European reference values for Doppler indices of left ventricular diastolic filling

Effect of food intake on commonly used pulsed Doppler and tissue Doppler measurements

OBJECTIVE

This study evaluates the effect of food intake on commonly used pulsed Doppler and tissue Doppler measurements.

METHODS

Twenty-three healthy subjects aged 25.6 ± 4.5 years were investigated. A wide selection of pulsed Doppler and tissue Doppler variables were measured before a standardized meal as well as and 30 and 110 minutes afterwards.

RESULTS

The following variables increased significantly (P < 0.05) 30 minutes after food intake: left ventricular stroke volume, left ventricular cardiac output, left ventricular outflow velocity-time integral, peak of early diastolic (E) and late diastolic (A) mitral flow velocities, pulmonary vein peak velocities in systole (S) and in diastole (D), S/D, pulsed tissue Doppler peak systolic velocities, and late diastolic velocities. Deceleration time of E-wave decreased significantly (P < 0.05). The change in measured variables between fasting and 30 minutes after the food intake ranged from 7% to 28%. There were no significant (P > 0.05) changes in E/A, early diastolic tissue Doppler velocities (e'), and E/e'. Most, but not all variables returned to baseline values 110 minutes after food intake.

CONCLUSIONS

This study shows that food intake affects several echocardiographic variables used to routinely assess diastolic function and hemodynamics. Further studies are warranted in older healthy subjects and in patients with various cardiac diseases to determine whether the findings are reproducible in such populations.

Heart failure with a normal ejection fraction

Nearly half of patients with symptoms of heart failure are found to have a normal left ventricular (LV) ejection fraction. This has variously been labelled as diastolic heart failure, heart failure with preserved LV function or heart failure with a normal ejection fraction (HFNEF). As recent studies have shown that systolic function is not entirely normal in these patients, HFNEF is the preferred term. The epidemiology, aetiology and possible pathophysiology of this contentious condition are reviewed. The importance of the remodelling process in determining whether a patient presents with systolic heart failure or HFNEF is emphasised and this can be used to classify patients in a more rational manner.

Diastolic heart failure. Paroxysmal or chronic?

Heart failure with preserved systolic function is considered by some to be synonymous with diastolic heart failure (DHF). Although recent epidemiological studies have suggested that DHF constitutes 30-50% of all patients with heart failure, many cardiologists dealing with ambulant heart failure patients on a daily basis find that the vast majority of heart failure patients have systolic dysfunction. What could be the reasons for this? Referral bias and varying diagnostic thresholds and interpretation of results could be one important reason. Heart failure with preserved systolic function comprises a heterogeneous group of conditions: whilst some patients may truly have DHF, others may have heart failure due to subtle systolic dysfunction (noted on tissue Doppler imaging of the left ventricular long axis). Other patients actually have pulmonary disease, obesity or ischaemic heart disease, and have their symptoms attributed to 'diastolic heart failure' on the basis of 'abnormal' mitral diastolic flow indices that may, in fact, simply reflect aging. True DHF may be much less prevalent than suggested. A further possibility is that heart failure in patients with diastolic dysfunction might be paroxysmal rather than chronic. This group of patients may present predominantly to acute units like accident and emergency, coronary care units and intensive care units and are, therefore unlikely to figure prominently in the usual outpatient population of chronic systolic left ventricular dysfunction.