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Effect of autonomic blockade on digoxin-induced ECG changes at rest and during exercise in healthy subjects

K Sundqvist1, T Jogestrand

  • 1Department of Clinical Physiology, Karolinska Hospital, Stockholm, Sweden.

Journal of Electrocardiology
|July 1, 1993
PubMed

Insights

Pharmacological autonomic blockade did not alter digoxin-induced ST-T changes during exercise. This suggests the autonomic nervous system is unlikely to mediate these digitalis-induced electrocardiographic effects.

Area of Science:

  • Cardiology
  • Pharmacology
  • Exercise Physiology

Background:

  • Digoxin is a cardiac glycoside used to treat heart failure and arrhythmias.
  • Digoxin can cause electrocardiographic (ECG) changes, including ST-T wave alterations.
  • The role of the autonomic nervous system in these digoxin-induced ECG changes is not fully understood.

Purpose of the Study:

  • To investigate the effect of pharmacological autonomic blockade on digoxin-induced ECG changes at rest and during exercise.
  • To determine if the autonomic nervous system mediates digitalis-induced ST-T segment alterations.

Main Methods:

  • Nine healthy male subjects underwent bicycle exercise tests.
  • Four conditions were tested: saline placebo, autonomic blockade (propranolol and atropine), digoxin administration followed by saline, and digoxin administration followed by autonomic blockade.
  • Electrocardiographic (ECG) changes, specifically ST-T segment alterations, were measured at rest and during exercise.

Main Results:

  • Digoxin administration led to significant ST-T segment depression compared to placebo conditions, both with and without autonomic blockade.
  • There was no significant difference in digoxin-induced ST-T changes between the saline placebo and the autonomic blockade conditions.
  • These findings indicate that autonomic blockade did not attenuate the ECG effects of digoxin.

Conclusions:

  • The autonomic nervous system is unlikely to be the primary mediator of digoxin-induced ST-T segment changes.
  • The observed ECG alterations are likely due to direct effects of digoxin on cardiac ion channels rather than indirect autonomic modulation.

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