Final answer:
The statement is true. Hyperkalemia with potassium levels reaching 7 to 10 mmol/L can severely impair cardiac function, leading to potentially fatal arrhythmias and cardiac arrest.
Step-by-step explanation:
The statement that hyperkalemia reaching 7 to 10 mmol/L can begin to affect normal cardiac function and is life-threatening is True. Hyperkalemia is a condition characterized by elevated potassium levels in the blood, which can have significant impacts on skeletal muscles, the nervous system, and most critically, the heart. Normal potassium levels usually range from 3.5 to 5.0 mmol/L, and levels exceeding 5.5 mmol/L are generally considered hyperkalemic. When these levels reach 7 to 10 mmol/L, the risk of cardiac complications increases significantly.
A person with hyperkalemia may experience the inability of cells to repolarize after depolarization. This repolarization is critical for muscle and nerve function, particularly for the heart. The heart might not relax properly after a contraction, leading to arrhythmias, and in severe cases, cardiac arrest. Symptoms may include muscle weakness, paralysis, palpitations, and in severe cases, life-threatening heart rhythm disturbances.