Publications by authors named "Ming-Lon Young"

31 Publications

Genotype Predicts Outcomes in Fetuses and Neonates With Severe Congenital Long QT Syndrome.

JACC Clin Electrophysiol 2020 11 26;6(12):1561-1570. Epub 2020 Aug 26.

Department of Cardiovascular Medicine (Division of Heart Rhythm Services), Mayo Clinic, Rochester, Minnesota, USA; Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota, USA; Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota, USA.

Objectives: This study sought to determine the relationship between long QT syndrome (LQTS) subtype (LTQ1, LTQ2, LTQ3) and postnatal cardiac events (CEs).

Background: LQTS presenting with 2:1 atrioventricular block or torsades de pointes in the fetus and/or neonate has been associated with risk for major CEs, but overall outcomes and predictors remain unknown.

Methods: A retrospective study involving 25 international centers evaluated the course of fetuses/newborns diagnosed with congenital LQTS and either 2:1 atrioventricular block or torsades de pointes. The primary outcomes were age at first CE after dismissal from the newborn hospitalization and death and/or cardiac transplantation during follow-up. CE was defined as aborted cardiac arrest, appropriate shock from implantable cardioverter-defibrillator, or sudden cardiac death.

Results: A total of 84 fetuses and/or neonates were identified with LQTS (12 as LQT1, 35 as LQT2, 37 as LQT3). Median gestational age at delivery was 37 weeks (interquartile range: 35 to 39 weeks) and age at hospital discharge was 3 weeks (interquartile range: 2 to 5 weeks). Fetal demise occurred in 2 and pre-discharge death in 1. Over a median of 5.2 years, there were 1 LQT1, 3 LQT2, and 23 LQT3 CEs (13 aborted cardiac arrests, 5 sudden cardiac deaths, and 9 appropriate shocks). One patient with LQT1 and 11 patients with LQT3 died or received cardiac transplant during follow-up. The only multivariate predictor of post-discharge CEs was LQT3 status (LQT3 vs. LQT2: hazard ratio: 8.4; 95% confidence interval: 2.6 to 38.9; p < 0.001), and LQT3, relative to LQT2, genotype predicted death and/or cardiac transplant (p < 0.001).

Conclusions: In this large multicenter study, fetuses and/or neonates with LQT3 but not those with LQT1 or LQT2 presenting with severe arrhythmias were at high risk of not only frequent, but lethal CEs.
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http://dx.doi.org/10.1016/j.jacep.2020.06.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7679474PMC
November 2020

External Cardioversion-Defibrillation with Pushing Down on the Chest Wall to Increase the Success Rate in Obese Patients.

Am J Case Rep 2020 Nov 16;21:e927009. Epub 2020 Nov 16.

Memorial Cardiac and Vascular Institute, Memorial Regional Hospital, Memorial HealthCare System, Hollywood, FL, USA.

BACKGROUND The energy delivered by a defibrillator is expressed in joules (J). However, current is what actually defibrillates the heart and is related to the voltage-to-impedance ratio. With the same energy, the lower the transthoracic impedance, the higher the current delivered. In obese patients, pushing the chest wall toward the heart during electric shock can result in an improved outcome. CASE REPORT We report the cases of 3 obese patients with previously failed cardioversion/defibrillation who had an eventual shock success. (1) A 17-year-old girl failed multiple defibrillation efforts for her recurrent ventricular fibrillation. After ECMO, with the physician pushing down the chest wall, a 200-J defibrillation converted her VF. (2) A 63-year-old man with recurrent atrial fibrillation (AF) had an unsuccessful 150-J shock followed by a successful 200-J cardioversion. His AF recurred. After amiodarone bolus, a 200-J shock converted it to sinus. Another recurrent AF failed 150-J cardioversion. With chest pushing down, a 150-J cardioversion was successful. (3) A 65-year-old man underwent elective cardioversion for AF. A 200-J shock was unsuccessful. A 200-J shock with pressure on the chest successfully converted it. CONCLUSIONS We performed successful electrical cardioversion/defibrillation with this "pushing down the chest while shocking" method. Many clinicians are still unaware of this method, especially in obese patients. With the increasing prevalence of obesity, it is urgent to perform a randomized study to confirm the efficacy and safety of this method, and integrate it into advanced cardiac life support protocols.
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http://dx.doi.org/10.12659/AJCR.927009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7680710PMC
November 2020

Using coronary sinus ostium as the reference for the slow pathway ablation of atrioventricular nodal reentrant tachycardia in children.

J Arrhythm 2020 Aug 11;36(4):712-719. Epub 2020 Jun 11.

Office of Human Research Memorial Healthcare System Hollywood FL USA.

Background: Successful slow pathway (SP) ablation sites for atrioventricular nodal reentrant tachycardia (AVNRT) are usually located inside the Koch's triangle (KT). This study aimed to determine the ablation site of SP using the coronary sinus (CS) ostium (CSO) as the reference and to evaluate the efficacy of the CSO-guided SP ablation.

Methods: A regional geometry around the KT was constructed by 3D mapping in 52 consecutive patients under age 18 with AVNRT. SP cryoablation was performed. If initial cryoablation was unsuccessful or cryoablation was deemed not suitable, then radiofrequency (RF) ablation was performed. The successful ablation site direction relative to the CSO was expressed as o'clock with the CSO viewed as a clock.

Results: Cryoablation was used as the primary energy source in 40 patients. Of which, 32 were successful and eight required additional RF ablation. Direct RF ablation was performed in 11 patients. Using the CSO as reference, the successful site with cryoablation was at its 2.2 ± 0.6 o'clock; the RF ablation success site was at CSO 2.7 ± 0.5 o'clock ( = .006). During a median follow-up of 12 month, there was 98% success of SP ablation in these patients, with one patient with RF ablation had a tachycardia recurrence.

Conclusions: Using CSO as reference, the cryoablation site at its 2:00 o'clock and RF ablation at its 3:00 o'clock are highly efficacious for SP ablation with good short-term outcomes, and may be a useful tool in guiding the ablation target for AVNRT.
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http://dx.doi.org/10.1002/joa3.12379DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7411203PMC
August 2020

Possible Propofol-Induced Priapism Following Cardiac Catheter Ablation in a Teenager.

