Yes. It may be absent in 2% of cases, usually because of compensatory mechanisms that prevent major septal shifts in inspiration. The most common are:
Isolated right heart tamponade: This has been described in patients with chronic renal failure who
are on hemodialysis. Regional tamponade can also occur in loculated pericardial effusions. In both cases,
the pericardial “water bag” is too asymmetric to cause a “real estate” competition between ventricles.
Aortic regurgitation (AR): In AR, the left ventricle can fill from the aorta during inspiration, which then
prevents the development of a “pulsus.” Hence, patients with aortic dissection (who have both AR
and tamponade) may often present without pulsus paradoxus.
Large atrial septal defect: The normal inspiratory increase in systemic venous return is counterbalanced
by a decrease in left-to-right shunt, resulting in minimal change in right ventricular volume.
Elevated left ventricular diastolic pressures: These occur in cases of severe left ventricular dysfunction.
The left ventricular pressure is too high to allow any ipsilateral septal shift in inspiration.
Severe rheumatoid spondylitis or disease of the bony thorax: Wide changes in intrathoracic pressure
are prevented by the relative immobility of the chest wall.
Severe hypotension and shock Coexistent conditions producing “reversed pulsus paradoxus”
Isolated right heart tamponade: This has been described in patients with chronic renal failure who
are on hemodialysis. Regional tamponade can also occur in loculated pericardial effusions. In both cases,
the pericardial “water bag” is too asymmetric to cause a “real estate” competition between ventricles.
Aortic regurgitation (AR): In AR, the left ventricle can fill from the aorta during inspiration, which then
prevents the development of a “pulsus.” Hence, patients with aortic dissection (who have both AR
and tamponade) may often present without pulsus paradoxus.
Large atrial septal defect: The normal inspiratory increase in systemic venous return is counterbalanced
by a decrease in left-to-right shunt, resulting in minimal change in right ventricular volume.
Elevated left ventricular diastolic pressures: These occur in cases of severe left ventricular dysfunction.
The left ventricular pressure is too high to allow any ipsilateral septal shift in inspiration.
Severe rheumatoid spondylitis or disease of the bony thorax: Wide changes in intrathoracic pressure
are prevented by the relative immobility of the chest wall.
Severe hypotension and shock Coexistent conditions producing “reversed pulsus paradoxus”