Kathryn K Collins

Boston Children's Hospital, Boston, MA, USA

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Publications (49)157.55 Total impact

  • Article: Fascicular and Nonfascicular Left Ventricular Tachycardias in the Young: An International Multicenter Study.
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    ABSTRACT: INTRODUCTION: The aim of this study was to evaluate the clinical presentation and outcomes of pediatric patients with ventricular tachycardia (VT) originating from left heart structures. METHODS AND RESULTS: This international multicenter retrospective study including 152 patients (age 10.0 ± 5.1 years, 62% male), divided into those with fascicular VT (85%, 129/152) and nonfascicular LV VT (15%, 23/152). All patients had a normal heart structure or only a minor cardiac abnormality. Adenosine was largely ineffective in both groups (tachycardia termination in 4/74 of fascicular VT and 0/5 of nonfascicular LV VT). In fascicular VT, calcium channel blockers were effective in 80% (74/92); however, when administered orally, there was a 21% (13/62) recurrence rate. In nonfascicular LV VT, a variety of antiarrhythmic therapies were used with no one predominating. Ablation procedures were successful in 71% (72/102) of fascicular VT and 67% (12/18) of nonfascicular LV VT on an intention to treat analysis. Major complications occurred in 5 patients with fascicular VT and 1 patient with nonfascicular LV VT. After a follow-up period of 2 years (1 day to 15 years), 72% of all patients with fascicular VT were off medications with no tachycardia recurrence. One patient died of noncardiac causes. In nonfascicular LV VT, follow-up was 3.5 years (0.5-15 years), P = 0.38. A total of 65% of these patients were free from arrhythmias. Two patients died suddenly (P < 0.01). CONCLUSION: The clinical course and outcomes of pediatric patients with fascicular VT and nonfascicular LV VT are varied. Catheter ablation procedures can be curative.
    Journal of Cardiovascular Electrophysiology 01/2013; · 3.06 Impact Factor
  • Article: Cryoablation for Presumed Atrioventricular Nodal Reentrant Tachycardia in Pediatric Patients.
    Mario Villasenor, Michael S Schaffer, Kathryn K Collins
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    ABSTRACT: Background: Little data exist on the outcomes of cryoablation for the treatment of presumptive atrioventricular nodal reentrant tachycardia (AVNRT) in a pediatric population. Methods: We performed a retrospective chart review of patients undergoing cryoablation from January 2006 to October 2010 for presumed AVNRT at the Children's Hospital Colorado. Inclusion criteria were age ≤ 18, normal heart structure, no prior ablation procedures, documented narrow complex tachycardia, and no inducible tachycardia or other tachycardia mechanisms during electrophysiology study. Results: Thirteen patients underwent cryoablation for presumed AVNRT. Cryoablation catheter tip size varied from 4 to 8 mm with a median of eight cryoablation lesions. Isoproterenol was utilized preablation in 54% and none postablation. Procedural endpoints, per written report, were loss of sustained slow pathway, change in Wenckebach cycle length, and no specific endpoint. Procedural endpoints, per measured data, were a decrease in patients exhibiting sustained slow pathway conduction. Maximum atrial-His (AH) interval with atrial overdrive pacing was reduced from 266 ms preablation to 167 ms postablation, p = 0.006. The number of patients with an AH jump was reduced from 6 to 2. After follow-up of 13.8 ± 14.3 months, 23% (3/13) had documented tachycardia recurrence. No statistical significance was determined when comparing electrophysiology testing parameters pre- and postablation among the group with recurrence versus the group without recurrence. Conclusions: Cryoablation can be considered as a safe alternative to radiofrequency ablation for the treatment of presumed AVNRT among pediatric patients, albeit with a recurrence rate of 23%. (PACE 2011;00:1-7).
    Pacing and Clinical Electrophysiology 09/2012; · 1.35 Impact Factor
  • Article: Follow-up of a modified Fontan randomized trial for intraatrial reentrant tachycardia prophylaxis.
