Diastolic function evaluation in children with ventricular arrhythmia.

Premature ventricular contractions (PVC) are frequently seen in children. We evaluated left ventricular diastolic function in PVC children with normal left ventricular systolic function to detect whether diastolic function disturbances affect physical performance. The study group consisted of 36 PVC children, and the control group comprised 33 healthy volunteers. Echocardiographic diastolic function parameters such as left atrial volume index (LAVI), left atrial strains (AC-R, AC-CT, AC-CD), E wave, E deceleration time (Edt), E/E' ratio, and isovolumic relaxation time (IVRT) were measured. In the cardiopulmonary exercise test (CPET), oxygen uptake (VO2 max) was registered. Evaluation of diastolic function parameters revealed statically significant differences between the patients and controls regarding Edt (176.58 ± 54.8 ms vs. 136.94 ± 27.8 ms, p < 0.01), E/E' (12.6 ± 3.0 vs. 6.7 ± 1.0, p < 0.01), and IVRT (96.6 ± 19.09 ms. vs. 72.86 ± 13.67 ms, p < 0.01). Left atrial function was impaired in the study group compared to controls: LAVI (25.3 ± 8.2 ml/m2 vs. 19.2 ± 7.5 ml/m2, p < 0.01), AC-CT (34.8 ± 8.6% vs. 44.8 ± 11.8%, p < 0.01), and AC-R-(6.0 ± 4.9% vs. -11.5 ± 3.5%, p < 0.01), respectively. VO2 max in the study group reached 33.1 ± 6.2 ml/min/kg. A statistically significant, moderate, negative correlation between VO2 max and E/E' (r = -0.33, p = 0.02) was found. Left ventricular diastolic function is impaired and deteriorates with the arrhythmia burden increase in PVC children. Ventricular arrhythmia in young individuals may be related to the filling pressure elevation and drive to exercise capacity deterioration.

Cardiopulmonary capacity is reduced in children with ventricular arrhythmia.

BACKGROUND: Premature ventricular contractions (PVCs) are frequently seen in children and are considered benign. A substantial group of adolescents with PVCs complain about a broad range of clinical symptoms, including low exertion tolerance. OBJECTIVE: The purpose of this study was to evaluate prospectively whether ventricular arrhythmia affects physical performance in adolescents with normal left ventricular function, using a cardiopulmonary exercise test (CPET) and evaluating the electrocardiographic (ECG) characteristics of patients with PVCs with regard to exercise capacity. METHODS: The study group consisted of 49 children with PVCs and normal left ventricular function. The control group consisted of 36 healthy volunteers. Standard ECG, 24-hour Holter ECG, and CPET were performed. PVCs were analyzed for QRS duration, bundle branch block pattern, QRS axis, and coupling interval (CInt). For CPET, heart rate (HR), oxygen uptake (VO2max), predicted VO2max, and VO2max expressed as a percentage of the predicted value (%VO2) were measured. RESULTS: In 37 patients (76%), arrhythmia subsided during exercise. Patients achieved lower VO2max (32.9 ± 6.3 mL/min/kg) than controls (40.4 ± 6.7 mL/min/kg; P <.01). %VO2 was 71.0 ± 13.7 in patients and 79.3 ± 12.2 in controls (P <.01). Exercise HR at which PVCs subsided correlated with VO2max (r = 0.3; P = .07). Patients with persisting arrhythmia performed worse than those in whom arrhythmia subsided during exercise (VO2max, P <.01; %VO2,P <.01). No correlation between QRS and CInt parameters and VO2max was observed. CONCLUSION: Patients with PVCs have lower aerobic capacity than their healthy peers. Further worsening of exercise capacity is present when PVCs are preserved during effort.

Assessment of the physical performance in children with asymptomatic pre-excitation.

