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.Question
What type of device therapy has this patient received?