Diastolic dysfunction is an abnormality of distensibility, filling, or relaxation of the left ventricle

• Irrespective of ejection fraction
• Irrespective of presence or absence of symptoms

Diastolic heart failure can be diagnosed when there are signs and symptoms of heart failure in a patient with a normal EF:

• Abnormal myocardial relaxation
• Increased filling pressure

Physiology of Diastolic dysfunction:

• Abnormal relaxation is the 1st manifestation
• Decreased compliance occurs later
• The main physiologic consequence of diastolic dysfunction is ↑ filling pressures (Aurigemma GP and WH Gaasch. N Engl J Med 2004;351:1097 – 1105)

Echocardiographic indices of diastolic dysfunction

• Mitral inflow: E/A inverted flow means first stage of diastolic function (not in infants, could be normal), in severe diastolic dysfunction E/A>2; DT <140

In adults E/A could be normal but is really pseudonormal, and with Valsalva maneuvers you can detect this abnormality, not valid for children.

• Pulmonary venous flow: S velocity, D velocity, S/D ratio and AR duration. In diastolic dysfunction D> S and AR duration is longer

In severe diastolic dysfunction AR dur is prolonged, and the difference between ARdur (duration of A contraction in pulmonary veins) minus Adur (duration of contraction in mitral flow) is > + 30ms : ARdur – Adur > 30ms

• Color M-Mode propagation velocity (Vp): Acquisition is performed in apical 4 view with M-mode scan line which is placed through the center of the LV inflow blood column from the mitral valve to apex. Vp correlates with relaxation, with angle of inclination < 45 severe diastolic dysfunction

• Tissue Doppler annulus velocities (TDI) (see next lesson)
• Left atrial volume (LAV): an entirely normal LAV can exclude clinically important diastolic dysfunction. Size and volume of LA increase as diastolic dysfunction progresses. LAV index does not change with age ~ 22+-6 ml/M2; LAV index ≥ 34 mL/m² in almost cases is associated high LV filling pressure.