Outcome of newborns with asymptomatic monomorphic ventricular arrhythmia

Incidence of non‐benign arrhythmia in neonatal intensive care unit: 18 years experience from a single center

Background

Non‐benign arrhythmias, which require urgent recognition and care in neonatal intensive care unit (NICU) settings, are rare but can severely impact neonates. We aimed to clarify the epidemiology and characteristics of non‐benign arrhythmias and their influence on neonates.

Methods

This single‐center retrospective study included patients admitted to the NICU at Kurashiki Central Hospital between January 2001 and December 2019. Only patients with structurally normal hearts were included. The use of direct cardioversion (DC), antiarrhythmic agents, and the presence of risk factors was reviewed from medical records.

Results

Of the 8082 admissions, 2919 patients (36.1%) were low birth weight infants (LBWI) weighing less than 1500 g. There were 23 patients with arrhythmias (nine of them were LBWIs) with an incidence of 0.28%. There were 16 patients with tachyarrhythmia (eight supraventricular tachycardia [SVT] cases, three atrial flutters [AFL] cases, three ventricular tachycardia cases, two junctional ectopic tachycardia cases), and seven with bradyarrhythmia (all with complete atrioventricular [AV] block). For tachyarrhythmia cases, seven patients required DC, and eight were on antiarrhythmic agents at the time of discharge. Two patients (28.5%) with complete AV block required pacemaker implantation before discharge. The treatment strategy was dependent on the type of arrhythmia. All patients were discharged without significant morbidities.

Conclusions

The incidence of non‐benign arrhythmias was as low as 0.28%. Arrhythmias can be managed successfully in neonates, yet risk factors related to mortality warrant further study.

Neonatal arrhythmias: diagnosis, treatment, and clinical outcome

Arrhythmias in the neonatal period are not uncommon, and may occur in neonates with a normal heart or in those with structural heart disease. Neonatal arrhythmias are classified as either benign or nonbenign. Benign arrhythmias include sinus arrhythmia, premature atrial contraction, premature ventricular contraction, and junctional rhythm; these arrhythmias have no clinical significance and do not need therapy. Supraventricular tachycardia, ventricular tachycardia, atrioventricular conduction abnormalities, and genetic arrhythmia such as congenital long-QT syndrome are classified as nonbenign arrhythmias. Although most neonatal arrhythmias are asymptomatic and rarely life-threatening, the prognosis depends on the early recognition and proper management of the condition in some serious cases. Precise diagnosis with risk stratification of patients with nonbenign neonatal arrhythmia is needed to reduce morbidity and mortality. In this article, I review the current understanding of the common clinical presentation, etiology, natural history, and management of neonatal arrhythmias in the absence of an underlying congenital heart disease.

Usefulness of ventricular premature complexes in asymptomatic patients ≤21 years as predictors of poor left ventricular function

Although ventricular premature complexes (VPCs) have been shown to correlate with decreased cardiac function in adults, the correlation of left ventricular (LV) function to VPCs in asymptomatic children remains unclear. The aim of this study was to determine the correlation of VPC burden with LV function in asymptomatic pediatric patients with structurally normal hearts. This was a retrospective analysis of patients aged ≤21 years with echocardiograms and 24-hour Holter monitors with ≥0.5% VPCs completed within 60 days of each other. LV fractional shortening (FS) was compared with VPC burden and VPC characteristics. Normal LV function was defined as FS ≥28%. Correlation between VPC burden and LV function was determined by regression analysis. Wilcoxon's rank-sum test was used to compare LV function with VPC characteristics. This study included 123 patients (77 male [63%]). The median age was 11.6 years (interquartile range 5.8 to 14.3). The median VPC burden was 11.2% (interquartile range 4.8% to 18.9%), and median FS was 36% (interquartile range 33% to 38%). There was no significant correlation between VPC burden and LV FS (p = 0.50). The presence of uniform versus multiform VPCs (p = 0.29), ventricular couplets (p = 0.37), or runs of ventricular ectopy (p = 0.19) were not associated with a decrease in LV FS. Twenty-two patients (18%) had VPC burden >24%, none of which had decreased LV FS. In conclusion, there was no significant relation between VPC burden or VPC characteristics and LV systolic function in this pediatric population with structurally normal hearts.

Frequent ventricular premature beats in children with a structurally normal heart: a cause for reversible left ventricular dysfunction?

Ventricular premature beats (VPBs) in a structurally normal heart generally are a benign condition. Rarely, however, reversible cardiomyopathy may develop. This study aimed to evaluate the incidence of cardiomyopathy among pediatric patients in a cohort with frequent VPBs and to examine the characteristics of the ventricular ectopic beats as well as therapeutic options. This study reviewed the charts of all pediatric patients between the ages of 1 day and 18 years seen at the University of Kentucky with the diagnosis of VPBs between 2003 and 2007. Frequent VPBs were defined as an ectopy burden of 5% or more in 24 h. Electrocardiograms, Holter monitors, and echocardiograms were reviewed. The review identified 28 patients (17 boys, age 13.3 ± 5.9 years, and 11 girls, age 13 ± 5.2 years) with frequent VPBs. The echocardiograms of four patients (2 boys, 14%) showed cardiomyopathy. Cardiac function normalized in all four patients, with spontaneous resolution of the VPBs (2 patients) or with antiarrhythmic therapy (2 patients). During a follow-up period of 2.7 ± 2.3 years, 32% of the patients without cardiomyopathy showed a marked spontaneous improvement in arrhythmia burden. Most of the patients showed VPBs with a left bundle branch block (LBBB) and inferior axis morphology. The most commonly associated symptoms were chest pain (17.8%) and dizziness and syncope (21.4%). Generally, VPBs in structurally normal hearts are considered benign. Rarely, a reversible cardiomyopathy can develop, requiring therapeutic intervention.

Heart rate variability in children with exercise-induced idiopathic ventricular arrhythmias

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.