Effects of cisapride on QTc interval in term neonates

QTc Interval Reference Values and Their (Non)-Maturational Factors in Neonates and Infants: A Systematic Review

QTc interval measurement is a widely used screening tool to assess the risk of cardiac diseases, arrhythmias, and is a useful biomarker for pharmacovigilance. However, the interpretation of QTc is difficult in neonates due to hemodynamic maturational changes and uncertainties on reference values. To describe trends in QTc values throughout infancy (1 year of life), and to explore the impact of (non)-maturational changes and medicines exposure, a structured systematic review (PROSPERO CRD42022302296) was performed. In term neonates, a decrease was observed over the first week of life, whereafter values increased until two months of age, followed by a progressive decrease until six months. A similar pattern with longer QTc values was observed in preterms. QTc is influenced by cord clamping, hemodynamic changes, therapeutic hypothermia, illnesses and sleep, not by sex. Cisapride, domperidone and doxapram result in QTc prolongation in neonates. Further research in this age category is needed to improve primary screening practices and QTcthresholds, earlier detection of risk factors and precision pharmacovigilance.

Pharmacological therapy of gastroesophageal reflux in preterm infants

Although gastroesophageal reflux (GER) is a very common phenomenon among preterm infants, its therapeutic management is still an issue of debate among neonatologists. A step-wise approach should be advisable, firstly promoting nonpharmacological interventions and limiting drugs to selected infants unresponsive to the conservative measures or who are suffering from severe GER with clinical complications. Despite of this, a concerning pharmacological overtreatment has been increasingly reported. Most of the antireflux drugs, however, have not been specifically assessed in preterm infants; moreover, serious adverse effects have been noticed in association to their administration. This review mainly aims to draw the state of the art regarding the pharmacological management of GER in preterm infants, analyzing the best piecies of evidence currently available on the most prescribed anti-reflux drugs. Although further trials are required, sodium alginate-based formulations might be considered promising; however, data regarding their safety are still limited. Few piecies of evidence on the efficacy of histamine-2 receptor blockers and proton pump inhibitors in preterm infants with GER are currently available. Nevertheless, a significantly increased risk of necrotizing enterocolitis and infections has been largely reported in association with their use, thereby leading to an unfavorable risk-benefit ratio. The efficacy of metoclopramide in GER's improvement still needs to be clarified. Other prokinetic agents, such as domperidone and erythromycin, have been reported to be ineffective, whereas cisapride has been withdrawn due to its remarkable cardiac adverse effects.

An algorithm for QT interval monitoring in neonatal intensive care units

QT surveillance of neonatal patients, and especially premature infants, may be important because of the potential for concomitant exposure to QT-prolonging medications and because of the possibility that they may have hereditary QT prolongation (long-QT syndrome), which is implicated in the pathogenesis of approximately 10% of sudden infant death syndrome. In-hospital automated continuous QT interval monitoring for neonatal and pediatric patients may be beneficial but is difficult because of high heart rates; inverted, biphasic, or low-amplitude T waves; noisy signal; and a limited number of electrocardiogram (ECG) leads available. Based on our previous work on an automated adult QT interval monitoring algorithm, we further enhanced and expanded the algorithm for application in the neonatal and pediatric patient population. This article presents results from evaluation of the new algorithm in neonatal patients. Neonatal-monitoring ECGs (n = 66; admission age range, birth to 2 weeks) were collected from the neonatal intensive care unit in 2 major teaching hospitals in the United States. Each digital recording was at least 10 minutes in length with a sampling rate of 500 samples per second. Special handling of high heart rate was implemented, and threshold values were adjusted specifically for neonatal ECG. The ECGs studied were divided into a development/training ECG data set (TRN), with 24 recordings from hospital 1, and a testing data set (TST), with 42 recordings composed of cases from both hospital 1 (n = 16) and hospital 2 (n = 26). Each ECG recording was manually annotated for QT interval in a 15-second period by 2 cardiologists. Mean and standard deviation of the difference (algorithm minus cardiologist), regression slope, and correlation coefficient were used to describe algorithm accuracy. Considering the technical problems due to noisy recordings, a high fraction (approximately 80%) of the ECGs studied were measurable by the algorithm. Mean and standard deviation of the error were both low (TRN = -3 +/- 8 milliseconds; TST = 1 +/- 20 milliseconds); regression slope (TRN = 0.94; TST = 0.83) and correlation coefficients (TRN = 0.96; TST = 0.85) (P < .0001) were fairly high. Performance on the TST was similar to that on the TRN with the exception of 2 cases. These results confirm that automated continuous QT interval monitoring in the neonatal intensive care setting is feasible and accurate and may lead to earlier recognition of the "vulnerable" infant.

