At-home determination of 24-h urine sodium excretion: Validation of chloride test strips and multiple spot samples.

Sodium intake and compliance with dietary sodium modification are typically assessed using a 24-h urine collection analyzed using flame photometry, but this is inconvenient. Spot urine samples have been investigated as alternatives to 24-h collections, but their accuracy is poor. Since sodium and chloride are present in equal concentrations in dietary salt, chloride test strips may provide a suitable proxy for at-home measurement of urine sodium concentrations. We aimed to determine whether (i) chloride test strips provide a reliable measure of urinary sodium compared to the gold standard flame photometry and (ii) multiple spot samples accurately reflect 24-h urine sodium. We recruited 43 participants (19 males) aged 23.6 ± 0.6 years to complete multiple consecutive spot samples (morning and evening) along with a 24-h urine sodium collection. Urine 24-h sodium estimates using chloride test strips (114.6 ± 7.5 mmol/day) were highly correlated (r = 0.900, p < 0.0001) with flame photometry (121.1 ± 7.7 mmol/day) with a bias of -6.53 ± 22.2 mmol/day. Use of a three-spot sample average (both morning and evening spot samples) with a correction factor applied (122.9 ± 4.1 mmol/day) provided a good approximation of 24-h sodium measured by flame photometry (125.6 ± 9.0 mmol/day), with a bias of -2.55 ± 43.9 mmol/day. Chloride test strips applied to a 24-h urine collection provide a highly accurate measure of urinary sodium excretion, permitting convenient at-home sample collection and analysis. Their application to multiple spot samples provides a reasonable approximation of sodium excretion that can be used to conveniently monitor attempts at dietary sodium manipulation, without the inconvenience of completing a 24-h urine sample.

Phospholamban cardiomyopathy: a Canadian perspective on a unique population.

INTRODUCTION: Phospholamban cardiomyopathy is an inherited cardiomyopathy, characterised by a defect in regulation of the sarcoplasmic reticulum Ca2+ pump, often presenting with malignant arrhythmias and progressive cardiac dysfunction occurring at a young age. METHODS: Phospholamban R14del mutation carriers and family members were identified from inherited arrhythmia clinics at 13 sites across Canada. Cardiac investigations, including electrocardiograms, Holter monitoring (premature ventricular complexes, PVCs), and imaging results were summarised. RESULTS: Fifty patients (10 families) were identified (median age 30 years, range 3-71, 46% female). Mutation carriers were more likely to be older, have low-voltage QRS, T­wave inversion, frequent PVCs, and cardiac dysfunction, compared to unaffected relatives. Increasing age, low-voltage QRS, T­wave inversion, late potentials, and frequent PVCs were predictors of cardiac dysfunction (p < 0.05 for all). Older carriers (age ≥45 years) were more likely to have disease manifestations than were their younger counterparts, with disease onset occurring at an older age in Canadian patients and their Dutch counterparts. DISCUSSION: Among Canadian patients with phospholamban cardiomyopathy, clinical manifestations resembled those of their Dutch counterparts, with increasing age a major predictor of disease manifestation. Older mutation carriers were more likely to have electrical and structural abnormalities, and may represent variable expressivity, age-dependent penetrance, or genetic heterogeneity among Canadian patients.

Exercise and the multidisciplinary holistic approach to adolescent dysautonomia.

AIM: To determine whether an eight-week strength training programme as part of a multidisciplinary approach would minimise symptoms and improve quality of life in patients with dysautonomia. METHODS: Adolescents referred to a tertiary-level cardiology service from May 2014-December 2015 with symptoms of dysautonomia were eligible. Participants completed an exercise test and a quality of life (QoL) questionnaire (PedsQL) prior to the intervention. Participants were asked to complete exercises five times per week. After eight weeks, participants returned for follow-up testing. Parents completed a proxy report of their child's QoL at both time points. RESULTS: A total of 17 participants completed the study protocol with an adherence rate of up to 50%. Post-intervention, QoL scores improved across all levels in the participants [total 65.2 (50.4-74.7) vs 48.9 (37.5-63.0); p = 0.006; psychosocial 65.8 (56.1-74.6) vs 50.0 (41.7-65.8); p = 0.010; physical 62.5 (37.5-76.6) vs 43.8 (25-68.5); p = 0.007] and their parent proxy reports [total 63.5 (48.7-81.3) vs 50.0 (39.3-63.0); p = 0.004; psychosocial 62.1 (52.1-81.3) vs 50.0 (39.6-59.2); p = 0.001; physical 62.5 (51.6-80.0) vs 50.0 (27.5-70.3); p = 0.003]. Treadmill time also improved (9.1 vs 8.0 minutes; p = 0.005). CONCLUSION: Following an eight-week strength training programme, dysautonomia patients report a significant improvement in both their quality of life and endurance time.

