What should be called a brisk 'Y' descent?

Patients with pericardial constriction show a prominent 'y' descent in right atrial and vena caval pressure traces. In all earlier hemodynamic descriptions of constrictive pericarditis, the 'y' descent has been described as 'brisk', 'sharp' or 'rapid' but no effort has been made to quantify the same. In this study, we have tried to objectively evaluate and describe this 'y' descent by measuring its negative slope (-dy/dt) at its steepest portion. Forty one patients were studied hemodynamically, 9 with constrictive pericarditis (Group I) and 32 normals (Group II). The negative slope of the 'y' descent in patients with constrictive pericarditis (69.95 +/- 23.04 mm Hg) was found to be significantly greater than normals (35.13 +/- 7.84 mm Hg, p < 10(-6). Discriminant analysis was used to determine its sensitivity, specificity, predictive value and overall accuracy, in the diagnosis of pericardial constriction. Value of > or = 45 mm Hg/sec was found to have the highest overall accuracy (0.88). The correlation between the right ventricular end diastolic pressure and the slope of 'y' descent in patients with pericardial constriction (r = 0.66) and in normals (r = 0.60) was fair. It is concluded that -dy/dt is significantly different in patients with constrictive pericarditis as compared to normals. The diagnostic utility of this parameter needs to be evaluated in patients with equivocal clinical and hemodynamic data, in those with occult pericardial constriction and in post-pericardiectomy cases where the pressures do not normalise immediately after adequate pericardial resection.