scholarly journals Noninvasive evaluation of left ventricular elastance according to pressure-volume curves modeling in arterial hypertension

2017 ◽  
Vol 313 (2) ◽  
pp. H237-H243 ◽  
Author(s):  
Benjamin Bonnet ◽  
Franck Jourdan ◽  
Guilhem du Cailar ◽  
Pierre Fesler

End-systolic left ventricular (LV) elastance ( Ees) has been previously calculated and validated invasively using LV pressure-volume (P-V) loops. Noninvasive methods have been proposed, but clinical application remains complex. The aims of the present study were to 1) estimate Ees according to modeling of the LV P-V curve during ejection (“ejection P-V curve” method) and validate our method with existing published LV P-V loop data and 2) test the clinical applicability of noninvasively detecting a difference in Ees between normotensive and hypertensive subjects. On the basis of the ejection P-V curve and a linear relationship between elastance and time during ejection, we used a nonlinear least-squares method to fit the pressure waveform. We then computed the slope and intercept of time-varying elastance as well as the volume intercept (V0). As a validation, 22 P-V loops obtained from previous invasive studies were digitized and analyzed using the ejection P-V curve method. To test clinical applicability, ejection P-V curves were obtained from 33 hypertensive subjects and 32 normotensive subjects with carotid tonometry and real-time three-dimensional echocardiography during the same procedure. A good univariate relationship ( r2 = 0.92, P < 0.005) and good limits of agreement were found between the invasive calculation of Ees and our new proposed ejection P-V curve method. In hypertensive patients, an increase in arterial elastance ( Ea) was compensated by a parallel increase in Ees without change in Ea/ Ees. In addition, the clinical reproducibility of our method was similar to that of another noninvasive method. In conclusion, Ees and V0 can be estimated noninvasively from modeling of the P-V curve during ejection. This approach was found to be reproducible and sensitive enough to detect an expected increase in LV contractility in hypertensive patients. Because of its noninvasive nature, this methodology may have clinical implications in various disease states. NEW & NOTEWORTHY The use of real-time three-dimensional echocardiography-derived left ventricular volumes in conjunction with carotid tonometry was found to be reproducible and sensitive enough to detect expected differences in left ventricular elastance in arterial hypertension. Because of its noninvasive nature, this methodology may have clinical implications in various disease states.

Heart ◽  
2001 ◽  
Vol 85 (5) ◽  
pp. 514-520
Author(s):  
W Y Kim ◽  
P Søgaard ◽  
P T Mortensen ◽  
H Kjærulf Jensen ◽  
A Kirstein Pedersen ◽  
...  

OBJECTIVESTo quantify the short term haemodynamic effects of biventricular pacing in patients with heart failure and left bundle branch block by using three dimensional echocardiography.DESIGNThree dimensional echocardiography was performed in 15 consecutive heart failure patients (New York Heart Association functional class III or IV) with an implanted biventricular pacing system. Six minute walk tests were performed to investigate the effect of biventricular pacing on exercise capacity. Data were acquired at sinus rhythm and after short term (2–7 days) biventricular pacing.RESULTSCompared with baseline values, biventricular pacing significantly reduced left ventricular end diastolic volume (EDV) by mean (SD) 4.0 (5.1)% (p < 0.01) and end systolic volume (ESV) by 5.6 (6.4)% (p < 0.02). Mitral regurgitant fraction was significantly reduced by 11 (12.1)% (p < 0.003) and forward stroke volume (FSV) increased by 13.9 (18.6)% (p < 0.02). Exercise capacity was significantly improved with biventricular pacing by 48.4 (43.3)% (p < 0.00001). Regression analyses showed that the percentage increase in FSV independently predicted percentage improvement in walking distance (r2 = 0.73, p < 0.0002). Both basal QRS duration and QRS narrowing predicted pacing efficacy, showing a significant correlation with %ΔEDV, %ΔESV, and %ΔFSV.CONCLUSIONSIn five of 15 consecutive patients with heart failure and left bundle branch block, biventricular pacing induced a more than 15% increase in FSV, which predicted a more than 25% increase in walking distance and was accompanied by an immediate reduction in left ventricular chamber size and mitral regurgitation.


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