Am J Case Rep 2020 Apr 5;21:e920692. Epub 2020 Apr 5.

Pediatric Cardiology, Golisano Children's Hospital of Southwest Florida, Fort Myers, FL, USA.

BACKGROUND Priapism is rarely reported as a potential complication after the cardiac ablation procedure. We report the case of a teenager admitted for atrial flutter ablation who developed priapism following the procedure. CASE REPORT A 16-year-old male with episodic atrial flutter came to our hospital for an electrophysiological study and catheter ablation. During the procedure, he was given IV propofol for anesthesia and IV heparin for anticoagulation. After the procedure, nursing noted that he had an erection, which persisted for 5 h, with complaints of discomfort. There was no known history of sickle cell disease or trauma to the perineum, nor did he endorse any prior prolonged erections. On physical examination, he had a circumcised phallus with rigid and non-tender corpora cavernosa. He was given 5 mg terbutaline PO, without improvement. Three hours later, a second dose of terbutaline was given. In addition, a penis corporal venous blood gas was taken, and the result was consistent with an ischemic priapism. He had detumescence 1-2 min later. The total duration of his priapism was 8 h. There was no swelling, pain, or any sequelae after detumescence. CONCLUSIONS Although priapism rarely occurs as a complication following catheter ablation procedures due to propofol use, prolonged priapism can result in corporal fibrosis and cause future erectile dysfunction. Recognition and treatment of priapism in the postoperative period may be delayed due to a patient's hesitance to express concerns. To prevent future erectile dysfunction, signs of priapism should be included in routine postoperative evaluation in male patients.
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http://dx.doi.org/10.12659/AJCR.920692DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7161937PMC
April 2020

Asymptomatic Idiopathic Belhassen Ventricular Tachycardia in a Neonate Detected Using 'Smart Sock' Wearable Smartphone-Enabled Cardiac Monitoring.

Am J Case Rep 2020 Feb 16;21:e921092. Epub 2020 Feb 16.

Department of Pediatrics, Plantation General Hospital, Plantation, FL, USA.

BACKGROUND Wearable smartphone-enabled cardiac monitoring devices can aid the diagnosis of asymptomatic tachycardia in neonates and infants. This report is of a rare case of left posterior fascicular ventricular tachycardia of Belhassen type detected in a neonate by 'smart sock' cardiac monitoring. CASE REPORT A premature baby boy at 37 weeks gestational age was discharged home after three days without complication, and was given 'smart socks' to wear. He was followed up daily for the management of hyperbilirubinemia, which was treated in the outpatient clinic with a phototherapy blanket. He was admitted to the emergency room (ER) at 6 days of age because his 'smart socks' identified a tachycardia of between 180-200 bpm. His parents reported no fever, cough, nasal congestion, or emesis. On examination in the ER, he was alert with no distress. An electrocardiogram (ECG) showed a sustained monomorphic and wide QRS tachycardia with a heart rate of 200 bpm, right bundle branch block (RBBB), and a superior axis that was compatible with a diagnosis of left posterior fascicular ventricular tachycardia of Belhassen type. The echocardiogram showed a structurally normal heart with normal cardiac function. His tachycardia spontaneously converted to normal sinus rhythm after four hours. He was discharged home three days later without further episodes of tachycardia. Cardiac monitoring using 'smart socks' continued at home, and no further arrhythmias were detected at one year of age. CONCLUSIONS The home use of smartphone-enabled technology to monitor the neonatal and infant cardiac heart rate can identify asymptomatic arrhythmias.
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http://dx.doi.org/10.12659/AJCR.921092DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7038639PMC
February 2020

Relation Between New York Heart Association Functional Class and Objective Measures of Cardiopulmonary Exercise in Adults With Congenital Heart Disease.

Am J Cardiol 2019 06 15;123(11):1868-1873. Epub 2019 Mar 15.

Adult Congenital Heart Center, Memorial Healthcare System, Hollywood, Florida.

We aimed to compare New York Heart Association (NYHA) functional class in adult congenital heart disease (ACHD) patients with objectively measured cardiopulmonary exercise testing (CPET) parameters. This study included retrospective review of ACHD patients who underwent a CPET between August 2014 and April 2018 at our center. Patients were grouped according to severity of CHD, and NYHA class as recorded in their medical record or estimated from the clinical narrative. A total of 175 ACHD patients (mean age 30 ± 11 years) with NYHA class I-III enrolled in the study. The NYHA functional class was II or III in most complex CHD. There was a strong inverse relation between NYHA class and peak oxygen consumption, oxygen uptake efficiency slope, and the double product at peak exercise (product of heart rate and systolic blood pressure) (p<0.0001). There was no relation between NYHA class and ventilation efficiency slope (p = 0.37). In conclusion, NYHA functional class correlates with objective measures of CPET, however there is wide variability in measured exercise capacity in each NYHA classification. Therefore, whereas NYHA class of patients is a simple measure for assessment of functional status, CPET is an important tool to identify the source of exercise limitation in ACHD patients.
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http://dx.doi.org/10.1016/j.amjcard.2019.02.053DOI Listing
June 2019

What have we learned in the last 20 years? A comparison of a modern era pediatric and congenital catheter ablation registry to previous pediatric ablation registries.

Heart Rhythm 2019 01 14;16(1):57-63. Epub 2018 Aug 14.

Division of Pediatric Cardiology, Department of Pediatrics, Seattle Children's Hospital, University of Washington, Seattle, Washington.

Background: Since the onset of pediatric catheter ablation, the pediatric electrophysiology community has reported outcomes via various registries (PAPCA [Prospective Assessment After Pediatric Cardiac Ablation], PCAR [Pediatric Catheter Ablation Registry]). Most recently, a modern era pediatric and congenital ablation registry (MAP-IT [Multicenter Pediatric and Congenital EP Quality Initiative]) was developed for eventual incorporation into the National Cardiovascular Data Registry (NCDR) IMPACT (Improving Pediatric and Adult Congenital Treatment) registry.

Objective: The purpose of this study was to describe initial findings from the MAP-IT pilot registry and to compare these findings to earlier registries.

