Native arteriovenous fistulae (AVF) remain the vascular access of choice for hemodialysis (HD). Despite being associated with superior long-term outcomes (cf. catheter use), little is known about the systemic hemodynamic consequences of AVFs. Repetitive myocardial injury (myocardial stunning) is an under-recognized common consequence of HD. The aim of this study was to examine the impact of AVF flow (Qa) on dialysis-induced cardiac injury. We studied 50 chronic HD patients. All patients underwent echocardiography (and subsequent quantitative offline analysis) at baseline, during and post dialysis, to assess left ventricular function and the development of regional wall motion abnormalities. Qa was measured using ionic dialysance. Patients were divided into Qa tertiles (<500, mean 291+/-101 mL/min, 500-1000, mean 739+/-130 mL/min and >1000, mean 1265+/-221 mL/min). There were no significant differences between the groups in terms of age, sex, diabetes, or resting ejection fraction. Patients with Qa>1000 mL/min had a lower prevalence of left ventricular hypertrophy (55% vs. 76%, P=0.01). Dialysis-induced myocardial stunning (seen in 65% of the patients studied) was significantly and sequentially reduced in those patients with higher Qas. This was seen in a lower number of segments and ventricular regions developing regional wall motion abnormalities, as well as a significantly reduced mean and cumulative percentage reduction in fractional shortening of those ventricular segments affected (-187+/-37%, -161+/-26%, and -101+/-25%, respectively, P=0.04). Relatively higher AVF flows appear to be associated with a lower level of observed HD-induced cardiac injury.