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    ABSTRACT:   Atrial arrhythmias represent significant morbidity and risk for mortality in Fontan patients. In a randomized trial involving patients undergoing a lateral tunnel Fontan between 1999 and 2001, Collins et al. investigated the safety and efficacy of a surgical atrial incision aimed at decreasing the incidence of intraatrial reentrant tachycardia (IART). The purpose of this study was to report the late follow-up of the aforementioned trial.   All surviving patients previously enrolled in the randomized trial were eligible for this follow-up study. Patients' legal guardians were contacted for informed consent and data were obtained form a retrospective chart review.   Of the 39 eligible patients, 29 were recruited: 15 in the intervention and 14 in the control groups. The median follow was 9.0 (1.2) years for the intervention group and 9.3 (1.1) years for the control group (P= .86). At most recent follow-up, there was no statistically significant difference in the demographic, echocardiographic, and electrophysiological data between the two groups. There was no late incidence of the primary outcome, IART. There were nine cases of late-onset sinus node dysfunction (SND): 5/15 in the intervention and 4/14 in the control groups (P= .99). There was only one late pacemaker implantation for early post-op SND.   At late follow-up 9 years post-Fontan, IART had not occurred in either group. There was no evidence of late-onset complications related to the interventional atrial incision. Further follow-up is warranted for this cohort.
    Congenital Heart Disease 05/2012; 7(3):219-25. · 0.90 Impact Factor
  • Article: Effectiveness of sotalol as first-line therapy for fetal supraventricular tachyarrhythmias.
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    ABSTRACT: Fetal supraventricular tachycardia (SVT) and atrial flutter (AF) can be associated with significant morbidity and mortality. Digoxin is often used as first-line therapy but can be ineffective and is poorly transferred to the fetus in the presence of fetal hydrops. As an alternative to digoxin monotherapy, we have been using sotalol at presentation in fetuses with SVT or AF with, or at risk of, developing hydrops to attempt to achieve more rapid control of the arrhythmia. The present study was a retrospective review of the clinical, echocardiographic, and electrocardiographic data from all pregnancies with fetal tachycardia diagnosed and managed at a single center from 2004 to 2008. Of 29 affected pregnancies, 21 (16 SVT and 5 AF) were treated with sotalol at presentation, with or without concurrent administration of digoxin. Of the 21, 11 (6 SVT and 5 AF) had resolution of the tachycardia within 5 days (median 1). Six others showed some response (less frequent tachycardia, rate slowing, resolution of hydrops) without complete conversion. In 1 fetus with a slow response, the mother chose pregnancy termination. The 5 survivors with a slow response were all difficult to treat postnatally, including 1 requiring radiofrequency ablation as a neonate. One fetus developed blocked atrial extrasystoles after 1 dose of sotalol and was prematurely delivered for fetal bradycardia. Three grossly hydropic fetuses with SVT showed no response and died within 1 to 3 days of treatment. In conclusion, transplacental sotalol, alone or combined with digoxin, is effective for the treatment of fetal SVT and AF, with an 85% complete or partial response rate in our series.
    The American journal of cardiology 03/2012; 109(11):1614-8. · 3.58 Impact Factor
  • Article: Clinical and electrophysiologic characteristics of antidromic tachycardia in children with Wolff-Parkinson-White syndrome.
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    ABSTRACT: Antidromic reciprocating tachycardia (ART) is a rare form of wide complex tachycardia in children with Wolff-Parkinson-White syndrome (WPW). The incidence and electrophysiologic characteristics of ART in children with WPW have not been well described. A multicenter retrospective analysis of all patients with WPW undergoing electrophysiology (EP) study from 1990 to 2009 was performed. Patients with clinical or inducible ART were included. A total of 1,147 patients with WPW underwent EP study and 30 patients had ART (2.6%) and were the subject of this analysis. The mean age was 16±3 years, weight was 65±16 kg, and tachycardia cycle length was 305±55 ms. There were two patients (7%) with congenital heart disease (both with Ebstein's anomaly). Four patients (13%) had more than one accessory pathway (AP). The location of the AP was left sided in 53% of patients and right sided in 47%, with septal location and left lateral pathways most commonly involved. AP conduction was found to be high risk in 17 patients (57%). Ablation was not attempted in two patients (7%) due to proximity to the HIS and risk of heart block. Ablation was acutely successful in 93% of the patients in whom it was attempted. ART is a rare finding in children undergoing EP study. Over half of the patients with ART were found to be high risk and multiple AP were uncommon. Unlike the adult population, ART occurred commonly with septal APs.
