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[Use of digoxin in patients with paroxysmal supraventricular tachycardia]
Abstract:
The effectiveness and electrophysiologic mechanisms of antiarrhythmic effect of digoxin were examined in 27 patients with paroxysmal atrioventricular nodal reciprocal tachycardia (PAVNRT) and supraventricular tachycardia (SVT) due to latent complementary conductive pathways, i. e. latent Wolff-Parkinson-White (WPW) syndrome. To assess antiarrhythmic action of digoxin, transesophageal pacing and plasma digoxin radioimmonoassays were used. Preventive antiarrhythmic efficiency of digoxin was 53% in PAVNRT patients, and 25% in SVT patients with latent WPW syndrome. Antegrade atrioventricular conduction block seems to be the mechanism of oral digoxin preventive effect. There was no relationship between antiarrhythmic efficiency of digoxin and its plasma level.
Insights
Digoxin showed a 53% preventive antiarrhythmic effect in paroxysmal atrioventricular nodal reciprocal tachycardia (PAVNRT) and 25% in supraventricular tachycardia (SVT) with latent Wolff-Parkinson-White (WPW) syndrome, likely via antegrade atrioventricular conduction block.
Area of Science:
- Clinical Electrophysiology
- Cardiology
- Pharmacology
Background:
- Supraventricular tachycardia (SVT) encompasses various arrhythmias, including paroxysmal atrioventricular nodal reciprocal tachycardia (PAVNRT).
- Latent Wolff-Parkinson-White (WPW) syndrome involves accessory pathways that can predispose individuals to SVT.
- Digoxin is a cardiac glycoside with known effects on atrioventricular nodal conduction.
Purpose of the Study:
- To evaluate the antiarrhythmic effectiveness of digoxin in patients with PAVNRT and SVT due to latent WPW syndrome.
- To elucidate the electrophysiologic mechanisms underlying digoxin's antiarrhythmic action in these conditions.
Main Methods:
- Study population: 27 patients diagnosed with PAVNRT or SVT secondary to latent WPW syndrome.
- Interventions: Transesophageal pacing to assess electrophysiologic parameters.
- Measurements: Plasma digoxin levels via radioimmunoassay to correlate drug concentration with efficacy.
Main Results:
- Digoxin demonstrated a 53% preventive antiarrhythmic efficiency in patients with PAVNRT.
- In SVT patients with latent WPW syndrome, the preventive efficiency of digoxin was 25%.
- The primary mechanism appears to be antegrade atrioventricular conduction block; no correlation was found between plasma digoxin levels and antiarrhythmic efficacy.
Conclusions:
- Digoxin exhibits a moderate preventive antiarrhythmic effect in PAVNRT and a lesser effect in SVT with latent WPW syndrome.
- The electrophysiologic mechanism is attributed to the induction of antegrade atrioventricular conduction block.
- Therapeutic efficacy is not directly related to plasma digoxin concentrations in this patient cohort.