Methods: Before entering the NCDR IMPACT registry, MAP-IT was active at 12 centers (11 in the United States) between October 2014 and April 2016. All electrophysiological studies for patients younger than 21 years and for patients of all ages with structural congenital heart disease were included. We compared the acute success, fluoroscopy and procedural times, and frequency of complications between MAP-IT and the earlier registries.

Results: Acute success rates have improved from the initial PCAR registry for both accessory and slow pathway substrates. Both fluoroscopy and procedural times have significantly decreased across the time periods (fluoroscopy time 47.6 ± 40 minutes to 7.0 ± 9.2 minutes; P <.001; procedural time 257 ± 157 minutes to 166 ± 84 minutes; P <.001).

Conclusion: Acute success rates and fluoroscopy and procedural times in pediatric ablation all have improved over the last 25 years.
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http://dx.doi.org/10.1016/j.hrthm.2018.08.013DOI Listing
January 2019

A Case of Lown-Ganong-Levine Syndrome: Due to an Accessory Pathway of James Fibers or Enhanced Atrioventricular Nodal Conduction (EAVNC)?

Am J Case Rep 2018 Mar 18;19:309-313. Epub 2018 Mar 18.

Heart Institute, Joe DiMaggio Children's Hospital, Hollywood, FL, USA.

BACKGROUND Lown-Ganong-Levine syndrome, includes a short PR interval, normal QRS complex, and paroxysmal tachycardia. The pathophysiology of this syndrome includes an accessory pathway connecting the atria and the atrioventricular (AV) node (James fiber), or between the atria and the His bundle (Brechenmacher fiber). Similar features are seen in enhanced atrioventricular nodal conduction (EAVNC), with the underlying pathophysiology due to a fast pathway to the AV node, and with the diagnosis requiring specific electrophysiologic criteria. CASE REPORT A 17-year-old man presented with a history of recurrent narrow-complex and wide-complex tachycardia on electrocardiogram (ECG). An electrophysiologic study showed an unusually short atrial to His (AH) conduction interval and a normal His to ventricle (HV) interval, without a delta wave. Two stable AH intervals coexisted in the same atrial pacing cycle length. In the recovery curve study, this pathway had a flat conduction curve without an AH increase until the last 60 ms, before reaching the effective refractory period. These ECG changes did not respond to an adenosine challenge. When this pathway became intermittent, there was a paradoxical response to adenosine challenge with conduction via a short AH interval, but without conduction block. Catheter ablation of the AV nodal region resulted in a normalized AH interval, decremental conduction properties, and resulted in a positive response to an adenosine challenge. CONCLUSIONS In this case of Lown-Ganong-Levine syndrome, electrophysiologic studies supported the role of the accessory pathway of James fibers.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5873329PMC
http://dx.doi.org/10.12659/ajcr.906767DOI Listing
March 2018

The clinical and genetic spectrum of catecholaminergic polymorphic ventricular tachycardia: findings from an international multicentre registry.

Europace 2018 03;20(3):541-547

Departments of Pediatrics/Medicine/Biochemistry & Molecular Biology, University of British Columbia, 4480 Oak Street, Room 1F3, Vancouver, BC, V6H 3V4, Canada.

Aims: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an ion channelopathy characterized by ventricular arrhythmia during exertion or stress. Mutations in RYR2-coded Ryanodine Receptor-2 (RyR2) and CASQ2-coded Calsequestrin-2 (CASQ2) genes underlie CPVT1 and CPVT2, respectively. However, prognostic markers are scarce. We sought to better characterize the phenotypic and genotypic spectrum of CPVT, and utilize molecular modelling to help account for clinical phenotypes.

Methods And Results: This is a Pediatric and Congenital Electrophysiology Society multicentre, retrospective cohort study of CPVT patients diagnosed at <19 years of age and their first-degree relatives. Genetic testing was undertaken in 194 of 236 subjects (82%) during 3.5 (1.4-5.3) years of follow-up. The majority (60%) had RyR2-associated CPVT1. Variant locations were predicted based on a 3D structural model of RyR2. Specific residues appear to have key structural importance, supported by an association between cardiac arrest and mutations in the intersubunit interface of the N-terminus, and the S4-S5 linker and helices S5 and S6 of the RyR2 C-terminus. In approximately one quarter of symptomatic patients, cardiac events were precipitated by only normal wakeful activities.

Conclusion: This large, multicentre study identifies contemporary challenges related to the diagnosis and prognostication of CPVT patients. Structural modelling of RyR2 can improve our understanding severe CPVT phenotypes. Wakeful rest, rather than exertion, often precipitated life-threatening cardiac events.
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http://dx.doi.org/10.1093/europace/euw389DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6059141PMC
March 2018

Acquired and congenital coronary artery abnormalities.

Cardiol Young 2017 Jan;27(S1):S31-S35

1Heart Institute,Joe DiMaggio Children's Hospital,Hollywood,Florida,United States of America.

Sudden unexpected cardiac deaths in approximately 20% of young athletes are due to acquired or congenital coronary artery abnormalities. Kawasaki disease is the leading cause for acquired coronary artery abnormalities, which can cause late coronary artery sequelae including aneurysms, stenosis, and thrombosis, leading to myocardial ischaemia and ventricular fibrillation. Patients with anomalous left coronary artery from the pulmonary artery can develop adequate collateral circulation from the right coronary artery in the newborn period, which remains asymptomatic only to manifest in adulthood with myocardial ischaemia, ventricular arrhythmias, and sudden death. Anomalous origin of coronary artery from the opposite sinus occurs in 0.7% of the young general population aged between 11 and 15 years. If the anomalous coronary artery courses between the pulmonary artery and the aorta, sudden cardiac death may occur during or shortly after vigorous exercise, especially in patients where the anomalous left coronary artery originates from the right sinus of Valsalva. Symptomatic patients with evidence of ischaemia should have surgical correction. No treatment is needed for asymptomatic patients with an anomalous right coronary artery from the left sinus of Valsalva. At present, there is no consensus regarding how to manage asymptomatic patients with anomalous left coronary artery from the right sinus of Valsalva and interarterial course. Myocardial bridging is commonly observed in cardiac catheterisation and it rarely causes exercise-induced coronary syndrome or cardiac death. In symptomatic patients, refractory or β-blocker treatment and surgical un-bridging may be considered.
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http://dx.doi.org/10.1017/S1047951116002201DOI Listing
January 2017

High Output Cardiac Failure Resolving after Repair of AV Fistula in a Six-Month-Old.

