Author/Authors :
Sadr‑Ameli, Mohammd Ali Department of Cardiac Electrophysiology - Rajaie Cardiovascular Medical and Research Center - Iran University of Medical Sciences, Tehran, Iran , Kamali, Farzad Department of Cardiac Electrophysiology - Rajaie Cardiovascular Medical and Research Center - Iran University of Medical Sciences, Tehran, Iran , Vahedinezhad, Milad Department of Cardiac Electrophysiology - Rajaie Cardiovascular Medical and Research Center - Iran University of Medical Sciences, Tehran, Iran , Sadrameli, Sadaf Department of Cardiac Electrophysiology - Rajaie Cardiovascular Medical and Research Center - Iran University of Medical Sciences, Tehran, Iran
Abstract :
Background: Refractory periods are measured by the extrastimulus technique, whereby a single extrastimulus is introduced at progressively
shorter coupling intervals until a response is no longer elicited. Purpose: As refractoriness of cardiac tissues depends on prior cycle length,
refractory periods should be determined at a fixed cycle length within the physiologic range. The extrastimulus is delivered after a train of 8 to
10 paced complexes to allow time for reasonable stabilization of refractoriness, which is usually accomplished after the first 3 or 4 paced beats.
Objectives: We conducted this study to compare the effect of 6 vs 8 stimuli in basic cycle length (BCL) in measurement of effective refractory
period (ERP). Materials and Methods: During electrophysiologic study (EPS) of 100 consecutive patients, anterograde and retrograde ERP
of atrioventricular node (AVN) were measured by introduction of 6 vs 8 stimuli in BCL and premature beat, then the results were compared.
Results: Recorded anterograde and retrograde ERP of AVN applying 6 vs 8 stimuli in BCL were compared and no difference was detected.
Conclusion: We concluded that for ERP measurement of AVN, 6 stimuli in BCL is comparable to 8 stimuli in reaching the steady state.
