A dromotropic agent is one which affects the conduction velocity of the AV node, and subsequently the rate of electrical impulses in the heart.^[1][2] The atrioventricular node (abbreviated AV node) is the tissue between the atria and the ventricles of the heart, which conducts the normal electrical impulse from the atria to the ventricles. ...

Agents that are dromotropic are often (but not always) inotropic and chronotropic. For example, parasympathetic stimulation is usually negatively dromotropic, ionotropic, and chronotropic. Inotropic: Affecting the force of muscle contraction. ... Chronotropic effects (from chrono-, meaning time) are those that change the heart rate. ... Anatomy and Physiology of the A.N.S. In contrast to the voluntary nervous system, the involuntary or autonomic nervous system is responsible for homeostasis, maintaining a relatively constant internal environment by controlling such involuntary functions as digestion, respiration, and metabolism, and by modulating blood pressure. ...

Non-dihydropyridine calcium channel blockers such as verapamil block the slow inward calcium current in cardiac tissues thereby having a negatively dromotropic, chronotropic and ionotropic effect^[3]. 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^[4]. Calcium channel blockers are a class of drugs with effects on the muscle of the heart and the muscles of the rest of the body. ... Verapamil (brand names: Isoptin®, Verelan®, Calan®) is a medical drug that acts as an L-type calcium channel blocker. ... angina tonsillaris see tonsillitis. ... Bradycardia, as applied in adult medicine, is defined as a heart rate of under 60 beats per minute, though it is seldom symptomatic until the rate drops below 50 beat/min [1]. It is also less commonly known as brachycardia. ... Congestive heart failure (CHF) (also called congestive cardiac failure and heart failure) is the inability of the heart to pump a sufficient amount of blood throughout the body, or requiring elevated filling pressures in order to pump effectively. ...

References

1. ^ http://circres.ahajournals.org/cgi/content/abstract/66/5/1391
2. ^ Dictionary at eMedicine Dromotropic
3. ^ http://etg.hcn.net.au/
4. ^ http://www.accessmedicine.com/content.aspx?aID=82370&searchStr=calcium+channel+blockers#82370