Study of Cardiac Rate and Rhythm Patterns in Ambulatory and Hospitalized Children

Advancements in the diagnosis and management of premature ventricular contractions in pediatric patients

Background

Premature ventricular contractions (PVCs) are relatively common arrhythmias in the pediatric population, with implications that range from benign to potentially life-threatening. The management of PVCs in children poses unique challenges, and recent advancements in diagnostic and therapeutic options call for a comprehensive review of current practices.

Methods

This review synthesizes the latest literature on pediatric PVCs, focusing on publications from the past decade. We evaluate studies addressing the epidemiology, pathophysiology, diagnosis, and treatment of PVCs in children, including pharmacological, non-pharmacological, and invasive strategies.

Results

The review identifies key advancements in the non-invasive detection of PVCs, the growing understanding of their genetic underpinnings, and the evolving landscape of management options. We discuss the clinical decision-making process, considering the variable significance of PVCs in different pediatric patient subgroups, and highlight the importance of individualized care. Current guidelines and consensus statements are examined, and areas of controversy or limited evidence are identified.

Conclusions

Our review underscores the need for a nuanced approach to PVCs in children, integrating the latest diagnostic techniques with a tailored therapeutic strategy. We call for further research into long-term outcomes and the development of risk stratification tools to guide treatment. The potential of emerging technologies and the importance of multidisciplinary care are also emphasized to improve prognoses for pediatric patients with PVCs.

Younger postnatal age is associated with a lower heart rate on Holter monitoring during the first week of life

To evaluate heart rate (HR), the presence of extrasystoles and other Holter findings among healthy newborns, and to collect data for new normal limits for Holter parameters in newborns. For this cross-sectional study, 70 healthy term newborns were recruited to undergo 24-h Holter monitoring. Linear regression analysis was used in HR analyses. The age-specific limits for HRs were calculated using linear regression analysis coefficients and residuals. The mean (SD) age of the infants was 6.4 (1.7) days during the recording. Each consecutive day of age raised the minimum and mean HR by 3.8 beats per minute (bpm) (95% CI: 2.4, 5.2; P < .001) and 4.0 bpm (95% CI: 2.8, 5.2; P < .001), respectively. Age did not correlate with maximum HR. The lowest calculated limit for minimum HR ranged from 56 bpm (aged 3 days) to 78 bpm (aged 9 days). A small number of atrial extrasystoles and ventricular extrasystoles were observed in 54 (77%) and 28 (40%) recordings, respectively. Short supraventricular or ventricular tachycardias were found in 6 newborns (9%).

CONCLUSION

 The present study shows an increase of 20 bpm in both the minimum and mean HRs of healthy term newborns between the 3rd and 9th days of life. Daily reference values for HR could be adopted in the interpretation of HR monitoring results in newborns. A small number of extrasystoles are common in healthy newborns, and isolated short tachycardias may be normal in this age group.

WHAT IS KNOWN

• The current definition of bradycardia in newborns is 80 beats per minute. • This definition does not fit into the modern clinical setting of continuously monitored newborns, where benign bradycardias are commonly observed.

WHAT IS NEW

• A linear and clinically significant increase in heart rate was observed in infants between the ages of 3 and 9 days. • It appears as though lower normal limits for heart rate could be applied to the youngest newborns.

Cardiac arrhythmias in postural tachycardia syndrome and orthostatic intolerance

BACKGROUND AND OBJECTIVES

There is sparse literature on cardiac arrhythmias and the utility of ambulatory rhythm monitoring in patients with postural tachycardia syndrome and orthostatic intolerance. This study's primary aim was to investigate the prevalence of arrhythmias in this population. Knowing the prevalence and types of arrhythmias in dysautonomia patients could influence the decision to pursue ambulatory rhythm monitoring and ultimately guide therapy.

METHODS

This retrospective descriptive study examined the frequency of cardiac arrhythmias, as detected by ambulatory rhythm monitoring, in children with postural tachycardia syndrome/orthostatic intolerance or syncope who were seen at the Children's National Hospital Electrophysiology Clinic between January 2001 and December 2020.

RESULTS

In postural tachycardia syndrome/orthostatic intolerance patients, arrhythmia was detected on 15% of 332 ambulatory rhythm monitors. In syncope patients, arrhythmia was detected on 16% of 157 ambulatory rhythm monitors, not significantly different from the postural tachycardia syndrome/orthostatic intolerance group. The difference in rate of arrhythmia detection between 24-hour Holter and 2-week Zio® monitoring was not statistically significant.

CONCLUSION

This study suggests that a substantial proportion of postural tachycardia syndrome/orthostatic intolerance patients may have concomitant underlying cardiac arrhythmias, at a frequency similar to what is seen in patients undergoing primary evaluation for cardiac symptoms such as chest pain, palpitations, and syncope. In the appropriate clinical context, physicians caring for postural tachycardia syndrome/orthostatic intolerance patients should consider additional evaluation for arrhythmias beyond sinus tachycardia.