AIMS: Pre-excitation syndrome can lead to recurrent supraventricular tachycardias (SVTs) and carries a risk of sudden cardiac death (SCD). However, an underestimated consequence of antegrade conduction through an accessory pathway is fusion of intrinsic and accessory conduction that causes asynchronous activation and myocardial contraction that could be a cause for cardiac dysfunction and dilation. It is not known to what extent pre-excitation affects myocardial and physical performance in those patients. The aim of the study was to assess to what degree ventricular pre-excitation affects physical performance in children, using cardio-pulmonary exercise testing (CPET). METHODS AND RESULTS: The study group consisted of 30 asymptomatic children, aged 8-17 years, with pre-excitation and no history or documentation of SVT compared to 31 healthy controls matched according to sex and age. All patients underwent routine cardiology assessment and then CPET. Echocardiography showed there were no differences in the left ventricular size and function between the study and control group. During the CPET both, patients and controls achieved maximal effort. Patients in the study group showed significantly lower values of VO2max and anaerobic threshold when compared to controls. The most affected subgroup was patients with persistent pre-excitation throughout the exercise. CONCLUSIONS: Physical performance is affected in children with pre-excitation. This effect is stronger in patients with persistent delta wave observed throughout the exercise.

Intracardiac atrial overdrive pacing as an alternative to extracorporeal membrane oxygenation in the treatment of cardiogenic shock due to drug refractory and incessant persistent junctional reciprocating tachycardia in a 7-month-old infant.

In the case of prolonged, undiagnosed persistent junctional reciprocating tachycardia in infants, compensatory mechanisms are exhausted leading to heart failure. However, when cardioverted to sinus rhythm patients often deteriorate due to cardiac output dependency on the higher rates. Extracorporeal membrane oxygenation (ECMO) is often used to stabilize their hemodynamic status. A 7-month-old female infant was admitted in cardiogenic shock due to drug refractory supraventricular tachycardia (SVT). Pharmacological cardioversion to sinus rhythm with heart rate (HR) of 90 bpm was achieved but resulted in hemodynamic deterioration and early recurrence of arrhythmia. Right atrial overdrive pacing (ODP) wire was introduced through femoral vein and allowed to override the tachycardia with 2:1 A:V block and HR of 160 bpm. ODP was continued for 24 h allowing to wean off the inotropic support. We postulate that ODP can be a safe and less invasive alternative to ECMO in stabilizing infants with cardiogenic shock due to intractable SVTs.

Evaluation of Galectin-3 Plasma Concentration in Adolescents with Ventricular Arrhythmia.

Galectin-3 (G3) is a biomarker known as an inflammatory state exponent. The aim of this paper was to analyze the G3 in adolescents with ventricular arrhythmia (VES) in order to evaluate its impact on myocardial tissue preservation. The study group (SG) consisted of 25 VES adolescents. The control group (CG) was 21 healthy children. G3 was assessed in the SG and CG. In the SG electrocardiography, Holter monitoring, echocardiography and CMR were performed. The G3 in SG was 13.45 ± 11.4 ng/mL and in CG 7.2 ± 2.0 ng/mL, p < 0.001. Moderate positive correlation between the G3 and z-score of the left ventricular diameter (r = 0.47, p = 0.041) and moderate negative correlation between the G3 and the left ventricular ejection fraction in cardiac magnetic resonance (CMR EF) (-0.49, p = 0.032) were found. According to the multiple linear regression analysis, CMR EF and VES were independent predictors for G3 elevation. Conclusion: Galectin-3 plasma concentration is elevated and correlates with the chosen left ventricular dysfunction parameters in adolescents suffering from ventricular arrhythmia. Further investigation is necessary to establish if elevated G3 is a useful biomarker for screening young individuals with ventricular arrhythmia who are at risk of structural cardiovascular pathology.

Management of Young Athletes with Asymptomatic Preexcitation-A Review of the Literature.

