What could happen without the plateau phase in cardiac muscle cells?

The plateau phase in cardiac muscle cells is vital for prolonging the action potential, which allows the heart muscle to contract and then relax adequately. This phase prevents the rapid re-excitation of the cardiac muscle, ensuring that the heart has enough time to fill with blood between beats and preventing excessive frequency of contractions.

Without the plateau phase, the heart muscle could enter a state of tetany, where contractions happen too frequently and do not allow sufficient time for relaxation. This could lead to a lack of effective blood pumping, potentially resulting in severe complications such as cardiac arrest. The presence of the plateau phase is critical for maintaining the coordinated and rhythmic contractions necessary for effective heart function, and its absence would result in continuous and uncontrolled muscle contraction rather than coordinated heartbeats.