What is the primary consequence of the refractory period in cardiac action potential?

The primary consequence of the refractory period in cardiac action potential is that it prevents premature contractions of the heart. This is crucial for the heart's proper functioning because the refractory period ensures that once the heart muscle has been stimulated to contract, it cannot immediately be stimulated again. This interval allows the heart to relax and fill with blood before the next contraction, preventing overlapped contractions that could lead to inefficient pumping or arrhythmias.

By creating a pause between contractions, the refractory period maintains a controlled and rhythmic heart rate, which is essential for optimal blood flow and coordination of the heart's chambers. This mechanism helps sustain normal heart rhythm and prevents the occurrence of dangerous arrhythmias that can arise from early or spontaneous depolarizations.