A simplified approach for evaluating sustained slow pathway conduction for diagnosis and treatment of atrioventricular nodal reentry tachycardia in children and adults

Usefulness of Galectin-3 as a Biochemical Marker to Detect Ventricular and Supraventricular Arrhythmias in Children

Galectin-3 (Gal-3) has been demonstrated to play a pivotal role in the pathogenesis of several fibrotic disorders. A number of studies have examined the relationship between galectin-3 levels and cardiac fibrosis in heart failure. Nevertheless, the role of galectin-3 in the etiology of supraventricular (SVa) and ventricular (Va) arrhythmias remains largely unexamined. The objective of this prospective study was to investigate the potential correlation between galectin concentration and the occurrence of idiopathic cardiac arrhythmias in pediatric patients. Biochemistry analysis was performed on 30 children (11-18 years; 14 boys and 16 girls). The control group consisted of 20 children. Cardiac arrhythmia was confirmed by a 24 h Holter ECG recording. Serum galectin-3 levels were measured via enzyme-linked immunosorbent assay (ELISA). Statistical analysis of the data showed significant associations between creatinine kinase (CK) and Gal-3 in patients with SVa (SVT-supraventricular tachycardia) arrhythmias, suggesting a potential effect of CK on Gal-3 levels. However, no correlation was identified between Gal-3 concentration and the occurrence of cardiac arrhythmias under investigation. We concluded that galectin-3 does not have the potential to be a biomarker in the diagnosis of idiopathic arrhythmias in pediatric patients.

Antiarrhythmic Drug Dosing in Children-Review of the Literature

Antiarrhythmic drugs represent a mainstay of pediatric arrhythmia treatment. However, official guidelines and consensus documents on this topic remain scarce. There are rather uniform recommendations for some medications (including adenosine, amiodarone, and esmolol), while there are only very broad dosage recommendations for others (such as sotalol or digoxin). To prevent potential uncertainties and even mistakes with regard to dosing, we summarized the published dosage recommendations for antiarrhythmic drugs in children. Because of the wide variations in availability, regulatory approval, and experience, we encourage centers to develop their own specific protocols for pediatric antiarrhythmic drug therapy.

Expression levels of serum circulating microRNAs in pediatric patients with ventricular and supraventricular arrhythmias

PURPOSE

Aberrant expression of various miRNA species has been implicated in numerous cardiac diseases, e.g., heart failure, hypertrophy, conduction disturbances, and arrhythmogenesis. The aim of this study was to determine whether miR-1, miR-133a, and miR-133b can serve as biomarkers in the diagnosis of ventricular (Va) and supraventricular (SVa) arrhythmias in pediatric patients.

MATERIALS AND METHODS

Molecular analysis included 30 patients with SVa or Va (13-17.5 years; 14 boys/16 girls) and 20 non-arrhythmic controls. Arrhythmia was confirmed by 24-h Holter ECG recording. miRNA was extracted from serum using the miRNeasy^R Serum/Plasma Kit. miScript SYBR Green PCR Kit (Qiagen) was used to quantify miRNA expression.

RESULTS

The levels of miR-1 and miR-133a expression were significantly higher in the SVa group than in the controls (p ​= ​0.0327 and p<0.0001, respectively). Additionally, both groups of patients with arrhythmia presented significantly lower expression levels of miR-133b than the controls (p<0.01 for both comparisons). The level of miR-133a expression in the SVa group was significantly higher than in the Va group (p ​= ​0.0124). ROC analysis demonstrated that the expressions of miR-1 and miR-133a could differentiate between the SVa patients and arrhythmia-free controls (AUC ​= ​0.7091, p ​= ​0.07 and AUC ​= ​0.8021, p ​= ​0.007, respectively). Furthermore, the expression of miR-133b was shown to distinguish patients with SVa and Va from the arrhythmia-free controls (AUC ​= ​0.7273, p ​= ​0.07 and AUC ​= ​0.8030, p ​= ​0.04, respectively).

CONCLUSIONS

miR-1, miR-133a, and miR-133b have the potential to become diagnostic biomarkers of arrhythmia in pediatric patients.

Ventricular-triggered atrial pacing: A new maneuver for slow-fast atrioventricular nodal reentrant tachycardia

BACKGROUND

Atrioventricular (AV) node duality is suggested by several electrophysiological findings, none of which are strong predictors of AV nodal reentrant tachycardia (AVNRT).

OBJECTIVE

The purpose of this study was to propose a novel maneuver to study conduction over the AV node and attempt to induce slow-fast AVNRT.

METHODS

Ventricular-triggered atrial pacing (VTAP) with decremental VA delay was carried out in 36 consecutive patients with slow-fast AVNRT and in 21 controls after conventional electrophysiology study. Maneuvers were repeated after ablation in patients with AVNRT.

RESULTS

VTAP resulted in a hysteretic conduction curve in 21 of 36 patients (58%) in the AVNRT group but only 4 of 21 patients (19%) in the control group (sensitivity 58; specificity 81%). This finding demonstrates sustained conduction in a slow conducting pathway and concealed retrograde conduction over a fast pathway. VTAP resulted in AVNRT induction in 15 of 25 inducible patients at baseline (60%), 4 of which were not inducible with incremental pacing or programmed atrial stimulation. VTAP resulting in a suspended p wave had 51% (39%-64%) sensitivity and 100% (89%-100%) specificity for predicting noninducibility in a given autonomic state.

CONCLUSION

VTAP is useful in patients with suspected slow-fast AVNRT. A hysteretic conduction curve demonstrates sustained conduction over a slow pathway and concealed retrograde conduction through the fast pathway, a finding in favor of slow-fast AVNRT. VTAP may facilitate AVNRT induction and proves to be an interesting complement to classic maneuvers. A suspended p-wave response specifically predicts noninducibility of slow-fast AVNRT in a given autonomic state, providing an interesting surrogate to noninducibility as a procedural end point.