Paramedic National Registry Practice

What is the most likely reason that a patient with a pulse of 190 is hypotensive?

1. Increased vascular resistance

2. Decreased diastolic fill time

3. Excessive fluid volume

4. Bradycardia

The correct answer is: Decreased diastolic fill time

A pulse of 190 beats per minute indicates tachycardia, which can significantly affect the hemodynamic status of a patient. When the heart beats rapidly, there is less time for the heart to fill with blood during diastole. This decreased diastolic fill time means that less blood is being pumped out with each heartbeat, leading to reduced stroke volume. As a result, even though the heart rate is elevated, the overall cardiac output may not be sufficient to maintain adequate blood pressure, leading to hypotension. The heart's ability to effectively perfuse vital organs becomes compromised due to this rapid rhythm, highlighting the importance of diastolic filling in ensuring adequate circulation and blood pressure. The other options focus on different physiological processes that might not directly correlate with the scenario of tachycardia and hypotension in the same manner. Increased vascular resistance could potentially elevate blood pressure, excessive fluid volume could lead to increased pressure, and bradycardia would typically result in lower heart rates, which is not applicable in this case. Thus, the primary connection between tachycardia and hypotension lies in the decreased diastolic fill time.