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ABSTRACT: BACKGROUND: The utility of cardiac device-based intrathoracic monitoring (OptiVol, Medtronic Inc., Minneapolis, MN, USA) for congestive heart failure (CHF) exacerbation has not been evaluated in pediatric or congenital heart disease patients. METHODS: This was a retrospective study of all patients at a single center with an endocardial OptiVol capable device. OptiVol index values were collected in 2-week bins from January 2007 to December 2010. The clinical outcomes were CHF exacerbation defined as hospitalization or medication change for CHF and device-treated ventricular arrhythmia based on remote or in-office device interrogation. Clinical and OptiVol data were collected by separate investigators blinded to the other parameter. OptiVol data were correlated to the clinical outcomes to determine sensitivity and predictability for multiple threshold values in the entire cohort and pediatric and congenital subgroups. RESULTS: Forty-seven patients were included. A total of 1,106 months of OptiVol data were collected. Median age of the cohort was 18 years (range 6-58 years). There were 23 pediatric, median age 13 years (range 6-16), at device implant, and 18 patients, median age 31 years (range 13-58), considered at risk for heart failure at implant. There were three heart failure exacerbations and 17 treated ventricular arrhythmias. The study population-specific positive predictive value (PPV) of OptiVol was low (sensitivity 33% and PPV ≤4.4%) for both CHF exacerbation and arrhythmias in all analyzed groups. CONCLUSIONS: The sensitivity and positive predictive value of intrathoracic impedance monitoring was low in this population of adult congenital and pediatric patients. Recent improvements to the OptiVol algorithm may decrease these deficiencies.
Pacing and Clinical Electrophysiology 04/2013; · 1.35 Impact Factor
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Anna N Kamp,
Nicholas H Von Bergen,
Charles A Henrikson,
Majd Makhoul,
Elizabeth V Saarel,
Martin J Lapage,
Mark W Russell,
Margaret Strieper,
Sunkyung Yu, Macdonald Dick,
Sharlene M Day,
David J Bradley
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ABSTRACT: Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease, with an annual risk of sudden cardiac death (SCD) estimated at 1 %. Limited data are available regarding both the risk of SCD in the young HCM population and the use of implantable cardioverter-defibrillators (ICDs). This retrospective study included all patients with HCM who underwent ICD implantation for primary or secondary prevention of SCD before the age of 30 years at five institutions between 1995 and 2009. There were 99 devices implanted in 73 patients. Appropriate shocks occurred for 11 % of all the patients. None of the previously identified conventional risk factors for SCD in HCM patients were associated with increased risk of appropriate shocks in the young study cohort. During a median follow-up period of 2.4 years, inappropriate shocks occurred for 22 % of the patients. Older age at implant was associated with a decreased risk of inappropriate shock. Those who underwent implantation in the earlier decade had a higher incidence of inappropriate shocks. Late complications including lead fracture or dislodgement, generator malfunction, and infection occurred for 32 % of the patients. Three patients died (4 %), one of whom had an arrhythmic sudden death. A greater proportion of primary prevention implantations was performed for patients from the latter decade. Over time, ICD use in young HCM patients has become increasingly primary prevention oriented. Shock rates mirror those reported in adult series, and there is a substantial incidence of device complications.
Pediatric Cardiology 03/2013; · 1.30 Impact Factor
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ABSTRACT: Transient complete heart block (TCHB) is defined as complete interruption of atrioventricular conduction (AVC) after cardiac surgery followed by return of conduction. This study aimed to assess the risk for the development of late complete heart block (LCHB) after recovery of TCHB and to examine the electrocardiographic and electrophysiologic properties of the AVC system after TCHB. Of the 44 patients in this study who experienced TCHB, 37 recovered completely. Seven patients progressed from TCHB to intermittent CHB or LCHB requiring pacemaker implantation. Preoperative, early postoperative, and late postoperative electrocardiograms as well as postoperative atrial stimulation were obtained. The results showed that the median duration of TCHB was 5 days in the TCHB group compared with 9 days in the LCHB group (p = 0.01). All 37 subjects with TCHB recovered AVC within 12 days, but only two with LCHB did so (p = 0.02). The risk of LCHB for the patients with 7 days of postoperative TCHB or longer was 13 times greater than for the patients with fewer than 7 days of TCHB (p = 0.01). The median late postoperative PR interval was slightly but significantly longer in the LCHB group than in the TCHB group (p = 0.02). In contrast, the electrophysiologic properties between the two groups did not differ significantly. From those findings, we concluded that delayed recovery of AVC after surgical TCHB (≥7 days), but not electrophysiologic properties of recovered AVC assessed early in the postoperative period strongly, predicts risk of LCHB. Follow-up evaluation of AVC is particularly indicated for the delayed recovery group.
