What term describes a slow heart rate, defined as less than 60 beats per minute?

• A. Bradycardia
• B. PND
• C. Orthopnea
• D. Vein

Answer: (A)

Bradycardia is the term for a slow heart rate, defined as a resting heart rate of less than 60 beats per minute in adults. It can be normal in well-trained athletes or during sleep, but in other cases it may indicate heightened vagal tone, intrinsic conduction system disease, or effects from medications (like beta-blockers or certain calcium channel blockers), as well as conditions such as hypothyroidism or electrolyte disturbances. In practice, you’d document it as bradycardia with a heart rate under 60 bpm, noting any associated symptoms or underlying causes. The other options describe symptoms or structures, not heart rate: paroxysmal nocturnal dyspnea and orthopnea are breathing-related signs of heart failure, and vein is an anatomical structure, not a rhythm term.