HV interval

Introduction

Conduction time after the impulse leaves the AV node to the time the ventricles are activated.

It is measured during electrophysiological studies.

The normal HV interval is 35-55 ms.

HV interval	clinical significance
35-55 ms	normal
50-70 ms	1%/year risk of complete heart block, no pacing recommended
70-100 ms	4%/year risk of complete heart block, pacing individualized
> 100 ms	8%/year risk of complete heart block, permanent pacing recommended