INTRODUCTION: The management of young athletes with asymptomatic preexcitation remains a challenge, regardless of the progress we have made in understanding the basis of condition and developing catheter ablation procedures. The risk of sudden death, however small, yet definite, being the first symptom is determining our approach. The aim of the study was to establish the current state of knowledge regarding the management of young athletes diagnosed with asymptomatic preexcitation, by conducting a literature review. MATERIAL AND METHODS: A comprehensive literature review was completed in accordance to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search was limited to English language publications using the following search terms: "asymptomatic" or "incidental" and "pre-excitation" or "Wolff-Parkinson-White" or "delta wave" and "athlete" or "sport". The search was supplemented by hand review of the bibliographies of previous relevant systematic reviews. RESULTS: The search resulted in 85 of abstracts, and the manual search of the bibliographies resulted in 24 additional papers. After careful analysis 10 publications were included in the review. In all but one of the presented papers, the authors used non-invasive methods and then either trans-esophageal or invasive EPS as a way to risk stratify asymptomatic patients. Evidence of rapid conduction through the accessory pathway was considered high risk and prompted sport disqualification. In the analysed reports there were combined: 142 episodes of the life-threatening events (LTE)/sudden death (SCD), of which 56 were reported to occur at rest, 61 during activity and no data were available for 25. CONCLUSIONS: athletic activity may impose an increased risk of life-threatening arrhythmias in patients with asymptomatic preexcitation; hence, a separate approach could be considered, especially in patients willing to engage in high-intensity, endurance and competitive sports.

Normative Values for Heart Rate Variability Parameters in School-Aged Children: Simple Approach Considering Differences in Average Heart Rate.

Background: Heart rate variability (HRV) analysis is a clinical tool frequently used to characterize cardiac autonomic status. The aim of this study was to establish normative values for short-term HRV parameters by considering their main determinants in school-aged children. Methods: Five-minute electrocardiograms were taken from 312 non-athlete children (153 boys) at age of 6 to 13 years for computation of conventional time- and frequency-domain HRV parameters. Heart rate (HR), respiratory rate, age, body mass index, and sex were considered as their potential determinants. Multiple regression analysis revealed that HR was the principal predictor of all standard HRV indices. To develop their universal normative limits, standard HRV parameters were corrected for prevailing HR. Results: The HRV correction for HR yielded the parameters which became independent on both sex and HR, and only poorly dependent on age (with small effect size). Normal ranges were calculated for both time- and frequency-domain indices (the latter computed with either fast Fourier transform and autoregressive method). To facilitate recalculation of standard HRV parameters into corrected ones, a calculator was created and attached as a Supplementary Material that can be downloaded and used for both research and clinical purposes. Conclusion: This study provides HRV normative values for school-aged children which have been developed independently of their major determinants. The calculator accessible in the Supplementary Material can considerably simplify determination if HRV parameters accommodate within normal limits.

Evidence for troponin C (TNNC1) as a gene for autosomal recessive restrictive cardiomyopathy with fatal outcome in infancy.

Restrictive cardiomyopathy is a rare form of pediatric cardiac disease, for which the known genes include MYH7, TNNT2, TNNI3, ACTC1, and DES. We describe a pediatric proband with fatal restrictive cardiomyopathy associated with septal hypertrophy and compound heterozygosity for TNNC1 mutations (NM_003280: p.A8V [c.C23T] and p.D145E [c.C435A]). This association between restrictive cardiomyopathy and TNNC1 mutations was strengthened by prospective observations on the second pregnancy in the family which revealed, in the presence of the same TNNC1 genotype, prenatally diagnosed hypertrophic cardiomyopathy which evolved into restrictive cardiomyopathy, heart failure and death at the age of 9 months. Contrary to previous reports, family and population analyses showed that each of the TNNC1 variants was not pathogenic when present alone. Our results (i) confirm that genetic backgrounds of hypertrophic cardiomyopathy and restrictive cardiomyopathy overlap and (ii) indicate that TNNC1 is a likely novel gene for autosomal recessive restrictive cardiomyopathy. © 2016 Wiley Periodicals, Inc.