{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,7]],"date-time":"2025-10-07T12:03:53Z","timestamp":1759838633606},"reference-count":0,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"4","content-domain":{"domain":["www.ahajournals.org"],"crossmark-restriction":true},"short-container-title":["Circulation"],"published-print":{"date-parts":[[1994,4]]},"abstract":"<jats:sec>\n            <jats:title>BACKGROUND<\/jats:title>\n            <jats:p>Signal-averaged ECG is a noninvasive test designed to detect \"late potentials.\" The effects of alterations in autonomic tone on the signal-averaged ECG have not been evaluated systematically.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>METHODS AND RESULTS<\/jats:title>\n            <jats:p>The effects of autonomic stimulation and blockade on the signal-averaged ECG were evaluated in 14 healthy subjects (8 men and 6 women; age, 28.5 +\/- 4.8 years) on 2 separate days. The signal-averaged ECG was recorded at baseline and after physiological and pharmacologic beta-adrenergic stimulation (tilt, exercise, and epinephrine and isoproterenol infusions), sequential and combined beta-adrenergic and parasympathetic blockade, and alpha-adrenergic stimulation before and after parasympathetic blockade. Analysis was performed with a bidirectional filter (40-Hz high-pass). Significant changes in the signal-averaged QRS duration from baseline (105.1 +\/- 12.0 milliseconds) were noted with tilt (96.8 +\/- 8.8 milliseconds), tilt after double blockade (97.5 +\/- 9.0 milliseconds), epinephrine (110.5 +\/- 11.8 milliseconds), and isoproterenol (99.6 +\/- 12.6 milliseconds). Changes in the root-mean-square voltage of the terminal 40 milliseconds and the low-amplitude (&lt; 40 microV) signal duration paralleled the changes in the QRS duration.<\/jats:p>\n          <\/jats:sec>\n          <jats:sec>\n            <jats:title>CONCLUSIONS<\/jats:title>\n            <jats:p>The signal-averaged ECG does not measure only \"fixed\" parameters but rather is altered under a variety of physiological and pharmacologic conditions. Upright tilt leads to shortening of the QRS duration before and after autonomic blockade; thus, the decrease in QRS duration with tilt may be related to factors other than changes in autonomic tone. These findings have implications for interpretation of the results of signal-averaged ECG.<\/jats:p>\n          <\/jats:sec>","DOI":"10.1161\/01.cir.89.4.1656","type":"journal-article","created":{"date-parts":[[2012,6,12]],"date-time":"2012-06-12T00:34:42Z","timestamp":1339461282000},"page":"1656-1664","update-policy":"http:\/\/dx.doi.org\/10.1161\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":34,"title":["Assessment of effects of autonomic stimulation and blockade on the signal-averaged electrocardiogram."],"prefix":"10.1161","volume":"89","author":[{"given":"J J","family":"Goldberger","sequence":"first","affiliation":[{"name":"Department of Medicine, Northwestern University, Chicago, Ill."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M W","family":"Ahmed","sequence":"additional","affiliation":[{"name":"Department of Medicine, Northwestern University, Chicago, Ill."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M A","family":"Parker","sequence":"additional","affiliation":[{"name":"Department of Medicine, Northwestern University, Chicago, Ill."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"A H","family":"Kadish","sequence":"additional","affiliation":[{"name":"Department of Medicine, Northwestern University, Chicago, Ill."}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"276","container-title":["Circulation"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.ahajournals.org\/doi\/pdf\/10.1161\/01.CIR.89.4.1656","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,5,12]],"date-time":"2024-05-12T15:35:39Z","timestamp":1715528139000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ahajournals.org\/doi\/10.1161\/01.CIR.89.4.1656"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1994,4]]},"references-count":0,"journal-issue":{"issue":"4","published-print":{"date-parts":[[1994,4]]}},"alternative-id":["10.1161\/01.CIR.89.4.1656"],"URL":"https:\/\/doi.org\/10.1161\/01.cir.89.4.1656","relation":{},"ISSN":["0009-7322","1524-4539"],"issn-type":[{"value":"0009-7322","type":"print"},{"value":"1524-4539","type":"electronic"}],"subject":[],"published":{"date-parts":[[1994,4]]},"assertion":[{"value":"1994-04-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}