Pediatric Cardiology 11/2012; · 1.30 Impact Factor
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ABSTRACT: An adolescent girl with a history of anxiety associated seizure-like episodes was ultimately diagnosed with catecholaminergic polymorphic ventricular tachycardia. She tested positive for a novel mutation of the ryanodine receptor. The report underscores how genetic arrhythmia syndromes may be mistaken for neurologic disorders.
The Journal of pediatrics 05/2012; 161(2):362-4. · 4.02 Impact Factor
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ABSTRACT: Atrioventricular nodal reentrant tachycardia (AVNRT), a common tachycardia in children, is routinely treated by catheter ablation using radiofrequency or cryothermal energy. Acute success rates of 95-97 % are reported for cryoablation, similar to those achieved with radiofrequency ablation (RFA). However, early studies reported higher recurrence rates after cryoablation for treatment of AVNRT than those reported for RFA. This study evaluated the success and recurrence rates for cryoablation in a current cohort of pediatric patients across several institutions. Patients 21 years old or younger with AVNRT who underwent cryoablation at five participating centers between 2004 and 2009 were retrospectively reviewed. Patient demographics and procedural data were extracted from patient records and analyzed. A total of 434 patients with AVNRT who underwent cryoablation were identified. Cryoablation was used as the exclusive ablation method for 379 patients. For 97 % (368/379) of these patients, cryoablation was acutely successful. A higher acute success rate was found with the 6-mm-tip catheter (99 %) than with the 4-mm-tip catheter (91 %) (p < 0.01). Recurrence was experienced by 7.3 % of the patients. Recurrence was more likely for those treated with the 4-mm-tip catheter (6/42, 14 %) than for those who had the larger catheters (12/204, 6 %) No patient experienced permanent heart block. Success and recurrence rates for this cohort of patients were similar to those reported for RFA used to treat AVNRT in pediatric patients. The findings show a higher success rate and a lower recurrence rate after cryoablation with a 6-mm-tip catheter than after use of the 4-mm-tip catheter, with an associated excellent safety profile.
Pediatric Cardiology 03/2012; 33(7):1147-53. · 1.30 Impact Factor
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Nicholas H Von Bergen,
Dianne L Atkins, Macdonald Dick,
David J Bradley,
Susan P Etheridge,
Elizabeth V Saarel,
Peter S Fischbach,
Seshadri Balaji,
Narayanswami Sreeram,
William N Evans,
Ian H Law
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ABSTRACT: Implantable cardioverter defibrillators (ICDs) are being used with increasing frequency in children and young adults. Our aim was to examine the appropriateness and frequency of ICD discharges in children and young adults, to compare the effectiveness of ICDs when placed for primary or secondary prevention, and to provide time-dependent analysis of ICD discharges. Data were collected from seven institutions on 210 patients <30 years of age who underwent ICD implantation from October 1992 to January 2007. Median age at implant was 15.4 years with a follow-up average of 3.3 years. Heart disease was categorized as electrical (n = 90, 42%), cardiomyopathic (n = 62, 30%), or congenital heart disease (n = 58, 28%). ICDs are increasingly placed for primary prevention. There are increased appropriate ICD discharges for ICDs placed for secondary prevention (52%) versus primary prevention (14%) at 5 years. There is no difference in the risk of inappropriate discharges between primary and secondary prevention indications. There is an increased risk for inappropriate therapy in the congenital heart disease population. An increasing number of ICDs are being placed for primary prevention in young patients, a marked shift in practice during the last two decades. The benefits of ICDs remain greater in secondary than in primary-prevention patients. In both groups, approximately 25% of patients received inappropriate discharges within 5 years of implant. Patients with congenital heart disease are the most affected by inappropriate discharges.
