol J, Caffarena-Calvar JM. Patent ductus arteriosus banding for circular shunting after pulmonary valvuloplasty. World J Pediatr Congenit Heart Surg<\/em>. 2017; 8(5): 643-645. \r\n\r\nChock VY, Rose LA, Mante JV, Punn R. Near-infrared spectroscopy for detection of a significant patent ductus arteriosus. Pediatr Res<\/em>. 2016; 80(5): 675-680. \r\n\r\nChock VY, Ramamoorthy C, Van Meurs KP. Cerebral oxygenation during different treatment strategies for a patent ductus arteriosus. Neonatology<\/em>. 2011; 100(3): 233-240. \r\n \r\nOhlsson A, Shah PS. Paracetamol (acetaminophen) for patent ductus arteriosus in preterm or low birth weight infants. Cochrane Database Syst Rev<\/em>. 2018; 4(4): CD010061. \r\n\r\n\r\n\r\n\r\n\r\n”,”redirect_url”:””}}}

{“questions”:{“tf7ir”:{“id”:”tf7ir”,”mediaType”:”image”,”answerType”:”text”,”imageCredit”:””,”image”:””,”imageId”:””,”video”:””,”imagePlaceholder”:””,”imagePlaceholderId”:””,”title”:”Authors: Jorge Guerrero, MD and Destiny F Chau, MD Arkansas Children\u2019s Hospital\/University of Arkansas for Medical Sciences, Little Rock, AR \r\n\r\nA five-year-old female child with a history of Williams-Beuren syndrome and mild supravalvar pulmonary stenosis is undergoing a diagnostic colonoscopy for abdominal pain. After an uneventful intraprocedural course with stable hemodynamics, ondansetron and acetaminophen are administered prior to emergence of anesthesia. Within a few minutes the electrocardiogram (ECG) shows torsades de pointes. The MOST LIKELY trigger for this arrhythmia is:\r\n”,”desc”:””,”hint”:””,”answers”:{“xrsh7”:{“id”:”xrsh7″,”image”:””,”imageId”:””,”title”:”A)\tLight anesthesia”},”v606t”:{“id”:”v606t”,”image”:””,”imageId”:””,”title”:”B)\tVenous air embolism”},”z1s56″:{“id”:”z1s56″,”image”:””,”imageId”:””,”title”:”C)\tOndansetron administration”,”isCorrect”:”1″},”h6mju”:{“id”:”h6mju”,”image”:””,”imageId”:””,”title”:”D)\tAcetaminophen administration”}}}},”results”:{“bwn36”:{“id”:”bwn36″,”title”:””,”image”:””,”imageId”:””,”min”:”0″,”max”:”1″,”desc”:”Williams or Williams-Beuren syndrome (WBS) is a genetic disease that affects 1: 8000-10,000 individuals. The syndrome has been linked to deletions of 1.5 to 1.8 base pairs on chromosome 7q11.25, which encompass the elastin gene (ELN). The cardiovascular findings associated with WBS are due to the lack of elastin production as a consequence of this gene deletion. Eighty percent of patients with WBS have cardiovascular manifestations, which include supravalvular aortic stenosis and pulmonary artery stenosis – typically the branch pulmonary arteries. Forty-five percent of patients with supravalvular aortic stenosis will also have coronary anomalies. Any artery may be involved, including the mid- thoracic aorta, renal arteries, carotid arteries, and cerebral arteries. \r\n\r\nUp to 14% of WBS patients will have a prolonged QTc\/JTc interval. This may be a contributing factor to a higher-than-normal incidence of adverse cardiac events related to WBS. Many patients with WBS exhibit increased prolongation of the QTc during periods of increased heart rate, which also occurs in patients with microvascular cardiac disease. The occurrence of ectopic beats may also suggest ischemia. However, a concurrent channelopathy due to the genetic deletion cannot be excluded. In a retrospective study by McCarty et al, patients with supravalvular aortic stenosis but without WBS were compared to patients with supravalvular aortic stenosis and WBS. The results demonstrated that the QTc was significantly prolonged in patients with WBS independent of the degree of myocardial hypertrophy as compared to patients without WBS. Additionally, patients with WBS whom underwent repair of obstructive outflow lesions did not show a regression of the prolonged QTc, which presumably would resolve in patients with supravalvular aortic obstruction without