[Assessment of left ventricular function by midwall fractional shortening in hemodialysis patients]

Midwall fractional shortening (MFS) is a useful index to evaluate left ventricular myocardial function in patients with essential hypertension. The study investigated the prevalence and characterization of low MFS in hemodialysis patients.

MFS was calculated from M-mode echocardiograms in 67 patients (34 males, 33 females) receiving maintenance hemodialysis in whom fractional shortening was normal. Plasma levels of atrial and brain natriuretic peptides were also measured in these patients before and after hemodialysis. MFS was evaluated by stress-corrected MFS (ratio of observed to predicted MFS). The relationship of MFS to circumferential end-systolic stress in 122 healthy subjects was used to calculate the predicted MFS.

Stress-corrected MFS was depressed in 18 of the 67 patients (26.9%). In the low MFS group, duration of hypertension was significantly longer (p < 0.05), wall thickness was significantly greater (p < 0.001), left ventricular dimension was significantly smaller (p < 0.0001), and relative wall thickness was significantly greater (p < 0.0001) than in the normal MFS group. Reduction of brain natriuretic peptide level by hemodialysis in the low MFS group was significantly higher (p < 0.05) than in the normal MFS group.

Depression of stress-corrected MFS may be common in hemodialysis patients. Long duration of hypertension and concentric geometry of the left ventricle occur in patients with low MFS.