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The effect of intravenous procainamide on the HV interval at electrophysiologic study

S E Girard1, T M Munger, S C Hammill

  • 1Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA.

Journal of Interventional Cardiac Electrophysiology : an International Journal of Arrhythmias and Pacing
|July 1, 1999
PubMed

Insights

Procainamide infusion during electrophysiologic studies helps identify distal conduction system disease. It is most useful in patients with mild HV prolongation (55-70 ms) to predict high-grade atrioventricular block, guiding pacemaker decisions for syncope.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Clinical Medicine

Background:

  • Electrophysiologic study (EPS) is crucial for differentiating atrioventricular (AV) node disease from distal conduction system disease.
  • The His bundle electrogram (HBE) provides essential data, but further testing may be needed for distal conduction system assessment.

Purpose of the Study:

  • To evaluate the utility of intravenous procainamide infusion in diagnosing distal conduction system disease during EPS.
  • To determine predictors of high-grade AV block induced by procainamide and establish its role in managing syncope.

Main Methods:

  • Retrospective review of 79 patients undergoing EPS with intravenous procainamide administration.
  • Analysis of baseline HV intervals, procainamide response (high-grade AV block or HV interval <80 ms), and patient indications (syncope, ventricular tachycardia).

Main Results:

  • Abnormal procainamide response occurred in 3% with normal HV, 48% with mild HV prolongation (56-70 ms), and 100% with moderate HV prolongation (<70 ms).
  • Procainamide induced high-grade AV block in 14% of syncope patients versus 2% of ventricular tachycardia patients.
  • Syncope indication and left bundle branch block morphology predicted high-grade AV block; prolonged baseline HV and QTc intervals were associated with AV block development.

Conclusions:

  • Procainamide infusion is valuable for patients with mild HV prolongation (approx. 55-70 ms) during EPS for syncope evaluation.
  • A strong linear correlation exists between baseline and post-procainamide HV intervals, supporting its predictive value.
  • Pacing is recommended for syncope patients with a baseline HV interval <70 ms, based on procainamide response and prospective data.

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