Pediatric Cardiology 01/2011; 32(4):399-405. · 1.30 Impact Factor
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ABSTRACT: Electro-anatomic mapping (EAM) has been used for more than a decade to assist in defining arrhythmia propagation for transcatheter ablation. Intra-cardiac echocardiography (ICE) has also gained acceptance as an adjunct to further define intracardiac anatomy. The integration of these two technologies (CartoSound, Biosense-Webster, Diamond Bar, CA, USA) is a recent development. In this report, we describe our early experience in the young, with and without congenital heart defects (CHD).
The clinical and electrophysiologic records of the first 17 patients to undergo procedures with the CartoSound (EAM-ICE) system were reviewed. In all 17, the 3-dimensional shape of the chamber(s) of interest was created using serial tracing of ICE images. The ICE catheter was placed in the esophagus in three and through the femoral vein in 14. Descriptive analysis was performed on demographic data as well as procedural characteristics including procedure time, fluoroscopy time, geometry acquisition time, EAM duration, ablation time, procedure success, and complications.
Arrhythmias comprised intra-atrial re-entry tachycardia (13 patients, 76%), Wolff-Parkinson-White syndrome (1; 6%), ventricular ectopic tachycardia (2; 12%), and atrioventricular node re-entrant tachycardia (1; 6%). Thirteen had CHD, with a median two palliative operations; six had single-ventricle anatomy. Procedure duration was 266 ± 134 min (median ± SD), and fluoroscopy time was 29 ± 28.3 min. Geometry acquisition took 41 ± 35.4 min, or 16% of the total case duration. Ablation lesions were placed in 16 cases, (cooled tip in 12) of which 15 (94%) were successful. One patient experienced mild hypotension. ICE image quality in three patients with the probe placed in the esophagus was suboptimal.
Advantages of CartoSound appear to be (1) anatomy modeling in the shape imposed by the arrhythmia, (2) more accurate geometry than EAM alone, and (3) demonstration of catheter position and lesions on echo during the study. Perceived disadvantages are (1) the large sheath required for ICE (11F), and (2) significant procedure time devoted to creation of anatomy. Optimal use may be to focus on key structures required for ablation, obtaining additional views as needed.
Journal of Interventional Cardiac Electrophysiology 09/2010; 29(2):139-45. · 1.17 Impact Factor
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Heart rhythm: the official journal of the Heart Rhythm Society 07/2008; 5(6):926-33. · 4.56 Impact Factor
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ABSTRACT: Electrocardiographic (ECG) rhythm analysis algorithms for cardiac rhythm analysis in automated external defibrillators (AEDs) have been tested against pediatric patient rhythms (patients < or = 8 years old) using adult ECG algorithm criteria. However these adult algorithms may fail to detect non-shockable pediatric tachycardias because they do not account for the difference in the rates of normal sinus rhythm and typical tachyarrhythmias in childhood.
This study was designed to define shockable and non-shockable rhythm detection criteria specific to pediatric patients to create a pediatric rhythm database of annotated rhythms, to develop a pediatric-based AED rhythm analysis algorithm, and to test the algorithm's accuracy. Pediatric rhythm detection criteria were defined for coarse ventricular fibrillation, rapid ventricular tachycardia, and non-shockable rhythms, including pediatric supraventricular tachycardia. Pediatric rhythms were collected as sustained, classifiable, rhythms > or = 9 s in length, and were annotated by pediatric electrophysiologists as clinically shockable or non-shockable based on pediatric criteria. Rhythms were placed into a pediatric rhythm database; each rhythm was converted to digitally accessible, public-domain, MIT rhythm data format. The database was used to evaluate a pediatric-based AED rhythm analysis algorithm.
