case_images: PMC3714068_01
case_images: Telemetry strip obtained preprocedure (A) showing narrow complex rhythm with a heart rate of 54 and immediately after arrest (B) showing wide complex rhythm at a heart rate of 63.
case_images: JCHIMP-2-19037-g001.jpg
case_images: PMC3714068_01_JCHIMP-2-19037-g001.jpg
case_images: F0001
case_images: Electrocardiogram revealed sinus bradycardia at a rate of 54 and a narrow QRS (Fig. 1A). At this time, LBBB was observed on the monitor (Fig. 1B).
case_images: 12-lead EKG obtained after metoprolol administration demonstrating normal conduction at heart rate of 53.
case_images: JCHIMP-2-19037-g002.jpg
case_images: PMC3714068_01_JCHIMP-2-19037-g002.jpg
case_images: F0002
case_images: Electrocardiogram revealed sinus bradycardia with a narrow QRS (Fig. 2).
case_images: 12-lead EKG obtained 3 hours after metoprolol administration at a heart rate of 63 demonstrating LBBB and normal conduction.
case_images: JCHIMP-2-19037-g003.jpg
case_images: PMC3714068_01_JCHIMP-2-19037-g003.jpg
case_images: F0003
case_images: Three and a half hours after the administration of metoprolol, heart rate increased to 64 and EKG revealed intermittent LBBB, with both narrow and wide QRS complexes, despite a stable heart rate (Fig. 3).
case_images: 12-lead EKG obtained three weeks earlier showing first degree heart block with T-wave inversions during normal conduction at slower rate of 49.
case_images: JCHIMP-2-19037-g004.jpg
case_images: PMC3714068_01_JCHIMP-2-19037-g004.jpg
case_images: F0004
case_images: At that time a narrow QRS and inferior and anterior T-wave inversions were noted, while the heart rate was 49 (Fig. 4).