Abstract
A 46-year-old man presented with advanced and complete atrioventricular block. He was diagnosed with human leukocyte antigen-B27-positive ankylosing spondylitis (AS) and treated with nonsteroidal anti-inflammatory drugs for AS. The severe atrioventricular block spontaneously improved and resolved after 3 months of therapy. Sequential cardiac magnetic resonance imaging demonstrated transient myocardial high-intensity signals in the basal septum close to the membranous portion of the septum. A pacemaker was not needed because of the reversible atrioventricular block.