Dr. Aavishkar Regmi on Instagram: "Paroxysmal nocturnal dyspnea (PND) is a classic symptom of heart failure, particularly left-sided heart failure. It refers to sudden episodes of shortness of breath that awaken the patient from sleep, typically after 1–2 hours of lying down. This occurs due to fluid redistribution from the lower extremities to the lungs when supine, leading to pulmonary congestion. Unlike orthopnea, which is relieved by simply propping up with pillows, PND often requires the pa