After a positive inotropic treatment for myocardial infarction, what is the expected change in systemic vascular resistance (SVR)?

After a positive inotropic treatment for myocardial infarction, what is the expected change in systemic vascular resistance (SVR)?

• A. Decreases
• B. Increases
• C. No change
• D. Decreases then increases

Answer: (B)

Positive inotropic therapy boosts the heart’s pumping strength, raising cardiac output. In many clinical inotropes used after myocardial infarction, the drug also carries vasoconstrictive effects (or prompts reflex sympathetic activation), which increase arterial tone. This raises systemic vascular resistance even as the heart’s contractility improves. So, the net effect on SVR can be an increase. (Agents that primarily dilate vessels, like milrinone, would tend to lower SVR, but the scenario in question points to an inotrope with vasoconstrictive potential, hence the rise in SVR.)

Positive inotropic therapy boosts the heart’s pumping strength, raising cardiac output. In many clinical inotropes used after myocardial infarction, the drug also carries vasoconstrictive effects (or prompts reflex sympathetic activation), which increase arterial tone. This raises systemic vascular resistance even as the heart’s contractility improves. So, the net effect on SVR can be an increase. (Agents that primarily dilate vessels, like milrinone, would tend to lower SVR, but the scenario in question points to an inotrope with vasoconstrictive potential, hence the rise in SVR.)