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Systemic alkalosis and digitalis related arrhythmias
Acta Medica Scandinavica. Supplementum
|January 1, 1981
Summary
Digitalis toxicity can cause arrhythmias even with normal potassium levels. Metabolic alkalosis, indicating low intracellular potassium, increases arrhythmia risk in patients on digoxin.
Area of Science:
- Cardiology
- Electrophysiology
- Pharmacology
Background:
- Digitalis-induced arrhythmias are common, yet hypokalemia (low serum potassium) is not always present.
- The clinical benefit of potassium supplementation for these arrhythmias suggests a complex relationship with potassium levels.
- Understanding the interplay between digitalis and potassium is crucial for managing cardiac arrhythmias.
Purpose of the Study:
- To investigate the paradox of digitalis-induced arrhythmias occurring without hypokalemia.
- To clarify the electrophysiologic effects of digitalis in relation to intracellular and extracellular potassium concentrations.
- To examine the role of metabolic alkalosis as a marker for intracellular potassium depletion and its impact on digitalis toxicity.
Main Methods:
- Analysis of electrophysiologic abnormalities induced by digitalis.
- Evaluation of electrophysiologic effects related to the ratio of intracellular to extracellular potassium.
- Utilizing metabolic alkalosis as an indicator of intracellular potassium depletion in patients with "therapeutic" digoxin levels.
Main Results:
- Digitalis toxicity and abnormal potassium ratios (intracellular vs. extracellular) have additive effects on arrhythmia development.
- Patients with metabolic alkalosis and normokalemia (normal serum potassium) on therapeutic digoxin concentrations showed a higher prevalence of arrhythmias.
- Metabolic alkalosis is presumed to mediate increased arrhythmia risk by altering the extra- to intracellular potassium ratio.
Conclusions:
- Arrhythmias associated with digitalis can occur due to intracellular potassium depletion, even with normal serum potassium levels.
- Metabolic alkalosis serves as a marker for this intracellular potassium imbalance, increasing susceptibility to digitalis-induced arrhythmias.
- These findings highlight the importance of considering intracellular potassium status in managing patients with digitalis toxicity and arrhythmias.