Causes of Reversed Pulsus Paradoxus

To the Editor: Massumi et al. (N Engl J Med 289:1272, 1973) recently described three causes of reversed pulsus paradoxus (inspiratory rise in the arterial blood pressure). We have observed this phenomenon in another clinical situation, during intermittent positive-pressure ventilation of a patient receiving circulatory support with an intrathoracic, intra-aortic, counterpulsation balloon pump (this balloon placed via the femoral artery and inflated during diastole boosts the cardiac output and decreases the afterload faced by the heart). A 59-year-old patient received this therapy for circulatory failure after a ventricular aneurysmectomy and coronary-artery bypass graft. The arterial blood pressure was recorded from ….