Investigations
12-lead ECG showed sinus rhythm with AV dissociation as a result of RV-only pacing. Device interrogation confirmed 100% RV pacing with underlying complete AV block with a broad escape rhythm (LBBB, QRS duration 132ms). TTE revealed a non-dilated LV with moderately impaired systolic function (LVEF 40-45%), with late septal activation consistent with RV apical pacing. RV function and pulmonary pressures were normal, with no significant valve abnormalities.