To verify and validate the reliability of diastolic function parameters and valvular flow velocities acquired during the handheld ultrasound device (HUD) echocardiographic examination. Study population consisted of the consecutive patients referred for consultation due to dyspnea or impaired exercise tolerance. All patients underwent brief bedside echocardiographic screening with HUD. Within the next 24 h all patients underwent full echocardiographic examination (treated as reference). 105 patients (58 men, mean age 65 ± 14 years) were enrolled in the study. All correlations of HUD and standard echo derived measurements were high or very high. Bland-Altman plot analysis revealed the underestimation bias for mitral inflow velocities- early (E) and late (A), ), mitral annular peak early diastolic velocity (e') was not burdened with bias. The agreement between the major HFA-PEFF score parameters showed either substantial or almost perfect agreement, minor parameter- moderate agreement. The correlation of the measurements of maximum mitral velocity was high with no clinically relevant bias. Kappa coefficient showed very good agreement between HUD and reference echocardiography for detecting accelerated blood flow through the mitral valve (Kappa coefficient 0.83). The assessment of the aortic valve showed a very good correlation, with a slight underestimation bias of -0.17 m/sec (P <
.001). Kappa coefficient showed good agreement between HUD and reference echocardiography for detecting accelerated blood flow (Kappa coefficient 0.74). HUD equipped with pulse and continuous wave Doppler modality enables reliable measurements of the parameters used during the left ventricle diastolic function assessment. Similarly, aortic and mitral peak jet velocities can be accurately measured using the mentioned devices.