A 65-year-old man complains of asphyxia, cough with pink foaming sputum, sensation of lack of air, and fear of death. He has orthopnea, pale skin, and acrocyanosis and is covered in cold sticky sweat. His respiration is harsh, in the lower posterior segments there are wet finely vesicular and moderately vesicular crackles on both sides. His respiratory rate is 40/min. The heart sounds are markedly muffled. At the cardiac apex, the gallop rhythm is observed. Make the right diagnosis: