PT  - JOURNAL ARTICLE
AU  - Taco Kind
AU  - Gerrina Ruiter
AU  - Theo J.C. Faes
AU  - Louis M. Handoko
AU  - Ingrid Schalij
AU  - Anton Vonk Noordegraaf
AU  - Nico Westerhof
TI  - Estimation of right ventricular isovolumic pressure in experimental pulmonary hypertension from a single ejecting beat
DP  - 2011 Sep 01
TA  - European Respiratory Journal
PG  - p1520
VI  - 38
IP  - Suppl 55
4099  - http://erj.ersjournals.com/content/38/Suppl_55/p1520.short
4100  - http://erj.ersjournals.com/content/38/Suppl_55/p1520.full
SO  - Eur Respir J2011 Sep 01; 38
AB  - In pulmonary hypertension (PH), assessment of right ventricle (RV) contractility from end-systolic pressure-volume relationships (ESPVR) is difficult due to the requirement of multiple-beats by alterations in cardiac preload. Several single-beat (SB) methods have been proposed to calculate ESPVR, mostly based on estimation of maximum isovolumic pressure (Pmax) using arbitrary wave shapes of isovolumic pressure. The purpose of this study was to derive experimentally the isovolumic pressure wave shape of the RV and to use this curve to compute Pmax(SB). Isovolumic pressure curves were determined by clamping the pulmonary artery in 4 control, 3 stable PH and 3 progressive PH rats. PH was induced by monocrotaline (MCT) 40 and 60 mg/kg, respectively. All curves were normalized in amplitude and duration to obtain the typical isovolumic pressure wave shape. This curve was used to estimate Pmax(SB) in 9 control, 7 MCT40 and 7 MCT60 rats from ejecting RV pressure curves. Pmax(SB) values were compared to values obtained from multiple pressure-volume loops by vena cava occlusion [Pmax(VCO)]. Three SB methods from literature were included for comparison. With our method close correlations were found between Pmax(SB) and Pmax(VCO) (r2=0.85, p<0.001). The other methods had r2 values of 0.74, 0.82, and 0.85; p<0.001. The latter two methods significantly underestimated Pmax(VCO) in MCT60 rats, and all three methods resulted in less realistic shapes of isovolumic pressure waves compared to our experimental curves. In conclusion, with our method realistic isovolumic pressure curves can be obtained providing accurate estimates of Pmax over a wide range of RV contractility.