A 77-year-old woman with a history of chronic rheumatoid arthritis and breast cancer presents to the emergency department with complaints of nausea and vomiting. She has had palpitation for some years and was treated with digitalis. An ECG is performed and depicted below (Figure 1).
Figure 1
The ECG shows bifascicular block and which of the following:
Show Answer
The correct answer is: E. Second-degree AV block mobitz type II.
Left axis deviation and right bundle branch block are present with sinus rhythm. The right half of the tracing shows 2:1 AV block. The dropped beats on the left side of the tracing show no antecedent prolongation of the PR interval compatible with second-degree AV block mobitz type II.
The etiology of this AV block in this case is most likely due to a history of adjunctive radiation therapy of breast cancer. Fibrosis due to aging is another etiology of advanced AV node conduction disease.
Lead aVL shows voltage of 12 mV but caution should be made diagnosing LVH in the presence of leftward axis deviation.
The patient underwent dual chamber pacemaker implantation.
References
Nelson WP. Diagnostic and Prognostic Implications of Surface Recordings from Patients with Atrioventricular Block. Card Electrophysiol Clin 2016;8:25-35.
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