This Article Abstract Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kikushima, S. Articles by Katagiri, T. Search for Related Content PubMed PubMed Citation Articles by Kikushima, S. Articles by Katagiri, T.

Triggering mechanism for neurally mediated syncope induced by head-up tilt test

Role of catecholamines and response to propranolol

^a Third Department of Internal Medicine, Showa University School of Medicine 1-5-8, Hatanodai, Shinagawa-ku, Tokyo, 142-0064, Japan

View larger version (33K): [in a new window]   Figure 1 Study design. This study consisted of three steps. If a positive response occurred in the initial step, the protocol turned to second step immediately. In the second step, HUT was performed again under identical conditions. In the third step, the patient was rechallenged with HUT after an injection of PROP.

View larger version (21K): [in a new window]   Figure 2 Sequential changes in hemodynamic and CAs during negative tilt testing without ISP. In patients negative for the HUT alone, mean BP and HR were stable (A). Although EP did not change statistically, NE showed a small but significant increase (B). *p < 0.01 when compared with baseline values.

View larger version (28K): [in a new window]   Figure 3 Sequential hemodynamic changes during positive tilt testing in the second step. HR increased during upright posture, although not significantly, until just before positive response (until –1 min). HR throughout tilt testing was significantly higher in the ISP-dependent group than in the ISP-independent group. Mean BP dropped suddenly to the same level in both groups. The pattern of sequential changes was similar in both groups. *p < 0.05 when compared between groups. p < 0.05 when compared with baseline values.

View larger version (43K): [in a new window]   Figure 4 Sequential changes in CAs during positive HUT alone or with ISP provocation. Baseline EP levels were similar in the two groups. In the ISP-independent group, EP levels increased gradually during upright posture and showed a significant increase at –3 min and a maximum increase at positive response (A). In the ISP-dependent group, EP levels increased gradually, and the difference reached the significance level at positive response (B). In both groups, there was statistical increase in NE levels at positive response (C, D). *p < 0.05. p < 0.01.

View larger version (23K): [in a new window]   Figure 5 Changes in EP after PROP. In the ISP independent group, EP showed a significant increase (A). In the ISP-dependent group, PROP responders had a mean 2.2-fold increase in EP levels at 15 min of tilting. Two PROP nonresponders showed a marked increase (29.2- and 11.7-fold) in EP levels (arrow) (B).