Recurrent congestive heart failure in a child due to probable myocarditis.

Recurrent congestive heart failure (CHF) attributable to myocarditis is a seldom-discussed entity in the scientific literature. This report describes the case of an 8-year-old girl who had three clinically identical episodes of CHF, beginning at the age of 5 years, with each episode preceded by a viral prodrome. The clinical features and the echocardiography and electrocardiogram findings were most supportive of myocarditis. Symptoms and investigations completely normalized between episodes. The third episode, associated with influenza A (strain H1N1) infection, led to cardiac arrest and death on day 2 after admission. Autopsy showed mild cardiomegaly with microscopic foci of myocardial fibrosis and extensive contraction band necrosis. This report is the first to describe recurrent CHF due to probable myocarditis in a pediatric patient.

A review of sudden unexpected death in the young in British Columbia.

BACKGROUND: Since 2008, all pediatric deaths in British Columbia have been reported to the coroner. The cause of death in pediatric sudden unexpected death (SUD) remains undetermined in 10% to 30% of cases. Before 2008, there was no standardized approach for referring relatives of SUD victims for follow-up medical testing to determine whether they were affected by the same condition. In the current era, genetic testing for primary electrical diseases can be used in cases of undetermined SUD when existing diagnostic methods fail. OBJECTIVE: To improve the clinical care of surviving relatives of SUD victims, the current practice of assessment of SUD in British Columbia was reviewed. The study also aimed to determine the prevalence of SUD and sudden cardiac death, types of postmortem investigations performed in SUD, and the use of genetic testing for primary electrical diseases in SUD from 2005 to 2007. METHODS: Cases involving individuals zero to 35 years of age, with a death due to natural disease or an undetermined cause were compiled from the British Columbia Coroners Service database. Cases were determined to be either sudden death due to a previously diagnosed condition or SUD. RESULTS: In individuals zero to 35 years of age, the prevalence of SUD was 9.21 per 100,000 and the prevalence of sudden cardiac death was 5.26 per 100,000. There were 35 cases of SUD in which a cause of death was unidentified after autopsy (autopsy- negative SUD). Specimens were collected, and specialists were consulted in 86% of these cases in the pediatric population and 14% in the adult population. A suggestion was made to relatives to seek medical attention in 26% of the autopsy-negative SUDs, and molecular autopsy was discussed in 9% of cases but performed in none. CONCLUSION: Currently, SUD in British Columbia is not managed in a way that optimizes a timely diagnosis for surviving relatives. A standardized protocol for SUD is needed to ensure optimization of diagnosis, genetic testing and referral of surviving relatives.

Cardiac risk assessment before the use of stimulant medications in children and youth: A joint position statement by the Canadian Paediatric Society, the Canadian Cardiovascular Society, and the Canadian Academy of Child and Adolescent Psychiatry.

Regulatory decisions and scientific statements regarding the management of attention-deficit hyperactivity disorder (ADHD) raise questions about the safety of medications and the appropriate pretreatment evaluation to determine suitability for treatment with medication. This is particularly true in the setting of known structural or functional heart disease. The present paper reviews the available data, including peer-reviewed literature, data from the United States Food and Drug Administration Web site on reported adverse reactions in children using stimulant medication, and Health Canada data on the same problem. A consensus-based guideline on appropriate assessment is provided, based on input from members of the Canadian Paediatric Society, the Canadian Cardiovascular Society and the Canadian Academy of Child and Adolescent Psychiatry, with specific expertise and knowledge in the areas of both ADHD and pediatric cardiology. The present statement advocates a thorough history and physical examination before starting stimulant medications, with an emphasis on the identification of risk factors for sudden death, but does not routinely recommend electrocardiographic screening or cardiac subspecialist consultation unless indicated by history or physical examination findings. A checklist for identifying children who are potentially at risk of sudden death (independent of ADHD or medications used to treat it) is provided. Although recommendations are based on the best evidence currently available, the committee further agrees that more research on this subject is necessary to optimize the approach to this common clinical scenario.