Case Rep Vasc Med 2016 14;2016:8564081. Epub 2016 Jan 14.

University of Miami Miller School of Medicine, Department of Pediatrics, Miami, FL 33136, USA.

Background. Acquired AVF in pediatrics are commonly caused by iatrogenic means, including arterial or venous punctures. These fistulae can cause great hemodynamic stress on the heart as soon as they are created. Case. A six-month-old 25-week gestation infant was referred for respiratory distress. Initial exam revealed tachypnea, tachycardia, and hypertension. There was a bruit noted on her left arm. An ultrasound showed an arteriovenous fistula. Its location, however, precluded intervention because of the high risk for limb-loss. An echocardiogram showed evidence of pulmonary hypertension that was treated with sildenafil and furosemide. However, no improvement was seen. On temporary manual occlusion of the fistula, the patient was noted to have increased her blood pressure and decreased her heart rate, suggesting significant hemodynamic effect of the fistula. The fistula was subsequently ligated and the patient clinically and echocardiographically improved. Conclusion. A patient in high output cardiac failure or pulmonary artery hypertension, especially prematüre patients with preexisting lung disease, should be probed for history of multiple punctures, trauma, or surgery and should have prompt evaluation for AVF. If it can be diagnosed and repaired, most of the cases have been shown to decrease the stress on the heart and reverse the pathologic hemodynamics.
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http://dx.doi.org/10.1155/2016/8564081DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4738936PMC
February 2016

Catecholaminergic polymorphic ventricular tachycardia in children: analysis of therapeutic strategies and outcomes from an international multicenter registry.

Circ Arrhythm Electrophysiol 2015 Jun 24;8(3):633-42. Epub 2015 Feb 24.

Background: Catecholaminergic polymorphic ventricular tachycardia is an uncommon, potentially lethal, ion channelopathy. Standard therapies have high failure rates and little is known about treatment in children. Newer options such as flecainide and left cardiac sympathetic denervation are not well validated. We sought to define treatment outcomes in children with catecholaminergic polymorphic ventricular tachycardia.

Methods And Results: This is a Pediatric and Congenital Electrophysiology Society multicenter, retrospective cohort study of catecholaminergic polymorphic ventricular tachycardia patients diagnosed before 19 years of age. The cohort included 226 patients, including 170 probands and 56 relatives. Symptomatic presentation was reported in 176 (78%). Symptom onset occurred at 10.8 (interquartile range, 6.8-13.2) years with a delay to diagnosis of 0.5 (0-2.6) years. Syncope (P<0.001), cardiac arrest (P<0.001), and treatment failure (P=0.008) occurred more often in probands. β-Blockers were prescribed in 205 of 211 patients (97%) on medication, and 25% experienced at least 1 treatment failure event. Implantable cardioverter defibrillators were placed in 121 (54%) and was associated with electrical storm in 22 (18%). Flecainide was used in 24% and left cardiac sympathetic denervation in 8%. Six deaths (3%) occurred during a cumulative follow-up of 788 patient-years.

Conclusions: This study demonstrates a malignant phenotype and lengthy delay to diagnosis in catecholaminergic polymorphic ventricular tachycardia. Probands were typically severely affected. β-Blockers were almost universally initiated; however, treatment failure, noncompliance and subtherapeutic dosing were often reported. Implantable cardioverter defibrillators were common despite numerous device-related complications. Treatment failure was rare in the quarter of patients on flecainide. Left cardiac sympathetic denervation was not uncommon although the indication was variable.
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http://dx.doi.org/10.1161/CIRCEP.114.002217DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4472494PMC
June 2015

Long-term follow-up of a pediatric cohort with short QT syndrome.

J Am Coll Cardiol 2013 Mar 30;61(11):1183-91. Epub 2013 Jan 30.

Department of Pediatrics (Cardiology), University of Kentucky, Lexington, KY 40202, USA.

Objectives: The purpose of this study was to define the clinical characteristics and long-term follow-up of pediatric patients with short QT syndrome (SQTS).

Background: SQTS is associated with sudden cardiac death. The clinical characteristics and long-term prognosis in young patients have not been reported.

Methods: This was an international case series involving 15 centers. Patients were analyzed for electrocardiography characteristics, genotype, clinical events, Gollob score, and efficacy of medical or defibrillator (implantable cardioverter-defibrillator [ICD]) therapy. To assess the possible prognostic value of the Gollob score, we devised a modified Gollob score that excluded clinical events from the original score.

Results: Twenty-five patients 21 years of age or younger (84% males, median age: 15 years, interquartile range: 9 to 18 years) were followed up for 5.9 years (interquartile range: 4 to 7.1 years). Median corrected QT interval for heart rate was 312 ms (range: 194 to 355 ms). Symptoms occurred in 14 (56%) of 25 patients and included aborted sudden cardiac death in 6 patients (24%) and syncope in 4 patients (16%). Arrhythmias were common and included atrial fibrillation (n = 4), ventricular fibrillation (n = 6), supraventricular tachycardia (n = 1), and polymorphic ventricular tachycardia (n = 1). Sixteen patients (84%) had a familial or personal history of cardiac arrest. A gene mutation associated with SQTS was identified in 5 (24%) of 21 probands. Symptomatic patients had a higher median modified Gollob score (excluding points for clinical events) compared with asymptomatic patients (5 vs. 4, p = 0.044). Ten patients received medical treatment, mainly with quinidine. Eleven of 25 index cases underwent ICD implantation. Two patients had appropriate ICD shocks. Inappropriate ICD shocks were observed in 64% of patients.

Conclusions: SQTS is associated with aborted sudden cardiac death among the pediatric population. Asymptomatic patients with a Gollob score of <5 remained event free, except for an isolated episode of supraventricular tachycardia, over an average 6-year follow-up. A higher modified Gollob score of 5 or more was associated with the likelihood of clinical events. Young SQTS patients have a high rate of inappropriate ICD shocks.
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http://dx.doi.org/10.1016/j.jacc.2012.12.025DOI Listing
March 2013

Dysfunctional potassium channel subunit interaction as a novel mechanism of long QT syndrome.

