Effects of transplantation on atrioventricular nodal accommodation and hysteresis.

摘要: In the present study, atrioventricular nodal accommodation and hysteresis characteristics were evaluated in awake, unsedated dogs, before (n = 10) after cardiac transplantation 10). Chronically instrumented animals atrially paced at a cycle length (CL) of 400 ms, followed by an abrupt decrease pacing CL to 300 return ms (with sustained for 60 s each CL). Atrioventricular conduction (assessed AH intervals) simultaneously monitored. Under control conditions, intervals lengthened rapidly [mean time interval lengthening stabilize (Tonset) 2 +/- 1 s], whereas more slowly (P less than 0.05) (Tonset 41 4 s). Similarly, increase CL, shortened base line 5 42 Thus appears be intrinsic response (present denervation transplantation) abrupt, atrial changes. Furthermore equivalence NS) responses symmetric decreases increases suggests that [i.e., nonequivalence responses], as seen under results primarily from extrinsic (neural) modification