Diagnosis of postoperative arrhythmias following paediatric cardiac surgery.

Arrhythmias are commonly encountered in the paediatric intensive care unit setting, most frequently in the setting of postoperative congenital heart disease. Postoperative arrhythmias are an important cause of morbidity in children in the postoperative period following cardiac surgery for congenital cardiac lesions. It is important for all paediatric critical care physicians involved in the care of these children to understand the potential mechanisms involved and how to make an accurate diagnosis. The existing literature has focused on small groups and specific arrhythmias. There is a paucity of literature to guide the clinician in approaching arrhythmias in the paediatric intensive care unit setting. Our objective was to review the recognition and diagnosis of paediatric arrhythmias in the postoperative period following congenital cardiac surgery. Timely and accurate identification of the rhythm disturbance is mandatory and allows for the institution of effective, rhythm specific management strategies.

Cardiac risk assessment before the use of stimulant medications in children and youth.

Regulatory decisions and scientific statements regarding the management of attention-deficit hyperactivity disorder (ADHD) raise questions about the safety of medications and the appropriate pretreatment evaluation to determine suitability for treatment with medication. This is particularly true in the setting of known structural or functional heart disease. The present paper reviews the available data, including peer-reviewed literature, data from the United States Food and Drug Administration Web site on reported adverse reactions in children using stimulant medication, and Health Canada data on the same problem. A consensus-based guideline on appropriate assessment is provided, based on input from members of the Canadian Paediatric Society, the Canadian Cardiovascular Society and the Canadian Academy of Child and Adolescent Psychiatry, with specific expertise and knowledge in the areas of both ADHD and paediatric cardiology. The present statement advocates a thorough history and physical examination before starting stimulant medications, with an emphasis on the identification of risk factors for sudden death, but does not routinely recommend electrocardiographic screening or cardiac sub-specialist consultation unless indicated by history or physical examination findings. A checklist for identifying children who are potentially at risk of sudden death (independent of ADHD or medications used to treat it) is provided. Although recommendations are based on the best evidence currently available, the committee further agrees that more research on this subject is necessary to optimize the approach to this common clinical scenario.

Medications used to manage supraventricular tachycardia in the infant a North American survey.

Supraventricular tachycardia is the most common pediatric arrhythmia, but there is no consensus and little evidence to guide its treatment. We sent a questionnaire to pediatric cardiologists in North America to assess the current practice pattern. Of 1534 surveys mailed, 352 (23%) were returned and 295 (19%) had complete data for analysis. In the acute setting, 11 different medications were chosen. The most commonly used in the infant without preexcitation were digoxin (42%), procainamide (21%), esmolol (13%), propranolol (10%), and amiodarone (8%). In the infant with preexcitation, propranolol (34%), procainamide (23%), esmolol (17%), amiodarone (11%), and digoxin (6%) were used. In the chronic setting, 8 different medications were chosen. The most commonly used in this scenario were digoxin (52%), propranolol (33%), amiodarone (4%), and sotalol (3%). In the infant with preexcitation, propranolol (70%), amiodarone (6%), digoxin (6%), atenolol (6%), and flecainide (5%) were used. Medication choices were influenced by additional electrophysiology training and preexcitation. Digoxin was used less in the setting of preexcitation. There are no comparative trials to explain the different medication choices. Although a number of medications may be efficacious, a randomized clinical trial is needed to offer further guidance.

Dilated cardiomyopathy masquerading as long QT syndrome.

Atrioventricular block has been described in association with cases of long QT syndrome and mortality is increased in this subgroup. We describe an infant with congenital QT prolongation and atrioventricular block with normal cardiac function, leading to the initial diagnosis of long QT syndrome. She subsequently developed dilated cardiomyopathy requiring cardiac transplantation. We postulate that the presenting electrocardiograph abnormalities were early manifestations of the myocardial disease, preceding the development of myocardial dysfunction by several months. The need for heightened surveillance in cases of QT prolongation with atrioventricular block is amplified by the possibility of an evolving cardiomyopathy.