Heart Rhythm 2013 May 2;10(5):728-37. Epub 2013 Jan 2.

Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida 33101, USA.

Background: The slowly-activating delayed rectifier current IKs contributes to repolarization of the cardiac action potential, and is composed of a pore-forming α-subunit, KCNQ1, and a modulatory β-subunit, KCNE1. Mutations in either subunit can cause long QT syndrome, a potentially fatal arrhythmic disorder. How KCNE1 exerts its extensive control over the kinetics of IKs remains unresolved

Objective: To evaluate the impact of a novel KCNQ1 mutation on IKs channel gating and kinetics

Methods: KCNQ1 mutations were expressed in Xenopus oocytes in the presence and absence of KCNE1. Voltage clamping and MODELLER software were used to characterize and model channel function. Mutant and wt genes were cloned into FLAG, Myc and HA expression vectors to achieve differential epitope tagging, and expressed in HEK293 cells for immunohistochemical localization and surface biotinylation assay.

Results: We identified 2 adjacent mutations, S338F and F339S, in the KCNQ1 S6 domain in unrelated probands. The novel KCNQ1 S338F mutation segregated with prolonged QT interval and torsade de pointes; the second variant, F339S, was associated with fetal bradycardia and prolonged QT interval, but no other clinical events. S338F channels expressed in Xenopus oocytes had slightly increased peak conductance relative to wild type, with a more positive activation voltage. F339S channels conducted minimal current. Unexpectedly, S338F currents were abolished by co-expression with intact WT KCNE1 or its C-terminus (aa63-129), despite normal membrane trafficking and surface co-localization of KCNQ1 S338F and wt KCNE1. Structural modeling indicated that the S338F mutation specifically alters the interaction between the S6 domain of one KCNQ1 subunit and the S4-S5 linker of another, inhibiting voltage-induced movement synergistically with KCNE1 binding.

Conclusions: A novel KCNQ1 mutation specifically impaired channel function in the presence of KCNE1. Our structural model shows that this mutation effectively immobilizes voltage gating by an inhibitory interaction that is additive with that of KCNE1. Our findings illuminate a previously unreported mechanism for LQTS, and validate recent theoretical models of the closed state of the KCNQ1:KCNE1 complex.
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http://dx.doi.org/10.1016/j.hrthm.2012.12.033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4770260PMC
May 2013

Low recurrence rate in treating atrioventricular nodal reentrant tachycardia with triple freeze-thaw cycles.

Pacing Clin Electrophysiol 2013 Mar 14;36(3):279-85. Epub 2012 Sep 14.

Department of Pediatrics, Division of Pediatric Cardiology, University of Miami, Miami, Florida.

Background: Cryoablation is an alternative to radiofrequency ablation in treating atrioventricular nodal reentrant tachycardia (AVNRT). However, its long-term effectiveness is in question when compared to radiofrequency ablation. We reviewed the results of cryoablation in children with AVNRT at our institute.

Methods: We performed a retrospective single-center chart review of consecutive patients ≤18 years of age with AVNRT who underwent cryoablation between January 2007 and August 2009. During cryoablation, a 6-mm-tip cryocatheter was used with temperature set to -80°C. Test lesions were performed at the presumed slow pathway location based on combined anatomic and electrophysiologic approach. If successful, ablation was then continued with triple freeze-thaw cycles (FTC) of 4 minutes each.

Results: A total of 53 patients (age range: 6.1-18.4 years, mean: 13.6 years, median: 13.2 years) underwent slow pathway modification with cryoablation. Acute success was achieved in 51 (96.2%) cases. Transient atrioventricular block was seen in 19 cases. The block occurred during FTC in eight patients (15%). The number of FTC was three in 47 (92.2%) patients. Less than three FTC were given in two patients due to transient heart block and four FTC were given in two patients with suspected catheter movement. Procedure duration was 177 ± 56 minutes; fluoroscopic time was 14 ± 11 minutes. Mean follow-up was 30.7 ± 10 (range 12-52, median 31) months. Recurrence of supraventricular tachycardia was seen in only one (1.96%) patient.

Conclusions: Triple FTC cryoablation lesions resulted in a low recurrence rate comparable to RF ablation in treating AVNRT without increased complications.
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http://dx.doi.org/10.1111/j.1540-8159.2012.03514.xDOI Listing
March 2013

Quality of life and psychosocial functioning of children with cardiac arrhythmias.

Cardiol Young 2013 Feb 18;23(1):82-8. Epub 2012 Apr 18.

Department of Pediatrics, Division of Clinical Psychology, University of Miami, Miami, FL 33101, USA.

Childhood cardiac arrhythmias may have a long-lasting impact on a family and typically require long-term medical follow-up. Whereas some arrhythmias are benign, others can be life threatening and require significant medical care. As with many chronic illnesses, it is important to study the potential psychosocial effects of childhood arrhythmias and how they may impact a child's quality of life. The purpose of this study was to create a quality of life measure specific to childhood arrhythmias and to describe the current psychosocial functioning of this population. A total of 46 families participated in a one-time paper and pencil assessment during their regularly scheduled clinic visits. Results indicated promise for the validity and reliability of this new measure. Children in the current sample also demonstrated a high degree of resiliency. Additional analyses with larger samples will be needed to verify the psychometric properties of this measure. Overall, the high functioning of many of these children despite medical trauma is promising. Future studies should consider using some screening measures to decide which children may be most in need of intervention.
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http://dx.doi.org/10.1017/S1047951112000388DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4155402PMC
February 2013

Congenital long QT 3 in the pediatric population.

Am J Cardiol 2012 May 21;109(10):1459-65. Epub 2012 Feb 21.

Department of Pediatrics, Steven and Alexandra Cohen Children's Medical Center of New York, New Hyde Park, USA.

