Final answer:
Decreased levels of sodium and potassium ions increase cardiac conduction signals. Altered sodium and potassium levels can affect heart rate and lead to arrhythmias. Hypokalemia and hyperkalemia have different effects on the heart.
Step-by-step explanation:
Decreased levels of sodium and potassium ions increase cardiac conduction signals.
Factors affecting heart rate include altered sodium and potassium levels.
Low sodium levels (hyponatremia) and high sodium levels (hypernatremia) may initially lead to tachycardia, while severely high hypernatremia and severe hyponatremia can lead to arrhythmias.
Hypokalemia (low potassium levels) also leads to arrhythmias, while hyperkalemia (high potassium levels) weakens and ultimately fails the heart.