Dromotropic

As Dromotropie (from ancient Greek δρόμος dromos. Barrel and τρόπος tropos: turn direction ) refers to the influence on the conduction of the heart. Positive Dromotropie means that the conduction is accelerated. This is caused by an increased initial calcium influx into the AV node cells; thus the threshold for reaching the action potential is reached faster and the excitation can thus be propagated faster. Negative Dromotropie means a slowing of conduction. However, this is achieved via an elevated initial potassium efflux from the muscle cell ( iKach ).

About β1 and less via β2 - adrenergic receptors of the sympathetic nervous system, both the Dromotropie and the inotropy ( contractility ) and chronotropy (contraction frequency) is increased to the heart and the lusitropy ( relaxation rate ) increases ( which also contributes to a positive change in cardiac output ).