24-Hour Electrocardiogram before and during Cisapride Treatment in Neonates and Infants

We studied prospectively the effects of cisapride on heart rate and rhythm using standard ECG and 24-hour ECG recordings in term and preterm neonates and infants. We studied subjects with gastroesophageal reflux disease (apparent life-threatening events, apneas, bradycardias) before and 3 days after starting cisapride (0.8 mg/kg/day in 4 doses). We performed standard ECGs for determination of corrected Q-T interval (QTc) and Q-T dispersion (QTd) and 24-hour ECG recordings for analysis of heart rate, heart rate variability, and heart rhythm. Fourteen term and 17 preterm subjects (gestational age range 28-36 weeks) were studied at a median chronological age of 29 (range 3-132) days. Cisapride significantly increased the QTc in preterm infants (before vs. after: 408 +/- 7 vs. 433 +/- 7 ms, p = 0.001). Two preterm and 1 term infant had a QTc >450 ms before cisapride. Four preterm (4/15 = 27%) and 2 term (2/13 = 15%) subjects had a QTc >450 ms on cisapride. After cisapride the QTd remained normal, and no relevant arrhythmias were documented on Holter recordings. Cisapride significantly decreased peak and mean heart rates of all study subjects without affecting the heart rate variability, while it increased the minimal heart rate of preterm infants only (before vs. after: 66 +/- 5 vs. 78 +/- 5 bpm, p = 0.02). The maximally measured R-R intervals (pauses) decreased after cisapride in preterm infants (before vs. after: 1.33 +/- 0.2 s vs. 1.05 +/- 0.2 s, p = 0.04). Although cisapride did cause a significant prolongation of the ventricular action potential duration in preterm infants, the QTd remained unaffected, and no clinically relevant arrhythmias were documented in this small sample. On the other hand, cisapride had a direct lowering effect on the maximal and mean heart rates of both term and preterm infants, while the drug increased the minimal heart rate and reduced the severity of bradycardia episodes in preterm infants.

How accurately can QT interval be measured in newborn infants?

We determined inter- and intra-observer variability of measurements of QT and heart rate corrected QT (QTc) interval in newborn infants. In 55 newborns, a standard 12-lead electrocardiogram (ECG) with rhythm strip was analysed independently by three observers. QT and the preceding RR interval were measured in three different beats. The QTc interval was calculated using the Bazett formula (QTc = QT/ radical RR). Observers repeated their measurements after the recruitment period blinded for their first reading. Inter- and intra-observer variability were determined using the Bland and Altman method. In total, 59 ECGs were recorded. Due to artifacts, six had to be excluded. A marked inter-observer variability was observed in the measurement of the QT and QTc interval. Important intra-observer variability was denoted, with differences up to 80 ms for QTc.

CONCLUSION

mainly due to high heart rates, important inter- and intra-observer variability hampers a correct interpretation of the QT interval in newborn infants. We suggest not to rely on one single measurement and to apply different methods of measurement and a margin of safety when interpreting QT and heart rate corrected QT intervals in these age groups for making therapeutic decisions.

Pharmacotherapy of gastro-oesophageal reflux disease in children: focus on safety

Gastro-oesophageal reflux (GOR) disease is very common and, in the majority of infants, is physiological. However, untreated GOR disease in infants and children is associated with a decrease in quality of life for the child and their parents. It may also cause sometimes more severe complications, such as oesophagitis, and causing, in rare cases, failure to thrive, oesophageal stricture, apnoea and even death. Every therapeutic intervention (non-drug treatment, medical treatment and surgery) is associated with morbidity and even mortality. Moreover, efficacy data of many medications in children are non-existing, limited or disappointing. The safety profile of cisapride is comparable to that of other therapeutic interventions or to the risk of non-treatment. Therefore, the therapeutic approach of GOR disease in infants and children needs to be well-balanced, considering therapeutic efficacy and side effects. This review will focus on the side effects of the different therapeutic options.

Long QT syndrome in dogs with tick toxicity (Ixodes holocyclus)

OBJECTIVE

To evaluate cardiac electrical function in dogs with tick toxicity.

DESIGN

A prospective clinical investigation of 39 client-owned dogs treated for naturally occurring tick toxicity.

PROCEDURE

An ECG was performed on each dog on several occasions; at admission to hospital with tick toxicity, 24 h later, at discharge from hospital when clinically normal and approximately 12 months later.

RESULTS

The mean QT interval corrected for heart rate (QTc) was prolonged at admission, 24 h and at discharge compared to the QTc measured 12 months later. T wave morphology was altered in dogs at admission. All other parameters were within normal limits.

CONCLUSIONS

The prolonged QTc interval and altered T wave morphology of dogs with tick toxicity reflects delayed cardiac repolarisation and is comparable with long QT syndrome (LQTS) in people who are predisposed to polymorphic ventricular tachycardia and sudden death. Resolution of ECG changes lagged behind clinical recovery.

Efficacy and tolerability of cisapride in children

As gastro-oesophageal reflux disease (GORD) in infants and children is a motility disorder which differs in pathophysiology and clinical course from GORD in adults, prokinetics should be considered the drug of choice in certain circumstances. Indeed, cisapride may result in improvement of feeding tolerance in premature infants. Cisapride has a better tolerability profile than a 'wait-and-see-if-improvement-comes-spontaneously' policy or the other therapeutic options available. A careful and critical review of published data suggests that cisapride may have a QTc-prolonging effect. However, provided the precautions for cisapride administration are followed, the QTc-prolonging effect remains consistently without clinically relevant adverse effects. Correct dosage and avoidance of concurrent treatment with macrolides and/or azoles are the most relevant tolerability recommendations in children. Although there is a need for a prokinetic with better efficacy, cisapride is currently the prokinetic with the best benefit-to-risk ratio available. Thus, withdrawal of cisapride would result in a significantly increased risk for severe complications in infants and children with GORD or other gastrointestinal motility disorders such as chronic intestinal pseudo-obstruction, gastroparesis and feed intolerance in premature infants.