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Robert T, Algalarrondo V, Mesnard L. Hyperkaliémie sévère ou menaçante : le diable est dans les détails. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/s13546-015-1125-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Landahl S, Lindblad B, Roupe S, Steen B, Svanborg A. Digitalis therapy in a 70-year-old population. ACTA MEDICA SCANDINAVICA 2009; 202:437-43. [PMID: 596243 DOI: 10.1111/j.0954-6820.1977.tb16861.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In the population study "70-year-old people in Gothenburg" 14% of the probands were found to be undergoing treatment with digitalis, 6% with digoxin, 6% with digitoxin and 2% with other glycosides. A comparison between results of the interview method and those of S-digoxin analyses indicates that the interview method was acceptable. As far as can be judged from S-digoxin analyses, only about 60% of the treated patients were on a dosage considered to be effective and free from obvious risks of side-effects. Out of the 130 70-year-olds who were on digitalis treatment, 37% had obvious symptoms of heart disease requiring such treatment, 34% lacked symptoms of arrhythmia and/or congestive failure but had heart volumes larger than those used as reference values in younger age groups, and 29% had no symptoms indicating digitalis treatment. At least 13% of the population had indications for digitalis therapy and about 75% of those apparently needing digitalis were on such treatment. Thus both over- and underdiagnosis of heart disease requiring digitalis therapy were common in this age group.
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ANTZELEVITCH CHARLES, DAVIDENKO JORGEM, SICOURI SERGE, COHEN LAWRENCE, IODICE ARTHUR, GOODROW ROBERT, GINTANT GARYA. Quinidine-Induced Early Afterdepolarizations and Triggered Activity. ACTA ACUST UNITED AC 2008. [DOI: 10.1111/j.1540-8167.1989.tb01571.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Min HK, Kim KS, Lee GS. Rocuronium-induced Neuromuscular Block after Long Pretreatment of Magnesium Sulfate in Rabbits. Korean J Anesthesiol 2007. [DOI: 10.4097/kjae.2007.52.4.443] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Hyoung Ki Min
- Department of Anesthesiology and Pain Medicine, College of Medicine, Hanyang University, Seoul, Korea
| | - Kyo Sang Kim
- Department of Anesthesiology and Pain Medicine, College of Medicine, Hanyang University, Seoul, Korea
| | - Gurn Seung Lee
- Department of Anesthesiology and Pain Medicine, College of Medicine, Hanyang University, Seoul, Korea
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Zehender M, Meinertz T, Just H. [Magnesium deficiency and magnesium substitution. Effect on ventricular cardiac arrhythmias of various etiology]. Herz 1997; 22 Suppl 1:56-62. [PMID: 9333593 DOI: 10.1007/bf03042656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
During recent years there has been an increasing but still controversial discussion on the antiarrhythmic effects and overall benefit of magnesium when directed to patients with various types of ventricular tachyarrhythmias. While magnesium is considered to be a simple, safe and cost-effective approach and many casuistic and empiric reports have indicated antiarrhythmic properties of magnesium in patients with suspected or manifest ventricular arrhythmias, controlled studies proving the antiarrhythmic and overall benefit and justifying a broader use of magnesium in treating various types of ventricular arrhythmias are missing or rare. At present, antiarrhythmic properties and clinical benefit of magnesium application has only been established in patients with torsade de pointes and digitalis-induced ventricular tachyarrhythmias. In perioperative patients at risk for ventricular tachyarrhythmias and in patients suffering from manifest heart failure, data may also indicate some antiarrhythmic properties of magnesium, however, in this case with a wide consensus that the prevention of magnesium deficit is more effective and preferred in most patients over the therapeutic application of magnesium. Another group of patients who may profit from such a therapeutic approach are patients with frequent ventricular arrhythmias and stable underlying heart disease, in whom a recently published double-blind, randomized study documented an antiarrhythmic effect of a 3 week treatment with potassium and magnesium. For all other types of ventricular tachyarrhythmias, the therapeutic use of magnesium can be considered as not harmful, but also as not proven to be effective.