There is insufficient knowledge concerning long-QT (LQT) 3 in the pediatric population to determine whether recommendations for more aggressive therapy in these patients are appropriate. An international multicenter review of 43 children with cardiac sodium channel (SCN5A) mutations and clinical manifestations of LQT syndrome without overlap of other SCN5A syndromes was undertaken to describe the clinical characteristics of LQT3 in children. Patients were aged 7.6 ± 5.9 years at presentation and were followed for 4.7 ± 3.9 years. There was significant intrasubject corrected QT interval (QTc) variability on serial electrocardiography. Forty-two percent presented with severe symptoms or arrhythmia and exhibited longer QTc intervals compared to asymptomatic patients. None of the 14 patients who underwent primary prevention implantable cardioverter-defibrillator (ICD) implantation received appropriate shocks in 41 patient-years of follow-up, while 2 of 6 patients who underwent secondary prevention ICD implantation received appropriate shocks in 30 patient-years of follow-up. Half of patients who underwent ICD implantation experienced inappropriate shocks or ICD-related complications. Mexiletine significantly shortened the QTc interval, and QTc shortening was greater in patients with longer pretreated QTc intervals. Two ICD patients with frequent appropriate ICD shocks showed immediate clinical improvement, with elimination of appropriate ICD shocks after mexiletine loading. In conclusion, severe symptoms are common in children with LQT3 and are associated with longer QTc intervals. ICD implantation is associated with significant morbidity. Mexiletine shortens the QTc interval, and it may be beneficial.
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http://dx.doi.org/10.1016/j.amjcard.2012.01.361DOI Listing
May 2012

Safety and results of cryoablation in patients <5 years old and/or <15 kilograms.

Am J Cardiol 2011 Aug 31;108(4):565-71. Epub 2011 May 31.

University of Michigan, Ann Arbor, Michigan, USA.

Current recommendations discourage elective radiofrequency ablation in patients <5 years old and/or weighing <15 kg, primarily because of the greater complication rate. To describe the current use, complications, and immediate outcomes of cryoablation in this patient population, a multicenter retrospective review of all patients <5 years old and/or weighing <15 kg who were treated with cryoablation for arrhythmia was performed. Eleven centers contributed data for 68 procedures on 61 patients. Of those, 34% were elective and 24% (n = 16) were both cryoablation and radiofrequency ablation. The median age and weight at ablation was 3.5 years (range 8 days to 9.9 years) and 15.2 kg (range 2.3 to 23), respectively. Congenital heart disease was present in 23% of the patients. The immediate success rate of cryoablation alone was 74%. No major complications occurred with cryoablation only; however, 2 of the 16 patients who underwent cryoablation and radiofrequency ablation had major complications. Of the 50 patients receiving cryoablation, 8 (16%) had variable degrees of transient atrioventricular block. The recurrence rate was 20% after cryoablation and 30% after cryoablation plus radiofrequency ablation. In conclusion, cryoablation appears to have a high safety profile in these patients. Compared to older and larger patients, the efficacy of cryoablation in this small, young population was lower and the recurrence rates were higher. Cryoablation's effect on the coronary arteries has not been fully elucidated and requires additional research.
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http://dx.doi.org/10.1016/j.amjcard.2011.03.089DOI Listing
August 2011

Focal atrial tachycardia originating from the donor superior vena cava after bicaval orthotopic heart transplantation.

Pacing Clin Electrophysiol 2010 Aug 5;33(8):e68-71. Epub 2010 Mar 5.

Departments of Pediatrics, Mackay Memorial Hospital and Mackay Medicine, Nursing and Management College, Taipei, Taiwan.

An 11-year-old boy, who underwent bicaval orthotopic heart transplantation for idiopathic dilated cardiomyopathy, had a focal atrial tachycardia originating from the donor superior vena cava. The pathogenesis of this tachycardia may be related to transplant rejection or transplant vasculopathy. Radiofrequency catheter ablation can eliminate this unique tachycardia and result in hemodynamic improvement.
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http://dx.doi.org/10.1111/j.1540-8159.2010.02711.xDOI Listing
August 2010

Short QT syndrome in a pediatric patient.

Pediatr Cardiol 2009 Aug 14;30(6):846-50. Epub 2009 Apr 14.

Children's Heart Specialists, Louisville, KY, USA.

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.
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http://dx.doi.org/10.1007/s00246-009-9439-9DOI Listing
August 2009

The most common site of success and its predictors in radiofrequency catheter ablation of the slow atrioventricular nodal pathway in children.

Pacing Clin Electrophysiol 2008 Oct;31(10):1300-6

Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan.

Background: Locating ablation targets on the slow pathway in children as one would in adults may not accommodate the dimensional changes of Koch's triangle that occur with heart growth. We investigated the most common site of success and the effect of a variety of variables on the outcome of slow pathway ablation in children.

Methods: A total of 116 patients (ages 4-16 years) with structurally normal hearts underwent radiofrequency ablation of either the antegrade or the retrograde slow pathway. Ablation sites were divided into eight regions (A1, A2, M1, M2, P1, P2, CS1, and CS2) at the septal tricuspid annulus.

Results: Ablation was successful in 112 (97%) children. The most common successful ablation sites were at the P1 region. The less the patient weighed, the more posteriorly the successful site was located (P = 0.023, OR 0.970, 95% CI 0.946-0.996), and the more likely the slow pathway was eliminated rather than modified: median weight was 46.7 kg (range, 14.5-94.3 kg) in the eliminated group and 56.5 kg (range, 20-82.6 kg) in the modified group (P = 0.021, OR 1.039, 95% CI 1.006-1.073).

Conclusions: The most common site of success for slow pathway ablation in children is at the P1 region of the tricuspid annulus. The successful sites in lighter children are more posteriorly located. Weight is also a predictor of whether the slow pathway is eliminated or only modified.
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http://dx.doi.org/10.1111/j.1540-8159.2008.01181.xDOI Listing
October 2008

New techniques of mapping and ablation for tachyarrhythmias in children.

Authors:
Ming-Lon Young

Future Cardiol 2008 May;4(3):321-31

Pediatric Cardiac Electrophysiology, Division of Pediatric Cardiology, University of Miami, PO Box 016960, R-76, Miami, FL 33101, USA.

Advancement in mapping and ablation technologies in the past decade has made arrhythmia treatment in children safer and more effective. Electroanatomical mapping systems with features of nonfluoroscopic navigation, 3D-geometry construction and color-coded arrhythmia mapping have been extensively used to map and ablate tachycardias in children. In addition, a variety of cooled radiofrequency ablation systems have been used in selected patients to create larger and deeper lesions. Cryoenergy ablation, with its reversible nature of tissue injury during the cooling phase, is emerging as the energy of choice for ablating perinodal arrhythmias to minimize the risk of inadvertent conduction block. Other evolving ablation systems, including cryoballoon, high-intensity focused ultrasound balloon and a hybrid catheter capable of delivering both radiofrequency and cryoenergy, are also under investigation. Finally, a remote navigation system that minimizes radiation exposure and will enable physicians of all skill levels to reach difficult target sites in children is on the horizon.
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http://dx.doi.org/10.2217/14796678.4.3.321DOI Listing
May 2008

Pharmacological therapy in children with atrioventricular reentry: which drug?

Curr Pharm Des 2008 ;14(8):753-61

Division of Pediatric Cardiology, University of Miami/ Miller School of Medicine, PO Box 016960 (R-76), Miami, FL 33101, USA.

Atrioventricular reentrant tachycardia (AVRT) is the most common cause of supraventricular tachycardia in young children. In nearly 70% of cases, there is manifest preexcitation on electrocardiogram. In the rest, the accessory pathway is concealed. Drugs control AVRT by affecting conduction through the atrioventricular node (beta-blockers, digoxin, verapamil) or accessory pathway (flecainide, propafenone) or both (sotalol, amiodarone). Adenosine is the drug of choice in acute management of AVRT in hemodynamically stable children. In adenosine-resistant cases, intravenous flecainide, procainamide, esmolol, propafenone and amiodarone are other treatment options. Hypotension and bradycardia can occur during administration of these drugs. Verapamil may be used to treat AVRT using a concealed pathway. Verapamil should be avoided in infants and in patients with decreased cardiac function. In chronic management, catheter ablation is the preferred treatment in older children with frequent AVRT. In infants and small children, ablation is associated with higher risk, and pharmacologic management is recommended. Beta-blockers are the preferred first line drugs for chronic management. In patients with concealed accessory pathway, digoxin and calcium channel blockers are alternative options. Sotalol, flecainide, propafenone and amiodarone can be prescribed in resistant cases. Flecainide and propafenone should be avoided in children with structurally abnormal hearts because of a higher risk of proarrhythmia. The initiation of flecainide, propafenone and sotalol therapy is recommended in an inpatient setting to monitor for proarrhythmias.
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http://dx.doi.org/10.2174/138161208784007644DOI Listing
June 2008

Clinical and electrophysiological characteristics of fasciculoventricular fibers in children.

Int J Cardiol 2008 Jan 26;123(3):257-62. Epub 2007 Mar 26.

Department of Pediatric Cardiology, University of Miami-Miller School of Medicine, Miami, FL 33101, USA.

Introduction: Fasciculoventricular (FV) fiber is a rare cause for ventricular preexcitation. It is usually described as an innocent bystander pathway. There is only limited data on FV fiber in children. Hence we evaluated the clinical and electrophysiological features of FV fiber in a group of 11 children.

Methods And Results: Of 215 children with manifest preexcitation who had electrophysiological studies at the University of Miami, 11 (5.1%) had characteristics of FV fiber. FV fiber was not directly responsible for any arrhythmias in these children. Three children had supraventricular tachycardia due to associated left sided Kent fiber and FV fiber was identified after the ablation of Kent fiber. One child had associated hypertrophic cardiomyopathy, another child had atrial septal defect and a third child had ventricular septal defect. The electrophysiological testing of FV fiber revealed AH interval of 40-95 ms and H-delta interval of 15-40 ms. Mapping study showed that the FV fiber was located on the right side of the heart in all patients: right anteroseptal in 9, right midseptal in 1 and it could not be mapped well in 1 as the delta wave was intermittent. We identified a discrete FV fiber depolarization spike in 9 patients, with a local FV fiber depolarization to delta wave interval of 5-20 ms (11+4 ms).

Conclusion: FV fiber is an uncommon cause for ventricular preexcitation in children and it can be associated with other conduction abnormalities and heart defects. FV fibers are commonly located at the right anteroseptal region and are not usually involved in any tachycardia. Discrete local FV fiber potential can be identified during electrophysiological testing of these patients.
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http://dx.doi.org/10.1016/j.ijcard.2006.12.006DOI Listing
January 2008

Carvedilol in children with cardiomyopathy: 3-year experience at a single institution.

J Heart Lung Transplant 2004 Jul;23(7):832-8

Department of Pediatrics, University of Miami School of Medicine, Miami, Florida 33101, USA.

Background: Carvedilol reduces mortality and hospitalization in adults with congestive heart failure. Limited information is available about its use in children.

Methods: We reviewed the medical records of 24 children with dilated cardiomyopathy and left ventricular ejection fraction of
Results: Carvedilol was initiated 14.3 +/- 23.3 (mean +/- SD) months after the diagnosis of cardiomyopathy. Mean age at initiation of therapy was 7.2 +/- 6.4 years. The mean initial and maximum doses were 0.15 +/- 0.09 and 0.98 +/- 0.26 mg/kg/day. Adverse effects occurred in 5 patients (21%). Two patients (8%) required discontinuation of the drug within 5 weeks of the initial dose. The remaining 22 patients tolerated carvedilol for a mean follow-up period of 26.6 +/- 14.7 months. Among these 22 patients, mean left ventricular ejection fraction improved from 24.6 +/- 7.6% to 42.2 +/- 14.2% (p < 0.001), and mean sphericity index from 0.86 +/- 0.11 to 0.74 +/- 0.10 (p < 0.001). New York Heart Association functional class improved in 15 patients (68%). One patient (4%) died and 3 (14%) were transplanted.

Conclusions: Carvedilol, in addition to standard therapy for dilated cardiomyopathy in children improves cardiac function and symptoms; it is well tolerated, with minimal adverse effects, but close monitoring is necessary as it might worsen congestive heart failure and precipitate asthma. Control studies are necessary to assess the effect of carvedilol on mortality and hospitalization rates.
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http://dx.doi.org/10.1016/j.healun.2003.07.025DOI Listing
July 2004

Effects of a blocked atrial beat on the atrioventricular nodal recovery property in patients with dual nodal pathways.

