We illustrate a case of persistent inappropriate sinus tachycardia after slow pathway atrio-ventricular (AV) nodal reentrant tachycardia cryoablation, and inadvertent fast pathway lesion with residual first-degree AV block in a 72-year-old man with a small Koch's triangle. At the end of the cryoprocedure, the patient presented with sinus tachycardia 100 b.p.m., while PR was 300 ms. An accelerated sinus rhythm and a PR prolongation persisted over time. The patient was successfully treated with ivabradine with no effect on atrioventricular node conduction.