Sedentary behaviour and bone health in older adults: a systematic review

Older adults spend more than 8 h/day in sedentary behaviours. Detrimental effects of sedentary behaviour (SB) on health are established, yet little is known about SB and bone health (bone mineral density; BMD) in older adults. The purpose of this review is to examine associations of SB with BMD in older adults. Five electronic databases were searched: Web of Science (Core Collection); PubMed; EMBASE; Sports Medicine and Education and PsycInfo. Inclusion criteria were healthy older adults mean age ≥ 65 years; measured SB and measured BMD using dual-energy X-ray absorptiometry. Quality was assessed using National Institute of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. After excluding duplicates 17813 papers were assessed; 17757 were excluded on title/abstract, 49 at full text, resulting in two prospective and five cross-sectional observational studies reviewed. Four were rated 'good' and three were rated 'fair' using the quality assessment criteria. Findings varied across the studies and differed by gender. In women, four studies reported significant positive associations of SB with BMD at different sites, and two found significant negative associations. Five studies which examined both men and women, men reported negative or no associations of SB with femoral neck, pelvic, whole body, spine or leg BMD. Whilst these findings suggest differences between men and women in the associations of SB with BMD, they may be due to the varying anatomical sections examined for BMD, the different methods used to measure SB, the varied quality of the studies included and the limited number of published findings.

Variation in Pediatric Post-Ablation Care: A Survey of the Pediatric and Congenital Electrophysiology Society (PACES)

Although catheter ablation is a standard treatment for pediatric arrhythmias, there are no consensus guidelines for follow-up care. This study describes the variation in post-ablation practices identified through a survey of the pediatric and congenital electrophysiology society (PACES). Pediatric and congenital electrophysiology society members were invited to participate in an online survey of post-ablation practices in September 2014. Survey questions targeted routine post-ablation practices for three common arrhythmia substrates: atrioventricular nodal reentry tachycardia, concealed accessory pathways (AP), and manifest APs. Significant practice variation was defined as <90% concordance among respondents. There were 70 respondents from 67 centers, 29 (41%) in practice for <10 years. Uniform practices included aspirin after left side ablation by 65 (93%), immediate post-procedure ECG by 63 (90%), and performance of outpatient follow-up in 69 (99%) including ECG in 97-100% depending on substrate. The majority, 57 (81%), have standardized follow-up independent of substrate. Post-procedural observation is highly variable, with 25 (36%) discharging patients on the day of ablation, 22 (33%) observing patients in hospital overnight, and 21 (30%) basing hospitalization on pre-defined criteria. Immediate post-procedure echo is performed after all ablations in only 16 (23%). Discharge from outpatient care occurs at a median time of 12 months for each arrhythmia substrate. Common post-ablation practices are evident among pediatric electrophysiologists. However, they report significant variation in post-procedure monitoring practices and testing. The rationale for these variances, and their impact on costs and outcomes, should be defined.

Follow-Up of a Prospective Surgical Strategy to Prevent Intra-Atrial Reentrant Tachycardia After the Fontan Operation

BACKGROUND

Intra-atrial reentrant tachycardia (IART) after the Fontan operation had an early reported incidence of 10% to 35% during early and intermediate follow-up and posed substantial management challenges.

METHODS AND RESULTS

To reduce the incidence of IART after the Fontan procedure, we performed a randomized, double-blind study to evaluate the impact of an incision in the right atrium joining the lateral tunnel suture line and the tricuspid valve annulus. Between March 1998 and September 2003, 134 subjects (median age: 1.8 years; range: 1.3-5.2 years; 91 men) were randomly assigned to receive the incision. All 134 patients had a form of single ventricle pathological anatomy. The clinical course, electrocardiograms, and Holter monitoring were available for review in 114 subjects at a median of 8.2-year follow-up (range: 0.9-11.9 years). There were 2 late deaths, neither subject had IART. The combined incidence of sustained IART was 3.5% (4/114). There was no difference in the occurrence of sustained IART between those subjects receiving the incision and those who did not (2 in each group) during follow-up. No patients of either group experienced short-term complications.

CONCLUSIONS

Despite the fact that the primary outcome of this trial was not reached, the most significant finding was that with current management, the incidence of IART is considerably lower than the early retrospective, observational studies suggested.

[Professionalization of Legal Dental Experts in Germany: Results of Studies on Structured Focus Groups]

BACKGROUND

Legal expert opinions are a crucial instrument of professional self-control in medicine. To give impulses for further development, focus groups were initiated to reflect upon the perspective of legal dental experts.

METHODS

5 focus group discussions on the topic "Professionalization of legal dental experts" were conducted. A total of 32 experienced legal dental experts participated in the discussions. The results were evaluated by qualitative content analysis.

