Natural history of ventricular premature contractions in children with a structurally normal heart: does origin matter?

AIMS: Premature ventricular contractions (PVCs) are thought to be innocent in children with normal hearts, especially if they disappear during exercise. The aim of our study was to study the natural history of PVCs in childhood and whether there is a difference between PVCs originating from the right [premature ventricular contraction with left bundle branch block (PVC-LBBB)] or the left ventricle [premature ventricular contraction with right bundle branch block (PVC-RBBB)]. METHODS AND RESULTS: We evaluated children with frequent PVCs and anatomically normal hearts (n= 59; 35M/24F) by 12-lead ECG, echocardiography, Holter recording, and an exercise test. Age at the first visit was 7.1 +/- 4.3 years (mean +/- SD), and follow-up was 3.1 +/- 3.1 years. We could evaluate each child for 2.5 +/- 1.5 times. Premature ventricular contraction with left bundle branch block was seen in 41% of the children; PVC-RBBB in 36%; and undetermined in 23%. Mean percentage PVCs in the Holter recording decreased (14.3 +/- 13.7% in the age group 1-3 years to 4.8 +/- 7.2% in the age group >OR=16 years; P= 0.08). Mean percentage PVC-LBBB did not change (12.3 +/- 21.4 vs. 11.7 +/- 5.5%), whereas PVC-RBBB decreased (16.3 +/- 4.2 to 0.6 +/- 1.4%; P < 0.02). CONCLUSION: We conclude that there is a difference in the natural history between PVC-LBBB and PVC-RBBB in children with an anatomically normal heart. Premature ventricular contraction with right bundle branch block disappears during childhood. Follow-up of these children seems not necessary. Premature ventricular contraction with left bundle branch block does not disappear and, therefore, it may be necessary to follow these children even during adulthood.

Developmental aspects of long QT syndrome type 3 and Brugada syndrome on the basis of a single SCN5A mutation in childhood.

OBJECTIVES: The aim was to investigate at what age electrocardiographic characteristics of long QT syndrome type 3 (LQT3) and Brugada syndrome (BS), based on a single SNC5A mutation, appear. BACKGROUND: The QT interval (QT) in LQT3 is prolonged during bradycardia. It is not clear yet if this is obvious in young children with a relative fast heart rate (HR). METHODS: Thirty-six children with an SNC5A gene mutation (1795insD) and 46 non-carrier siblings were investigated. In different age groups, HR, QT, QTc, and ST-segment elevation on a 12-lead electrocardiogram (ECG), and HR, QT, QTc, and DeltaQT after the longest pause in a Holter (recording) were evaluated. RESULTS: In all age groups, HR at rest tended to be lower in carriers than in non-carriers, and QT was longer in carriers than in non-carriers. The Brugada phenotype was found >5 years. Gender specific differences were not identified. The QT at lower HR and DeltaQT were longer in carriers than in non-carriers. A QTc of > or =0.44 s at the lowest HR (sensitivity 100%; specificity 88.4%) and DeltaQT > or =60 ms (sensitivity 100%; specificity 82.6%) were good predictors for having LQT3. CONCLUSIONS: We conclude that electrocardiographic characteristics of LQT3 and BS show age-dependent penetrance. A QT prolongation and conduction disease were present from birth onwards, whereas ST-segment elevation only developed >5 years. Good tools for clinical diagnosis of LQT3 in this family are QTc at the lowest HR and DeltaQT after a pause in a Holter, even at very young age.

Sinus node function in children with congenital complete atrioventricular block.

AIMS: Children with congenital complete atrioventricular block (CCAVB) often need pacemaker therapy. In these children, it may be preferable to use single-lead VDD pacing, but for VDD pacing a normal sinus node function is required. Our aim was to study sinus node function in children with CCAVB. METHODS AND RESULTS: We longitudinally evaluated sinus rate in 36 children with CCAVB and normal anatomy of the heart. The rate of sinus rhythm on a 12-lead ECG, in Holter recordings, and exercise tests were evaluated at regular intervals. Age at the first visit of the children was 2.5+/-3.3 years (mean+/-SD). Follow-up was 10.6+/-7.3 years. The rate of sinus rhythm on a 12-lead ECG was at every age within the normal values for age (e.g. 0-1 year: 153+/-24 bpm, and 17-18 years: 76+/-4 bpm). Lowest and highest sinus rates in the Holter recordings were normal. During exercise, mean sinus rate in the total group of children increased from 92+/-8 at rest to 171+/-9 bpm at maximal exercise. CONCLUSION: We conclude that sinus node function is normal in children with CCAVB. Because of the normal increase in sinus rate during exercise, a single-lead VDD pacemaker can be safely implanted in these children.

