Points
LV filling patterns have a U-shaped relation with LV diastolic function, with similar values seen in healthy normal subjects and patients with cardiac disease. Although this distinction is not an issue when reduced LV systolic function is present, the problem of recognizing PNF and diastolic heart failure in patients with normal EFs was the main impetus for developing the multiple ancillary measures to assess diastolic function discussed in subsequent sections.
Sinus tachycardia and first-degree AV block can result in partial or complete fusion of the mitral E and A waves. If mitral flow velocity at the start of atrial contraction is >20 cm/s, mitral A-wave velocity may be increased, which reduces the E/A ratio. With partial E-wave and A-wave fusion, mitral DT may not be measurable, although IVRT should be unaffected.
With atrial flutter, LV filling is heavily influenced by the rapid atrial contractions, so that no E velocity, E/A ratio, or DT is available for measurement. If 3:1 or 4:1 AV block is present, multiple atrial filling waves are seen, with diastolic mitral regurgitation (MR) interspersed between nonconducted atrial beats.
In these cases, PA pressures calculated from Doppler TR and PR velocities may be the best indicators of increased LV filling pressures when lung disease is absent.