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Affiliation(s)
- M Zehender
- Abteilung für Kardiologie, Universitätsklinik Freiburg
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Kline JA, DeStefano AA, Schroeder JD, Raymond RM. Magnesium potentiates imipramine toxicity in the isolated rat heart. Ann Emerg Med 1994; 24:224-32. [PMID: 8037388 DOI: 10.1016/s0196-0644(94)70134-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
STUDY OBJECTIVE To study the effect of magnesium on cardiac function and hemodynamics during imipramine toxicity. DESIGN After stabilization, isolated, beating rat hearts were perfused with Krebs-Henseleit bicarbonate buffer (KHB) solution containing 2.0 mg/L imipramine (IMIP) and 2.4 mEq [Mg2+] until toxicity, defined as 25% widening of the ventricular depolarization duration (VDD). Experiments were performed at either constant coronary perfusion pressure or flow. SETTING Animal research laboratory of a large, urban hospital. MEASUREMENTS Heart rate, VDD, left ventricular pressure and +/- dP/dt, and coronary flow. INTERVENTIONS On onset of toxicity, KHB+IMIP was switched to either control (KHB+IMIP), magnesium (KHB+IMIP+4.0 or 6.0 mEq/L [Mg2+]), or hypertonic alkaline treatment (165 mEq/L [Na+], pH 7.55). RESULTS At a constant coronary perfusion pressure of 100 mm Hg, magnesium at 6.0 mEq produced significant decreases in heart rate, left ventricular pressure, +dP/dt, and increase in VDD versus control. With coronary flow held constant, magnesium reduced left ventricular pressure and +dP/dt but not heart rate or VDD. Incidences of electromechanical dissociation and asystole were higher with magnesium versus control. Hypertonic alkaline treatment tended to improve all parameters in constant pressure and constant flow experiments. CONCLUSION Magnesium potentiates IMIP-induced negative inotropic effects and cardiac conduction defects in isolated rat hearts.
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Affiliation(s)
- J A Kline
- Department of Emergency Medicine, Carolinas Medical Center, Charlotte, North Carolina
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Abstract
Magnesium has been reported as an effective medical therapy in an expanding array of conditions. Evidence investigating magnesium's use is presented, with a number of studies suggesting it should be seriously considered in such conditions as ischemic heart disease, cardiac arrhythmias, and asthma. Magnesium balance and metabolism are briefly reviewed, and then various hypotheses are presented that may explain magnesium's physiologic mechanisms of action, most likely involving calcium and potassium flux across cellular membranes in smooth muscle. In a number of the conditions to be discussed, it has been uncertain whether magnesium administration serves the purpose of merely correcting an underlying deficiency state or of utilizing a specific pharmacologic effect of magnesium. Magnesium deficiency is a relatively common condition, and predisposing factors as well as recent methods for assessing total body stores of magnesium are discussed. Physicians should be familiar with the numerous conditions and therapeutics that are risk factors for an underlying magnesium deficiency and in which empiric magnesium replacement should be considered. Guidelines for administration of parenteral magnesium are presented with specific focus on the low risk of adverse effects, as suggested by the large and rapid dosing regimens used in many of the clinical studies discussed here.
