Abstract
Background
The effectiveness of cardiac resynchronization therapy (CRT) in patients without left bundle branch block (non-LBBB) QRS morphology is limited, compared to those with LBBB. Still, a substantial part of these patients can benefit from therapy and additional selection criteria are needed to identify these patients.
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 (fQRS). 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 ≥109 μVs (p<0.001) and in those without fQRS present (p=0.004) (figure 1).
Figure 1
Conclusion
A large QRS area and the absence of fQRS are positively associated to event free survival in non-LBBB patients treated with CRT. Whereas currently used patient selection cut-off QRS duration is not associated to outcome in these patients. These data may provide additional value for the non-LBBB patient selection for CRT and warrant prospective evaluation of these ECG features.
Acknowledgement/Funding
None
Left ventricular dimensions predict risk of appropriate shocks but not mortality in cardiac resynchronization therapy-defibrillator recipients with left bundle-branch block and non-ischemic cardiomyopathy
