Final answer:
Hypocalcemia, or low calcium levels, can have negative effects on the cardiac action potential. This can result in abnormal cardiac rhythms and potentially cardiac arrest.
Step-by-step explanation:
Hypocalcemia, a condition characterized by abnormally low levels of calcium, can have negative effects on the cardiac action potential. Calcium ions play a critical role in the cardiac muscle's action potential by contributing to the prolonged plateau phase and absolute refractory period. Without adequate levels of calcium, the heart may have difficulty contracting properly, leading to abnormal cardiac rhythms and potential cardiac arrest.