A Case with Concealed Sinus Node Dysfunction Being Manifested with Oral Azelnidipine

Abstract

We present a case with azelnidipine induced symptomatic bradycardia. An 84 year-old female patient had begun taking azelnidipine at a daily dose of 16 mg for hypertension. One month later, she was admitted to our hospital complaining of dizziness and faintness due to bradycardia. Her electrocardiogram on admission showed sinus arrest with atrioventricular junctional escape rhythm at a rate of 40 beats per minute (bpm). Azelnidipine was immediately discontinued, and her heart rate was returned to sinus rhythm and 75 bpm the next day. An electrophysiological study was subsequently performed and maximum sinus node recovery time was 3,065 msec at a rate of 200 bpm. However, the blood concentration of azelnidipine at the time of admission was in the usual therapeutic range (7.89 ng/ml). Although azelnidipine does not show reactive increase in sympathetic tone following vasodilatation, there is no report of azelnidipine induced severe sinus bradyarrhythmia. We believe that latent sinus node dysfunction was unmasked by azelnidipine in this case.