Extrasystoles or short bradycardias of the newborn seldom require subsequent 24-hour electrocardiographic monitoring

AIM

To retrospectively assess the indications for and findings on 24-hour electrocardiographic (Holter) monitoring in newborns, focussing on bradycardias and extrasystoles.

METHODS

Data included 337 term-born infants. Holter indications were categorised into bradycardias below 80 beats per minute, extrasystoles, any tachycardia and other. Heart rate below 60 beats per minute, pathological atrioventricular conduction, supraventricular or ventricular tachycardia, or either atrial premature contractions over 10% or ventricular premature contractions over 5% of total beats were defined as significant arrhythmia on Holter.

RESULTS

The median age was 6 days (range: 2-62 days). Bradycardia (42%) or extrasystoles (32%) were the most common Holter indications. Fifty-three infants (16%) had significant arrhythmia on Holter. Heart disease or 12-lead electrocardiogram expressing extrasystoles or conduction abnormalities were associated with significant arrhythmias (p = 0.046 and p < 0.001, respectively). Twenty-seven of 109 infants (25%) with extrasystoles as a Holter indication had abnormal Holter results, but only seven (6.4%) had significant arrhythmia on Holter if the 12-lead electrocardiogram was normal. No pathology was found behind bradycardias below 80 beats per minute in the absence of heart disease.

CONCLUSION

Among term newborns with extrasystoles or bradycardias, Holter monitoring could be targeted to infants with heart disease or abnormal electrocardiograms.

When Should Premature Ventricular Contractions Be Considered as a Red Flag in Children with Cardiomyopathy?

Premature ventricular contractions (PVCs) are common and generally benign in childhood and tend to resolve spontaneously in most cases. When PVCs occur frequently, an arrhythmia-induced cardiomyopathy may be present requiring medical or catheter ablation. PVCs are only rarely the manifestation of a cardiomyopathy. The purpose of this review is to provide some tips and tricks to raise the suspicion of a cardiac disease based on the presence and characteristics of PVCs in children.

Incidental electrocardiogram abnormalities in children undergoing polysomnography

STUDY OBJECTIVES

Monitoring electrocardiogram (ECG) is an integral component of pediatric polysomnography (PSG). There is limited data regarding arrhythmia and conduction disturbances in the pediatric population undergoing a PSG. In this work we present abnormal ECG findings during PSG in our sleep center.

METHODS

A retrospective chart review from children who underwent PSG read by a single Sleep Medicine physician in the last year was carried out. Findings in children without cardiac disease and with first or second degree atrioventricular block (AVB) were compared to those from children with premature ventricular contractions (PVC).

RESULTS

A total of 1,235 PSGs were included. Twenty-four children (9 girls and 15 boys) aged 2-17 years (median 9 years) were identified with arrhythmias or conduction disturbances (1.9%). Nineteen out of 24 of these children (79.2%) had obstructive apnea-hypopnea index (oAHI) > 1 event/h; this frequency was not significantly different from that found in the whole group of 1,235 children. No statistically significant difference was found between children with AVB or PVC. Seven out of nine children with AVB and seven out of 10 with PVC had oAHI > 1 event/h, while eight children with AVB out of nine and four out of 10 with PVC were males (Fisher exact test p=0.04). None of the children were found to have a structural or conduction abnormality when referred to cardiology.

CONCLUSIONS

Our study supports that ECG abnormalities are rare in PSGs of children and not associated with cardiac disease or sleep disorders but appear more commonly in males.

Can the 12-lead ECG distinguish RVOT from aortic cusp PVCs in pediatric patients?

BACKGROUND

The ability to differentiate right ventricular outflow tract (RVOT) from coronary cusp (CC) site of origin (SOO) by 12-lead ECG in pediatric patients may impact efficacy and procedural time. The objective of this study was to predict RVOT versus CC SOO by ECG in pediatric patients.

METHODS

Pediatric patients (<21 years) without structural heart disease with RVOT or CC premature ventricular contraction (PVC) ablations performed (2014-2018) were evaluated through multi-institution retrospective review. Demographics, ECG PVC parameters, ablation site, recurrence, and repeat procedures were collected.

RESULTS

Thirty-seven patients were evaluated (mean age 14.6 years, weight 60.6 kg): 11 CC and 26 RVOT PVC SOO. CC PVCs were less likely to exhibit left bundle branch block (64% vs 100%, P = .005), had larger R-wave amplitude in V1 (0.27 vs 0.11 mV, P = .03), larger R/S ratio in V1 (0.37 vs 0.09, P = .003), and had precordial transition in V3 or earlier (73% vs 15%, P = .002). A composite score was created with the following variables: isodiphasic or positive QRS in V1, R/S ratio in V1 > 0.05, S wave in V1 < 0.9 mV, and precordial transition at or before V3. Composite score ≥ 2 was associated with a CC SOO (OR 42.0, P = .001, and AUC 0.86).