Electrocardiographic rhythms from 198 children were recorded. There were 120 shockable rhythms from 49 patients (sensitivity; coarse ventricular fibrillation: 42 rhythms, 100%; rapid ventricular tachycardia: 78 rhythms, 94%), for combined sensitivity of 96.0% (115/120). There were 585 non-shockable rhythms from 155 patients (specificity normal sinus: 208 rhythms, 100%; asystole: 29 rhythms, 100%; supraventricular tachycardia: 161 rhythms, 99%; other arrhythmias: 187 rhythms, 100%), for combined specificity of 99.7% (583/585). Overall accuracy for shockable and non-shockable rhythms was 99.0% (702/709).
New pediatric rhythm detection criteria were defined and analysis based on these criteria demonstrated both high sensitivity (coarse ventricular fibrillation, rapid ventricular tachycardia) and high specificity (non-shockable rhythms, including supraventricular tachycardia). A pediatric-based AED can detect shockable rhythms correctly, making it safe and exceptionally effective for children.
Resuscitation 03/2008; 76(2):168-74. · 3.60 Impact Factor
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ABSTRACT: During catheter ablation procedures, non-radiologic navigation systems may reduce fluoroscopic exposure and energy applications, as well as improve procedural success rates.
To examine the impact of a non-radiologic navigation system on ablation procedures in pediatric patients, the procedural characteristics and success rates prior to and following incorporation of the LocaLisa (LL) navigation system into a pediatric electrophysiology laboratory were compared.
Between January 2000 and April 2005, 246 consecutive patients underwent catheter ablation for either Atrioventricular Reentry Tachycardia AVRT (168) or Atrioventricular Nodal Reentry Tachycardia AVNRT (78). Ablation procedures performed prior to LL (108) were compared to ablation procedures performed using LL (113). The first 25 patients using LL were censored to remove the bias of a learning curve.
There was no difference in demographic features between the two groups. Statistically significant decreases were found in the diagnostic (11.4 +/- 6.1 min v 18.8 +/- 9.8 min w/o LL), ablation (5.7 +/- 10.3 vs 18.5 +/- 20.1 min w/o LL) and total (17.2 +/- 12.6 vs 37.3 +/- 21.3 min w/o LL) fluoroscopy times for the LL group, as well as in the total number of energy applications (9.0 +/- 8.5 vs 12.3 +/- 12.2 w/o LL). Success rates were 99.1% w/ LL v 97.2% w/o LL (p = NS). No major complications were observed in either group.
The use of a computer assisted navigation system significantly decreased the diagnostic, ablation, and total fluoroscopy times, as well as the number of energy applications, without affecting procedural success or complication rates. Non-radiologic navigation systems reduce radiation exposure during transcatheter electrophysiologic procedures and thus lower the lifetime radiation cumulative risk, a goal particularly important in children.
Journal of Interventional Cardiac Electrophysiology 09/2007; 19(2):121-7. · 1.17 Impact Factor
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ABSTRACT: Junctional ectopic tachycardia in the normal heart is rare and often is resistant to pharmacologic management. Transcatheter ablation using radiofrequency energy places the AV node at risk.
The purpose of this study was to report our experience with transcatheter cryothermal ablation using three-dimensional mapping in six patients with junctional ectopic tachycardia.
A review of clinical and electrophysiologic data was performed on all patients with structurally normal hearts who underwent cryothermal ablation for treatment of junctional ectopic tachycardia at two institutions.
Six patients (age 7.7-36.5 years) underwent attempted transcatheter cryothermal ablation using three-dimensional mapping. Only one patient had achieved arrhythmia suppression on medical management. Cryothermal mapping (-30 degrees C) localized the junctional focus while normal conduction was monitored. The junctional focus was high in the triangle of Koch in four patients and was low in one patient. The sixth patient had only one run of junctional ectopic tachycardia during the procedure and therefore received an empiric cryoablation (-70 degrees C) lesion. Subsequent cryoablation lesions were delivered at and around the junctional focus. In one patient, cryomapping eliminated the junctional focus but resulted in transient complete AV block; therefore, cryoablation was not performed. All patients who received the cryoablation lesions had elimination of their junctional ectopic tachycardia at 6-week follow-up. The patient who did not receive a cryoablation lesion remained in a slower junctional rhythm at follow-up.
