PMC3714068_01
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.
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F0001
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).
12-lead EKG obtained after metoprolol administration demonstrating normal conduction at heart rate of 53.
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F0002
Electrocardiogram revealed sinus bradycardia with a narrow QRS (Fig. 2).
12-lead EKG obtained 3 hours after metoprolol administration at a heart rate of 63 demonstrating LBBB and normal conduction.
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F0003
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).
12-lead EKG obtained three weeks earlier showing first degree heart block with T-wave inversions during normal conduction at slower rate of 49.
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F0004
At that time a narrow QRS and inferior and anterior T-wave inversions were noted, while the heart rate was 49 (Fig. 4).