PMC4104694_01
Baseline ECG shows sinus rhythm at about 84 bpm with a normal rate-corrected QT (QTc) interval of 442 ms (Hodges formula), with non-specific T wave inversions in the inferolateral leads. The borderline rightward QRS axis may be a normal variant. Color illustration online.
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F1
Initial electrocardiogram (ECG) is shown in Fig. 1.
Junctional bradycardia at 57 bpm, with broad, deep QT(U) complexes in the anterior-lateral and inferior leads (as shown above, present in leads II and V5). The QTc is markedly prolonged at 623 ms. After the second QRS complex, a burst of torsade de pointes ventricular tachycardia occurs with characteristic "twisting of the points"morphology best seen in the rhythm strips. The non-sustained torsade de pointes episode terminates with a fusion complex (arrow), before the junctional rhythm resumes at a rate of 65 bpm with a markedly prolonged QTc of 749 ms. Artifact simulating pacemaker activity is noted at the end of the tracing. Color illustration online.
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F2
Subsequent ECGs, obtained 3 days after admission, are shown below (Figs. 2 and 3).
ECG taken about 16 hours later after the previous tracing demonstrates a junctional escape-capture bigeminal rhythm. Marked ST elevations consistent with a current of injury pattern are seen in the anterior-lateral and inferior leads, and are most evident in the second beat of these couplets. Note that the second beat in the couplets shows a pseudo-right bundle branch block pattern, with an apparent R-prime wave followed by downsloping ("coved") ST-segment elevations in V1-V3 (V1 shown above) with negative T-waves, characteristic of a Brugada-type pattern (arrowheads). The enhanced repolarization abnormalities in the second of the R-R (i.e., short) cycle beats may be related to their more abbreviated action potential durations or due to rate dependent conduction slowing. Color illustration online.
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F3
Subsequent ECGs, obtained 3 days after admission, are shown below (Figs. 2 and 3).