KUSSMAUL'S SIGN

In healthy individuals, breathing in (inspiring) increases venous return to the right heart. Any evident neck vein distension, therefore, should diminish during inspiration.

In patients with conditions that impair venous return to the right heart inspiration may be associated with an absence of jugular vein collapse or a paradoxical rise in the jugular column (video). This is called Kussmaul's sign.

Cardiac conditions that may be associated with a positive Kussmaul's sign include right atrial myxoma, tricuspid stenosis, constrictive pericarditis, pericardial effusion, restrictive myocardopathy, and severe pulmonary hypertension. Overall, the commonest cause is severe right-sided congestive heart failure.

Superior vena cava obstruction can also result in a positive Kussmaul's sign.