What does arrhythmia refer to in medical terms?

Arrhythmia refers specifically to an irregular heart rate or rhythm, which means the heart may beat too quickly, too slowly, or with an unpredictable pattern. This condition can arise from various issues affecting the electrical signals that coordinate heartbeats, leading to potentially serious consequences for cardiovascular health. Understanding arrhythmia is crucial in a pharmacy setting, as it may influence medication management and patient counseling, especially regarding drugs that can affect heart rate or rhythm, such as antiarrhythmic agents.

The other options highlight different medical conditions unrelated to heart rhythm: fluid accumulation in the joints refers to a joint issue, high blood pressure indicates hypertension, and a type of cancer affecting the blood points to hematological concerns, none of which align with the definition of arrhythmia.