A 28-year-old patient complains of severe shortness of breath during even mild physical exertion, dizziness, forced body position (semi-sitting), and subfebrile body temperature.According to the patient's medical history, her condition was gradually deteriorating over the course of the last 1.5 months after a case of an acute respiratory viral infection. Auscultation detects harsh respiration and dry crackles, the heart sounds are rhythmic and severely muffled, Blood pressure - 110/70 mm Hg. Chest X-ray shows that the shadow of the heart is severely expanded in both directions, the cardiac waistline is smoothed out. What is the most likely diagnosis in this case?stenosis