[Evaluation of left ventricular function by systolic time intervals].

Background: Evaluation of left ventricular systolic function, usually based on the assessment of the ejection fraction, is increasingly supplemented by other more sophisticated techniques such as 3D echocardiography and speckle tracking. However these methods require a high technicity and a good echogenicity. As heart failure leads to lengthening of aortic pre-ejectional time (PET) and shortening of left ventricular ejection time (ET), systolic time intervals (STI) were proposed for the evaluation of systolic myocardial performance.

Aim: to establish a correlation between left ventricular ejection fraction (LVEF) and STI and determine a cut-off value of PET/ET ratio to diagnose a LVEF inferior to 35%.

Methods: 109 consecutive patients referred to two echocardiographic laboratories had measurements of STI and LVEF estimated by Simpson biplane method. Patients included were in sinus rhythm with a heart rate<100 beats per minute. Patients with atrial fibrillation, pacemaker or prosthetic valves were excluded.

Results: Feasibility of STI measurements was 100%. A significant negative correlation between PET and LVEF was found (r=-0.49, p<0.0001). LVEF was also significantly correlated to ET (r=0.44, p<0.0001). PET/ET ratio was significantly correlated to LVEF (r=-0.63, p<0.0001). Receiver operating curve analyses revealed a cut-off value of PET/ET ratio of 0.33 to diagnose a LVEF<35% with a sensitivity of 85% and a specificity of 78%.

Conclusion: STI, easy to obtain and useful in case of poor quality echographic window, are an interesting alternative to evaluate systolic left ventricular function and may be used to detect alteration of LVEF.