RESULTS

A catalogue of 68 ideas was generated for improvement and divided into 15 categories. Among these were periodic quality circles, interprofessional exchange, supervision of novices and periodic feedback for legal dental experts and dentists.

CONCLUSION

Self-reflection can be included as an instrument for quality improvement of legal dental expert opinions.

Transseptal access in pediatric and congenital electrophysiology procedures: defining risk

PURPOSE

Transseptal puncture (TSP) is commonly used to access the left heart for catheter ablation procedures. The specific complication risk of this procedure has not been determined. This study assesses the risk of TSP using a single standard technique during electrophysiology study (EPS) in pediatrics and congenital heart disease (CHD).

METHODS

Retrospective cohort study of patients undergoing TSP during EPS at the University of Michigan Congenital Heart Center between 1999 and 2011.

RESULTS

There were 373 left heart ablation procedures during the study period. Excluded were six adults without CHD, five procedures using an alternative imaging modality, five procedures using retrograde aortic access, one transhepatic access, and one where TSP was performed during a prior procedure. Included were 321 pediatric (≤18 years old without CHD) TSP procedures (median age 13 years) and 34 TSP procedures in patients with CHD (median age 28 years). There was one complication directly attributable to TSP: needle perforation of the left atrium without development of effusion in the pediatric group. Post-procedure echocardiograms were performed in 351 (99 %) cases, showing only trivial effusions in seven (1.9 %).

CONCLUSIONS

This single center experience over 12 years shows the risk of TSP in pediatric and CHD patients to be low, with a 0.3 % (95 % confidence interval (CI) 0, 0.9 %) risk for complications directly related to TSP using only single plane fluoroscopy for visualization.

Cardiac implantable electronic device remote monitoring surveillance in pediatric and congenital heart disease: Utility relative to frequency

BACKGROUND

Heart Rhythm Society expert consensus provides recommendations for surveillance monitoring of cardiac implantable electronic devices (CIEDs), but limited data are available for the pediatric and congenital heart disease population.

OBJECTIVE

The purpose of this study was to determine the rate of actionable events during CIED surveillance in this population, assess the utility of routine CIED remote monitoring, and assess the potential benefit from more frequent monitoring.

METHODS

This was a retrospective cohort study of all CIED patients followed at a pediatric and congenital heart center and enrolled in the Medtronic Carelink system with either (1) a chronic (implanted for >6 months) CIED followed between July 1, 2010, and July 1, 2012, on a bimonthly schedule; or (2) a new CIED (implanted <6 months) between July 1, 2008, and July 1, 2012, followed on a monthly schedule.

RESULTS

Aggregate mean age was 20 ± 13.7 years. There were 608 interrogations on newly implanted CIEDs with an actionable event rate of 11 per 100 patient-years. There were 2614 interrogations of chronic CIEDs with an actionable event rate of 22 per 100 patient-years. The odds of an actionable event on an asymptomatic remote monitoring transmission was lower than if symptomatic (odds ratio 0.04, 95% confidence interval 0.03-0.07). Tachyarrhythmia was the most common event. Predictors of actionable events were identified.

CONCLUSION

In this population of pediatric and congenital heart disease patients, the rate of actionable events was low, especially on asymptomatic interrogations. Most actionable events were due to tachyarrhythmia. A more frequent than every 90-day monitoring schedule does not appear to be of significant benefit.

Implanted defibrillators in young hypertrophic cardiomyopathy patients: a multicenter study

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.

Research accomplishments in pediatric electrophysiology: a historical review

Arrhythmia management in young patients plays a small but important role within the broader discipline of cardiac electrophysiology (EP). By virtue of its sharp focus on developmental cardiology, congenital heart defects, and hereditary channelopathies, pediatric EP has contributed in significant ways to improved understanding of rhythm disorders in patients of all ages. Scientific progress in the field was recently reviewed at the 2012 meeting of the Heart Rhythm Society, where historical details of pioneering investigations in pediatric EP were highlighted. In this article, we hope to summarize those details and acknowledge the roles of individuals and organizations that were instrumental in developing the subspecialty.

Arrhythmogenic channelopathy syndromes presenting as refractory epilepsy

BACKGROUND

Children and young adults with potentially lethal cardiac channelopathies often present to medical care with a history of syncope or seizures due to episodic ventricular arrhythmias and associated cerebral hypoperfusion.

METHODS

Two important types of genetic arrhythmia syndromes-long QT syndrome and catecholaminergic polymorphic ventricular tachycardia-are discussed using relevant case examples. The pathophysiology and distinguishing clinical features of these conditions are reviewed.

RESULTS

The patients in each case were ultimately diagnosed with a cardiac channelopathy as the cause for their syncope and refractory seizures. With appropriate medical management, no further events have occurred to date.

CONCLUSIONS

Cardiac channelopathies can be misdiagnosed as refractory epilepsy when in fact these events represent convulsive syncopes. Knowledge of and suspicion for these arrhythmogenic conditions may expedite diagnosis and improve outcomes.

Pattern of recovery for transient complete heart block after open heart surgery for congenital heart disease: duration alone predicts risk of late complete heart block

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.

Cryoablation therapy for atrioventricular nodal reentrant tachycardia in children: a multicenter experience of efficacy

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.

Iatrogenic atrioventricular reentrant tachycardia following Bjork/Fontan palliation of tricuspid atresia: Electro-anatomic mapping, ablation, review and possible mechanism

This case report describes the successful ablation of an iatrogenic accessory pathway in a Fontan patient. A 15-year-old girl with tricuspid atresia was palliated with a Bjork modification Fontan procedure; six years later she developed supraventricular tachycardia. Electro-anatomic mapping during electrophysiology study localized a concealed iatrogenic atrioventricular accessory pathway and facilitated successful ablation using radiofrequency energy. This report reviews the reported cases of anomalous atrioventricular conduction (antegrade only, retrograde only [Hager, et al., J Thorac Cardiovasc Surg 2005;130:48-53], both [Liberman, et al., Pacing Clin Electrophysiol 2000;23:914-6]) after the Fontan/Bjork repair, outlines a potential pathophysiologic mechanism for the post-operative tachyarrhythmia and highlights the usefulness of electro-anatomic mapping in identifying unusual arrhythmias in post-operative patients with complex congenital heart disease.

[Attitudes of dental legal expert witnesses on their present status in Germany and approaches to the development of the profession]

BACKGROUND

Dental litigation has a key role for the autonomy of the dental profession. We conducted a study among legal dental expert witnesses in order to reflect the present situation and reveal the potential for professional development.

METHODS

A questionnaire was distributed among 161 participants of the Karlsruhe training for legal dental experts between 2004 and 2009. They were asked to describe and to reflect on the present situation of dental litigation in Germany.

RESULTS

83 questionnaires were returned (51.6%). The main reason to become a legal dental expert was to "support the profession". 68 participants (85.0%) think that civil action resulting from dental treatment will become more frequent. The quality of dental expert opinions is considered to be in need of improvement. Strategies to optimise dental expert opinions and to deal with the potential growing number of claims are developed.

CONCLUSION

Basic and advanced training for dental expert witnesses assures the quality of dental expert opinions and also provides a chance for the further development of the dental profession.

Multicenter study of the effectiveness of implantable cardioverter defibrillators in children and young adults with heart disease

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.

Experience with CartoSound for arrhythmia ablation in pediatric and congenital heart disease patients

PURPOSE

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).

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

THE INFLUENCE OF THE PLASMA COLLOIDS ON THE GRADIENT OF CAPILLARY PERMEABILITY

The influence of osmotic conditions on the gradient of capillary permeability disclosed by the distribution into mammalian muscle of vital dyes has been tested experimentally. The percentage of circulating blood proteins was increased in rabbits by the injection of compatible plasma, or of compatible serum concentrate obtained by means of a new method of ultrafiltration which has proved both rapid and effective. It was found that when this had been done and the circulatory conditions had stabilized themselves, the gradient of capillary permeability still existed, though its effective extent was less than under normal circumstances. When the percentage of circulating blood proteins was reduced, on the other hand, by repeated bleedings with return of the cells, either as such or suspended in the protein-free fluid obtained by dialysis of serum, the extent of the gradient of capillary permeability was broadened and dye passed out into the tissue more readily than usual from the capillary as a whole. In contrast to these findings injection of a very hypertonic dextrose solution during the period when dye was escaping had no perceptible effect on the gradient of capillary permeability. The observed phenomena cannot be explained by a flow of dye-stained fluid into or out of the blood vessels. The gradient of capillary permeability exists independently of osmotic conditions, though its extent can be markedly influenced by altering the amount of circulating blood proteins. A considerable proportion of the dye used to study the gradient is adsorbed upon these proteins, as subsidiary experiments have shown. This happening provides a sufficient cause for the differences observed in the extent of the gradient when the percentage of proteins is increased or diminished. The evidence like that of previous papers indicates that the cause for the gradient is to be found in a structural differentiation along the capillary, such that the barrier offered by its wall progressively diminishes on the way to the venule. Most current estimates of the effective osmotic pressure of the blood proteins fail to take into account the existence of local differences in permeability along the capillary.

Sensitivity and specificity of an automated external defibrillator algorithm designed for pediatric patients

OBJECTIVE

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Impact of a computer assisted navigation system on radiation exposure during pediatric ablation procedures

BACKGROUND

During catheter ablation procedures, non-radiologic navigation systems may reduce fluoroscopic exposure and energy applications, as well as improve procedural success rates.

