Background: Alterations in Doppler-derived diastolic filling patterns are common among elderly persons, but their physiological and prognostic significance remains uncertain, particularly in asymptomatic older persons without overt cardiac disease. This study was designed to determine whether early mitral inflow deceleration time (DT) prolongation is of physiological significance in asymptomatic elderly subjects.
Methods and results: In 15 asymptomatic patients aged 60 to 93 years with no history of heart failure (HF) or edema, we performed two-dimensional and Doppler echocardiography and 60-minute head-out, isothermic water immersion to produce circulatory volume expansion. Plasma levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were measured immediately before and after water immersion. Seven of 15 patients had a normal mitral early DT (160 to 240 milliseconds; group 1) and 8 of 15 patients had DT prolongation (> 240 milliseconds; group 2). Group 2 subjects had significantly smaller chamber sizes and increased relative wall thickness without increased left ventricular mass. Head-out water immersion produced greater increases in plasma ANP levels in group 2 subjects with longer DTs despite similar degrees of circulatory volume expansion in each group. In contrast, plasma BNP levels did not increase significantly with water immersion in either group.
Conclusion: Early DT prolongation in asymptomatic elderly subjects is associated with increased relative wall thickness and enhanced ANP increments after central volume expansion. Such exaggerated responses suggest that, in the elderly, a prolonged DT has physiological significance and may represent a precursor to symptomatic diastolic HF, a condition known to be associated with advancing age.