Beck's triad of cardiac tamponade includes all, except?

Beck's triad: Hypotension Soft or absent hea sounds Jugular venous distention with a prominent x descent but an absent y descent. There are both limitation of ventricular filling and reduction of cardiac output. There may be reduction in amplitude of the QRS complexes, and electrical alternans of the P, QRS, or T waves should raise the suspicion of cardiac tamponade.