    Pacing and Clinical Electrophysiology 02/2012; 35(4):480-8. · 1.35 Impact Factor
  • Article: Pediatric and Adult Congenital Endocardial Lead Extraction or Abandonment Decision (PACELEAD) survey of lead management.
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    ABSTRACT: Nonfunctional, dysfunctional, recalled, or additional endocardial leads in pediatric and congenital heart disease patients pose significant challenges for management. There are no set standards for lead extraction in this patient population. Physician members of the Pediatric and Adult Congenital Electrophysiology Society (PACES) were contacted via e-mail and invited to respond to a 33-question online Pediatric and Adult Congenital Endocardial Lead Extraction or Abandonment (PACELEAD) survey. Responses were received from 75 of 138 (54%) physician members of PACES. Institutional volumes of device placement (<25 devices/year for 51% of responders), patients with abandoned leads (<25 patients for 71%), and lead extractions (<10 extractions/year for 51% and no extractions for 29%) were low for the majority of responders. Personal experience with lead extraction was also minimal with 49% not performing the procedure and 39% with less than 40 leads extracted as primary operator. Most responders (54, 72%) refer their lead extractions to another practitioner or facility with more experience. Responders were more likely to recommend lead extraction (>70%) for class IIa indications such as bacteremia, chronic pain that is not medically manageable, and functional leads with ipsilateral venous occlusion. Lead abandonment was favored (>70%) for one class IIb indication, a functional lead that is not currently being used. Optimal lead management is challenging in pediatric and congenital heart disease patients, and considerable variability of practice is reported in their care. Low institutional and personal volumes may account for this variability.
    Pacing and Clinical Electrophysiology 09/2011; 34(12):1621-7. · 1.35 Impact Factor
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    Article: Impact of the permanent ventricular pacing site on left ventricular function in children: a retrospective multicentre survey.
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    ABSTRACT: Chronic right ventricular (RV) pacing is associated with deleterious effects on cardiac function. In an observational multicentre study in children with isolated atrioventricular (AV) block receiving chronic ventricular pacing, the importance of the ventricular pacing site on left ventricular (LV) function was investigated. Demographics, maternal autoantibody status and echocardiographic measurements on LV end-diastolic and end-systolic dimensions and volumes at age <18 years were retrospectively collected from patients undergoing chronic ventricular pacing (>1 year) for isolated AV block. LV fractional shortening (LVFS) and, if possible LV ejection fraction (LVEF) were calculated. Linear regression analyses were adjusted for patient characteristics. From 27 centres, 297 children were included, in whom pacing was applied at the RV epicardium (RVepi, n = 147), RV endocardium (RVendo, n = 113) or LV epicardium (LVepi, n = 37). LVFS was significantly affected by pacing site (p = 0.001), and not by maternal autoantibody status (p = 0.266). LVFS in LVepi (39 ± 5%) was significantly higher than in RVendo (33 ± 7%, p < 0.001) and RVepi (35 ± 8%, p = 0.001; no significant difference between RV-paced groups, p = 0.275). Subnormal LVFS (LVFS < 28%) was seen in 16/113 (14%) RVendo-paced and 21/147 (14%) RVepi-paced children, while LVFS was normal (LVFS ≥ 28%) in all LVepi-paced children (p = 0.049). These results are supported by the findings for LVEF (n = 122): LVEF was <50% in 17/69 (25%) RVendo- and in 10/35 (29%) RVepi-paced patients, while LVEF was ≥ 50% in 17/18 (94%) LVepi-paced patients. In children with isolated AV block, permanent ventricular pacing site is an important determinant of LV function, with LVFS being significantly higher with LV pacing than with RV pacing.
    Heart (British Cardiac Society) 09/2011; 97(24):2051-5. · 4.22 Impact Factor
  • Article: Syncope during exercise: just another benign vasovagal event?
