Key result
Isoproterenol and nitroglycerin induce head-up tilt syncope at similar rates despite differing physiologic mechanisms.
Why the study?
Do isoproterenol and nitroglycerin induce syncope via different mechanisms during head-up tilt in patients with unexplained syncope?
Population
145 individuals total: 90 patients with unexplained syncope and 12 controls in the first study; 43 patients…
Comparison
Isoproterenol infusion during 20-minute head-up… vs Intravenous nitroglycerin during 20-minute…
Design
RCT, randomly allocated
Follow-up
20 to 40 minutes
Authors
Loading...
Both agents are interchangeable for tilt-table testing; confirms distinct mechanisms via epinephrine versus LV volume.
RCT (n=145)
Randomly allocated
Do isoproterenol and nitroglycerin induce syncope via different mechanisms during head-up tilt in patients with unexplained syncope?
Absolute Event Rate: 65% vs 65.2%
p-value: p=NS
Nitroglycerin triggers head-up tilt-induced syncope primarily by increasing epinephrine levels, whereas isoproterenol induces syncope by decreasing left ventricular volume.
Takase et al. (2001) conducted an RCT in Unexplained syncope (n=145). Isoproterenol vs. Nitroglycerin (250 to 1,500 microg/hour) was evaluated on Positive head-up tilt response (p=NS). Isoproterenol and nitroglycerin induced syncope during head-up tilt at similar rates (65.0% vs 65.2%; P=NS), with nitroglycerin increasing epinephrine and isoproterenol decreasing LV volume.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: