engleski

The shape of the aortic outflow velocity profile revisited. Is there a relation between its asymmetry and ventricular function in coronary artery disease?

Myocardium contracts in the beginning of ejection causing outflow acceleration, resulting in asymmetric outflow velocity profiles peaking around 1/3 of ejection and declining when force development declines. Aims was to demonstrate that decreased contractility in coronary artery disease (CAD) changes outflow timing and profile symmetry. 79 patients undergoing routine full dose dobutamine stress-echo (DSE) were divided into 2 groups based on resting wall-motion and DSE-response: DSE negative (DSEneg) (35/79) and positive (DSEpos) (44/79) which were compared to 32 healthy volunteers. Aortic CW-Doppler traces at rest were analyzed semi-automatically ; time-to-peak (Tmod), ejection-time (ETmod), rise- (trise) and fall-time (tfall) were quantified. Asymmetry (asymm) was calculated as the normalized difference of left and right half of the spectrum. Normal curves were triangular, early-peaking, while patients showed more rounded shapes and later peaks. Trise was longest in DSEpos. Tfall was shortest in DSEpos, followed by controls and DSEneg. Asymm was lowest in DSEpos, followed by controls and DSEneg. Abnormally symmetric profiles (asymm<0.25) were found in none of the controls, 2.9% DSEneg and 27.3% DSEpos. A good correlation was found between assym and ejection fraction (EF) and Tmod/ETmod and EF. Notably, an LV dynamic gradient was induced in 71.4% DSEneg and in 18.2% DSEpos, associated with LV hypertrophy and supernormal (very asymmetric) traces. Decreased myocardial function results in a more symmetrical outflow, while very asymmetrical traces suggest increased contractility, potentially inducing intra-cavity gradients during DSE. Therefore, including outflow symmetry as a clinical measurement provides additional information on patients with CAD.

left ventricular outflow trace; doppler echocardiography; dobutamine stress echocardiography; left ventricular function; hemodynamics

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