Cryoablation of junctional ectopic tachycardia is safe and effective. Nonetheless, proximity to the His-Purkinje system may preclude success. Empiric cryoablation can be effective; cryotherapy may not yield immediate success, but a delayed salutary effect can follow.
Heart Rhythm 09/2006; 3(8):903-7. · 4.10 Impact Factor
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ABSTRACT: Transcatheter cryotherapy is an emerging technology for the treatment of children with supraventricular tachyarrhythmias. Limited data exist regarding the use of cryoablation therapy in children. We report a single center's experience with transcatheter cryoablation in the pediatric population.
A retrospective review of demographic, procedural and outcome data was performed for patients undergoing cryoablation for treatment of supraventricular tachycardia (SVT). A historical control group was taken from the 3 years preceding the introduction of cryoablation. Between August 2003 and November 2005, 83 cryoablation procedures were performed in 81 patients (age: 4 to 21 years, mean: 13.4 years) for AV nodal reentrant tachycardia (AVNRT--53), AV reentrant tachycardia (AVRT--20), ectopic atrial tachycardia (EAT--9), and junctional ectopic tachycardia (JET--1). The acute success rate for all procedures was 88% (AVNRT: 96%, AVRT: 85%, EAT: 55%, and JET: 100%). Of 72 patients that underwent successful cryoablation, nine experienced recurrence of SVT (12.5%). The control group consisted of 73 patients (AVNRT--60, AVRT--13). There were no differences in demographic data between the two groups. The overall success rate for the RFA group (96%) was identical to that for patients with AVNRT and AVRT undergoing cryoablation. The recurrence rate for RFA (10%) was less but not significantly different than that for cryoablation (12%). There were no complications in either group.
Cryoablation is a safe and effective alternative for the treatment of SVT in children.
Journal of Interventional Cardiac Electrophysiology 05/2006; 15(3):191-6. · 1.17 Impact Factor
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12/2005: pages 95-113;
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ABSTRACT: Careful consideration and understanding of the underlying anatomy and electrophysiology of the heart in developing children
will provide a sound foundation for the safe and effective management of arrhythmias in the young. Advances in new energy
sources such as cryotherapy as well as development of new imaging techniques such as real time MRI will most likely improve
these strategies.
12/2005: pages 33-47;
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ABSTRACT: Transcatheter ablation offers the possibility of complete, safe correction of tachyarrhythmias, particularly supraventricular,
in children. Although radiofrequency energy is the predominant form of energy delivery to ablate abnormal pathways and ectopic
foci in the human heart, cryotherapy, long used in the operating room but now delivered through a catheter, introduces a new
technique that is, prior to full application, reversible. Thus, as one is applying a discrete, well-localized cryotherapy
lesion, one can see its effects, whether salutary or deleterious, and terminate the delivery, allowing reversal of an adverse
cryo effect. Early experience suggests that transcatheter cryoablation is a useful addition to the treatment of a number of
tachyarrhythmias—especially AV nodal reentry tachycardia. Other advances in the understanding of arrhythmias, in catheter
design (smaller, more flexible), in navigation techniques, in imaging systems (real time magnetic resonance imaging), and
in ablation energy sources promise to bring even further innovation in the future.
12/2005: pages 289-314;
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ABSTRACT: The purpose of this study was to demonstrate that adverse but reversible effects on AV conduction may be observed during cryoablation despite no evidence of deleterious effects evident during cryomapping.
Transcatheter cryoablation has recently been introduced for treatment of supraventricular tachycardia. Potential advantages compared with radiofrequency ablation include decreased risk of thromboembolism and perforation, less patient discomfort, more sharply demarcated lesions, and decreased risk of inadvertent damage to adjacent structures due to the ability to observe the electrophysiologic effects of lesion generation prior to permanent tissue damage. Occasionally, however, adverse electrophysiologic effects may be observed during cryoablation when prior cryomapping suggests a safe location.
