4 weeks after myocardial infarction a 56-year-old patient developed acute heart pain, pronounced dyspnea. Objectively: the patient's condition is extremely grave, there is marked cyanosis of the face, swelling and throbbing of the neck veins, peripheral pulse is absent, carotid artery pulse is rhythmic, 130/min., BP is 60/20 mm Hg. Auscultation of the heart reveals extremely muffled sounds, percussion reveals heart border extension in both directions. What is the optimal treatment tactic for this patient?