Nocturnal dyspnea in heart failure is most commonly associated with which condition?

Nocturnal dyspnea in heart failure is most commonly associated with which condition?

• A. Myocardial infarction
• B. Left heart failure
• C. Right heart failure
• D. Pulmonary embolism

Answer: (B)

Paroxysmal nocturnal dyspnea arises when lying down increases venous return to the heart. In left-sided heart failure, the left ventricle cannot efficiently handle this higher preload, causing a rise in pulmonary capillary pressure and pulmonary edema. The result is breathlessness that wakes the person at night. This pattern is a classic sign of left-sided heart failure, which is why that option is the best choice. While myocardial infarction can precipitate heart failure and pulmonary embolism can cause dyspnea, the nocturnal, heart‑failure–related breathing difficulty during sleep is most characteristic of left-sided failure.

Paroxysmal nocturnal dyspnea arises when lying down increases venous return to the heart. In left-sided heart failure, the left ventricle cannot efficiently handle this higher preload, causing a rise in pulmonary capillary pressure and pulmonary edema. The result is breathlessness that wakes the person at night. This pattern is a classic sign of left-sided heart failure, which is why that option is the best choice. While myocardial infarction can precipitate heart failure and pulmonary embolism can cause dyspnea, the nocturnal, heart‑failure–related breathing difficulty during sleep is most characteristic of left-sided failure.