Carolina Escudero

Predictors of myocardial recovery in pediatric tachycardia-induced cardiomyopathy

BACKGROUND Tachycardia-induced cardiomyopathy (TIC) carries significant risk of morbidity and mortality, although full recovery is possible. Little is known about the myocardial recovery pattern. OBJECTIVE The purpose of this study was to determine the time course and predictors of myocardial recovery in pediatric TIC. METHODS An international multicenter study of pediatric TIC was conducted. Children ≤18 years with incessant tachyarrhythmia, cardiac dysfunction (left ventricular ejection fraction [LVEF] <50%), and left ventricular (LV) dilation (left ventricular end-diastolic dimension [LVEDD] z-score ≥2) were included. Children with congenital heart disease or suspected primary cardiomyopathy were excluded. Primary end-points were time to LV systolic functional recovery (LVEF ≥55%) and normal LV size (LVEDD z-score <2). RESULTS Eighty-one children from 17 centers met inclusion criteria: median age 4.0 years (range 0.0-17.5 years) and baseline LVEF 28% (interquartile range 19-39). The most common arrhythmias were ectopic atrial tachycardia (59%), permanent junctional reciprocating tachycardia (23%), and ventricular tachycardia (7%). Thirteen required extracorporeal membrane oxygenation (n = 11) or ventricular assist device (n = 2) support. Median time to recovery was 51 days for LVEF and 71 days for LVEDD. Two (4%) underwent heart transplantation, and 1 died (1%). Multivariate predictors of LV systolic functional recovery were age (hazard ratio [HR] 0.61, P = .040), standardized tachycardia rate (HR 1.16, P = .015), mechanical circulatory support (HR 2.61, P = .044), and LVEF (HR 1.33 per 10% increase, p=0.005). For normalization of LV size, only baseline LVEDD (HR 0.86, P = .008) was predictive. CONCLUSION Pediatric TIC resolves in a predictable fashion. Factors associated with faster recovery include younger age, higher presenting heart rate, use of mechanical circulatory support, and higher LVEF, whereas only smaller baseline LV size predicts reverse remodeling. This knowledge may be useful for clinical evaluation and follow-up of affected children.

Electrophysiologic Considerations in Congenital Heart Disease and Their Relationship to Heart Failure

Current survival rates for complex forms of congenital heart disease (CHD) are excellent, allowing for an ever-growing population of adult survivors. Previous interventions and complex physiology, including the systemic right ventricle and single ventricle circulations, predispose these patients to heart failure and arrhythmias. The relationship between arrhythmias and heart failure in CHD is complex: cause and effect are not always readily separated. Therefore, the assessment and management of these patients requires an understanding of the relationship between the 2, with careful review of risk factors and arrhythmia substrates. Several forms of CHD predispose to arrhythmias even in the absence of surgical intervention because of abnormalities of the conduction system and intrinsic structural malformations. Surgical interventions might result in sinus node dysfunction and propensity for supraventricular and ventricular arrhythmias. Arrhythmias are important risk factors for sudden death in the CHD population. Device therapies directed at maintaining chronotropic competence, cardiac resynchronization, and preventing sudden death are increasingly used. These challenges unique to CHD underscore recommendations for such complex patients to be referred to specialized centres with expertise in managing CHD and its complications. In this review, we explore the complex interplay between arrhythmogenesis, CHD, and heart failure.

Characterization of Myocardial Repolarization Reserve in Adolescent Females With Anorexia Nervosa

Background— Patients with anorexia nervosa exhibit abnormal myocardial repolarization and are susceptible to sudden cardiac death. Exercise testing is useful in unmasking QT prolongation in disorders associated with abnormal repolarization. We characterized QT adaptation during exercise in anorexia. Methods and Results— Sixty-one adolescent female patients with anorexia nervosa and 45 age- and sex-matched healthy volunteers performed symptom-limited cycle ergometry during 12-lead ECG monitoring. Changes in the QT interval during exercise were measured, and QT/RR-interval slopes were determined by using mixed-effects regression modeling. Patients had significantly lower body mass index than controls; however, resting heart rates and QT/QTc intervals were similar at baseline. Patients had shorter exercise times (13.7±4.5 versus 20.6±4.5 minutes; P<0.001) and lower peak heart rates (159±20 versus 184±9 beats/min; P<0.001). The mean QTc intervals were longer at peak exercise in patients (442±29 versus 422±19 ms; P<0.001). During submaximal exertion at comparable heart rates (114±6 versus 115±11 beats/min; P=0.54), the QTc interval had prolonged significantly more in patients than controls (37±28 versus 24±25 ms; P<0.016). The RR/QT slope, best described by a curvilinear relationship, was more gradual in patients than in controls (13.4; 95% confidence interval, 12.8–13.9 versus 15.8; 95% confidence interval, 15.3–16.4 ms QT change per 10% change in RR interval; P<0.001) and steepest in patients within the highest body mass index tertile versus the lowest (13.9; 95% confidence interval, 12.9–14.9 versus 12.3; 95% confidence interval, 11.3–13.3; P=0.026). Conclusions— Despite the absence of manifest QT prolongation, adolescent anorexic females have impaired repolarization reserve in comparison with healthy controls. Further study may identify impaired QT dynamics as a risk factor for arrhythmias in anorexia nervosa.

