Cardiotonic effect

A cardiotonic effect refers to the pharmacological or physiological action of increasing the force and efficiency of myocardial contraction, commonly termed a positive inotropic effect (StatPearls, NBK544235). It is not a specific molecular target, such as a protein or enzyme, but rather a therapeutic outcome or a class of drug actions (PubChem, Cardiotonic Agents). This effect is typically sought in the management of acute or chronic heart failure and cardiogenic shock to maintain systemic perfusion (Wikipedia, Cardiotonic agent). Various molecular targets mediate this response, including the sodium-potassium ATPase (inhibited by cardiac glycosides like Digoxin), beta-1 adrenergic receptors (stimulated by catecholamines like Dobutamine), and phosphodiesterase 3 (inhibited by inodilators like Milrinone). While beneficial for improving hemodynamics, cardiotonic agents often increase myocardial oxygen demand and can predispose patients to life-threatening arrhythmias (PubMed, PMID: 25660554).

Other names

Positive inotropic effectInotropyCardiac stimulationMyocardial contractility enhancement

Cardiotonic effects are achieved through multiple mechanisms including inhibition of the Na+/K+-ATPase pump, agonism of beta-1 adrenergic receptors, or inhibition of phosphodiesterase 3 (PDE3), all of which lead to increased intracellular calcium availability for the contractile apparatus (StatPearls, NBK544235).