A dromotropic agent is one which affects the conduction speed (in fact the magnitude of delay) in the AV node, and subsequently the rate of electrical impulses in the heart. Positive dromotropy increases conduction velocity (e.g. epinephrine stimulation), negative dromotropy decreases velocity (e.g. vagal stimulation).
How do you remember dromotropic?
As mentioned, these can be remembered by the mnemonic: I Know! Sax 5th Avenue. If asked, there are actually five major classifications of your inotropic, chronotropic, and dromotropic drugs (A, B, C, D, and E). You can remember that because of the “5th” in your mnemonic.
What is the difference between chronotropic and inotropic and dromotropic?
Stimulation of the Beta1-adrenergic receptors in the heart results in positive inotropic (increases contractility), chronotropic (increases heart rate), dromotropic (increases rate of conduction through AV node) and lusitropic (increases relaxation of myocardium during diastole) effects.
