Evidence exists that left ventricular function is impaired in chronic uremic patients. During hemodialysis (HD) treatment, myocardium undergoes electrolyte, hemodynamic and neuro-humoral stress; however, data about the acute changes on ventricular function are controversial. Aim of the present study was to evaluate the effect of a single hemodialysis session on left ventricular (LV) systolic and diastolic function using pulsed tissue Doppler imaging (TDI) sampled by echocardiography. The study group included 20 uremic patients (17 males, aged 51±13 yrs) on maintenance HD, free from clinically overt cardiac dysfunction who underwent echocardiography with pulsed TDI 30 min prior and 30 min after a HD session. TDI was performed by placing the sample volume in the center of the basal lateral segment and the basal interventricular septum in the apical four-chamber view. Myocardial systolic wave (S_m) and early (E_m) and atrial (A_m) diastolic waves were measured. On standard sonography examination, no significant changes in LV systolic function parameters were observed after HD, but the indices for LV diastolic function deteriorated significantly (peak E, 75.4±11.2 vs. 58.8±12.5 cm/s, P<0.01; E/A ratio, 1.0±0.3 vs. 0.8±0.2, P<0.01). However, regarding TDI measures following HD, the patients exhibited a lower S_m peak (septum: 7.6±1.1 vs. 5.9±0.8 cm/s; lateral wall: 7.7±1.7 vs. 6.8±1.2 cm/s, P<0.001), a lower E_m peak (septum: 8.3±1.6 vs. 6.3±1.7 cm/s; lateral wall: 10.2±2.4 vs. 7.1±1.9 cm/s, P<0.001), and a reduced E_m/A_m ratio (septum: 1.0±0.4 vs. 0.7±0.2; lateral wall: 1.2±0.5 vs. 0.7±0.2, P<0.001, respectively), as compared to pre-HD parameters. Of interest, peak E_m, and E_m/A_m ratio of the lateral wall were negatively related to ultrafiltration rate (r=–0.60, P<0.05 and –0.69, P<0.01, respectively). Our data indicate that a single hemodialysis session is associated with acute deterioration of diastolic and systolic parameters of myocardial function, as assessed by TDI. These reversible changes could be considered as a cardiac stunning that seems to be related to the ultrafiltration rate and then to the interdialysis weight gain. These findings suggest that low ultrafiltration volume and/or limited interdialytic weight gain are cardioprotective measures in hemodialysis patients.