Drugs

, Volume 31, Supplement 4, pp 78–84 | Cite as

Potassium Loss, Ventricular Irritability, and the Risk of Sudden Death in Hypertensive Patients

  • O. Bryan Holland
Section 3: Electrolyte Changes and the Myocardium: Defining the Risk

Summary

In the past, potassium depletion in both non-digitalised patients and in patients without cardiac disease was thought to cause no adverse cardiac effects. However, several studies have now demonstrated a significant incidence of ventricular ectopic activity (VEA) with diuretic-induced hypokalaemia, even in hypertensive patients without overt heart disease. Additional evidence suggests that sudden death may occasionally result from this VEA. Potassium repletion with potassium-sparing diuretics or with potassium chloride supplementation has generally demonstrated a beneficial therapeutic effect in reducing VEA. However, after diuretic therapy occasional patients may have persistent VEA which may result from focal myocardial lesions associated with potassium depletion. In contrast, diuretic therapy in which normokalaemia is maintained has only been associated with a very low occurrence of VEA. Thus, with the preservation of normokalaemia, diuretic therapy for hypertension does not appear to be associated with the significant hazards of VEA.

Keywords

Hypertensive Patient Diuretic Therapy Ventricular Ectopic Activity Medical Research Council Working Party Potassio 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Résumé

Auparavant, une déplétion en potassium chez des malades non digitalisés et chez des malades indemnes de maladie cardiaque était censée n’avoir aucun effet cardiaque nocif Cependant, plusieurs études ont maintenant montré qu’il existe une incidence significative d’activité ectopique ventriculaire (A.E.V.) avec les diurétiques inducteurs d’hypokaliémie même chez les hypertendus sans maladie cardiaque patente. Des preuves s’ajoutent pour suggérer que cette A.E. V. peut éventuellement conduire à une mort subite. Une réplétion en potassium avec des diurétiques d’épargne du potassium ou avec un supplément en chlorure de potassium s’est généralement montrée d’un bénéfice thérapeutique intéressant en réduisant cette A.E.V. Cependant, après un traitement diurétique, certains malades sont susceptibles d’avoir uneA.E. V. persistante qui peut résulter de lésions myocardiques focalisées associées à la déplétion potassique. A l’inverse, le traitement diurétique pendant lequel on maintient une normokaliémie n’a été associé qu’à une très faible survenue d’A.E. V. Ainsi, en préservant une normokaliémie, le traitement diurétique à visée antihypertensive n’apparait pas associé de façon significative à des problèmes d’A.E. V.

Zusammenfassung

In der Vergangenheit glaubte man, daβ ein Kalium-Mangel sowohl in nicht-digitalisierten Patienten als auch in Patienten ohne Herzkrankheit keine kardialen Nebenwirkungen erzeugt. In verschiedenen Studien wurde jedoch jetzt eine signifikante Häufigkeit einer ventrikulären ektopischen Aktivität (VEA) mit der Diuretika-induzierten Hypokaliämie selbst bei Hypertonikern ohne offensichtliche Herzkrankheit nachgewiesen. Zusätzliche Hinweise lassen vermuten, daβ gelegentlich ein plötzlicher Herztod Ergebnis dieser VEA sein kann. Eine Kalium-Auffüllung mit Kalium-sparenden Diuretika oder mit Supplementen von Kaliumchlorid zeigte im allgemeinen einen günstigen therapeutischen Effekt bei der Reduktion der VEA. Nach einer diuretischen Therapie können jedoch gelegentlich bei Patienten persistierende VEA als Ergebnis von mit einem Kalium-Mangel im Zusammenhang stehenden fokalen myokardialen Läsionen vorliegen. Dagegen kommt bei einer diuretischen Therapie, in der eine Normokaliämie aufrecht erhalten wird, es nur zu einem sehr niedrigen Auftreten einer VEA. Bei Bewahrung einer Normokaliämie scheint daher die diuretische Therapie bei der Hypertonie nicht mit den bedeutenden Gefahren einer VEA in Verbindung zu stehen.

Resumen

Antaño se creía que el agotamiento de las reservas de potasio no causaba efectos cardiacos adversos en los pacientes no digitalizados y en los que no padecían enfermedad cardiaca; sin embargo, varios estudios han demostrado que hay una incidencia significativa de actividad ventricular extópica (AVE) incluso en los pacientes hipertensos sin cardiopatía manifiesta. Otros datos adicionales sugieren que la muerte repentina puede derivarse ocasionalmente de esta AVE. La repleción potasica con diuréticos ahorradores de potasio o con suplementos de cloruro potásico ha tenido por lo general un efecto terapéutico beneficioso reduciendo la A VE; sin embargo, después de la terapéutica diurética algunos pacientes muestran una A VE persistente que resultaría de lesiones miocárdicas focales asociadas al agotamiento de potasio. En cambio, la terapéutica diurética en la que se mantiene la normocaliemia sólo ha aparecido asociada a una baja incidencia de AVE. Por tanto, preservando la normocaliemia, la terapéutica diurética de la hipertensión no parece ir acompañada de los riesgos de la AVE.

Resumo

No passado, considerava-se que a depleção de potássio tanto em pacientes rão digitalizados como nos pacientes sem doença cardíaca, não causasse efeitos cardíacos adversos. Entretanto, diversos estudos revelaram uma incidência significante de atividade ectópica do ventrículo (AEV), acompanhada de hipopotassemia induzida por diuréticos, mesmo em pacientes com hipertensão mas sem doença cardíaca manifesta. Outros dados evidenciam que a morte súbita pode resultar ocasionalmente de uma tal AEV. A reposição de potássio por meio de diuréticos poupadores de potássio ou de suplementação com cloreto de potássio geralmente demonstrou ser eficaz para a redução de AEVs. Contudo, após terapia com diuréticos, pode ocorrer que as AEVs persistam em alguns pacientes, possiveimente como resultado de lesões focais do miocárdio associadas à depleção de potássio. Por outro lado, a terapia com diuréticos, em que se mantém a concentração de potássio, foi associada a apenas uma baixa ocorrência de AEVs. Desse modo, em se preservando as concentrações normais de potássio, o tratamento com diuréticos para a hipertensão não parece estar associado a riscos significativos de AEVs.

Riassunto

Negli anni scorsi si riteneva che la deplezione potassica non causasse effetti cardiaci dannosi in pazienti non digitalizzati o senza cardiopatie. Tuttavia parecchi studi hanno ora dimostrato una significativa incidenza di ectopie ventricolari (EV) in corso di ipopotassiemia indotta da diuretici, anche in pazienti ipertesi senza una cardiopatia manifesta. Ulteriori evidenze suggeriscono che la morte improvvisa possa svilupparsi a seguito di queste EV. L’uso di diuretici risparmiatori di potâssio o supplement di cloruro di potassio si sono in genere dimostrati utili nel ridurre le EV. Tuttavia, dopo la terapia diuretica alcuni pazienti possono avere persistenti EV che possono essere causate da lesioni miocardiche focali associate a deplezione potassica. Al contrario, in corso di trattamento diuretico associato a normale potassiemia sono state osservate molto raramente EV. Pertanto, mantenendo normali livelli plasmatici di potassio, la terapia dell’ipertensione con diuretici non sembra associata a rischi significativi di EV.

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Copyright information

© ADIS Press Limited 1986

Authors and Affiliations

  • O. Bryan Holland
    • 1
  1. 1.University of Texas Medical BranchGalvestonUSA

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