"First-degree AV block-a benign entity?" Insertable cardiac monitor in patients with 1st-degree AV block reveals presence or progression to higher grade block or bradycardia requiring pacemaker implant.

ICM either revealed progression of 1st-degree AV block to a higher grade block (53%) or detected an already existing more severe bradycardia warranting an IPG in 40.5% patients. This finding supports the conclusion that 1st-degree AV block might be a risk marker for more severe intermittent conduction disease and is not benign in all patients. Further studies may reveal patient subgroups which are at risk for demonstrating or developing higher grade AV block and may warrant a future IPG implantation.