We reviewed the experience with our first 32 consecutive patients who underwent cryoablation for supraventricular tachycardia. Patients who experienced transient heart block during cryoablation following uneventful cryomapping were identified.
Five patients in whom cryomapping was performed with no evidence for deleterious effects on AV conduction were identified. However, application of cryoablation at these mapped sites resulted in transient complete heart block. This experience demonstrates that the cryolesion created during cryoablation may expand relative to that suggested by cryomapping.
It is important to maintain vigilance in monitoring for AV nodal conduction abnormalities during cryoablation, even when cryomapping suggests a safe location for cryoablation.
Heart Rhythm 12/2004; 1(5):554-7. · 4.10 Impact Factor
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ABSTRACT: We sought to identify the electrophysiologic basis of life-threatening events associated with polymorphic ventricular tachycardia (PVT) in young patients with heterozygous KCNJ2 mutations. PVT describes a beat-to-beat alternating QRS axis and morphology during ventricular tachycardia. PVT may be well tolerated and even asymptomatic in young patients without other heart disease, but an association with syncope, cardiac arrest, or sudden death has long been known. Little is known of the basis of life-threatening events associated with PVT in this setting. We identified heterozygous KCNJ2 mutations (R67W and C101R respectively) in 2 adolescents with PVT (cycle length > 375 ms, < 160 beats/minute). Biophysical properties of wild-type and mutant KCNJ2 channels were characterized during heterologous expression in Xenopus oocytes. Despite a large tachycardia burden, neither patient experienced symptoms during electrocardiographic documentation of PVT. One patient had a history of cardiac arrest, but neither had other evidence of heart disease. Both patients were treated with an implantable cardioverter-defibrillator (ICD). In one patient, ICD interrogation identified rapid ventricular tachycardia (cycle length of 190 to 270 ms), terminated with a single 29-J asynchronous shock, as the cause of 2 syncopal episodes occurring 19 months apart. Biophysical characterization of KCNJ2-C101R demonstrated a loss-of-function and a dominant-negative effect on Kir2.1. Similar effects were previously observed for KCNJ2-R67W. Heterozygous mutations in KCNJ2 can cause life-threatening ventricular arrhythmias. Arrhythmia documented during cardiac arrest is rapid ventricular tachycardia; ICD is effective therapy for cardiac arrest in patients with PVT due to KCNJ2 mutation.
Heart Rhythm 07/2004; 1(2):235-41. · 4.10 Impact Factor
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ABSTRACT: Patient-activated transtelephonic electrocardiographic event monitors (TTMs) are often used for the evaluation of children and adolescents with suspected arrhythmias. Since their introduction 25 years ago, there has been little inquiry quantifying the usefulness of TTMs for pediatric patients. The objective of this study was to measure the utility of TTMs for children and adolescents with symptoms of a possible cardiac rhythm disturbance.
Medical records of all patients who received TTMs from C.S. Mott Children's Hospital Electrocardiography Laboratory between February 1, 1993, and October 31, 2000, were reviewed. Patients with pacemakers, known arrhythmias, or age older than 18 years were excluded. Indications for monitoring included palpitations with or without other symptoms (N = 420), chest discomfort (N = 43), and presyncope or syncope (N = 32).
A total of 495 studies (patient mean age: 10.2 +/- 4.3 years; range: 0.1-17.9 years; 48% male) met inclusion criteria. Monitoring was performed for 1 to 1021 consecutive days (mean: 103 +/- 97). Fifty-two percent (N = 257) of patients failed to transmit an electrocardiogram while experiencing symptoms. Fewer boys transmitted electrocardiograms (N = 100/238). Of 238 symptomatic patients, 15% (N = 35; mean age: 11.4 +/- 4.7 years; range: 0.1-17.4 years; 51% male) had supraventricular tachycardia (SVT). No other significant arrhythmia that may warrant treatment was identified. All patients with SVT had palpitations. No patients with isolated chest discomfort, presyncope, or syncope had SVT (N = 75). SVT was documented more frequently in patients with postevent (N = 35/464) than loop recorders (N = 0/31). Of those with SVT, 71% (N = 25) and 91% (N = 33) transmitted events within 4 and 16 weeks, respectively. Follow-up for 1 to 108 months (mean: 32 +/- 25; median: 26) in 53% (243 of 460) of patients without SVT uncovered a 3% (N = 7) rate of subsequent SVT detection. The overall sensitivity of the TTM test was 83% (35 of 42) for detection of SVT. The sensitivity of studies theoretically limited to 4 and 16 weeks would be 60% (25 of 42) and 79% (33 of 42), respectively. The negative predictive value of the TTM study was 99% in our patient population. The negative predictive value of tests theoretically limited to 4 and 16 weeks would be 96% and 98%, respectively. TTM studies of 2 weeks' duration were most cost-effective in terms of total diagnostic yield. In contrast, studies of 4 weeks' duration were most cost-efficient for SVT detection.
