A 55-year-old man is brought to the emergency department because of shortness of breath and confusion for 4 hours. He has hypertension and chronic kidney disease requiring hemodialysis. An ECG shows low voltage with electrical alternans. Physical examination is most likely to show which of the following findings?
1) Elevated jugular venous pressure
2) Pulsus paradoxus
3) S3 gallop
4) Pericardial friction rub
5) Pulsus alternans