After anesthetization a 55-year-old patient felt sudden attack of weakness, pain behind his breastbone irradiating to his left arm and scapular area, palpitation. Objectively: the patient is conscious, inert, his forehead is covered with cold sweat, the skin is pale, AP is 90/60 mm Hg, heart tones are dull, pulse is thready and arrhythmic. What state is developing?