Pacing Clin Electrophysiol 2003 Nov;26(11):2091-5

Taipei Veterans General Hospital and National Yang-Ming University, Taiwan.

Dual AVN physiology can be demonstrated by a variety of maneuvers. To determine whether AVN recovery times following a blocked extrastimulus facilitate or obscure detection of dual AVN physiology, 11 patients (9-17 years) were studied with dual AVN pathways by using single and double atrial extrastimuli. With a single atrial extrastimuli, the premature atrial stimulus (A2) was coupled to basic atrial beats (A1). The fast and slow AVN recovery curves were constructed with plots of the nodal conduction time against the recovery time (A1A2,A2H2). With double atrial extrastimuli, a fixed blocked A2 beat (A2B) was followed by a scanning atrial beat (A3). The nodal recovery property post-A2B was studied by plots of A2BA3,A3H3. In all patients the recovery curve of the fast pathway post-A2B had a leftward shift when compared to that of the pre-A2B curve (i.e., the AH was shortened at the same recovery time). The window of slow pathway conduction post-A2B disappeared totally in five patients and decreased significantly in six patients (post-A2B: 26 +/- 42 ms; pre-A2B: 80 +/- 65 ms, P < 0.05). In the six patients that still had slow pathway conduction post-A2B, the slow pathway effective refractory period post-A2B was significantly less than that of pre-A2B (215 +/- 38 vs 268 +/- 16 ms, P < 0.05). The fast pathway effective refractory period post-A2B was also diminished significantly (235 +/- 62 vs 357 +/- 76 ms, P < 0.0001). The authors conclude that blocked atrial beats decrease the visibility of the slow pathway conduction.
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http://dx.doi.org/10.1046/j.1460-9592.2003.00325.xDOI Listing
November 2003

Rate dependent bundle branch block induced by hyperkalemia.

Pacing Clin Electrophysiol 2003 Sep;26(9):1909-10

Department of Pediatrics, University of Miami, Florida, USA.

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http://dx.doi.org/10.1046/j.1460-9592.2003.00291.xDOI Listing
September 2003

Multiple accessory pathways in pediatric patients with Wolff-Parkinson-White syndrome.

Am J Cardiol 2003 May;91(10):1178-83

Department of Pediatrics, University of Miami, Florida 33101, USA.

The characteristics of multiple accessory pathways in children have not been previously studied. Records were reviewed of 317 consecutive pediatric patients with Wolff-Parkinson-White syndrome who underwent electrophysiologic study and radiofrequency catheter ablation at our institution. Twenty-eight patients (9%) had multiple pathways (a total of 64 pathways: 21 patients had 2, 6 had 3, and 1 patient had 4 pathways). The locations were left free wall (22 pathways), right free wall (19 pathways), posteroseptal (17 pathways), and anteromidseptal (6 pathways). Of these 64 pathways, 55 were ablated successfully without complications, 5 failed ablation, and 4 fasciculoventricular fibers did not require treatment. Three patients had a newly found pathway at the repeat session. Three patients had atrioventricular nodal reentrant tachycardia and the slow pathway area was modified. One patient had failed initial ablation and had a successful ablation using a 3-dimensional electroanatomic mapping system. Compared with patients with a single pathway, those with multiple pathways exhibited a higher incidence of antidromic tachycardia, a shorter anterograde accessory pathway effective refractory period (<250 ms), a longer fluoroscopic time (65 +/- 43 vs 39 +/- 46 minutes, p <0.05), and a larger number of unsuccessful attempts (9 +/- 16 vs 5 +/- 8, p <0.05). Success rate (92% vs 93%) and recurrence rate (1.7% vs 2.1%) were similar in both groups. This study demonstrates that multiple pathways are not rare in pediatric patients and that multiple pathways contrast with a single pathway in a variety of conduction properties.
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http://dx.doi.org/10.1016/s0002-9149(03)00263-7DOI Listing
May 2003

MR evaluation of arrhythmogenic right ventricular cardiomyopathy in pediatric patients.

AJR Am J Roentgenol 2003 Apr;180(4):1135-41

Department of Radiology, University of Miami School of Medicine, Jackson Memorial Hospital, WW279, 1611 N.W. 12th Ave., Miami, FL 33136, USA.

Objective: The aim of our study was to correlate the findings of three MR imaging sequences with the clinical findings of possible arrhythmogenic right ventricular cardiomyopathy in pediatric patients.

Materials And Methods: Twenty-six consecutive pediatric patients underwent MR imaging with ECG-gated non-breath-hold spin-echo T1-weighted non-fat-suppressed and fat-suppressed sequences. The MR images were evaluated for thinning or fat signal in the right ventricular wall and for enlargement or increased trabeculation of the right ventricle or right ventricular outflow tract. Cine MR imaging was used to assess wall motion abnormalities. Cardiac biopsy was performed in 17 patients. Biopsy results and other clinical findings suggesting arrhythmogenic right ventricular cardiomyopathy were tabulated.

Results: Two MR imaging studies were of poor quality as a result of arrhythmias, and one study was incomplete. In the 23 remaining patients, there were (mean +/- SD) 1.5 +/- 1.0 and 0.8 +/- 1.0 findings of possible arrhythmogenic right ventricular cardiomyopathy in the non-fat-suppressed and the fat-suppressed sequences, respectively. Fat-compatible signal in the myocardium was detected in 16 (70%) of 23 non-fat-suppressed studies and in five (22%) of 23 fat-suppressed studies (p = 0.003). The non-fat-suppressed sequence had a higher sensitivity (75% vs 43%) and a lower specificity (38% vs 75%) for fatty infiltration than did the fat-suppressed sequence when correlated with the biopsies. The linear correlation between all MR findings and all clinical diagnostic criteria, including biopsy, was better for the combination of cine and both T1 sequences (r = 0.58) than for the non-fat-suppressed (r = 0.53) or fat-suppressed (r = 0.46) T1 sequences alone.

Conclusion: MR imaging showed moderate correlation with the clinical criteria in the diagnosis of arrhythmogenic right ventricular cardiomyopathy.
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http://dx.doi.org/10.2214/ajr.180.4.1801135DOI Listing
April 2003