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Affiliation(s)
- R M McLean
- Department of Medicine, Yale School of Medicine, New Haven, Connecticut 06510
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Affiliation(s)
- M A Arsenian
- Department of Internal Medicine, Cape Ann Medical Center, Gloucester, MA 01930
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Affiliation(s)
- J R Purvis
- Department of Family Medicine, East Carolina University, School of Medicine, Greenville, North Carolina 27858-4354
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Hilton TC, Fredman C, Holt DJ, Bjerregaard P, Ira GH, Janosik DL. Electrophysiologic and antiarrhythmic effects of magnesium in patients with inducible ventricular tachyarrhythmia. Clin Cardiol 1992; 15:176-80. [PMID: 1551265 DOI: 10.1002/clc.4960150308] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Intravenous magnesium is reported to be effective in the treatment of ventricular arrhythmias associated with hypomagnesemia, digitalis toxicity, or prolongation of the QT interval. In most previous reports, magnesium was added to conventional antiarrhythmic drugs that had failed. There are few data on the antiarrhythmic efficacy of magnesium as monotherapy in patients without these associated abnormalities. Ten patients with life-threatening ventricular arrhythmia and inducible ventricular tachyarrhythmia by programmed electrophysiologic testing were treated with intravenous magnesium. Following magnesium infusion, all patients still had inducible ventricular tachyarrhythmia. Moreover, magnesium therapy was not associated with significant changes in ventricular refractory period or in the morphology, cycle length, or hemodynamic response to induced ventricular tachycardia. These data suggest that intravenous magnesium has no significant electrophysiologic or antiarrhythmic effects in patients with life-threatening ventricular arrhythmia and inducible ventricular tachyarrhythmia.
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Affiliation(s)
- T C Hilton
- Department of Internal Medicine, St. Louis University Medical Center, Missouri
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Kafiluddi R, Kennedy RH, Seifen E. Effects of buffer magnesium on positive inotropic agents in guinea pig cardiac muscle. Eur J Pharmacol 1989; 165:181-9. [PMID: 2476321 DOI: 10.1016/0014-2999(89)90711-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Experiments examined effects of extracellular Mg2+ concentration (Mgo2+) on dose-dependent actions of strophanthidin, norepinephrine, Bay K-8644 and extracellular Ca2+ (Cao2+) in electrically stimulated atrial and ventricular muscle isolated from guinea pig heart. Mgo2+ itself elicited a concentration-dependent negative inotropic effect. Elevation of Mgo2+ between 0.6 and 12 mM increased the concentration of strophanthidin necessary to produce its toxic effects without affecting the maximum developed tension prior to toxicity. Similarly, Mgo2+ did not alter the maximum contractile force elicited by cumulative addition of norepinephrine, Bay K-8644 or Cao2+, but increased their ED50 values. These data suggest that interactions between Mgo2+ and the four positive inotropic agents were not mediated by effects on receptor binding or Na+,K+-ATPase, but rather by alterations at one or more steps involved in excitation-contraction coupling.
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Affiliation(s)
- R Kafiluddi
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock 72205
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Green SM, Naftel J. Antiarrhythmic efficacy of magnesium in the setting of life-threatening digoxin toxicity. Am J Emerg Med 1989; 7:347-8. [PMID: 2712905 DOI: 10.1016/0735-6757(89)90197-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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Davidenko JM, Cohen L, Goodrow R, Antzelevitch C. Quinidine-induced action potential prolongation, early afterdepolarizations, and triggered activity in canine Purkinje fibers. Effects of stimulation rate, potassium, and magnesium. Circulation 1989; 79:674-86. [PMID: 2917391 DOI: 10.1161/01.cir.79.3.674] [Citation(s) in RCA: 154] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Early afterdepolarization (EAD)-induced triggered activity is thought to contribute to the cardiac arrhythmogenic effects of several class I antiarrhythmic agents. The combination of quinidine therapy, bradycardia, and hypokalemia is known to predispose to torsade de pointes, which is a form of atypical polymorphous ventricular tachycardia commonly associated with long QT intervals. Recent clinical reports have shown suppression of quinidine-induced torsade de pointes