Derives from the Greek word "Dromos", meaning running, a course, a race. A dromotropic agent is one which affects the conduction speed in the AV node, and subsequently the rate of electrical impulses in the heart.

Agents that are dromotropic are often (but not always) inotropic and chronotropic

Chronotropic

Chronotropic effects are those that change the heart rate.Chronotropic drugs may change the heart rate by affecting the nerves controlling the heart, or by changing the rhythm produced by the sinoatrial node...

. For example, parasympathetic stimulation is usually negatively dromotropic, inotropic, and chronotropic.

Non-dihydropyridine calcium channel blockers such as verapamil

Verapamil

Verapamil is an L-type calcium channel blocker of the phenylalkylamine class. It has been used in the treatment of hypertension, angina pectoris, cardiac arrhythmia, and most recently, cluster headaches. It is also an effective preventive medication for migraine...

 block the slow inward calcium current in cardiac tissues thereby having a negatively dromotropic, chronotropic and inotropic effect. This (and other) pharmacological effect makes these drugs useful in the treatment of angina pectoris. Conversely, they can lead to
symptomatic disturbances in cardiac conduction and bradyarrhythmias, and may aggravate left ventricular failure.