NREMT Paramedic Practice

What physiological response is typically seen in an inferior myocardial infarction (MI)?

1. Sympathetic response with high blood pressure

2. Parasympathetic response with low blood pressure

3. Neutral response with normal blood pressure

4. Mixed response with fluctuating blood pressure

The correct answer is: Parasympathetic response with low blood pressure

In the context of an inferior myocardial infarction, the physiological response predominantly involves a parasympathetic response, which is characterized by a reduction in blood pressure. The inferior wall of the heart is usually supplied by the right coronary artery, and when an inferior MI occurs, it can lead to increased vagal tone due to irritation of the vagus nerve. This elevated vagal stimulation can manifest as bradycardia (a slower heart rate) and hypotension (lower blood pressure). The parasympathetic nervous system primarily works to promote "rest-and-digest" functions, which includes decreasing the heart rate and dilating blood vessels, leading to lower blood pressure. This is in contrast to an anterior MI, which is more likely to elicit a sympathetic response characterized by increased heart rate and blood pressure. Therefore, the choice that describes the physiological response of an inferior MI as leading to a parasympathetic response with low blood pressure accurately reflects the typical clinical presentations and mechanisms involved following an inferior myocardial infarction.