NREMT Paramedic Practice

What is a potential effect of acidosis on the cardiovascular system?

1. Increased myocardial contractility

2. Decreased heart rate

3. Arrhythmias

4. Enhanced oxygen delivery

The correct answer is: Arrhythmias

Acidosis, which refers to an excess of acid in the bodily fluids, can significantly impact the cardiovascular system, particularly by contributing to arrhythmias. The acidic environment alters the electrochemical gradients that are crucial for normal heart function. This disruption can lead to changes in the myocardial action potentials and increased irritability of cardiac cells, which promotes the development of arrhythmias. Additionally, acidosis may impair the heart's ability to properly depolarize and repolarize, further exacerbating the risk of abnormal heart rhythms. In contrast, other options do not accurately reflect the physiological impacts of acidosis on the cardiovascular system. For instance, increased myocardial contractility is typically associated with alkalosis or stimulation of the sympathetic nervous system rather than acidosis. Similarly, a decreased heart rate is counterintuitive, as acidosis often leads to compensatory mechanisms that might increase heart rate as the body attempts to maintain cardiac output. Enhanced oxygen delivery is also unlikely in a state of acidosis, as the accumulation of hydrogen ions can impair hemoglobin's oxygen-carrying capacity, shifting the oxygen-hemoglobin dissociation curve to the right (the Bohr effect), which means less oxygen is delivered to tissues.