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Presbyopietherapie mit Femtosekundenlaser

Presbyopia is by far the most common refractive error worldwide, with no permanent therapeutic option available. All efforts to restore accommodation by the use of surgery have not led to a generally accepted therapy. However, there is evidence from an animal model that the use of a femtosecond (fs) laser might influence the modulus of elasticity in the lens. Fs-laser impulses can create intralenticular disruption in animal eyes as well as human cadaver lenses and improve elasticity. The concept of treating presbyopia with fs-laser requires a new, complex theory combining the optical and the mechanical aspects of accommodation in the eye. Diagnostic tools for measuring optical change in power and geometrical modification as the eye views from far to near are needed to obtain objective clinical data. A non-invasive treatment of presbyopia to restore accommodation might be possible in the future.

Transcatheter cryotherapy for the treatment of supraventricular tachyarrhythmias in children: A single center experience

INTRODUCTION

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.

METHODS AND RESULTS

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.

CONCLUSIONS

Cryoablation is a safe and effective alternative for the treatment of SVT in children.

Transcatheter cryothermal ablation of junctional ectopic tachycardia in the normal heart

BACKGROUND

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.

OBJECTIVES

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Radiofrequency ablation for supraventricular tachycardia in children < or =15 kg is safe and effective

Risks associated with radiofrequency ablation (RFA) have been reported to be increased in children < or =15 kg. We sought to compare the safety and efficacy of RFA in children <15 kg with those between 15.1 and 20 kg. Clinical, electrophysiologic, and RFA data for all patients < or =20 kg who underwent RFA for supraventricular tachycardia between January 1994 and January 2003 were reviewed. Patients were divided into those < or =15 kg (group 1, n = 25) and those between 15.1 and 20 kg (group 2, n = 44). The two groups differed significantly in age and weight by design (group 1: mean weight, 11.9 +/- 3.0 kg; age, 2.8 +/- 1.9 years; group 2: weight, 18.0 +/- 1.5 kg; age, 5.1 +/- 1.1 years). There were no significant differences in other baseline characteristics except for incidence of structural heart disease (28% group 1 vs 7% group 2, p < 0.01). No significant differences in mechanism of tachycardia, arrhythmia cycle length, number of total and brief RFA applications, total RFA time, average and maximum RFA temperatures, total procedure duration, short-term success rate (96% group 1 vs 86% group 2, p = 0.17), long-term success rate (91% group 1 vs 89% group 2, p = 0.76), or major complications (8.0% group 1 vs 2.3% group 2, p = 0.39) were found. There were no procedure-related deaths in either group. These data suggest that, in two large volume electrophysiology centers, the procedural risks and outcomes of RFA are similar between patients weighing less than 15 kg and those between 15.1 and 20 kg.

Polymorphic ventricular tachycardia and KCNJ2 mutations

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.

Transtelephonic electrocardiographic monitors for evaluation of children and adolescents with suspected arrhythmias

OBJECTIVE

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.

METHODS

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).

RESULTS

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.

CONCLUSIONS

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.

Pulmonary function abnormalities in children with sickle cell disease

BACKGROUND

Adults with sickle cell disease (SCD) have restrictive lung function abnormalities which are thought to result from repeated lung damage caused by episodes of pulmonary vaso-occlusion; such episodes start in childhood. A study was therefore undertaken to determine whether children with SCD have restrictive lung function abnormalities and whether the severity of such abnormalities increases with age.

METHODS

Sixty four children with SCD aged 5-16 years and 64 ethnic matched controls were recruited. Weight and sitting and standing height were measured, and lung function was assessed by measurement of lung volumes and forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF) before and after bronchodilator.

RESULTS

Compared with the control subjects, the children with SCD had lower mean (SD) sitting height (69 (6.3) cm v 73 (7.7) cm; p=0.004), sitting:standing height ratio (0.50 (0.02) v 0.51 (0.01); p<0.0001), weight (33 (10.9) kg v 41 (14.9) kg; p=0.001), functional residual capacity measured by a helium gas dilution technique (1.2 (0.3) l v 1.3 (0.4) l; p=0.04), FEV1 (1.5 (0.5) l v 1.9 (0.7) l; p=0.0008), FVC (1.7 (0.6) l v 2.1 (0.8) l; p=0.001), and PEF (3.9 (1.3) l/s v 4.8 (1.5) l/s; p=0.0004). The effect of age on lung function differed significantly between the children with SCD and the controls for total lung capacity and vital capacity measured by plethysmography and functional residual capacity measured by helium gas dilution.

CONCLUSION

Lung function differs significantly in children with SCD compared with ethnic matched controls of a similar age. Our results suggest that restrictive abnormalities may become more prominent with increasing age.