Noninvasive assessment of left atrial maximum dP/dt by combination of transmitral and pulmonary venous flow

Noninvasive assessment of left atrial maximum dP/dt by combination of transmitral and pulmonary venous flow Original Research Article Pages 795-801 Satoshi Nakatani, Mario J. Garcia, Michael S. Firstenberg, Leonardo Rodriguez, Richard A. Grimm, Neil L. Greenberg, Patrick M. McCarthy, Pieter M. Vandervoort, James D. Thomas Close Close preview | PDF (251 K) | Related articles | Related reference work articles AbstractAbstract | Figures/TablesFigures/Tables | ReferencesReferences Abstract OBJECTIVES The study assessed whether hemodynamic parameters of left atrial (LA) systolic function could be estimated noninvasively using Doppler echocardiography. BACKGROUND Left atrial systolic function is an important aspect of cardiac function. Doppler echocardiography can measure changes in L volume, but has not been shown to relate to hemodynamic parameters such as the maximal value of the first derivative of the pressure (L dP/dtmax). METHODS Eighteen patients in sinus rhythm were studied immediately before and after open heart surgery using simultaneous L pressure measurements and intraoperative transesophageal echocardiography. Left atrial pressure was measured with micromanometer catheter, and L dP/dtmax during atrial contraction was obtained. Transmitral and pulmonary venous flow were recorded by pulsed Doppler echocardiography. Peak velocity, and mean acceleration and deceleration, and the time-velocity integral of each flow during atrial contraction was measured. The initial eight patients served as the study group to derive multilinear regression equation to estimate L dP/dtmax from Doppler parameters, and the latter 10 patients served as the test group to validate the equation. previously validated numeric model was used to confirm these results. RESULTS In the study group, L dP/dtmax showed linear relation with L pressure before atrial contraction (r = 0.80, p < 0.005), confirming the presence of the Frank-Starling mechanism in the LA. Among transmitral flow parameters, mean acceleration showed the strongest correlation with L dP/dtmax (r = 0.78, p < 0.001). Among pulmonary venous flow parameters, no single parameter was sufficient to estimate L dP/dtmax with an r2 > 0.30. By stepwise and multiple linear regression analysis, L dP/dtmax was best described as follows: L dP/dtmax = 0.1 M-AC + 1.8 P-V − 4.1; r = 0.88, p < 0.0001, where M-AC is the mean acceleration of transmitral flow and P-V is the peak velocity of pulmonary venous flow during atrial contraction. This equation was tested in the latter 10 patients of the test group. Predicted and measured L dP/dtmax correlated well (r = 0.90, p < 0.0001). Numerical simulation verified that this relationship held across wide range of atrial elastance, ventricular relaxation and systolic function, with L dP/dtmax predicted by the above equation with r = 0.94. CONCLUSIONS combination of transmitral and pulmonary venous flow parameters can provide hemodynamic assessment of L systolic function. Article Outline • Methods • Study population • Measurements • Analysis • Mathematical modeling • Statistical analysis • Results • Relationship between L pressure and L dP/dtmax • Correlation between L dP/dtmax and Doppler parameters in the study group • Validation of the estimated L dP/dtmax in the test group. • Between-patient and within-patient effects • Model results •Discussion • Index of L systolic function • Estimation of L dP/dtmax by Doppler parameters • Study limitations • Clinical implications • Conclusions • References