with intravenous administration of magnesium sulfate. To provide further understanding of these relations, we used standard microelectrode techniques to examine the time course of quinidine-induced action potential prolongation, EAD, and triggered activity development and the dependence of these changes on [K+]0, [Mg2+]0, and stimulation frequency in isolated Purkinje fiber preparations exposed to low concentrations of the drug. At slow stimulation rates, the quinidine-induced increase of action potential duration was slow to develop and failed to reach a steady state after 3 hours of exposure to the drug. EAD and EAD-induced triggered activity generally became apparent 70-90 minutes after adding the drug. Quinidine produced triggered activity in 10 of 22 preparations superfused with Tyrode's solution containing normal [K+]0 (3.5-4.0 mM) and in six other preparations when [K+]0 was reduced. In the presence of normal [K+]0, two types of EAD and triggered activity were distinguished. In four of 10 preparations, this activity arose from phase 2 of the action potential; in eight of 10, it was associated with phase 3; and in two experiments, both types were present in the same preparation. The incidence of both forms of triggered responses depended greatly on the rate of stimulation. Triggered activity arising from phase 3 was always manifest at rates considerably slower than those giving rise to phase 2 activity. Both forms of triggered activity were sensitive to changes in the extracellular concentration of potassium and magnesium. Lower-than-normal levels of these electrolytes facilitated the manifestation of triggered activity, whereas elevated levels suppressed or caused a shift in the frequency-dependence of the activity. Phase 2, but not phase 3, EADs were abolished in response to increased [Mg2+]0. The data show a clear congruity between the conditions that predispose to torsade de pointes in the clinic and the conditions under which quinidine may induce triggered activity and marked action potential prolongation in isolated Purkinje fibers.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- J M Davidenko
- Masonic Medical Research Laboratory, Utica, New York 13504
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Propp DA, Hogan T, Mattimore J. Nausea, dyspnea, and heart block in an 86-year-old patient with congestive heart failure. Ann Emerg Med 1988; 17:261-7. [PMID: 3345020 DOI: 10.1016/s0196-0644(88)80120-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- D A Propp
- Division of Emergency Medicine, Lutheran General Hospital, Park Ridge, Illinois 60068
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Kulick DL, Hong R, Ryzen E, Rude RK, Rubin JN, Elkayam U, Rahimtoola SH, Bhandari AK. Electrophysiologic effects of intravenous magnesium in patients with normal conduction systems and no clinical evidence of significant cardiac disease. Am Heart J 1988; 115:367-73. [PMID: 3341171 DOI: 10.1016/0002-8703(88)90483-8] [Citation(s) in RCA: 68] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Parenteral magnesium has been used for several decades in the empiric treatment of various arrhythmias, but the data on its electrophysiologic effects in man are limited. We evaluated the electrophysiologic effects of magnesium sulfate (MgSO4) administration in eight normomagnesemic patients with normal mononuclear cell magnesium content, who had no clinically significant heart disease and had normal baseline electrophysiologic properties. After administration of intravenous MgSO4, serum magnesium rose significantly from 1.9 +/- 0.1 to 4.4 +/- 1.7 mg/dl (p less than 0.02). During a maintenance magnesium infusion, we observed significant prolongation of the ECG PR interval (145 +/- 18 to 155 +/- 26 msec, p less than 0.05), AH interval (77 +/- 27 to 83 +/- 26 msec, p less than 0.002), antegrade atrioventricular (AV) nodal effective refractory period (278 +/- 67 to 293 +/- 67 msec, p less than 0.05), and sinoatrial conduction time (60 +/- 34 to 76 +/- 32 msec, p less than 0.02). No significant effect was observed on sinus cycle length, sinus node recovery time, intra-atrial or intraventricular conduction times, QRS duration (during both sinus rhythm and ventricular pacing), QT interval, HV interval, paced cycle length resulting in AV nodal Wenckebach block, AV nodal functional refractory period, retrograde ventriculoatrial (VA) effective refractory period, or atrial and ventricular refractory periods. These findings, in conjunction with the demonstrated ability of magnesium to block slow channels for sodium movement, may provide an explanation of the mechanism by which magnesium exerts its effect in the treatment of atrial and junctional arrhythmias.
