J Nucl Med 1999 Jan;40(1):6-11
Cardiac sympathetic nervous system in early essential hypertension assessed
by 123I-MIBG.
Sakata K, Shirotani M, Yoshida H, Kurata C.
Sympathetic overactivity has been noted in various clinical stages of essential
hypertension. The purpose of this study is to investigate
123I-metaiodobenzylguanidine (MIBG) uptake and washout in patients with
borderline and mild hypertension. METHODS: To assess cardiac sympathetic
function in essential hypertension, we performed 123I-MIBG cardiac imaging and
echocardiography in 25 normotensive, 25 borderline hypertensive and 24 mildly
hypertensive men. Age and body mass index were similar in the three groups.
RESULTS: Regarding the echocardiographic variables, the left ventricular mass
index (LVMI) was significantly higher in the mildly hypertensive group
(125.6+/-28.6 g/m2) than in the normotensive (99.9+/-20.7 g/m2) and the
borderline hypertensive (110.0+/-24.4 g/m2) groups (P < 0.001 and P <
0.05, respectively). Regarding the scintigraphic variables, the heart-to-mediastinum
(H/M) ratio was significantly lower in the mildly hypertensive group (1.8+/-0.3)
than in the normotensive (2.1+/-0.3) and the borderline hypertensive (2.1+/-0.2)
groups. In contrast, the washout rate was significantly higher in the mildly
hypertensive group (17.6%+/-10.8%) than in the normotensive (7.0%+/-4.9%) and
the borderline (11.9%+/-8.9%) hypertensive groups (P< 0.001 and P< 0.02,
respectively). In addition, the borderline hypertensive group had a
significantly higher washout rate than the normotensive group (P < 0.05).
MIBG washout rate had a strong positive correlation with LVMI (r = 0.77, P <
0.0001). In contrast, the H/M ratio had a weak negative correlation with LVMI (r
= -0.40, P < 0.0006). CONCLUSION: During the course of establishment of
essential hypertension, the washout rate becomes higher with the advance of
hypertension and with the development of left ventricular hypertrophy. Thus, we
suggest a strong relationship between cardiac sympathetic activity and the
advance of hypertension at its early stages.
