Heart Rate Variability in Children with Exercise-Induced Idiopathic Ventricular Arrhythmias

Abstract

Ventricular arrhythmias (VAs) are common pediatric rhythm disorders requiring comprehensive laboratory evaluation. Although usually idiopathic, implying a benign character and favorable prognosis, the initial clinical approach is still not established in all cases. Considering their prognostic significance, exercise-induced (precipitated or aggravated) VAs usually require additional diagnostics, treatment, and follow-up. A number of reports have presented experimental and clinical evidence that increased sympathetic activity can initiate, or at least facilitate, VAs. Recent data highlight the relationship between exercise-induced idiopathic VAs (IVAs) and the long-term risk of cardiovascular death. The aim of this study was to assess the utility of heart rate variability (HRV) analysis as a noninvasive method for estimating autonomic nervous activity in children with exercise induced IVAs. The study included 42 children with IVAs, who were divided into two groups: children with exercise induced (precipitated or aggravated) IVAs and children with exercised-suppressed IVAs. Time-domain HRV parameters were analyzed from 24-h ambulatory electrocardiography recordings, and the majority of children underwent an exercise stress test using the McMaster protocol. The results of this study showed no significant changes in parasympathetic index, i.e., the square root of the mean of the sum of the squares of the differences between adjacent NN intervals (the length between two successive heartbeats) between the groups examined. On the other hand, we observed diminished time-domain values for the standard deviation of all adjacent NN intervals, as well as diminished time-domain values for standard deviation of the averages of NN intervals in all 5-min segments in the group of children with exercise-induced IVAs, implicating increased sympathetic activity in such individuals. HRV analysis could be a helpful diagnostic method, giving useful information regarding cardiac autonomic control in some children with exercise-induced IVAs.

Heart Rate Variability in Children with Tricyclic Antidepressant Intoxication

“…In many conditions, the balance between the sympathetic and parasympathetic systems is affected, and cardiac autonomic function disorders appear [28, 29]. Abnormalities on HRV as a marker of cardiac autonomic control are presumed to be risk factors for arrhythmia, and it has been shown that they can be used as reliable noninvasive markers of the presence of an underlying disease [30–33]. In our study, HRV abnormalities were clearly shown in children with TCA intoxication during the first 24 hours of their admission.…”

“…Decreased time-domain parameters, particularly SDNN, gave an idea about the association between the HRV results and ECG findings. Bjelakovic et al [33] found a marked decrease in the SDNN and SDANN levels in adults with exercise-induced ventricular arrhythmia, and they suggested that this decrease might be related to the direct effect of the sympathetic system on myocardial electrical activity. Changes in the RMSDD and pNN50 components also indicated that the autonomic system was affected by TCA poisoning via the vagus nerve.…”

State of the art paper The role of G protein coupled receptor kinases in neurocardiovascular pathophysiology

“…The classification of neurocardiological disorders by Goldstein [1] is as follows: 1) Sympathetic disorders -diseases in which activation of the catecholamine system worsens an independent pathological state (coronary artery disease, arrhythmias as long QT syndrome, sudden death, heart failure (HF)) as well as diseases in which abnormal catecholaminergic function is etiologic (sympathetic neurocirculatory failure, hypertension, cardiac necrosis and cardiomyopathy), and 2) Vagally mediated disorders -both neurally mediated syncope (vasovagal syncope, carotid sinus hypersensitivity) and vagally mediated atrial fibrillation. Neural regulation of the CV system can be studied by using different techniques [2][3][4][5][6][7][8]. G protein related kinases (GRKs) exist in 7 isoforms -GRK 1-7.…”

Sinus node dysfunction in patients with Fontan circulation: could heart rate variability be a predictor for pacemaker implantation?

“…Heart rate variability (HRV) has been shown to be a marker of autonomic nervous system regulation of the heart. Changes in HRV are also associated with arrhythmias such as supraventricular and ventricular arrhythmias [ 8 , 9 ]. Specifically, in studies by Bergfeldt et al and Sosnowski et al, HRV was described as significantly higher in adult patients with SND than in controls [ 10 , 11 ].…”