Clinical introduction A 78-year-old man presents following a syncopal episode in the setting of intermittent sinus bradycardia and left bundle branch block (LBBB). With symptoms likely due to documented intermittent sinus node dysfunction, and finding of a diseased left bundle, a pacemaker was inserted (online supplementary figure 1 shows the electrode position in a PA fluroscopy view). His baseline ECG is shown in figure 1A, with a QRS width of 160 ms, and his echocardiogram revealed a left ventricular ejection fraction of 45%. His ECG day 1 postdevice insertion is shown in figure 1B. His device check confirmed excellent function. His QRS width on ECG postdevice insertion is now normalised to 80 ms.
Supplementary file 1
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Contributors All authors have substantial contribution to the conception, writing and editing of the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
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