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Affiliation(s)
- D L Kulick
- Department of Medicine, LAC-USC Medical Center 90033
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Zwerling HK. Does exogenous magnesium suppress myocardial irritability and tachyarrhythmias in the nondigitalized patient? Am Heart J 1987; 113:1046-53. [PMID: 3031970 DOI: 10.1016/0002-8703(87)90078-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Shattock MJ, Hearse DJ, Fry CH. The ionic basis of the anti-ischemic and anti-arrhythmic properties of magnesium in the heart. J Am Coll Nutr 1987; 6:27-33. [PMID: 3294971 DOI: 10.1080/07315724.1987.10720162] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The role of magnesium (Mg) in the prevention of ischemia-induced injury during cardioplegic arrest and in the treatment of cardiac arrhythmias has been considered. Although Mg possesses negative inotropic properties, potassium (K) is more effective than Mg in inducing cardiac arrest. The rationale for the inclusion of Mg in cardioplegic solutions therefore lies not in its cardioplegic properties, but in its ability to influence other cellular events such as the loss of Mg and K and perhaps to counter the detrimental effects of ischemia by antagonizing calcium (Ca) overload. Most of the Mg in the cardiac cell is complexed with high energy phosphate compounds and the loss of Mg during ischemia may restrict the repletion of ATP upon reperfusion and so impair the return of normal contractile function. The ability of Mg to limit K efflux from the cell is of importance not only in the prevention of ischemia-induced K loss but also in the treatment of digitalis-induced arrhythmias. Elevation of extracellular Mg has been shown to reduce the intracellular sodium ion activity ([Na]i) and this decline in [Na]i can be related to the negative inotropic properties of Mg. Mg may therefore exert some of its antiarrhythmic and antiischemic effects by limiting [Na]i-stimulated Ca influx (or facilitating Ca efflux) and hence preventing cellular Ca overload.
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Reisdorff EJ, Clark MR, Walters BL. Acute digitalis poisoning: the role of intravenous magnesium sulfate. J Emerg Med 1986; 4:463-9. [PMID: 3549866 DOI: 10.1016/0736-4679(86)90176-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Acute digitalis poisoning is a complex emergency with a reported mortality rate of 3% to 25%. In severe overdose, the sodium, potassium-adenosine triphosphatase system is severely inhibited, leading to cardiac dysrhythmias and an elevation of the serum potassium. Magnesium, a cofactor regulating this ion transport system, can successfully treat acute digitalis-induced rhythm disturbances and restore the transmembrane potassium gradient. This paper discusses the cellular mechanism involved in digitalis toxicity and reviews the literature concerning the use of magnesium in acute cardiac glycoside poisoning.
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French JH, Thomas RG, Siskind AP, Brodsky M, Iseri LT. Magnesium therapy in massive digoxin intoxication. Ann Emerg Med 1984; 13:562-6. [PMID: 6742564 DOI: 10.1016/s0196-0644(84)80534-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A potentially fatal case of massive digitalis intoxication is presented. Recurrent ventricular fibrillation failed to respond to lidocaine or phenytoin, but responded dramatically to magnesium sulfate infusion. A review of the literature and previous clinical studies, as well as the case reported here, appears to indicate that magnesium sulfate given intravenously in adequate quantities (2 to 3 g in one minute followed by 2 g/h for 4 to 5 h) is effective in controlling ventricular irritability caused by toxic levels of digitalis preparations.
