Effect of isometric effort upon mitral regurgitation severity--echo Doppler study

Isometric effort increases the severity of mitral regurgitation (MR) by augmenting the afterload and the regurgitant fraction. The worsening of MR may be different in various patients and can explain the differences in effort capacity of patients with identical rest mitral regurgitation. We studied 25 patients with MR of various etiologies, submitted to handgrip (maximal voluntary contraction), the severity of MR being evaluated by the determination of regurgitant area (colour Doppler). There was a 42% increase of the regurgitant area from 3.26 to 4.66 cm2 (p < 0.05). The increase was greater for ischemic MR (59%) than for MR in dilated cardiomyopathy (26%), the last value not being explained by a lower EF because rest EF was similar in patients with and without an increase of MR severity during maximal voluntary contraction. The individual analysis of the results showed an increase of the MR severity in 1/2 of the patients, in whom the left atrial dimension was greater, though the effort capacity was the same in the two subsets of patients. It is concluded that colour Doppler is a simple and valuable method for studying the influence of isometric exercise upon MR severity, this being increased in 1/2 of the patients, with a positive correlation with ischemic etiology of the disease, left atrial dimension, but not with the patients' effort capacity.