title: Right ventricular function with hypoxic exercise: effects of sildenafil.
abstract: The effect of sildenafil on right ventricular contractility in hypoxic exercise is unknown, whereas reports have shown that sildenafil is associated with a smaller increase in pulmonary vascular resistance and right ventricular systolic pressure (RVSP) with exercise at high altitude. The present study evaluates the changes induced by controlled hypoxia on right ventricular pressure and performance with and without sildenafil administration. Tricuspid annular isovolumic acceleration (IVA) and annular velocities were measured in 14 healthy subjects at rest and after maximal exercise in a cross-over, double blind placebo controlled trial in three situations: normoxia, normobaric hypoxia with, and normobaric hypoxia without the administration of 100 mg sildenafil. RVSP, assessed by Doppler echocardiography, was determined from the peak tricuspid regurgitation pressure gradient. RVSP during rest increased from 26.9 +/- 2.3 mmHg in normoxia to 37.8 +/- 6.9 mmHg in hypoxia, p < 0.01; sildenafil administration reduced RVSP in hypoxia to 30.5 +/- 5.6, p < 0.01. Compared to normoxia at rest, IVA increased similarly with peak exercise in normoxia and hypoxia(sildenafil) (by 2.37 and 1.90 m/s(2), respectively), but the observed increase in IVA during exercise was smaller (0.86 m/s(2), p < 0.05) in hypoxia(placebo). Right ventricular contractility, as estimated by IVA at peak exercise is increased with the administration of sildenafil as compared to placebo, and is not different from the values seen during exercise in normoxia. This effect seems independent of the effect of sildenafil on RVSP.
authors.affiliation: Department of Cardiology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark. jesper.kjaergaard@rh.regionh.dk
authors.forename: Jesper
authors.initials: J
authors.lastname: Kjaergaard
authors.forename: Eric M
authors.initials: EM
authors.lastname: Snyder
authors.forename: Christian
authors.initials: C
authors.lastname: Hassager
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Olson
authors.forename: Jae K
authors.initials: JK
authors.lastname: Oh
authors.forename: Bruce D
authors.initials: BD
authors.lastname: Johnson
authors.forename: Robert P
authors.initials: RP
authors.lastname: Frantz
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006352:Heart Ventricles / Q000187:drug effects / Q000503:physiopathology*; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology* / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects*; D005082:Physical Exertion / Q000187:drug effects*; D010879:Piperazines / Q000008:administration & dosage*; D011687:Purines / Q000008:administration & dosage; D000068677:Sildenafil Citrate; D013450:Sulfones / Q000008:administration & dosage*; D014665:Vasodilator Agents / Q000008:administration & dosage; D016278:Ventricular Function, Right / Q000187:drug effects*
chemical_list: D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014665:Vasodilator Agents; D000068677:Sildenafil Citrate