Which of the following is a symptom of left-sided heart failure?

In left-sided heart failure, one of the primary symptoms is dyspnea, which refers to difficulty or discomfort in breathing. This occurs because the left side of the heart is responsible for pumping oxygenated blood from the lungs to the rest of the body. When the left ventricle fails to function effectively, blood can back up into the pulmonary circulation, leading to increased pressure in the pulmonary veins and causing fluid to leak into the alveoli of the lungs. This fluid accumulation results in pulmonary congestion and manifests as shortness of breath or dyspnea, particularly during physical activity or when lying flat.

The other options represent symptoms more typical of right-sided heart failure or systemic effects resulting from left-sided heart failure. For instance, peripheral edema and ascites are often associated with fluid accumulation due to right-sided heart failure, while jugular venous distension is indicative of elevated pressures in the venous system, which occurs when the right side of the heart is unable to pump blood adequately. Thus, dyspnea is a hallmark symptom specifically linked to the complications arising from left-sided heart dysfunction.