Right atrial volume and phasic function in pulmonary hypertension.
BACKGROUND
Few studies have focused on right atrial (RA) structure and function in pulmonary hypertension (PH). We sought to evaluate RA volume and phasic function using cardiac magnetic resonance (CMR), and to examine their clinical relevance in PH.


METHODS
We prospectively studied 50 PH patients and 21 control subjects. RA volume and indices of phasic function (reservoir volume, ejection fraction [EF], and conduit volume) were evaluated by CMR.


RESULTS
Maximum RA volume index was significantly higher in PH patients (56 [44-70] ml/m(2)) than in controls (40 [30-48] ml/m(2)) (p<0.001). Reservoir volume index was significantly lower in PH than in controls (p<0.001), but conduit volume index was higher in PH than in controls (p=0.008). RA EF was similar when comparing the two groups (p=0.925). Interestingly, RA EF was increased in PH patients with WHO functional class III patients as compared with controls (p<0.001) but was reduced in advanced PH patients with WHO functional class IV (p<0.01). Maximum RA volume and RA EF significantly correlated with pulmonary hemodynamic indices, atrial and brain natriuretic hormone levels, and CMR-derived right ventricular indices. By contrast, RA reservoir volume correlated with cardiac index and 6-minute walk distance.


CONCLUSIONS
PH is associated with increased size, decreased reservoir function, and increased conduit function of the right atrium. RA systolic function indicated by RA EF increases in patients with mild to moderate PH but decreases in patients with advanced PH. Varying associations between RA indices and conventional PH indices suggest their unique role in the management of PH.
First Department of Medicine, Hokkaido University Hospital, Japan.
Takahiro
T
Sato
Ichizo
I
Tsujino
Noriko
N
Oyama-Manabe
Hiroshi
H
Ohira
Yoichi M
YM
Ito
Asuka
A
Yamada
Daisuke
D
Ikeda
Taku
T
Watanabe
Masaharu
M
Nishimura
D000328:Adult; D000368:Aged; D016280:Atrial Function, Right / Q000502:physiology*; D016022:Case-Control Studies; D005260:Female; D006325:Heart Atria / Q000473:pathology*; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011446:Prospective Studies