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| [[Puzzle_2006_4_154 Answer|Answer]] | | [[Puzzle_2006_4_154 Answer|Answer]] |
| [[Image:Puzzle_2006_4_154_fig2.jpg|Figure 2|thumb]]
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| A careful look at the ECG reveals no clear P waves.
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| There is a bradycardic rhythm with initially a slight
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| irregularity in the QRS complexes. In the last part of
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| the ECG, QRS complexes follow each other on a
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| regular basis with 1440 ms intervals (see rhythm strip
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| at the bottom). The QRS width is 120 ms. The ST
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| segments are markedly deviated: ST elevation in lead
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| III and less evident in lead II and aVF and ST depression
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| in leads I, aVL, V1 and V3. In addition there
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| is ST elevation in lead aVR.
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| Based on these ECG changes, the diagnosis should
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| be atrial fibrillation and inferior-posterior myocardial
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| infarction. The slow heart rate suggests the presence
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| of advanced AV-nodal conduction block, a common
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| feature in the setting of inferior wall infarction. ST
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| elevation in lead aVR suggests that the right ventricle
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| is involved as well. A further indication of RV involvement
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| is the rightward displacement of the precordial
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| leads (i.e. the next step should be a rightward pooled
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| ECG; figure 2). This ECG shows clear ST elevation in
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| the right precodial leads and now a regular slow ventricular
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| rhythm, substantiating the diagnosis of advanced
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| AV nodal conduction block (i.e. total AV block in the
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| presence of atrial fibrillation). Acute coronary
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| angiography revealed an (anticipated) proximal right
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| coronary artery occlusion.
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| In both ECGs lead V2 is probably not at the correct
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| position, it is either at the position of V1 (and V1 at the
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| position of V2) or even more displaced to the right.
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