<prompt> Pulsus alternans occurs in -Constrictive pericarditisViral myocarditisHypokalemiaMyocardial infarction  <response>: pulses alternans is seen in 3 conditons alarge pericardial effusion bleft ventricular failure casthma so the answer is MI where there is left ventricular failure. Ref Harrison 20th edition pg 1523 