Measurements were made of simultaneous pulmonary artery wedge (PA
w
) and left ventricular diastolic (LV
ed
) pressures 39 times during 21 venous and left ventricular cardiac catheterization studies in eight animals with brisket disease. Each animal was studied during the acute phase of the disease. The remaining 13 studies were carried out in six animals at various intervals during spontaneous recovery from pulmonary hypertension and heart failure. A pressure gradient between PA
w
and LV
ed
(δP) which averaged 14.6 ± 1.6 (SE) mm Hg was demonstrated in 12 measurements during seven studies in four animals (group A). The δP in 27 measurements during 14 studies in six animals averaged 2.4 ±0.8 mm Hg (group B). Venous resistance (R
v
) represented 39±5% of the total resistance (R
T
) of pulmonary vessels in group A and 13±4% in group B studies. The δP and R
v
/R
T
in group A animals are consistent with findings caused by pulmonary venous obstruction. The obstruction was interpreted to represent the effect of pulmonary venoconstriction.
Thirty patients with primary cardiac compression due to constrictive pericarditis, lax effusion, or cardiac tamponade and an additional seven patients with spurious evidence of cardiac compression or with pericardial effusion playing an unimportant role in the circulatory disorder were studied. Rather stringently defined physical findings were sought which might allow discrimination between cardiac disorders. The following conclusions are drawn from the results.
1. Constrictive pericarditis is associated with venous and auscultatory phenomena which do not allow separation from other forms of heart disease causing congestive heart failure. Kussmaul's sign is present in less than 40%; pulsus paradoxus as classically defined is rare.
2. In lax pericardial effusion, Kussmaul's sign and Friedreich's sign, along with third heart sounds, are not present. Pulsus paradoxus is inconstant with tranquil breathing but is regularly induced by deep inspiration. There is inspiratory decrease in venous pressure and pericardial pressure. Cardiac index is normal and venous pressure is less than 12 mm Hg. Circulatory distress is not apparent.
3. Tamponade induces signs of circulatory distress and is regularly characterized by pulsus paradoxus but Friedreich's sign, a third heart sound, as well as Kussmaul's venous sign, are absent. The venous pressure exceeds 12 mm Hg. There is an inspiratory decrease in venous pressure and pericardial pressure. The low cardiac index is usually relieved by tap. When aortic stenosis is present, respiratory variation in left ventricular systolic pressure may not be reflected by clinical pulsus paradoxus.
4. Spurious signs of cardiac compression may be due to (1) respiratory disease, (2) severe myocardial disease and incidental effusion, or (3) obesity. In the respiratory disease pulsus paradoxus, normal cardiac index, low venous pressure, and venous and pericardial-pressure decrease with inspiration are present. The second group does not show pulsus paradoxus and the elevated venous pressure, diastolic dip, and third heart sounds are due to heart failure. Obesity may cause pulsus paradoxus and increased peripheral venous pressure, which does not reflect central venous pressure. These findings seem related to inspiratory collapse of extrathoracic vessels.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.