CONCLUSIONS

12-lead ECG of PVCs from the CC was associated with larger V1 R-wave amplitude, larger R/S ratio in V1, and precordial transition at or before V3. A composite score may help predict PVC/VT arising from the CC.

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.

Late arrhythmias after surgery for transposition of the great arteries

The evolution of surgical techniques for transposition of the great arteries (TGA) provides a moving target for the assessment of late arrhythmias. Imposed on varying anatomical substrates are progressive surgical interventions, each with its own set of sequelae. Analysis of the risk of arrhythmia development requires division into which arrhythmia is present, for which form of transposition, undergoing what type of surgery, and in which surgical era. For purposes of this review, available data on d-TGA undergoing Senning repairs, Mustard repairs, and arterial switch repairs and congenitally corrected TGA undergoing double switch repairs are reviewed.

REM-related bradyarrhythmia syndrome

Cardiac arrhythmias during sleep are relatively common and include a diverse etiology, from benign sinus bradycardia to potentially fatal ventricular arrhythmias. Predisposing factors include obstructive sleep apnea and cardiac disease. Rapid eye movement (REM)-related bradyarrhythmia syndrome (including sinus arrest and complete atrioventricular block with ventricular asystole) in the absence of an underlying cardiac or physiologic sleep disorder was first described in the early 1980s. Although uncertain, the underlying pathophysiology likely reflects abnormal autonomic neural-cardiac inputs during REM sleep. The autonomic nervous system (ANS) is a known key modulator of heart rate fluctuations and rhythm during sleep and nocturnal heart rate reflects a balance between the sympathetic-parasympathetic systems. Whether the primary trigger for REM-related bradyarrhythmias reflects abnormal centrally mediated control of the ANS during REM sleep or anomalous baroreflex parasympathetic influences is unknown. This review focuses on the salient features of the REM-related bradyarrhythmia syndrome and explores potential mechanisms with a particular assessment of the relationship between the ANS and nocturnal heart rate fluctuations.

Prevalence of early postoperative arrhythmias in children with delayed open-heart surgery for severe congenital heart disease

BACKGROUND; Our aim was to determine the incidence, risk factors and outcome of early postoperative arrhythmias in children with delayed treatment of severe congenital heart disease.

METHODS

A prospective study was conducted in 141 consecutive children with delayed referral from emerging countries, who underwent open-heart surgery.

RESULTS

Sinus node dysfunction was noted in 5 cases. Preoperative moderate extrasystoly was common and its incidence significantly increased in the postoperative phase. Overall, 9 patients required specific antiarrhythmic therapy: 6 for sustained atrioventricular reciprocating tachycardia, and 3 respectively for atrial flutter, atrial fibrillation and junctional ectopic tachycardia. Non-sustained atrioventricular and ventricular tachycardia required no therapy in respectively 6 and 1 case. Postoperative complete atrioventricular block was observed in 6 patients and remained permanent in 3. No major complications resulted from those arrhythmias. Preoperative low oxygen saturation, preoperative arrhythmias, as well as long cardiopulmonary bypass time and aortic cross-clamp time, were risk factors for early postoperative arrhythmias.

CONCLUSIONS

Children with delayed surgery for congenital heart disease are at risk of developing early postoperative arrhythmias depending on the complexity of their disease and of its treatment. However, their prevalence (14%) is not higher than in the general population of cardiac children.

Normal limits for heart rate as established using 24-hour ambulatory electrocardiography in children and adolescents

BACKGROUND

To the best of our knowledge, normal limits of heart rate with respect to gender, and as established using 24-hour ambulatory Holter electrocardiography, have yet to be published for the entire age range of children and adolescents.

OBJECTIVES

To establish the normal limits for heart rate in newborns, infants, children, and adolescents of both genders.

PATIENTS AND METHODS

We obtained 24-hour Holter recordings from 616 healthy subjects aged from birth to 20 years with structurally normal hearts. The subjects were not receiving medication, and had not been submitted to prior cardiac intervention. Off-line analysis was performed with Mars 8000 scanners, analysing 5 consecutive RR intervals by the software available for automatic calculation of heart rate. All subjects were in sinus rhythm. Best-fit non-linear regressions were applied to correlate age and gender with minimum and mean heart rate, as well as with maximal RR-interval, and to calculate the 5th, 25th, 75th and 95th percentiles.

RESULTS

We observed significant gender-dependent differences in heart rate for persons aged 10 years and older, with the males exhibiting lower minimal and mean heart rates, and higher RR-intervals, than the females. Correlation of heart rate with age and gender could be established with sufficient accuracy using non-linear regression (p less than 0.0001): Minimum heart rate (male: R(2)=0.778, female: R(2) = 0.664) and mean heart rate (male: R(2) = 0.820, female: R(2) = 0.736) decreased with age, while the maximal RR-interval prolonged (male: R(2) = 0.562, female: R(2) = 0.486). Age and gender-related graphs of centiles were constructed.

CONCLUSIONS

Heart rate, as documented using Holter recodings, can be correlated with age and gender, permitting establishments of normal gender-specific limits for children and adolescents.