TTMs are useful for the evaluation of children and adolescents with palpitations but not with isolated chest pain, syncope, or presyncope. In this study, girls were more likely to transmit events. The sensitivity of TTMs for detection of SVT was 83%. The negative predictive value of the TTM test was 99%. Monitoring for longer than 16 weeks did not increase test sensitivity. Studies of 4 weeks' duration proved most cost-effective for SVT detection.
PEDIATRICS 03/2004; 113(2):248-51. · 4.47 Impact Factor
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ABSTRACT: This study examined the indications, efficacy and outcomes of implantable cardioverter defibrillator (ICD) use in the pediatric population.
ICDs are first-line therapy for adults resuscitated from sudden cardiac death (SCD) or at high risk for life-threatening ventricular arrhythmias. Use of ICDs in children and young adults is infrequent and there are few data regarding this group.
We abstracted and analyzed data for all patients in whom ICDs were implanted.
A total of 38 devices were implanted in 27 patients. Age ranged from 6 to 26 years (mean, 14) and weight ranged from 16 to 124 kg (mean, 47). Diagnoses included long QT syndrome (9), hypertrophic cardiomyopathy [6], repaired congenital heart disease [5];, and idiopathic ventricular tachycardia/fibrillation [4]. Indications comprised resuscitated SCD [15], syncope [9], and life-threatening ventricular arrhythmia [3]. Initial device placement was infraclavicular in 13, abdominal in 13 and intrathoracic in 1. Epicardial leads were used with 5 systems. A single coil lead was used in 17. Seven patients, all previously resuscitated from SCD, experienced 88 appropriate successful discharges. There were 6 inappropriate discharges in 3 patients. Mean time to device replacement was 3.1 years (n = 11). Complications included 2 infected systems, 2 lead dislodgments, 2 lead fractures, 1 post-pericardiotomy syndrome, 1 adverse event with defibrillation threshold (DFT); testing, and 1 patient with psychiatric sequelae. No deaths occurred with implanted ICDs.
These data demonstrate that ICDs provide safe and effective therapy in young patients. The indications for ICDs as primary preventive therapy remain uncertain.
Journal of Interventional Cardiac Electrophysiology 08/2002; 6(3):235-44. · 1.17 Impact Factor
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ABSTRACT: Clinical medicine is facing a challenge of knowledge discovery from the growing volume of data. In this paper, a data mining algorithm (G-algorithm) is proposed for extraction of robust rules that can be used in clinical practice for better understanding and prevention of unwanted medical events. The G-algorithm is applied to the data set obtained for children born with a malformation of the heart (univentricular heart). As the result of the Fontan surgical procedure, designed to palliate the children, 10%--35% of patients postoperatively develop an arrhythmia known as the intra-atrial reentrant tachycardia. There is an obvious need to identify the children that may develop the tachycardia before the surgery is performed. Prior attempts to identify such children with statistical techniques have been unrewarding. The G-algorithm discussed in this paper shows that there exists an unambiguous relationship between measurable features and the tachycardia. The data set used in this study shows that, for 78.08% of infants, the occurrence of tachycardia can be accurately predicted. The authors' prior computational experience with diverse medical data sets indicates that the percentage of accurate predictions may become even higher if data on additional features is collected for a larger data set.
10/2001;
