Left ventricular pre-ejection time (LVPET) is associated with myocardial efficiency. LVPET increases in patients with heart failure and decreases after cardiac resynchronisation therapy (CRT) with variation according to pacing site.

The objective of this study was to evaluate the relationship between electrocardiogram (ECG) parameters and LVPET in patients with CRT.

It was an observational, prospective, and monocentric study. From May 2017 to October 2017, all patients who underwent CRT with left quadripolar lead in Rouen University Hospital were included. LVPET was evaluated by echocardiography and defined as the time between the beginning of the QRS and the beginning of pulsed doppler signal positioned in left ventricular outflow tract in apical view. The following parameters on 12-leads ECG were assessed: QRS width in V3, sum of QRS amplitude in all lead. Measures were performed during bi-ventricular pacing (at each pacing point of the quadripolar lead: D1, M2, M3, P4), left ventricular pacing, right ventricular pacing, and spontaneous rhythm. Partial correlation test was used.

Seventeen patients were included. In each patient, LVPET was correlated with QRS width (P=0.02, R=0.194) and QRS amplitude (P<0.001, R=0.427). The following relationship was observed: the lower is the LVPET, the lower is the QRS amplitude and the narrow is the QRS width. In each patient, mean variation of QRS width was equal to 64.7±29.4%, mean variation of LVPET was equal to 37.1±16.4% and mean variation of QRS amplitude was equal to 53.2±27.4%.

QRS width and QRS amplitude varies according to the pacing site after CRT and are correlated with left ventricular pre-ejection time. These ECG parameters could be helpful to optimize CRT.