What does inotropy refer to in cardiac physiology?

What does inotropy refer to in cardiac physiology?

• A. A drug that affects cardiac contractile force.
• B. The speed of electrical conduction through the AV node.
• C. A measure of heart rate variability.
• D. The relaxation of the ventricular muscle during diastole.

Answer: (A)

Inotropy is about the contractile strength of the heart muscle—the force generated during ventricular contraction. It describes how hard the heart squeezes, not how fast it beats or how it relaxes. A drug that changes this contractile force is an inotropic agent: positive inotropes increase the force of contraction, while negative inotropes decrease it. The other options point to conduction speed through the AV node (dromotropy), heart rate variability (chronotropic aspects), or diastolic relaxation (lusitropy), none of which describe contractile strength. So the statement about a drug that affects cardiac contractile force best captures what inotropy refers to.

Inotropy is about the contractile strength of the heart muscle—the force generated during ventricular contraction. It describes how hard the heart squeezes, not how fast it beats or how it relaxes. A drug that changes this contractile force is an inotropic agent: positive inotropes increase the force of contraction, while negative inotropes decrease it. The other options point to conduction speed through the AV node (dromotropy), heart rate variability (chronotropic aspects), or diastolic relaxation (lusitropy), none of which describe contractile strength. So the statement about a drug that affects cardiac contractile force best captures what inotropy refers to.