Background: Left ventricular diastolic dysfunction has been well described;
diastolic abnormalities of the LA are less frequently recognized and poorly
understood.
Objective: The purpose of this study was
to investigate the clinical, hemodynamic and echocardiographic features of left
atrial (LA) diastolic dysfunction.
Methods: Patients with atrial
fibrillation (AF), severe LA enlargement, and pulmonary venous hypertension
(PVH, Group 1) were compared to patients with pulmonary arterial hypertension
(PAH), normal LA size and sinus rhythm (Group 2). All underwent right heart catheterization and
transthoracic echo to evaluate hemodynamics and LA function. Mitral
regurgitation was evaluated by transesophageal echocardiography. LA diastolic
function was measured by comparing filling fraction, pulmonary venous flow and
compliance.
Results: Right atrial, pulmonary artery
systolic and mean pressures were similar. Mean wedge pressure were increased in Group 1, 20.8±2.6 versus 9.7±2.8
mm of Hg (p<0.0001). The most striking hemodynamic difference was large V
wave in Group 1 without significant mitral regurgitation. LA filling fraction was abnormal in Group 1,
11.4%±8.5 compared to Group 2, 111.5%±44 (p<0.0001). LA compliance was
0.39±0.27 ml/m2/mmHg in Group 1 versus 6.8±4.54 ml/m2/mmHg
in Group 2 (p=0.001). There was a strong
negative correlation between the V wave and LA filling fraction (r=‑0.756,
p<0.001). The ratio of the height of
the transmitral E wave divided by the S/D ratio (the LA diastolic dysfunction
index) correlated very strongly with the V wave (r=0.907, p<0.001).
Conclusion: LA diastolic dysfunction is present in some patients with long standing
AF and PVH. LA diastolic dysfunction, in addition to left ventricular diastolic
dysfunction, may contribute to the syndrome of heart failure with preserved
left ventricular systolic function.
Credits: J. Thomas Heywood, M.D., F.A.C.C.; Srikanth Seethala, MD; Tariq Khan, M.D.; Allen Johnson M.D., F.A.C.C.; Michael Smith, M.D.; David Rubenson, M.D., F.A.C.C.