Abstract Background Our objective were to know whether coronary flow velocity reserve measured by transthoracic Doppler echocardiography, as marker of microvascular integrity, affects the recovery of global systolic function. Secondly, we intended to define the best cut-off point of coronary flow velocity reserve to predict recovery of global systolic function. Methods We studied 57 patients with coronary flow recorded by transthoracic Doppler echocardiography, after suffering a first anterior acute myocardial infarction and undergoing a successful primary percutaneous coronary intervention (TIMI 3 flow). We measured, at discharge and at 1 month: ejection fraction, volume indexes and anterior wall motion score index. Coronary flow in left anterior descending artery was detected by transthoracic Doppler echocardiography and coronary flow velocity reserve was calculated. Results After applying ROC curves, 1.54 was the best cut-off value of coronary flow velocity reserve for detection of recovery of global systolic function. Ejection fraction only increased significantly in patients with normal coronary flow velocity reserve. Only end-systolic volume index increased significantly at 1 month in patients with impaired coronary flow velocity reserve. Conclusion We showed that coronary flow velocity reserve, measured by transthoracic Doppler echocardiography, influence the recovery of global systolic function, mainly by ventricular dilation. Furthermore, a quite lower value of coronary flow velocity reserve than that used for diagnostic purpose should be used to predict improvement of systolic function.