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Chronotropic effects (from chrono-, meaning time, and tropos, "a turn") are those that change the heart rate. Chronotropic drugs may change the heart rate and rhythm by affecting the electrical conduction system of the heart and the nerves that influence it, such as by changing the rhythm produced by the sinoatrial node. Positive chronotropes ...
A cardiac stimulant is a drug which acts as a stimulant of the heart – e.g., via positive chronotropic action (increased heart rate) and/or inotropic action (increased myocardial contractility). They increase cardiac output (the amount of blood pumped by the heart over time).
Epinephrine (adrenaline). Activation of β 1 receptors induces positive inotropic, chronotropic output of the cardiac muscle, leading to increased heart rate and blood pressure, secretion of ghrelin from the stomach, and renin release from the kidneys.
Beta-blockade of the β 1 receptor will inhibit cAMP from phosphorylating, and it will decrease the ionotrophic and chronotropic effect. Note that drugs may be cardioselective, or act on β 1 receptors in the heart only, but still have intrinsic sympathomimetic activity. Acebutolol (has intrinsic sympathomimetic activity, ISA) [80] Atenolol [80 ...
The adrenergic receptors or adrenoceptors are a class of G protein-coupled receptors that are targets of many catecholamines like norepinephrine (noradrenaline) and epinephrine (adrenaline) produced by the body, but also many medications like beta blockers, beta-2 (β 2) antagonists and alpha-2 (α 2) agonists, which are used to treat high ...
It is important to note that certain medications, such as Milrinone and Digoxin, possess overlapping classifications due to their ability to engage multiple mechanisms of action. Their inotropic properties make cardiactonic agents critical in addressing inadequate perfusion , and acute heart failure conditions including cardiogenic shock , as ...
β 1-Adrenergic receptor agonists, also known as beta-1 agonists, are a class of drugs that bind selectively to the β 1-adrenergic receptor.As a result, they act more selectively upon the heart. β-Adrenoceptors typically bind to norepinephrine release by sympathetic adrenergic nerves and to circulating epinephrine.
The mechanisms of sympathomimetic drugs can be direct-acting (direct interaction between drug and receptor), such as α-adrenergic agonists, β-adrenergic agonists, and dopaminergic agonists; or indirect-acting (interaction not between drug and receptor), such as MAOIs, COMT inhibitors, release stimulants, and reuptake inhibitors that increase the levels of endogenous catecholamines.