UNLABELLED: 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.
UNLABELLED: 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 hypertensivemen. 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.