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Updated: Jul 13, 2026

Impact of Intracardiac Neurons on Cardiac Electrophysiology and Arrhythmogenesis in an Ex Vivo Langendorff System
Published on: May 22, 2018
The effects of atropine on sinoatrial conduction time directly measured from sinus node electrogram. A comparison
Abstract:
The effects of atropine on sinoatrial conduction time (SACT) measured directly (SACTD) from the sinus node electrogram (SNE) were investigated in 15 patients with normal sinus node function. A comparison was undertaken with the results furnished by indirect methods which employ premature (SACTS) and asynchronous atrial stimulation (SACTN) to calculate SACT. In the control state SACTD was 92.5 +/- 16.4 ms, SACTS 78.2 +/- 22 ms, and SACTN 97.9 +/- 32.2 ms. After atropine SACTD was 70.6 +/- 15.6 ms (P less than 0.0005), SACTS 46.7 +/- 14.3 ms (P less than 0.0005) and SACTN 43.1 +/- 12.7 ms (P less than 0.0005). Mean percent decreases of SACTN (51.6 +/- 21) and SACTS (37.4 +/- 18) were statistically greater than that of SACTD (23.5 +/- 13.3) (P less than 0.0005 and P less than 0.01 respectively). While the reduction of SACTS and SACTN was greater than that of sinus cycle length (SCL) (29.2%), SACTD showed a reduction significantly less than that of SCL (P less than 0.005). Thus, SNE recording confirms that atropine induces a shortening of SACT in normal patients, but significantly less than that indicated by indirect methods.
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