The Effect of Intravenous Potassium on Myocardial Contractility and Cardiac Dynamics

Leight, Leonard; Roush, George C.; Rafi, Esmail; McGaff, Charles J.

doi:10.1097/00132586-196502000-00028

Cited by 2 publications

(3 citation statements)

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“…The maintenance of cardiae ouput and systemic pressure at control values reflects the finding in "open-chest" animals (Leight, Roush, Rafi and McGaff, 1963); apart from tachycardia, hyperkalaemia eaused no notable changes in the general haemodynamics of the animals now studied.…”

Section: Discussionsupporting

confidence: 71%

Effects of Hyperkalaemia Upon the General and Coronary Haemodynamics of the Dog

Maxwell¹

1965

Aust J Exp Biol Med

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Section: Discussionsupporting

confidence: 71%

Effects of Hyperkalaemia Upon the General and Coronary Haemodynamics of the Dog

Maxwell¹

1965

Aust J Exp Biol Med

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“…Leonard and Hajdu found both in isolated amphibian and mammalian tissues that the usual alteration of the forcefrequency relationship produced by strophanthidin was not affected by twice normal K concentrations in the bath (38). Similarly, Leight, Roush, Rafi, and McGaff observed that normal dogs, K-depleted, and hyperkalemic animals all showed quantitatively similar inotropic responses to acetylstrophanthidin (15).…”

Section: Resultsmentioning

confidence: 71%

“…Changes in contractile force induced by alterations in body temperature were also precluded. There is no reason to believe that the addition of K itself augmented contractility, since numerous studies both in vivo and in vitro have shown that this ion either does not alter the contractile state of the heart or, when given in large doses, actually reduces it (11)(12)(13)(14)(15)(16)(17). Furthermore, in the control dogs the infusion of KCl did not materially alter contractile force.…”

Section: Resultsmentioning

confidence: 99%

Studies on digitalis. 13. A comparison of the effects of potassium on the inotropic and arrhythmia-producing actions of ouabain.

Williams¹,

Klocke²,

Braunwald³

1966

J. Clin. Invest.

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Although it is generally recognized that digitalis-induced arrhythmias can be suppressed by the administration of potassium (1-3), it is not clear whether the potassium ion also influences the positive inotropic effect exerted by the glycosides on the intact mammalian heart. Clarification of this problem is important in the understanding of the interrelationships between the actions of glycosides and potassium, and is clinically significant in view of the frequency with which potassium is administered to patients who are or have been receiving digitalis. Accordingly, the present investigation was undertaken to determine the manner in which potassium suppression of ouabaininduced arrhythmias affects the augmentation of ventricular contractile force produced by the administration of the glycoside. MethodsTen mongrel dogs, weighing between 10 and 25 kg, were anesthetized with intravenous sodium pentobarbital (35 mg per kg) and ventilated with a positive displacement pump that was supplied with a mixture of room air and 100% 02. The right ventricle was exposed through a median sternotomy, a Walton-Brodie strain gauge arch (4) was sutured to the right ventricle, and the muscle segment beneath the gauge was stretched approximately 50% beyond its initial length. This maneuver allows recording of the changes in contractile force of the segment of myocardium between the points of attachment of the gauge despite some changes in right ventricular dimensions (5). Heparin, 5 mg per kg, was administered intravenously. With a compressed air-blood reservoir that was connected to a femoral artery through a large bore cannula, mean arterial pressure was maintained constant despite any changes in blood volume that might have occurred as a consequence of bleeding or blood withdrawal for plasma K concentration. Body tempera-* Submitted for publication June 9, 1965; accepted November 26, 1965. f Address requests for reprints to Dr. Eugene Braunwald, Cardiology Branch, National Heart Institute, Bethesda, Md. 20014. ture was monitored with a thermistor probe placed in the superior vena cava and was maintained constant with heating pads. Femoral arterial pressure was measured with a Statham P23D strain gauge transducer, and arterial blood was withdrawn at intervals for determinations of plasma K by flame photometry. Right ventricular contractile force, arterial pressure, and a limb lead of the electrocardiogram were recorded continuously on a direct-writing oscillograph. In two of the ten animals the sinoatrial node was crushed and heart rate maintained constant by stimulating the right atrium at a rate just above the spontaneous rate. Two animals had undergone bilateral adrenalectomy 1 week before the experiment and were then maintained on steroid replacement therapy.After control measurements, an intravenous dose of ouabain, 30 tzg per kg, was administered over a 5-minute period. Ten to 15 minutes later a constant infusion of ouabain, 30 jzg per kg per hour, was begun and was continued for the remainder of the experiment. Ouabai...

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The Effect of Intravenous Potassium on Myocardial Contractility and Cardiac Dynamics

Cited by 2 publications

References 0 publications

Effects of Hyperkalaemia Upon the General and Coronary Haemodynamics of the Dog

Effects of Hyperkalaemia Upon the General and Coronary Haemodynamics of the Dog

Studies on digitalis. 13. A comparison of the effects of potassium on the inotropic and arrhythmia-producing actions of ouabain.

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