A nurse is caring for a patient diagnosed with heart failure. The provider has ordered a medication to help improve the patient's cardiac output. Cardiac output can be defined as the volume of blood the heart pumps per minute. The formula to determine cardiac output is: CO = SV x HR, where CO is cardiac output, SV is stroke volume, and HR is heart rate. In this situation, if the patient has a stroke volume of 70 mL and a heart rate of 80 beats per minute, the cardiac output would be: CO = ____ mL/min.