An Echocardiographic Study of Left Ventricular Size and Cardiac Function in Adolescent Females with Anorexia Nervosa

OBJECTIVE This retrospective case-control study investigated cardiac dimensions and ventricular function in female adolescents with anorexia nervosa (AN) compared with controls. METHODS Echocardiographic measurements of left ventricular (LV) dimensions, LV mass index, left atrial size and cardiac index were made. Detailed measures of systolic and diastolic ventricular function were made including tissue Doppler imaging. Patients were stratified by body mass index ≤10th percentile (AN ≤ 10th) and >10th percentile (AN > 10th). RESULTS Ninety-five AN patients and 58 controls were included. AN and AN ≤ 10th groups had reduced LV dimensions, LV mass index, left atrial size and cardiac index compared with controls. There were no differences between groups in measures of systolic function. Measures of diastolic tissue Doppler imaging were decreased in AN and AN ≤ 10th. No differences in echocardiographic measurements existed between controls and AN > 10th. DISCUSSION Female adolescents with AN have preserved systolic function and abnormalities of diastolic ventricular function. AN ≤ 10th may be a higher risk group.

The Medical Management of Pediatric Arrhythmias

Opinion statementArrhythmias are an important cause of morbidity and mortality in children. Despite recent technological advances in treatment, pharmacologic therapy remains the most common treatment modality for pediatric arrhythmias. The choice of antiarrhythmic agent, the duration of therapy, and the dosing schedule depend on multiple factors including the recurrence risk and the arrhythmia burden (the latter being determined by the hemodynamic effect of the arrhythmia), and the frequency and duration of episodes. As with all pediatric medications, consideration must be given to the drug formulation, palatability, adverse effects and adherence issues. There are very few randomized trials available to guide the choice of therapy for pediatric arrhythmias, and thus treatment options often reflect physician or institutional preferences. Although various classification schemes exist, we classify antiarrhythmic agents based on their primary site of action: atrial muscle/accessory pathway (class IA, IC, and III agents); the atrioventricular node (beta-blockers, calcium channel blockers, digoxin, and class III agents); or ventricular muscle (class I and III agents). This type of categorization assists in the approach to treatment required for each type of arrhythmia encountered.

Jellyfish-Like Accessory Mitral Valve Tissue Causing Near-Collapse in a Young Child.

Accessory mitral valve tissue (AMVT) causing left ventricular outflow tract obstruction (LVOTO) is rare. We report a case of AMVT causing severe LVOTO resulting in acutely progressive symptoms of near-collapse. Urgent surgical resection eliminated the patient’s life-threatening symptoms. AMVT should be considered among potential LVOTO diagnoses, and early surgical intervention may be required.

Doppler Echocardiography Assessment of Aortic Stiffness in Female Adolescents with Anorexia Nervosa

Background: Anorexia nervosa (AN) is associated with abnormalities in biomarkers of cardiovascular risk. Arterial stiffness, as measured by pulse‐wave velocity (PWV), is also a risk factor for cardiovascular disease. The aims of this study were to determine the stiffness of the aorta in female adolescents with AN and to determine if either the severity or the type of AN was associated with PWV. Methods: This was a retrospective case‐control study. Adolescent patients with a clinical diagnosis of AN were included. Aortic diameter and pulse‐wave transit time over a portion of the thoracic aorta were measured using Doppler echocardiography, and PWV was calculated. Results: There were 94 female patients with AN and 60 adolescent female control subjects. There was no significant difference in age between patients with AN and control subjects (15.5 ± 1.7 vs 15.1 ± 2.6 years, P = .220). Body mass index (16.0 ± 2.4 vs 19.7 ± 2.7 kg/m2, P < .001) and body mass index percentile (9.4 ± 15.6 vs 45.5 ± 26.2, P < .001) were significantly lower for patients with AN than control subjects. PWV (443 ± 106 vs 383 ± 77 cm/sec, P < .001) was significantly higher in patients with AN than control subjects. Similar differences from control subjects were found in patients with AN with both lower and higher body mass index percentiles and also in patients with AN with the restrictive or the binge‐purge subtype. Conclusions: Female adolescents with AN have increased aortic stiffness compared with control subjects. This study suggests that patients with AN may be at increased risk for future cardiovascular disease. Future studies are required to determine the reversibility of these changes with weight restoration. HighlightsPulse‐wave velocity, a surrogate for aortic stiffness, was measured in patients with AN using Doppler echocardiography.Female adolescents with AN have increased thoracic aortic stiffness.Patients with AN may be at increased risk for cardiovascular disease.Aortic stiffness in patients with AN is not predicted by BMI.

