FIGURE 1
A, Baseline 12 lead Electrocardiogram (ECG) with lead II magnified in the lower panel showing wide complex rhythm at a rate of 70 bpm (lower rate of pacemaker) with intermittent narrower QRS complexes (140 ms) of a different morphology. B, Long rhythm strip recorded while application of magnet showing transition from wide to narrower complex rhythm (85 bpm). The magnet response starts after the arrow. C, Upper left hand panel depicts a previous ECG without pacing (intrinsic rhythm). The upper right hand panel shows the 12 leas long rhythm strip ECG recorded during magnet response. The lower panel shows a magnified view of leads aVF, V1, and V2. Atrial pacing spikes (black arrows), onset of magnet response (blue arrow), and atrial/ventricular rates are also illustrated (please also refer to discussion).