Post-hoc diagnosis of congenital long QT syndrome in patients with tetralogy of Fallot.

This report describes two patients diagnosed with congenital long QT syndrome after surgical repair of tetralogy of Fallot. Despite the fact that both patients had preoperative electrocardiograms demonstrating QT prolongation, neither was diagnosed until long after their surgeries, when they or their relatives presented with symptoms of long QT syndrome. A brief discussion highlights the reasons why long QT syndrome may be overlooked in patients with structural heart defects and the clinical importance of identifying these patients preoperatively.

Evolution of heart rate control after transplantation: conduction versus autonomic innervation.

In cardiac transplantation, the donor organ is not initially innervated and demonstrates decreased heart rate variability (HRV). However, HRV may improve after several months. The mechanism for HRV improvement has not been elucidated; autonomic "reinnervation" of the donor heart has been proposed. The role of atrioatrial conduction from recipient to donor organ has not been evaluated. We prospectively evaluated cardiac transplant patients with a limited electrophysiology study at the time of their surveillance biopsies. Recordings were made of recipient and donor signals, observing conduction properties between recipient and donor atria. Holter recordings were analyzed and HRV was determined using spectral analysis techniques, recording mean RR interval, low-frequency power (LF), high-frequency power (HF), and the LF/HF ratio. These were compared to published norms. From November 1999 to May 2000, 21 patients (6 female) who underwent cardiac transplantation participated at a median age of 101 months (range, 4.1-217 months). Time posttransplant ranged from 26 days to 71 months. Holter data were available for 20 patients and demonstrated dissociated P waves in 13 (65%). The mean heart rate on Holter was 111 beats per minute (bpm) (range, 85-161 bpm). We were able to record distinct recipient atrial signals in 16 of 21 (76%) patients. The average recipient tissue heart rate was 55% that of the donor heart rate. We documented atrioatrial association in only 1 patient. HRV did not reach normal values for most patients and did not increase with time posttransplantation. The LF values were in the normal range for most patients, whereas 3 patients had normal HF values and 2 patients had values just below normal. Recipients of heart transplantation have a predominantly sympathetic influence of HRV. These preliminary data suggest that atrioatrial conduction does not play a role in reestablishing normal heart rate control following pediatric cardiac transplantation.

Predictors of refractory tachycardia in infants with supraventricular tachycardia.

Reentrant supraventricular tachycardia (SVT) is the most common arrhythmia in infants. There are few predictors as to which patients will have recurrent or refractory SVT. We retrospectively reviewed records of all infants with SVT evaluated at The Hospital for Sick Children, Toronto, between January 1, 1995, and December 31, 1999. Patients with reentrant SVT documented in infancy and structurally normal hearts were included. Patients were placed in two groups: the "simple" group consisted of patients with SVT completely controlled by not more than one medication, and the "complex" group consisted of patients with recurrent episodes requiring at least one medication change for control. Forty-two cases were analyzed-23 in the simple group and 19 in the complex group. One patient in each group died. Age at presentation was 50.4 +/- 13.2 days for the simple group versus 10.2 +/- 2.5 days for the complex group (p <0.01). Complex patients were treated with a median of three medications and were more likely to have echocardiographically reduced ventricular function. The surface electrocardiogram RP interval during SVT was significantly longer in complex patients (p <0.001). There were no differences between the groups in gender, cycle length in SVT or sinus rhythm, the presence of pre-excitation, initial medication choice, or duration of therapy. Recurrent SVT in infancy is associated with younger age and/or ventricular dysfunction at presentation and also with slower ventriculoatrial conduction. The similar duration of therapy for simple and complex patients suggests that the early clinical course of SVT in infancy is not predictive of long-term outcome.

Balloon angioplasty of right ventricular outflow tract conduits.

