The MVO2 value is easy to calculate. You simply multiply the heart rate and systolic blood pressure, the resulting number is the MVO2 value.
The single value doesn't mean much to anyone but if you compare values, you can tell whether the patient's heart is more or less burdened.
EXAMPLE:13:01 48 yo W M with chest pressure, VS BP-130/90, P-68
13:06 After one Nitro, chest pressure worse, VS BP-102/70, P-101
MVO2 = SBP * HR
Why did the patient get worse? If you gave the patient a Nitro while they were standing or sitting up, you may have caused a reflex tachycardia and increased the work of the heart! (you should always give Nitro to your patients lying reclined if possible)