Purpose: To evaluate the association of additional baseline 12-lead ECG features; with clinical and echocardiographic outcomes in CRT-treated non-LBBB patients.
Methods: Pre-implantation 12-lead ECGs from 790 consecutive non-LBBB CRT patients from 3 implanting centres in the Netherlands, were evaluated for the presence of predefined ECG parameters. QRS morphology (right bundle branch block and intraventricular conduction delay), QRS duration (=/< 150ms), QRS area (=/< 109µVs), left ventricular activation time (=/< 125ms) and the presence of fragmented QRS. The association with the primary endpoint, the combination of left ventricular assist device implantation, cardiac transplantation and all-cause mortality, was evaluated.
Results: There was a significantly lower occurrence of the primary endpoint in non-LBBB patients with QRS area =109µVs (p<0.001) and in those without PR prolongation (p<0.001), and without fQRS (p=0.004). (Figure 1)
Conclusion: A larger QRS area is positively associated to all-cause mortality, LVAD implantation and cardiac transplantation. The presence of fragmented QRS is negatively associated with long term clinical outcome in non-LBBB patients. QRS duration, morphology and LVAT however were not associated to the occurrence of long term events in non-LBBB patients treated with CRT. These data may provide additional value for patient selection for CRT in non-LBBB patients and warrant prospective studies.