The autonomic nervous activities influence the conduction and the functional refractory period (FRP) of the atrioventricular (AV) node. We evaluated the FRP of the AV node using RR-interval plotting of Holter ECGs in atrial fibrillation (AF). We plotted points on X-Y plane as (X, Y)=(RRn, RRn+1), successively from the RR-intervals. Since the RR-intervals were irregular and were limited by the shortest RR-intervals in AF, the dots fanned out along the X-axis. We analyzed the curvilinear envelope along the X-axis {FRP curve) every 1-hour and compared diurnal variation of the curves between 27 AF-patients with impaired cardiac functions and 65 patients with normal cardiac functions. As the indices of the FRP curve, minimum and maximum Y-values of the curve and the difference of minimum and maximum values were used. The minimum values were shortened during daytime in normal group, and the maximum values were not significantly different between day and nighttime in both groups. Thus, the diurnal change was lost in the patients with impaired cardiac functions.
展开▼