    Taha Bat, Kathryn K Collins, Michael S Schaffer
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    ABSTRACT: In general, syncope in children and adolescents is a benign event. Syncope during exercise may identify patients with a potentially fatal condition. Catecholaminergic polymorphic ventricular tachycardia is characterized by life-threatening ventricular arrhythmias, usually polymorphic ventricular tachycardia or ventricular fibrillation, occurring under conditions of exercise or emotional stress. Catecholaminergic polymorphic ventricular tachycardia is a familial condition that presents with exercise-induced syncope or sudden death in children or young adults. Detailed evaluation should be considered for patients who have syncope during exercise, injure themselves during the fall (i.e., unprotected faint with no antecedent warning prodrome), or who have a family history of syncope, early sudden cardiac death, myocardial disease, or arrhythmias.
    Current opinion in pediatrics 07/2011; 23(5):573-5. · 2.01 Impact Factor
  • Article: Safety and results of cryoablation in patients <5 years old and/or <15 kilograms.
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    ABSTRACT: 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.
    The American journal of cardiology 05/2011; 108(4):565-71. · 3.58 Impact Factor
  • Article: Cryoablation of the slow atrioventricular nodal pathway via a transbaffle approach in a patient with the Mustard procedure for d-transposition of the great arteries.
    Anthony C McCanta, Joseph D Kay, Kathryn K Collins
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    ABSTRACT: The ablation of atrioventricular (AV) nodal reentrant tachycardia in patients with the Senning or Mustard procedure is quite challenging because these atrial baffle procedures isolate the AV node from systemic venous access. Cryoablation is commonly utilized for AV nodal slow pathway modification in patients with structurally normal hearts. The cryoablation technique offers the advantage of monitoring AV nodal conduction during lesions, with the ability to terminate a lesion prior to permanent injury to the AV node. This case describes the successful cryoablation of the slow AV nodal pathway via the transbaffle approach in a patient with d-transposition of the great arteries status post the Mustard procedure.
    Congenital Heart Disease 04/2011; 6(5):479-83. · 0.90 Impact Factor
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    Article: Impact of the permanent ventricular pacing site on left ventricular function in children: a retrospective multicentre survey for the Working Group for Cardiac Dysrhythmias and Electrophysiology of the Association for European Paediatric Cardiology*
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    ABSTRACT: Background Chronic right ventricular (RV) pacing is associated with deleterious effects on cardiac function. Objective In an observational multicentre study in children with isolated atrioventricular (AV) block receiving chronic ventricular pacing, the importance of the ventricular pacing site on left ventricular (LV) function was investigated. Methods Demographics, maternal autoantibody status and echocardiographic measurements on LV end-diastolic and end-systolic dimensions and volumes at age <18 years were retrospectively collected from patients undergoing chronic ventricular pacing (>1 year) for isolated AV block. LV fractional shortening (LVFS) and, if possible LV ejection fraction (LVEF) were calculated. Linear regression analyses were adjusted for patient characteristics. Results From 27 centres, 297 children were included, in whom pacing was applied at the RV epicardium (RVepi, n¼147), RV endocardium (RVendo, n¼113) or LV epicardium (LVepi, n¼37). LVFS was significantly affected by pacing site (p¼0.001), and not by maternal autoantibody status (p¼0.266). LVFS in LVepi (3965%) was significantly higher than in RVendo (3367%, p<0.001) and RVepi (3568%, p¼0.001; no significant difference between RV-paced groups, p¼0.275). Subnormal LVFS (LVFS<28%) was seen in 16/113 (14%) RVendo-paced and 21/147 (14%) RVepi-paced children, while LVFS was normal (LVFS$28%) in all LVepi-paced children (p¼0.049). These results are supported by the findings for LVEF (n¼122): LVEF was <50% in 17/69 (25%) RVendo-and in 10/35 (29%) RVepi-paced patients, while LVEF was $50% in 17/18 (94%) LVepi-paced patients. Conclusion In children with isolated AV block, permanent ventricular pacing site is an important determinant of LV function, with LVFS being significantly higher with LV pacing than with RV pacing.
    Heart 02/2011; 2011(97):2051.
  • Article: Epicardial left atrial appendage and biatrial appendage accessory pathways.
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    ABSTRACT: Acute success rates of accessory pathway ablation for Wolff-Parkinson-White (WPW) syndrome can exceed 95%, with rare failures attributed to anatomically complex epicardial connections. Right atrial appendage to right ventricle pathways have been reported, but their left-sided counterparts have only recently been described. The purpose of this study was to report three unique cases of WPW syndrome in children with left atrial appendage and biatrial appendage connections. Three young patients with high-risk accessory pathways (accessory pathway effective refractory period = 190-240 ms) had unsuccessful endocardial ablations despite aggressive efforts with various catheter techniques. One patient had a left atrial appendage to left ventricular connection; the other two had biatrial appendage pathways connected to their respective ventricular surfaces. The latter two patients had a history of ventricular fibrillation: one experiencing ventricular fibrillation in the electrophysiology laboratory and the other suffering from ventricular fibrillation arrest at home. All three patients were taken to the operating room, where the appendages were noted to be diffusely adherent to their ventricles by fibrofatty connections. Dissection of the appendages led to loss of preexcitation and no further tachycardia. Surgical management of atrial appendage accessory pathways should be considered if aggressive attempts at endocardial ablation have failed.
    Heart rhythm: the official journal of the Heart Rhythm Society 12/2010; 7(12):1740-5. · 4.56 Impact Factor
  • Article: Axillary versus infraclavicular placement for endocardial heart rhythm devices in patients with pediatric and congenital heart disease.
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    ABSTRACT: Our objective was to evaluate the implant and mid-term outcomes of transvenous pacemaker or internal cardioverter-defibrillator placement by alternative axillary approaches compared to the infraclavicular approach in a pediatric and congenital heart disease population. We conducted a retrospective review of all patients with new endocardial heart rhythm devices placed at 4 pediatric arrhythmia centers. A total of 317 patients were included, 63 had undergone a 2-incision axillary approach, 51 a retropectoral axillary approach, and 203 an infraclavicular approach. Congenital heart disease was present in 62% of the patients. The patients with the 2-incision axillary approach were younger and smaller. The patients with the retropectoral axillary approach were less likely to have undergone previous cardiac surgery and were more likely to have had an internal cardioverter-defibrillator placed. The duration of follow-up was 2.4 ± 1.9 years for the 2-incision axillary, 2.6 ± 2.6 years for retropectoral axillary, and 3.5 ± 1.4 years for the infraclavicular technique (p = 0.01). No differences were seen in implant characteristics, lead longevity, implant complications, lead fractures or dislodgements, inappropriate internal cardioverter-defibrillator discharges, or device infections among the 3 groups. In conclusion, our data support that the outcomes of axillary approaches are comparable to the infraclavicular approach for endocardial heart rhythm device placement and that axillary approaches should be considered a viable option in patients with pediatric and congenital heart disease.
    The American journal of cardiology 12/2010; 106(11):1646-51. · 3.58 Impact Factor
  • Article: Use of cryoablation for treatment of tachyarrhythmias in 2010: survey of current practices of pediatric electrophysiologists.
    Kathryn K Collins, Michael S Schaffer
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    ABSTRACT: Cryoablation for arrhythmia substrates in pediatrics has been available since 2003. The purpose of this study was to evaluate the current approach of pediatric electrophysiologists to the use of cryoablation in the current era. We sent an Internet link to an online survey to all members of the Pediatric and Congenital Electrophysiology Society. Individuals and not institutions were surveyed. A total of 70 responses were received. Responding physicians were largely invasive pediatric electrophysiologists (94%) who practice at mid- to high-volume centers (>50 ablation procedures/year). Survey responders report that cryoablation was utilized for <50% of the ablation volume, and most utilize it for only 10%. With respect to specific arrhythmia substrates, 41% of responders use cryoablation as first-line therapy for atrioventricular nodal reentrant tachycardia. For accessory pathways, 94% report that cryoablation would only be utilized after mapping the accessory pathway to a "high-risk location." Other arrhythmia substrates considered for cryoablation would be accessory pathways mapped to high-risk areas, junctional ectopic tachycardia, a parahisian ectopic atrial tachycardia, or an atrial tachycardia near the phrenic nerve. For pediatric electrophysiologists who responded to the survey, radiofrequency energy remains the primary energy source for ablation. The current use of cryoablation technology is directed at arrhythmia substrates near the normal conduction system or other "high-risk" areas.
    Pacing and Clinical Electrophysiology 11/2010; 34(3):304-8. · 1.35 Impact Factor
  • Article: Ventricular ectopy following successful cryoablation for Wolff-Parkinson-White syndrome in the right posterior septum: a case report.
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    ABSTRACT: We report a case of new onset ventricular ectopy following cryothermal ablation of a right posterior septal accessory pathway. To our knowledge, this is the first report of secondary arrhythmias from cryothermal ablation of atrial arrhythmias.
    Congenital Heart Disease 11/2010; 5(6):614-9. · 0.90 Impact Factor
  • Article: Incidental dual atrioventricular nodal physiology in children and adolescents: clinical follow-up and implications.
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    ABSTRACT: Dual atrioventricular (AV) nodal physiology is a substrate for the development of AV nodal reentrant tachycardia (AVNRT). However, the risk of developing AVNRT in patients with dual AV nodal physiology is not known. The purpose of this study is to identify the risk of developing AVNRT in children and adolescents with incidental findings of dual AV nodal physiology after accessory pathway ablation. This is a single center retrospective study of patients who underwent intracardiac electrophysiology study at The Children's Hospital, Denver, from March 1993 to August 2008, with findings of dual AV nodal physiology after successful ablation of an accessory pathway. Follow-up was obtained by chart review with the primary outcome of recurrent supraventricular tachycardia. Extended clinical follow-up was also achieved through phone contact with patients or parents of patients. Mean age at initial electrophysiology study was 12.8 years (±3.7 years). Follow-up was obtained on all 66 patients for a mean duration of 3.1 years (±2.8 years). Mean age at follow-up was 15.8 years (±4.6 years). Recurrent supraventricular tachycardia occurred in nine of the 66 patients (13.6%). AVNRT was induced in two of the 66 patients (3.0%). This study supports the hypothesis that incidental dual AV nodal physiology does not predict AVNRT in children and adolescents with after successful accessory pathway ablation.
    Pacing and Clinical Electrophysiology 10/2010; 33(12):1528-32. · 1.35 Impact Factor
  • Article: Use of a wearable automated defibrillator in children compared to young adults.
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    ABSTRACT: A wearable automated external defibrillator has been shown to be efficacious in the prevention of sudden death in adults who had a history of cardiac arrest but who did not have a permanent internal cardioverter/defibrillator (ICD) placed. The use of a wearable defibrillator has not been established in the pediatric population. We retrospectively reviewed the clinical database for the wearable external defibrillator from ZOLL Lifecor Corporation (Pittsburgh, PA, USA). We compared the use of the wearable defibrillator in patients ≤18 years of age to those aged 19-21 years. There were 81 patients ≤18 years of age (median age = 16.5 years [9-18] and 52% male). There were 103 patients aged 19-21 years (median age = 20 years [19-21] and 47% male). There was no difference between groups in average hours/day or in total number of days the patients wore the defibrillator. In patients ≤18 years of age, there was one inappropriate therapy and one withholding of therapy due to a device-device interaction. In patients aged 19-21 years, there were five appropriate discharges in two patients and one inappropriate discharge in a single patient. It is reasonable to consider the wearable automated external defibrillator as a therapy for pediatric patients who are at high risk of sudden cardiac arrest but who have contraindications to or would like to defer placement of a permanent ICD. As there were no appropriate shocks in our patients ≤18 years of age, this study cannot address efficacy of the therapy.
    Pacing and Clinical Electrophysiology 09/2010; 33(9):1119-24. · 1.35 Impact Factor
  • Article: Cryoablation with an 8-mm tip catheter for pediatric atrioventricular nodal reentrant tachycardia is safe and efficacious with a low incidence of recurrence.
