To examine the cardiodynamics of pulsus paradoxus, simultaneous intrathoracic and cardiac pressures, coronary blood flow, and cardiac volumes were measured before and after the development of pulsus paradoxus in spontaneously breathing, closed-chest dogs subjected to cardiac tamponade. Pulsus paradoxus was associated with equalization of mean right atrial (from 2.8 ± 1.2 to 11.2 ± 1.3 mm Hg, p