Insights on Atrial Fibrillation in Congenital Heart Disease

Patients with congenital heart disease (CHD) have been surviving late into adulthood, with atrial arrhythmias being the most common long-term complication. In recent reports, atrial fibrillation (AF) tended to be the most common form of arrhythmias among groups of patients with adult CHD (ACHD) older than 50 years of age. When compared with their adult counterparts without CHD, AF in patients with ACHD has been characterized by a higher incidence and prevalence, younger age of onset, and a greater risk of progression to persistent AF. Risk factors for the development of AF are not well known but include older age, left atrial dilation, systemic hypertension, and multiple cardiac surgeries. Data on management options such as optimal antiarrhythmic drug therapy, indications for anticoagulation, and efficacy and safety of catheter ablation are limited. There is a crucial need for further research exploring management, prevention, and monitoring strategies for the growing ACHD patient population with AF. This report will provide a contemporary review of the epidemiology, pathophysiology, and management options for AF in this complex patient population.

A Doppler Echocardiographic Study of the Myocardial Inotropic Response to Peak Semisupine Exercise in Healthy Children: Development of a Simplified Index of Myocardial Reserve

Background: Stress echocardiography has been advocated for the detection of abnormal myocardial function and unmasking diminished myocardial reserve in pediatric patients. The aim of this study was to create a simplified index of myocardial reserve, derived from the myocardial inotropic response to peak semisupine exercise in healthy children, and illustrate its applicability in a sample of pediatric oncology patients. Methods: In this prospective analysis, children (7–18 years of age) with normal cardiac structure and function performed semisupine stress echocardiography to volitional fatigue. The quotient of wall stress at peak systole and heart rate–corrected velocity of circumferential fiber shortening were calculated at baseline and at peak exercise, the difference of which was termed the index of myocardial reserve (IMR). The IMR was also calculated in a retrospective sample of pediatric oncology patients with normal resting left ventricular function who had received anthracycline treatment and had performed the same exercise protocol to illustrate utility. Results: Fifty healthy subjects (mean age, 13.2 ± 2.6 years) and 33 oncology patients (mean age, 12.7 ± 4.0 years) were assessed. In the healthy children at peak exercise, heart rate–corrected velocity of circumferential fiber shortening significantly increased (from 1.17 ± 0.17 to 1.58 ± 0.24 circ · sec−1, P < .001), while the quotient of wall stress at peak systole significantly decreased (from 75.3 ± 17.1 to 55.3 ± 13.8 g · cm−2, P < .001), shifting the plot of the relationship between the two parameters upward and to the left. The mean IMR was −30.8 ± 17.8, and the normal distribution ranged from −4.7 (fifth percentile) to −67.3 (95th percentile). The IMR was abnormal in 10 oncology patients who were treated with anthracyclines. Conclusions: The authors have developed a novel IMR. Relative to the normal distribution of this IMR in healthy subjects, it is possible to identify patients with abnormal myocardial reserve. Thus, this study demonstrates the application of the IMR to aid in clinical decision making in individual patients. HighlightsSemisupine cycle ergometry is ideal for imaging during exercise in pediatric patients.Stress echocardiography may unmask diminished myocardial reserve.A novel index of myocardial reserve has been developed, providing clinicians with a simplified approach to assess patients.

ECHO-DOPPLER ASSESSMENT OF AORTIC STIFFNESS IN ADOLESCENT FEMALES WITH ANOREXIA NERVOSA

BACKGROUND: Anorexia nervosa (AN) is associated with cardiovascular complications and abnormalities of biomarkers associated with cardiovascular risk. Arterial stiffness, which is a risk factor for cardiovascular disease, has not been previously studied in patients with AN. This study aimed to determine the biophysical properties of the aorta in adolescent females with AN as compared to control subjects usingDoppler echocardiography. METHODS: This was a retrospective case-control study. Aortic diameter and pulse wave transit time were measured with echoDoppler. Blood pressure was recorded at the time of the echocardiogram. Pulse wave velocity (PWV), aortic input impedance (Zi), characteristic impedance (Zc), arterial pressure-strain elastic modulus (Ep), and arterial wall stiffness index (b-index) were calculated. Patients were divided into those with BMI or > 10th percentile to assess the effect of patient malnutrition on the biophysical properties of the aorta. RESULTS: There were 94 adolescent females with AN and 60 adolescent female controls. There was no difference in age between AN patients and controls (15.5 1.7 vs 15.1 2.6 years, p1⁄40.220). BMI (16.0 2.4vs 19.7 2.7, p 10th percentile. Using multiple linear regression, the only independent predictor of PWV was the presence of AN. CONCLUSION: The increased PWV, which is the most sensitive indicator of vascular dysfunction, indicates increased aortic stiffness in adolescent females with AN compared to controls. Increased PWV was not related to the degree of patient malnutrition. Our study suggests that patients with AN may be at increased risk of future cardiovascular disease. Further studies are required to determine if these changes persist with treatment and to determine long term outcomes.