PubMed1978
The purpose of this work is to reconsider practical value of three prediction formulae of left ventricular ejection time (LVET): the Wood's coefficient, the Weissler's residual and the multivariate residual. Two series of patients are presented: (1) an aortic series of 160 patients, with pure or nearly pure stenosis in 46 cases, pure insufficiency in 57 cases, and stenosis plus insufficiency in 57 cases, and (2) a reference series of 200 patients without aortic disease. All the patients were catheterized, with measurement of cardiac output by Fick's method. In all the aortic patients, the aortic "gradient" was measured, the amount of aortic regurgitation assessed by cineangiography, and the presence of absence of aortic valve calcification checked with an image intensifier. LVET tends to increase according to the importance of the "gradient" and of the insufficiency. However, the isolated use of this increase as a predictor of severity of aortic lesions is not more rewarding than just looking for aortic valve calcification except in pure aortic insufficiency. Sensitivity or specificity of the prediction can be increased by various combinations of both observations--LVET and calcification--; their respective interest will depend upon the target. Probability of false positive or negative predictions can be estimated in both series of patients and in various subgroups of aortic lesions. False negative predictions have been analysed in patients with pure or nearly pure stenosis and a "gradient" of 50 mm Hg or higher . Based on any of the three LVET predictions formulae, they are chiefly observed in the absence of calcification--i.e. in younger patients--probably because stenosis here is less severe. Based on the Wood's or Weissler's coefficient, false negative predictions are also relatively frequent in patients with a decreased stroke volume; this doesn't occur if the LVET prediction formula takes stroke volume into account, as in the multivariate residual. Three types of patients with pure or nearly pure stenosis and a "gradient" of 50 mm Hg or higher can be described: (a) without calcification and with a normal stroke volume: the patient is young, his stenosis is moderately severe, and LVET tends to increase but most often remains within normal limits; (b) with calcification and a normal stroke volume: the patient is notably older, his stenosis is severe, and LVET is most often increased; (c) with calcification and a decreased stroke volume at rest, which suggests a decreased myocardial performance; here, age and stenosis are similar to the preceding subgroup observations, but LVET is often normal if stroke volume is not taken into account.