Palliation of complex congenital heart disease, requiring reconstruction of the right ventricular outflow tract (RVOT), is standard practice. Survival of the homograft is a limiting factor. We examined the role of balloon angioplasty (BAP) in prolonging conduit life. Twelve patients underwent 15 BAP procedures between February 1989 and October 1997. The median age at conduit insertion was 28 months with detection of a significant echo gradient 42 months later. Calcification of homografts, with attendant obstruction and valve dysfunction, was present in all patients. BAP was performed within 1 month of echocardiography and reduced the gradient from a median of 57 to 38 mmHg (p < 0.0005). Echocardiographic follow-up showed persistent gradients (median 68 mmHg) and 11/12 patients went on to conduit replacement after BAP. Only one patient had replacement deferred as a result of BAP. Complications requiring intervention occurred in 20% of the procedures and included bleeding and an unusual balloon fracture. Although BAP can reduce the pressure gradient across the RVOT conduit, the effect is transient and the delay of surgery is not due to improved hemodynamic function. Approximately 10% of cases will benefit from BAP alone, but given the high rate of complications, we do not recommend this procedure as a means of prolonging conduit life.

Echocardiography and pulmonary function testing in childhood onset systemic lupus erythematosus.

The aim of this paper was to investigate the frequency of echocardiography (ECHO) and pulmonary function test (PFT) abnormalities in childhood onset systemic lupus erythematosus (SLE), and to determine the relationship of these abnormalities to disease activity. The charts of 50 patients with childhood onset SLE attending a pediatric rheumatology clinic were reviewed for ECHO and PFT studies. The frequency and description of ECHO and PFT abnormalities were documented. Possible associations of PFT and ECHO abnormalities with clinical cardiopulmonary disease, radiographic findings, and measures of lupus disease activity were evaluated. Forty patients (80%) had at least one ECHO study. Twenty-seven (68%) had an abnormal initial study. Nine of 14 patients with an initial abnormal ECHO had normal findings on repeated study. Three abnormalities were considered moderately severe. Thirty-three patients (66%) had at least one PFT performed. Sixteen (48%) were abnormal initially. Four of these 'abnormal' studies were repeated and the abnormalities persisted. Nine patients (27%) were considered to have a severe abnormality. Thirty-one children (62%) had both studies performed. An initial abnormal ECHO and abnormal PFT was found in 10 (32%) of these children. No relationship between ECHO or PFT abnormality and any measure of disease activity (physician's global assessment, anti DNA, C3 or ESR) could be found. Occult cardiac and pulmonary disease as demonstrated by ECHO or PFT occurs frequently in childhood onset SLE. If we wish to understand the natural history of these abnormal heart and lung findings, it will be necessary to do serial testing with ECHO and PFTs in this population.

Spontaneously terminating apparent ventricular fibrillation during transesophageal electrophysiological testing in infants with Wolff-Parkinson-White syndrome.

This article describes two infants with Wolff-Parkinson-White (WPW) syndrome in whom apparent VF occurred without antecedent AF or atrial flutter during routine transesophageal electrophysiological testing. Remarkably, this arrhythmia terminated spontaneously in both infants. The documentation of self-limited apparent VF, or polymorphic ventricular tachycardia close to VF, in transesophageal testing adds another dimension to the management of WPW.

Coil occlusion of the patent ductus arteriosus: lessons learned.

PURPOSE: To review the clinical outcomes of catheter-directed coil occlusion (coil occlusion) of persistently patent ductus arteriosus (PDA) at a pediatric tertiary care hospital. METHODS: A retrospective review of all patients referred to the Cardiac Catheterization Laboratory for coil occlusion at our institution was performed. Twenty-one consecutive patients (12 female) underwent coil occlusion and follow-up between May 1995 and December 1997. We undertook PDA occlusion if: (a) the PDA narrowed to less than 4 mm on echocardiogram and (b) the minimum body weight was approximately 10 kg. Standard right and retrograde left heart catheterization was performed, followed by coil occlusion. Color-flow mapping (CFM) was used intra-procedurally to confirm occlusion of the PDA with a follow-up study several weeks later. RESULTS: The median age and weight of the patients were 33 months and 13.2 kg, respectively. Fourteen patients received one coil, with six requiring a second coil and one requiring multiple coils. Initial follow-up was at a median of 2.4 months. At latest follow-up, 2 patients still have persistent flow at the ductal level. The coils were deployed without complication or embolization. CONCLUSIONS: A review of our first 21 cases demonstrated three important lessons: (1) the maximum diameter of the PDA suitable for coil occlusion is approximately 3 mm; (2) CFM must show complete obliteration of flow in the catheterization lab in order to ensure occlusion of the PDA at follow-up; and (3) the Jackson detachable system allows for precise placement of the coil, often within another coil.