Longitudinal echocardiographic follow-up in children with congenital complete atrioventricular block.

BACKGROUND: Due to a low heart rate (HR) in children with congenital complete atrioventricular block (CCAVB), a larger stroke volume of the left ventricle (LV) may be expected. If so, end-diastolic (LVEDD) and end-systolic (LVESD) diameters may be enlarged and even dilated cardiomyopathy (DCM) may occur. The aim of this study was to answer the question if children with CCAVB develop LV dilatation. Furthermore, we investigated whether LV dilatation would decrease after pacing. METHODS: We longitudinally evaluated echocardiographic data (LVEDD, LVESD, shortening fraction [SF]) in 36 children with CCAVB. Age at the first visit was 2.5 +/- 3.3 years (mean +/- SD); follow-up 10.6 +/- 7.3 years. RESULTS: Three children had DCM, already at 1st visit. LVEDD and LVESD Z scores in all children with CCAVB were larger than in normal controls (LVEDD Z score 1.38 +/- 1.80; LVESD Z score 0.64 +/- 1.35). Both Z scores were larger when HR was lower. Both Z scores increased over time in children who met criteria for pacing, but did not change in non-paced children. Physiologic pacing decreased both Z scores. SF of all children was normal and remained normal during follow-up (0.39 +/- 0.05 1st visit vs 0.39 +/- 0.06 last visit). CONCLUSIONS: We conclude that children with CCAVB have LV dilatation, which is progressive in children who met criteria for pacing. LV dilatation regressed by physiologic pacing. LV dilatation was larger when HR was lower. SF does not deteriorate over time. DCM occurs early in the disease and does not develop during childhood, not even in children with LV dilatation.

Pharmacological treatment of young children with permanent junctional reciprocating tachycardia.

Our objective was to assess the efficacy of pharmacological treatment in reducing the incidence of permanent junctional reciprocating tachycardia in young children, or to bring the mean heart rate over 24 h to a normal level. We included 21 children with a median age of 0.05 year seen with permanent junctional reciprocating tachycardia over the period 1990 through 2001. Of these children, two had abnormal left ventricular function. Follow-up visits were made at least every 6 months. We registered the presence of the tachycardia over 24 h, the mean heart rate over 24 h, and cardiac function. Treatment was started with propafenone alone, or in combination with digoxin as the first choice. Treatment was effective in 14 cases (67%), with either complete disappearance of the tachycardia after discontinuation of medication, or continuation in sinus rhythm with medication; partially effective in 4 cases (20%) when the mean heart rate over 24 h on the last Holter recording was less than 1 standard deviation above the normal for age; but was not effective in the remaining 3 cases (14%). In 3 patients treated with propafenone, or 13 given propafenone and digoxin, treatment was effective in 12 (75%), partially effective in 2 (13%), and ineffective in the other 2 (13%). All 21 children had a normal left ventricular function at the end of follow-up. The median duration of follow-up was 2.4 years. Permanent junctional reciprocating tachycardia had disappeared spontaneously in one-third of the children, 5 being less than 1 year old. Adverse effects, seen in 5 cases, were mild or asymptomatic. No signs of proarrhythmia were registered. Pharmacological treatment, either with propafenone alone, or in combination with digoxin, is safe and effective in young children with permanent junctional reciprocating tachycardia. The mean heart rate is normalized, and cardiac function is restored and preserved. Radiofrequency ablation may be delayed to a safer age, with the arrhythmia disappearing spontaneously in one-third.

Ventricular fibrillation without overt cardiomyopathy as first presentation of organic cation transporter 2-deficiency in adolescence.

This case report describes ventricular fibrillation without overt cardiomyopathy as the presenting symptom of primary carnitine deficiency due to organic cation transporter 2 (OCTN2)-deficiency in a 15-year-old girl. Normally this disease presents early in life with hypoketotic hypoglycemia, muscle weakness, and/or cardiomyopathy. The patient fully recovered after carnitine supplementation. Recognition of this disease is important because its treatment is easy and effective.