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Smith TW, Antman EM, Friedman PL, Blatt CM, Marsh JD. Digitalis glycosides: mechanisms and manifestations of toxicity. Part III. Prog Cardiovasc Dis 1984; 27:21-56. [PMID: 6146162 DOI: 10.1016/0033-0620(84)90018-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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23
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Smith TW, Antman EM, Friedman PL, Blatt CM, Marsh JD. Digitalis glycosides: mechanisms and manifestations of toxicity. Part II. Prog Cardiovasc Dis 1984; 26:495-540. [PMID: 6326196 DOI: 10.1016/0033-0620(84)90014-8] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Smith TW, Antman EM, Friedman PL, Blatt CM, Marsh JD. Digitalis glycosides: mechanisms and manifestations of toxicity. Part I. Prog Cardiovasc Dis 1984; 26:413-58. [PMID: 6371896 DOI: 10.1016/0033-0620(84)90012-4] [Citation(s) in RCA: 94] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Wang L, Zhao HY. The effect of magnesium on erythrocytic electrolytes in digitalis toxicity. ACTA ACADEMIAE MEDICINAE WUHAN = WU-HAN I HSUEH YUAN HSUEH PAO 1983; 3:236-41. [PMID: 6316223 DOI: 10.1007/bf02856887] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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McCarty MF. Management of acute myocardial infarction with natural physiological agents. Med Hypotheses 1983; 11:449-65. [PMID: 6415374 DOI: 10.1016/0306-9877(83)90090-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A number of natural physiological agents deserve evaluation in the treatment of acute myocardial infarction. Prostacyclin and magnesium dilate large coronary arteries and could promote collateral circulation to ischemic regions, especially if used in conjunction with alpha-agonists to prevent a drop in coronary perfusion pressure. In addition, prostacyclin has anti-aggregatory and de-aggregatory effects on platelets and a stabilizing action on hypoxic tissue, while magnesium has anti-arrhythmic, potassium-retaining, and fibrinolytic effects, all of which could improve the outcome in acute MI. Adenosine or ribose infusion could be used to promote rapid repletion of adenine nucleotides in reperfused tissue, but unfortunately arteriolar vasodilation by adenosine might reduce collateral perfusion by "coronary steal". High-dose insulin has positive-inotropic (at minimal oxygen cost) and potent anti-arrhythmic actions that have not been adequately tested in previous clinical trials of "polarizing solutions". Carnitine infusion could improve the bioenergetics of ischemic myocardium by relieving inhibition of mitochondrial adenine nucleotide translocase.
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Abstract
Magnesium imbalance is clinically significant. It is common, treatable, and frequently overlooked. We review the literature describing magnesium deficit and excess syndromes and formulate specific treatment protocols.
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Opie LH. Reply. Am J Cardiol 1980. [DOI: 10.1016/0002-9149(80)90454-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Woods WT, Katholi RE, Urthaler F, James TN. Electrophysiological effects of magnesium on cells in the canine sinus node and false tendon. Circ Res 1979; 44:182-8. [PMID: 761301 DOI: 10.1161/01.res.44.2.182] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Kramer P. Digitalis pharmacokinetics and therapy with respect to impaired renal function. KLINISCHE WOCHENSCHRIFT 1977; 55:1-11. [PMID: 319291 DOI: 10.1007/bf01469777] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The various cardiac glycosides differ significantly in their retention as a result of renal failure. In the case of digoxin, digitoxin, and strophanthin the retention is directly related to the normal renal clearance of these cardiac glycosides: Strophanthin has the highest clearance and the most marked prolongation of pharmacological action in renal failure, whereas digitoxin shows the lowest renal clearance and even in uremic patients a total elimination comparable to normal subjects as a result of increased hepatic clearance; digoxin takes an intermediate position. The quantity of a cardiac glycoside and its metabolites excreted by the kidneys depends, besides the renal clearance, on the plasma concentration which increases considerably during the first days after onset of treatment. From the daily dose approximately 90% of strophanthin, 70% of digoxin, 50% of digitoxin plus metabolites are excreted by normal kidneys under steady-state conditions. The efficiency of hemodialysis in the elimination of cardiac glycosides is low (3-5%) if estimated in relation to a single dose injected before dialysis and high (30-50%) if estimated in relation to the excretory capacity of normal kidneys during a period corresponding to the duration of a dialysis. During hemodialysis the plasma concentration of digoxin decreases as rapidly as in patients with normal renal function. Beside the efficiency of dialysis this finding may be explained by the decrease in the apparent volume of distribution of cardiac glycosides in patients with advanced renal failure; a reduced tissue protein binding seems likely to be the main reason for these changes in chronic renal insufficiency. A reduced volume of distribution and a reduced myocardial sensitivity are the main reasons for a very low predictability of the necessary individual maintenance dose of cardiac glycosides from the creatinine clearance. In patients with advanced renal insufficiency the tolerance to cardiac glycosides is reduced with respect to the daily dose, but it is rather increased in relation to the plasma concentration required to maintain the positive inotropic effect. The combination of hyperkalemia, hypermagnesemia, bypocalcemia and acidosis which is found almost exclusively with chronic renal failure, may explain the reduced myocardial sensitivity. Dosage regimens based on the measurement of creatinine-clearance are of little help in "effective digitalisation". Serial measurements of steady-state plasma concentration of cardiac glycosides may be the only way to reduce the risk of under- and overtreatment in patients with impaired renal function.
