{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,20]],"date-time":"2026-05-20T17:51:24Z","timestamp":1779299484965,"version":"3.51.4"},"reference-count":22,"publisher":"S. Karger AG","issue":"3-4","license":[{"start":{"date-parts":[[2007,1,1]],"date-time":"2007-01-01T00:00:00Z","timestamp":1167609600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/www.karger.com\/Services\/SiteLicenses"},{"start":{"date-parts":[[2007,1,1]],"date-time":"2007-01-01T00:00:00Z","timestamp":1167609600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/www.karger.com\/Services\/SiteLicenses"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Neuropsychobiology"],"published-print":{"date-parts":[[2007]]},"abstract":"<jats:p>&lt;i&gt;Background:&lt;\/i&gt; Anxiety symptoms are associated with a marked increase in sudden cardiac death, suggesting an abnormality in cardiac autonomic function. Our previous studies show a relationship between R amplitude variability and sympathetic function.&lt;i&gt;Methods:&lt;\/i&gt;We examined the effects of \u03b2-adrenergic stimulation on R and T amplitude variability in panic disorder patients by infusing the \u03b2-adrenergic agonist isoproterenol in 6 panic disorder patients and 11 normal subjects. The ECG signal was analyzed before the infusion and 5 min after the infusion was started. The outcome measures were the R and T detrended variance normalized for mean amplitudes (R&lt;sub&gt;vm&lt;\/sub&gt; and T&lt;sub&gt;vm&lt;\/sub&gt;) and the R&lt;sub&gt;vi&lt;\/sub&gt; and T&lt;sub&gt;vi&lt;\/sub&gt;, measures which are normalized for the inter-beat interval variability in addition. &lt;i&gt;Results:&lt;\/i&gt; Patients with panic disorder had significantly more variability in R and T amplitude than normal controls and the R amplitude variability was increased further by \u03b2-adrenergic stimulation with isoproterenol, which was more pronounced in the patients. &lt;i&gt;Conclusions:&lt;\/i&gt; The isoproterenol-associated increase in R amplitude variability occurred in controls in the absence of significant anxiety. However, the increase in R amplitude variability was greater in patients with panic disorder, suggesting a greater sensitivity to \u03b2-adrenergic effects of isoproterenol or to isoproterenol-induced anxiety.<\/jats:p>","DOI":"10.1159\/000108380","type":"journal-article","created":{"date-parts":[[2007,9,17]],"date-time":"2007-09-17T14:27:08Z","timestamp":1190039228000},"page":"213-218","source":"Crossref","is-referenced-by-count":14,"title":["Exaggerated Beat-to-Beat R Amplitude Variability in Patients with Panic Disorder after Intravenous Isoproterenol"],"prefix":"10.1159","volume":"55","author":[{"given":"Vikram K.","family":"Yeragani","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Robert","family":"Pohl","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Karl-J\u00fcrgen","family":"B\u00e4r","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pratap","family":"Chokka","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Manuel","family":"Tancer","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"127","published-online":{"date-parts":[[2007,9,17]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","DOI":"10.1136%2Fbmj.295.6593.297"},{"key":"ref2","doi-asserted-by":"publisher","DOI":"10.1161%2F01.CIR.89.5.1992"},{"key":"ref3","doi-asserted-by":"publisher","DOI":"10.1161%2F01.CIR.85.1.164"},{"key":"ref4","doi-asserted-by":"publisher","DOI":"10.1007%2FBF01824992"},{"key":"ref5","doi-asserted-by":"publisher","DOI":"10.1111%2Fj.1540-8167.1998.tb00130.x"},{"key":"ref6","doi-asserted-by":"publisher","DOI":"10.1016%2FS0165-1781%2897%2900136-4"},{"key":"ref7","doi-asserted-by":"publisher","DOI":"10.1016%2FS0165-1781%2800%2900119-0"},{"key":"ref8","doi-asserted-by":"publisher","DOI":"10.1002%2F1520-6394%282000%2912%3A2%3C67%3A%3AAID-DA2%3E3.0.CO%3B2-C"},{"key":"ref9","doi-asserted-by":"publisher","DOI":"10.1016%2FS0165-1781%2802%2900319-0"},{"key":"ref10","doi-asserted-by":"publisher","DOI":"10.1097%2F00005344-199210000-00015"},{"key":"ref11","doi-asserted-by":"publisher","DOI":"10.1016%2FS0165-1781%2803%2900235-X"},{"key":"ref12","doi-asserted-by":"publisher","DOI":"10.1016%2FS0165-1781%2896%2902998-8"},{"key":"ref13","doi-asserted-by":"publisher","DOI":"10.1002%2Fda.10129"},{"key":"ref14","doi-asserted-by":"publisher","DOI":"10.1159%2F000066388"},{"key":"ref15","doi-asserted-by":"publisher","DOI":"10.1016%2FS0002-9149%2896%2900030-6"},{"key":"ref16","doi-asserted-by":"publisher","DOI":"10.1007%2Fs10558-005-7674-0"},{"key":"ref17","doi-asserted-by":"publisher","DOI":"10.1111%2Fj.1469-8986.1991.tb00731.x"},{"key":"ref18","doi-asserted-by":"publisher","DOI":"10.1111%2Fj.1469-8986.1989.tb01957.x"},{"key":"ref19","doi-asserted-by":"publisher","DOI":"10.1016%2F0165-1781%2895%2902608-Y"},{"key":"ref20","doi-asserted-by":"publisher","DOI":"10.1159%2F000284130"},{"key":"ref21","doi-asserted-by":"publisher","DOI":"10.1016%2F0006-3223%2888%2990224-7"},{"key":"ref22","doi-asserted-by":"publisher","DOI":"10.1017%2FS146114570100219X"}],"container-title":["Neuropsychobiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/108380","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.karger.com\/Article\/Pdf\/108380","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,4,24]],"date-time":"2025-04-24T02:58:27Z","timestamp":1745463507000},"score":1,"resource":{"primary":{"URL":"https:\/\/karger.com\/article\/doi\/10.1159\/000108380"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2007]]},"references-count":22,"journal-issue":{"issue":"3-4","published-online":{"date-parts":[[2007,10,1]]}},"URL":"https:\/\/doi.org\/10.1159\/000108380","archive":["Portico"],"relation":{},"ISSN":["0302-282X","1423-0224"],"issn-type":[{"value":"0302-282X","type":"print"},{"value":"1423-0224","type":"electronic"}],"subject":[],"published":{"date-parts":[[2007]]}}}