Restrictive left ventricular filling pattern does not result from increased left atrial pressure alone

Background - The restrictive filling pattern seen with severe heart failure ( HF) may be due to diastolic dysfunction with elevated left ventricular ( LV) diastolic pressure or may be merely a manifestation of an overfilled LV as a result of increased left atrial (LA) pressure. We investigated whether the LV restrictive filling pattern is due to elevated LA pressure alone. Methods and Results - We studied conscious dogs instrumented to measure LA pressure, LV pressure, and 3 LV diameters. LV filling dynamics were evaluated in 2 situations with similar elevations of LA pressure: in normal animals after rapid volume loading with dextran 500 mL and in animals with pacing-induced HF with restrictive filling. With HF, there was increased LV chamber stiffness and slow relaxation. Volume loading and HF had similar heart rates (129 +/- 19 versus 131 +/- 15 bpm) and LA pressure ( 22.1 +/- 5.8 versus 22.6 +/- 3.3 mm Hg). The peak early filling rate ( E) was increased with both HF and volume loading. However, in HF, the peak mitral annular velocity (E') was decreased and delayed, and the E deceleration time was shorter. In contrast, with volume loading, E' was increased and not delayed. Conclusion - The restrictive filling pattern is distinguished from overfilling of a normal ventricle by a reduced and delayed E' and a shortened E deceleration time that reflect slow relaxation and increased LV stiffness.