Chronotropic effects are those that change the heart rate
Heart rate
Heart rate is the number of heartbeats per unit of time, typically expressed as beats per minute . Heart rate can vary as the body's need to absorb oxygen and excrete carbon dioxide changes, such as during exercise or sleep....


Chronotropic drugs
Destroy Rebuild Until God Shows are an American post-hardcore band formed in 2010. They released their debut self-titled album on February 22, 2011.- Formation :...

 may change the heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

 rate by affecting the nerves controlling the heart, or by changing the rhythm
Rhythm may be generally defined as a "movement marked by the regulated succession of strong and weak elements, or of opposite or different conditions." This general meaning of regular recurrence or pattern in time may be applied to a wide variety of cyclical natural phenomena having a periodicity or...

 produced by the sinoatrial node
Sinoatrial node
The sinoatrial node is the impulse-generating tissue located in the right atrium of the heart, and thus the generator of normal sinus rhythm. It is a group of cells positioned on the wall of the right atrium, near the entrance of the superior vena cava...

. Positive chronotropes increase heart rate; negative chronotropes decrease heart rate.

A dromotrope
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....

 affects atrioventricular node
Atrioventricular node
The atrioventricular node is a part of the electrical control system of the heart that coordinates heart rate. It electrically connects atrial and ventricular chambers...

 (AV node) conduction. A positive dromotrope increases AV nodal conduction, and a negative dromotrope decreases AV nodal conduction. A lusitrope
Lusitropy is a term used to describe myocardial relaxation. The increase in calcium uptake by cardiomyocytes leads to increased myocardial contractility , but the myocardial relaxation, or lusitropy, decreases.-Positive:...

 is an agent that affects diastolic relaxation.

Many positive inotropes affect preload and afterload
Afterload is the tension or stress developed in the wall of the left ventricle during ejection. Following Laplace's law, the tension upon the muscle fibers in the heart wall is the product of the pressure within the ventricle, multiplied by the volume within the ventricle, divided by the wall...


Negative Chronotropes

Chronotropic variables in systolic myocardial left and right. 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 introducti of digitalis
Digitalis is a genus of about 20 species of herbaceous perennials, shrubs, and biennials that are commonly called foxgloves. This genus was traditionally placed in the figwort family Scrophulariaceae, but recent reviews of phylogenetic research have placed it in the much enlarged family...

, though it turns out that digitalis has an inotropic effect rather than a chronotropic effect.
  • Beta blockers such as metoprolol
    Metoprolol is a selective β1 receptor blocker used in treatment of several diseases of the cardiovascular system, especially hypertension. The active substance metoprolol is employed either as metoprolol succinate or metoprolol tartrate...

  • Acetylcholine
    The chemical compound acetylcholine is a neurotransmitter in both the peripheral nervous system and central nervous system in many organisms including humans...

  • Digoxin
    Digoxin INN , also known as digitalis, is a purified cardiac glycoside and extracted from the foxglove plant, Digitalis lanata. Its corresponding aglycone is digoxigenin, and its acetyl derivative is acetyldigoxin...

  • The non-dihydropyridine calcium channel blocker
    Calcium channel blocker
    A calcium channel blocker is a chemical that disrupts the movement of calcium through calcium channels.CCB drugs devised to target neurons are used as antiepileptics. However, the most widespread clinical usage of calcium channel blockers is to decrease blood pressure in patients with...

    s diltiazem
    Diltiazem is a non-dihydropyridine member of the class of drugs known as calcium channel blockers, used in the treatment of hypertension, angina pectoris, and some types of arrhythmia....

     and 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...

Positive Chronotropes

  • Most Adrenergic agonists
  • Atropine
    Atropine is a naturally occurring tropane alkaloid extracted from deadly nightshade , Jimson weed , mandrake and other plants of the family Solanaceae. It is a secondary metabolite of these plants and serves as a drug with a wide variety of effects...

  • Dopamine
    Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...

  • Epinephrine
    Epinephrine is a hormone and a neurotransmitter. It increases heart rate, constricts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. In chemical terms, adrenaline is one of a group of monoamines called the catecholamines...

  • Isoproterenol
    Isoprenaline or isoproterenol is a medication used for the treatment of bradycardia , heart block, and rarely for asthma...

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