What is the normal HV interval?

• A. 5-15 ms
• B. 20-30 ms
• C. 35-55 ms
• D. 60-80 ms

Answer: (C)

The HV interval represents the time from the His bundle activation to the onset of ventricular activation, reflecting conduction through the His–Purkinje system. The normal range is about 35–55 milliseconds. This range is what you expect for the rapid, coordinated spread of impulse from the His bundle through the ventricles; it indicates intact conduction within the distal conduction system.

Why this range fits best: values within roughly 35–55 ms show normal conduction time from His to ventricular activation. If the HV interval is prolonged beyond this, it points to disease in the His–Purkinje pathway (infra-nodal conduction disease), which can have important implications for pacing decisions and risk of block. An HV interval shorter than the normal range is uncommon and not considered a typical normal finding; when seen, it’s usually investigated for measurement variability or other unusual electrophysiologic circumstances.