WBS. Further studies are needed to elucidate the etiology of the prolonged QTc (ie the role of channelopathies, microvascular abnormalities and related ischemia, or a combination of both). In general, a prolonged QTc can be an isolated finding or it can occur in the setting of cardiac structural lesions. A prolonged QTc can lead to torsades de pointes and may degrade to ventricular fibrillation. It is prudent to avoid drugs that prolong QTc especially if QTc prolongation is already present. Many medications used for anesthesia and sedation, including the potent inhaled anesthetics, can prolong QTc. \r\n\r\n\r\nOther features associated with WBS include a \u201ccocktail-like\u201d personality, high degree of anxiety, attention deficit hyperactivity disorder, and aversion to loud noises. Patients with WBS have intelligence quotients around 50-60. Facial characteristics include a broad forehead, stellate iris, wide nasal bridge, upward pointing nose, large mouth with thick lips, periorbital thickness, and pointed chin. Patients with WBS may exhibit hypercalcemia early in life as well as subclinical hypothyroidism and may develop glucose intolerance progressing to diabetes mellitus in adulthood. They also have a propensity for colic as infants, chronic otitis media, poor dentition and scoliosis. The underlying pathophysiology of WBS predisposes these patients to require more medical attention and undergo more procedures than the general population. Additionally, they are 25-100 times more likely to have an adverse cardiovascular event than the general population. A great majority of events occur when receiving sedation or general anesthesia. Factors that increase the risk of adverse cardiac events are greater severity of supravalvular aortic stenosis (gradient >40 mm Hg), bilateral ventricular outflow obstructive lesions, coronary artery involvement, and a prolonged QTc of 460 ms or greater. Many of the adverse cardiovascular events seem to be related to imbalances in the myocardial oxygen supply and demand related to the vasodilatory and tachycardic effects of anesthetic agents. However, not all of the adverse cardiovascular events can be attributed to ischemia as the sole cause. \r\n\r\n\r\nOf the choices given in this scenario, ondansetron is the most likely trigger for torsades de pointes. It is known to prolong the QTc. In the setting of an uneventful intraoperative course and stable hemodynamics, the timing of ondansetron administration and subsequent presentation of torsades de pointes suggests that this patient with WBS had an abnormal prolonged QTc which was worsened by the ondansetron. Light anesthesia, venous air embolism, and acetaminophen are unlikely causes for torsades de pointes. \r\n\r\n\r\nReferences: \r\n\r\n\r\nStaudt GE, Eagle SS. Anesthetic considerations for patients with Williams syndrome. J Cardiothorac Vasc Anesth<\/em>. 2021; 35(1): 176-186. \r\n\r\n\r\nCollins RT, Collins MG, Schmitz ML, Hamrick JT. Peri-procedural risk stratification and management of patients with Williams syndrome. Congenit Heart Dis<\/em>. 2017; 12(2): 133-142. \r\n\r\n\r\nPober BR. Williams-Beuren syndrome. N Engl J Med<\/em>. 2010; 362(3): 239-252. \r\n\r\n\r\nMcCarty HM, Tang X, Swearingen CJ, Collins RT 2nd. Comparison of electrocardiographic QTc duration in patients with supravalvar aortic stenosis with versus without Williams syndrome. Am J Cardiol<\/em>. 2013; 111(10): 1501-1504. \r\n\r\n\r\nCollins RT 2nd, Aziz PF, Swearingen CJ, Kaplan PB. Relation of ventricular ectopic complexes to QTc interval on ambulatory electrocardiograms in Williams syndrome. Am J Cardiol<\/em>. 2012; 109(11): 1671-1676. \r\n\r\n\r\nCollins RT 2nd, Aziz PF, Gleason MM, Kaplan PB, Shah MJ. Abnormalities of cardiac repolarization in Williams syndrome. Am J Cardiol<\/em>. 2010; 106(7): 1029-1033. \r\n\r\n\r\n\r\n”,”redirect_url”:””}}}