Sélection des patients à la stimulation biventriculaire

In heart failure patients with a large QRS width, biventricular pacing has been shown to improve the fonctional status as well as hemodynamic parameters. However, there are non-responders despite of wide QRS complexes (between 15 and 35%). Patients selection might not rely only on electrical parameters. From an electrophysiological concept, clinicians moved toward a more electromechanical analysis, by using non-invasive tools such as Tissue Doppler imaging. Thereby, more than the QRS width, identification of intra-left ventricular asynchrony appears to be a crucial criterion for selecting responders to biventricular pacing. From this fact, several studies have demonstrated the efficacy of biventricular pacing to improve heart failure patients with narrow QRS but with intra-left ventricular asynchrony. Another parameter has been thought to be predominant, i.e. the left ventricular pacing site. If the pacing lead is located within a “slow conduction” area (at this time very difficult to identify during the implant procedure), biventricular pacing will generate a new asynchrony counteracting the beneficial expected. Thus, biventricular pacing appears to be more an electromechanical concept than exclusively electrical for selecting responders. Still, the optimal location of the left ventricular pacing lead remains to be determined.