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Abstract
Serum magnesium estimation was done in 19 children who had heart failure of varied etiology. Five of nine toxic patients and three of 10 nontoxic ones had magnesium deficiency (serum magnesium less than 1.5 mEq. per liter). Mean serum magnesium level was significantly lowered (P less than 0.01) in 19 children and it was further lowered in nine toxic patients (P less than 0.001) as well as in eight hypomagnesemic patients (P less than 0.001) than in healthy control subjects. Mean serum digoxin level in toxic patients was significantly higher than in nontoxic ones (P less than 0.05). In three cases magnesium sulfate was successfully used for the management of cardiac arrhythmias.
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Specter MJ, Schweizer E, Goldman RH. Studies on magnesium's mechanism of action in digitalis-induced arrhythmias. Circulation 1975; 52:1001-5. [PMID: 1182944 DOI: 10.1161/01.cir.52.6.1001] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The mechanism by which magnesium affects digitalis-induced arrhythmias was studied in dogs with and without beta-receptor blockade. Digoxin was infused at a rate of 2.5mug/kg/min until ventricular tachycardia developed, then half the animals were given MgSO4, the other half saline. In animals given MgSO4, sinus rhythm was immediately re-established; in animals given saline, ventricular tachycardia persisted. In animals with beta-receptor blockade, MgSO4 was as effective in abolishing ventricular tachycardia as in those without beta-receptor blockade. We found no evidence that magnesium re-activated digoxin-inhibited (Na+, K+)-ATPase, altered myocardial or microsomal digoxin binding, or acted via the autonomic nervous system. Magnesium's direct effect on calcium and potassium fluxes across the myocardial cell membrane may be the mechanism of its antiarrhythmic action in digitalis-toxic arrhythmias.
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36
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Abstract
Magnesium deficiency can occur in congestive heart failure, after diuresis with furoxemide, ethacrynic acid and mercurials, and with digitalis intoxication, diabetic acidosis, acute and chronic alcoholism, delerium tremens, cirrhosis, malabsorption syndromes, protracted postoperative cases, open heart surgery, the diuretic phase of acute tubular necrosis, and with hypoparathyroidism, primary aldosteronism, juxta-glomerular hyperplasia and pancreatitis. Two cases of serious ventricular arrhythmias associated with magnesium depletion are described. Clinical manifestations are vague but center around neurologic symptoms such as weakness, tremors, stupor, coma, nausea, vomiting and anorexia. Serious cardiac arrhythmias also occur with magnesium depletion. Magnesium appears to be very useful in hypomagnesemic or digitalis-toxic tachyarrhythmias. Magnesium may also be valuable in normomagnesemic tachyarrhythmias. Ten to fifteen milliliters of a 20 percent magnesium sulfate solution, given intravenously over 1 minute, followed by a slow 4 to 6 hour infusion of 500 ml of 2 per cent magnesium sulfate in 5 per cent dextrose in water is recommended. Recurrence of arrhythmias is common and a second infusion of magnesium sulfate may be necessary. Hypermagnesemia occurs frequently in renal insufficiency, and magnesium therapy may then be contraindicated. Serum levels above 5.5 meq/liter should be avoided. Loss of deep tendon reflexes and a decrease in respiratory rate can be used as guides to magnesium therapy. A plea is made for frequent analysis of serum magnesium so that more knowledge can be gained regarding this important biologic element in cardiovascular disorders.
