Cardiac Output

[MIRASHYINI BASKAR]

According to the formula, CO is directly proportional to HR means when heart rate increases, Cardiac output should increase too. However, when the HR increase, less blood is pumped frm atria to ventricle means cardiac output decreases in that case. I'm confused.

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[Radetzky]

It depends. The decrease in stroke volume is less than the increase in HR so on balance CO increases, up to a certain point. That point is a HR of about 150 in healthy hearts, less in not so healthy hearts.

 

[Esmolol]

As above. It’s not a rule that one-and-done. Generally - yes - HR goes up, SV goes up then CO goes up. But then things can get more nuanced.