PMC10284657_01
Presenting ECG, which demonstrates third-degree AV block with a narrow complex ventricular escape rhythm of 36 BPM.
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Several electrocardiograms (ECGs) performed at the time of presentation in the emergency department demonstrated third-degree AV block (Figure 1).
Follow-up ECG, which demonstrates first-degree AV block with markedly prolonged PR interval of 512 ms.
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The transition to first-degree AV block was later confirmed on an ECG performed about 10 hours after arrival (Figure 2).
ECG stress test at peak exercise, which demonstrates intermittent high-grade 2 : 1 AV block.
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Subsequently, during an exercise ECG stress test, the patient was found to have high-grade intermittent 2 : 1 second-degree AV block at rest and with exertion (Figure 3).