Which electrolyte condition will likely result in tachycardia?

• A. Hypercalcemia
• B. Hypokalemia
• C. Hyperkalemia
• D. Hypocalcemia

Answer: (B)

Hypokalemia is known to cause various cardiovascular effects, one of which is tachycardia. Low potassium levels can lead to increased cardiac excitability and altered conduction pathways, which can provoke rapid heart rates as the heart struggles to maintain adequate rhythm and function.

This condition affects the electrical activity in the heart, as potassium is crucial for maintaining normal cell membrane potential and conduction of action potentials. When potassium levels drop, it can lead to an imbalance in the electrolytes, causing the heart to work harder and possibly resulting in tachycardia.

In the context of other electrolyte conditions: hypercalcemia may slow the heart rate rather than increase it, and hyperkalemia can also lead to arrhythmias, but they typically present with a different pattern than tachycardia. Hypocalcemia can lead to increased neuromuscular excitability but is not directly linked to an increase in heart rate in the same manner as hypokalemia. Hence, hypokalemia stands out as the electrolyte disturbance most likely to result in tachycardia.