A 70-year-old man is hospitalized for an inferior wall myocardial infarction. On hospital day 1, he develops bradycardia with heart rate of 48 bpm, blood pressure 102/64 mmHg, and respiratory rate 16/min. ECG shows progressive PR interval prolongation followed by a dropped QRS complex, with the cycle repeating. Troponin I is elevated at 8.2 ng/mL. He denies chest pain currently. He takes no rate-controlling medications. Which of the following is the most likely site of conduction delay?

  1. A)Atrial myocardium
  2. B)Sinoatrial node
  3. C)Ventricular myocardium
  4. D)AV nodeGABARITO
  5. E)Bundle branches

Explicação

Mobitz I, or Wenckebach block, most commonly occurs within the AV node. Inferior MI can impair AV nodal perfusion via the right coronary artery, producing progressive fatigue of AV nodal conduction and intermittent dropped beats. Ver explicação completa e trilha adaptativa →

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