 | This articleneeds additional citations forverification. Please helpimprove this article byadding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Chronotropic" – news ·newspapers ·books ·scholar ·JSTOR(August 2013) (Learn how and when to remove this message) |
Chronotropic effects (fromchrono-, meaning time, andtropos, "a turn") are those that change theheart rate.
Chronotropicdrugs may change theheart rate andrhythm by affecting theelectrical conduction system of the heart and thenerves that influence it, such as by changing therhythm produced by thesinoatrial node. Positive chronotropes increase heart rate; negative chronotropes decrease heart rate.
Adromotrope affectsatrioventricular node (AV node) conduction. A positive dromotrope increases AV nodal conduction, and a negative dromotrope decreases AV nodal conduction. Alusitrope is an agent that affects diastolic relaxation.
Many positiveinotropes affectpreload andafterload.
Chronotropic variables can be considered in systolic myocardial left and right sides. Left sided systolic chronotropy can be appreciated as Aortic Valve open to close time. Right sided variables are represented by pulmonary valve open to close time. Inverted as diastolic chronotropy, the variables are aortic valve close to open and pulmonic close to open time. Pharmaceutical manipulation of chronotropic properties was perhaps first appreciated by the introduction ofdigitalis, though it turns out that digitalis has aninotropic effect rather than a chronotropic effect.
 | Thisdrug article relating to thecardiovascular system is astub. You can help Wikipedia byexpanding it. |