{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,22]],"date-time":"2025-10-22T10:30:05Z","timestamp":1761129005471},"reference-count":0,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"3","content-domain":{"domain":["www.ahajournals.org"],"crossmark-restriction":true},"short-container-title":["Circulation"],"published-print":{"date-parts":[[1976,9]]},"abstract":"<jats:p>The ratio of pulmonary to systemic vascular resistance (Rp\/Rs) largely determines the amount of left-to-right shunting and pulmonary to systemic flow rat (Qp\/Qs) in the presence of a large isolated ventricular septal defect. The possibility that pharmacologic reduction of systemic vascular resistance with alpha-adrenergic receptor blockade or beta-adrenergic receptor stimulation would increase the ratio Rp\/Rs, and therefore reduce the ratio Qp\/Qs, was studied in dogs in which ventricular septal defects had been surgically created. Administration of phentolamine and phenoxybenzamine caused a 42% reduction in Rs and no reduction in Rp. Qs was unchanged and Qp declined by 24% and the ratio Qp\/Qs fell by 32%. Infusion of the beta-adrenergic receptor stimulant isoproterenol also reduced Qp\/Qs. However, this was accomplished as a result of an increase in Qs and at the expense of an increase in heart rate. As a decline in the ratio Qp\/Qs has been shown to be beneficial to patients with large left-to-right shunts, pharmacologic reduction of systemic vascular resistance may prove to be helpful in treating congestive heart failure in those patients with large left-to-right shunts at the ventricular level who are refractory to the usual decongestive measures.<\/jats:p>","DOI":"10.1161\/01.cir.54.3.472","type":"journal-article","created":{"date-parts":[[2012,6,11]],"date-time":"2012-06-11T23:57:40Z","timestamp":1339459060000},"page":"472-477","update-policy":"http:\/\/dx.doi.org\/10.1161\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":33,"title":["Hemodynamic effects of vasodilator agents in dogs with experimental ventricular septal defects."],"prefix":"10.1161","volume":"54","author":[{"given":"D P","family":"Synhorst","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"R M","family":"Lauer","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"D B","family":"Doty","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M J","family":"Brody","sequence":"additional","affiliation":[],"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.54.3.472","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,5,12]],"date-time":"2024-05-12T14:05:11Z","timestamp":1715522711000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ahajournals.org\/doi\/10.1161\/01.CIR.54.3.472"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1976,9]]},"references-count":0,"journal-issue":{"issue":"3","published-print":{"date-parts":[[1976,9]]}},"alternative-id":["10.1161\/01.CIR.54.3.472"],"URL":"https:\/\/doi.org\/10.1161\/01.cir.54.3.472","relation":{},"ISSN":["0009-7322","1524-4539"],"issn-type":[{"type":"print","value":"0009-7322"},{"type":"electronic","value":"1524-4539"}],"subject":[],"published":{"date-parts":[[1976,9]]},"assertion":[{"value":"1976-09-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}