Reversed Pulsus Paradoxus

The term "reversed pulsus paradoxus" may be used to describe an inspiratory rise of the arterial systolic and diastolic pressures, presumably related to an inspiratory increase in left ventricular stroke output. We have observed a reversed pulsus paradoxus in three unrelated clinical circumstances: idiopathic hypertrophic subaortic stenosis, isorhythmic ventricular rhythms and during intermittent inspiratory positive-pressure breathing in the presence of left ventricular failure. These unusual respiration-related fluctuations of blood pressure must be differentiated from the usual pulsus paradoxus of cardiac tamponade. (N Engl J Med 289:1272–1275, 1973)