Conclusions

Very high scar burden in the basal septum as assessed using cardiac MRI is a strong predictor of failure to deliver the lead to the left bundle area. However, once the lead is delivered, scar burden is no impediment to successful stimulation. Cardiac MRI is a useful pre-procedural planning step, and future development of specialised tools to advance a lead through a heavily scarred basal septum could be beneficial because it would likely still achieve a narrow QRS.
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