BackgroundNo longitudinal study compared associations of echocardiographic indexes of diastolic left ventricular function studies with conventional (CBP) and daytime ambulatory (ABP) blood pressure in the general population. Methods and ResultsIn 780 Flemish (mean age, 50.2years; 51.7% women), we measured left atrial volume index (LAVI), peak velocities of the transmitral blood flow (E) and mitral annular movement (e) in early diastole and E/e 9.6years (median) after CBP and ABP. In adjusted models including CBP and ABP, we expressed associations per 10/5-mmHg systolic/diastolic blood pressure increments. LAVI and E/e were 0.65/0.40mL/m(2) and 0.17/0.09 greater with higher systolic/diastolic ABP (P0.028), but not with higher baseline CBP (P0.086). e was lower (P0.032) with higher diastolic CBP (-0.09cm/s) and ABP (-0.19cm/s). When we substituted baseline CBP by CBP recorded concurrently with echocardiography, LAVI and E/e remained 0.45/0.38mL/m(2) and 0.15/0.08 greater with baseline ABP (P0.036), while LAVI (+0.53mL/m(2)) and E/e (+0.19) were also greater (P<0.001) in relation to concurrent systolic CBP. In categorized analyses of baseline data, sustained hypertension or masked hypertension compared with normotension or white-coat hypertension was associated with greater LAVI (24.0 versus 22.6mL/m(2)) and E/e (7.35 versus 6.91) and lower e (10.7 versus 11.6cm/s; P0.006 for all) with no differences (P0.092) between normotension and white-coat hypertension or between masked hypertension and sustained hypertension. ConclusionsABP is a long-term predictor of diastolic left ventricular function, statistically outperforming distant but not concurrent CBP. Masked hypertension and sustained hypertension carry equal risk for deterioration of diastolic left ventricular function.