Heart Rate Variability and Atria Function in Children at Late Follow-Up Evaluation After Atrioventricular Node Slow-Pathway Radiofrequency Ablation

This study was designed to assess the changes in the conductive system, autonomic dysfunction, and global and regional function of the atria and ventricles in children late after slow-pathway radiofrequency ablation (RFA). The study enrolled 22 children, who has successfully undergone RFA 2 to 5 years previously (RFA group) and 20 healthy children (control group). Electrophysiologic study was performed for the RFA group. Holter monitoring and echocardiography were performed for all the children. At a late follow-up assessment, the RFA children were free of paroxysms, whereas 8 of the 22 children (36%) reported transient palpitations. Both mean and maximal heart rates (HR) were significantly increased, whereas indices of HR variability (% of succesive normal sinus RR intervals exceeding 50 ms [pNN50], root mean square of the succesive normal sinus RR interval difference [rMSSD], high-frequency component [HFC]) were significantly decreased in the RFA group compared with preablation and control data. Left atrial (LA) and right atrial (RA) volumes were significantly higher, and atria deformation indices were significantly lower in the RFA group. Correlations were found between the mean HR and the volumes of LA (r = 0.477; p < 0.001) and RA (r = 0.512; p < 0.001). A negative correlation between the maximal LA volume and the longitudinal strain rate (SR) during relaxation (r = –0.476; p = 0.03) and a positive correlation between the minimal LA volume and both longitudinal SR (r = 0.361; p = 0.03) and strain (ε) (r = 0.375; p = 0.024) during contraction were shown. These data suggest a possible link between atrial dysfunction and the hyperadrenergic state after RFA

Relationship of Natriuretic Peptides with Left Atrial Structure and Function within 1 Month after Electrical Cardioversion in Patients with Persistent Atrial Fibrillation

Atrial fibrillation (AF) despite the absence of heart failure is related to increased levels of natriuretic peptides (NPs). NPs have not been widely investigated in relation to left atrium (LA) function after sinus rhythm (SR) restoration and duration of AF. The aim of the study was to determine the changes of NPs levels and to define their relation with LA phasic function after electrical cardioversion (ECV). Methods. The study included 48 persistent AF patients with restored SR after ECV. NT-proANP and NT-proBNP were measured for all patients before the ECV. LA phasic function (reservoir, conduit, and pump phases) was assessed using echocardiographic volumetric analysis within the first 24 hours after ECV. Patients were repeatedly tested after 1 month in case of SR maintenance. Results. After 1 month, SR was maintained in 26 (54%) patients. For those patients, NT-proBNP decreased significantly (p=0.0001), whereas NT-proANP tended to decrease (p=0.13). Following 1 month after SR restoration, LA indexed volume decreased (p=0.0001) and all phases of LA function improved (p=<0.01). Patients with AF duration < 3 months had lower NT-proANP compared to patients with AF duration from 6 to 12 months (p = 0.005). Higher NT-proANP concentration before ECV was associated with lower LA reservoir function during the first day after SR restoration (R=-0.456, p=0.005), whereas higher NT-proBNP concentration after 1 month in SR was significantly related to lower LA reservoir function (R=-0.429, p=0.047). Conclusions. LA indexed volume, all phases of LA function, and NT-proBNP levels improved significantly following 1 month of SR restoration. Preliminary results suggest that higher baseline NT-proANP levels and higher NT-proBNP for patients with maintained SR for 1 month are related to lower LA reservoir function. The longer duration of persistent AF is associated with higher NT-proANP concentration