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    ABSTRACT: Cryoablation with 4- and 6-mm tip ablation catheters has been demonstrated to be safe and effective in the treatment of atrioventricular nodal reentrant tachycardia (AVNRT) in pediatric patients, albeit with a higher rate of clinical recurrence. Limited information is available regarding efficacy, mid-term outcomes, and complications related to the use of the 8-mm Freezor Max Cryoablation catheter (Medtronic, Minneapolis, MN, USA) in pediatric patients. We performed a retrospective review of all pediatric patients with normal cardiac anatomy who underwent an ablation procedure for treatment of AVNRT using the 8-mm tip Cryoablation catheter at three large pediatric academic arrhythmia centers. Cryoablation with an 8-mm tip catheter was performed in 77 patients for treatment of AVNRT (female n = 40 [52%], age 14.8 +/- 2.2 years, weight 62.0 +/- 13.9 kg). Initial procedural success was achieved in 69 patients (69/76, 91%). Transient second- or third-degree atrioventricular (AV) block was noted in five patients (6.5%). There was no permanent AV block. Of the patients successfully ablated with Cryotherapy, there were two recurrences (2/70, 2.8%) over a follow-up of 11.6 +/- 3.3 months. Cryoablation with an 8-mm tip ablation catheter is both safe and effective with a low risk of recurrence for the treatment of AVNRT in pediatric patients.
    Pacing and Clinical Electrophysiology 03/2010; 33(6):681-6. · 1.35 Impact Factor
  • Article: Cryothermal catheter ablation of atrioventricular nodal reentrant tachycardia in a pediatric patient after atrioventricular canal repair.
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    ABSTRACT: Anatomic displacement of the atrioventricular node and associated conduction tissue in atrioventricular septal defects has been previously described. In spite of the increasing use of cryothermal catheter ablation in the pediatric population, there remains very little literature regarding its use in congenital heart disease. We describe successful cryothermal modification of the slow atrioventricular nodal pathway in a 12-year-old patient with a previously repaired partial atrioventricular septal defect and inducible atrioventricular nodal reentrant tachycardia. The use of a steerable catheter to locate the displaced His signal combined with the use of cryothermal energy allowed for the safe and effective treatment of this patient's tachycardia.
    Congenital Heart Disease 01/2010; 5(1):66-9. · 0.90 Impact Factor
  • Article: The spectrum of long-term electrophysiologic abnormalities in patients with univentricular hearts.
    Kathryn K Collins
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    ABSTRACT: Patients with univentricular hearts experience a wide range of electrophysiolgic abnormalities which tend to develop years after cardiovascular surgical interventions. Intra-atrial reentrant tachycardia (atrial flutter) in the Fontan population is the most common arrhythmia and, as such, has the largest body of literature addressing its cause and treatment. However, sinus node dysfunction, other atrial arrhythmias, ventricular arrhythmias, and cardiac dysynchrony also occur in this patient population. The purpose of this article is to review the prevalence, mechanisms, and treatment of these electrophysiologic abnormalities within the single ventricle and Fontan patient.
    Congenital Heart Disease 10/2009; 4(5):310-7. · 0.90 Impact Factor

Institutions

  • 2012
    • Boston Children's Hospital
      • Department of Cardiac Surgery
      Boston, MA, USA
    • Albert Einstein College of Medicine
      • Department of Pediatric Radiology
      New York City, NY, USA
  • 2011–2012
    • Children's Hospital Colorado
      • Department of Cardiology
      Aurora, CO, USA
    • Hacettepe University
      Ankara, Ankara, Turkey
  • 2010
    • Columbia University
      • Division of Pediatric Cardiology
      New York City, NY, USA
  • 2009–2010
    • Akron Children's Hospital
      Akron, OH, USA
    • University of Colorado Colorado Springs
      Colorado Springs, CO, USA
  • 2008–2010
    • University of Colorado Denver
      Denver, CO, USA
  • 2002–2007
    • University of California, San Francisco
      • • Division of Cardiology
      • • Department of Pediatrics
      San Francisco, CA, USA
  • 2002–2006
    • Stanford University
      • • Department of Pediatrics
      • • Division of Pediatric Cardiology
      Stanford, CA, USA
  • 2005
    • Lucile Packard Children’s Hospital at Stanford
      Palo Alto, CA, USA
  • 2003
    • Emory University
      Atlanta, GA, USA