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37
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Abstract
Triamterene, amiloride, ethacrynic acid, and furosemide were studied to determine whether they modified the digitalis-induced egress of myocardial potassium which is thought to facilitate the development of digitalis arrhythmias. In a control group of 15 dogs, potassium was measured in samples obtained simultaneously from the femoral artery (FA) and the coronary sinus (CS) in a control period and at intervals after the administration of 1 mg. of acetylstrophanthidin. Acetylstrophanthidin caused a significant increase in cardiac A-V difference in the potassium concentration (CS-FA) averaging 0.47 mEq. per liter. In a group of 10 dogs, when 175 mg. of triamterene was infused prior to the acetylstrophanthidin, the rise in A-V differnece was abolished and the arrhythmias often aborted. In contrast, the infusion of potent diuretics (40 mg. of furosemide in five dogs and 100 mg. of ethacrynic acid in another five dogs) prior to acetylstrophanthidin, caused a doubling of the maximal A-V potassium difference. This study suggests that the clinical administration of antikaliuretic drugs may prevent the arrhythmias of digitalis toxicity not only by reducing kaliuresis and subsequent hypokalemia, but by a myocardial effect which antagonized the digitalis-induced loss of myocardial potassium. Contrariwise, potent diuretics may facilitate digitalis arrhythmias through a myocardial action causing a greater egress of myocardial potassium, thus explaining the development of arrhythmias despite normal serum potassium levels. These potent diuretics should be used cautiously, especially when given intravenously to patients receiving digitalis.
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38
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Worthley LI. Lithium toxicity and refractory cardiac arrhythmia treated with intravenous magnesium. Anaesth Intensive Care 1974; 2:357-60. [PMID: 4447250 DOI: 10.1177/0310057x7400200411] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
A case of refractory cardiac arrhythmia induced by lithium and controlled by intravenous magnesium sulphate is described The mechanism of action of the magnesium in controlling the arrhythmia is discussed.
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39
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Ghani MF, Smith JR. The effectiveness of magnesium chloride in the treatment of ventricular tachyarrhythmias due to digitalis intoxication. Am Heart J 1974; 88:621-6. [PMID: 4419576 DOI: 10.1016/0002-8703(74)90248-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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40
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41
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42
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Ferrier GR, Moe GK. Effect of calcium on acetylstrophanthidin-induced transient depolarizations in canine Purkinje tissue. Circ Res 1973; 33:508-15. [PMID: 4752852 DOI: 10.1161/01.res.33.5.508] [Citation(s) in RCA: 124] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The role of calcium ions (Ca
2+
) in the generation of transient depolarizations (TDs) by acetylstrophanthidin was examined. Transmembrane activity was recorded from isolated canine false tendons exposed to acetylstrophanthidin; concentrations from 7.5 x 10
-8
to 2 x 10
-7
g/ml caused TDs coupled to driven action potentials and depressed slow diastolic depolarization. TDs could reach threshold and induce extrasystoles. Elevation of the Ca
2+
concentration increased the amplitude of TDs induced by acetylstrophanthidin. High Ca
2+
concentration (12.5 mM) caused TDs and depression of slow diastolic depolarization in the absence of acetylstrophanthidin. Elevation of potassium (K
+
) concentration depressed and reduction of K
+
concentration potentiated TDs caused by either acetylstrophanthidin or high Ca
2+
concentration. The production of TDs and the depression of slow diastolic depolarization by acetylstrophanthidin were reversed by reduction of the Ca
2+
concentration or addition of manganese (2 mM) to the superfusing Tyrode's solution. The results suggest that TDs and arrhythmias produced by acetylstrophanthidin may be caused by a transient Ca
2+
influx.
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43
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Abstract
The pharmacokinetics of acetyl strophanthidin (AS) were studied in dogs and human subjects by the use of a newly developed radioimmunoassay. This method has a sensitivity of 0.1 ng of AS per ml and is applicable to direct measurement of AS in unextracted plasma, urine, or bile. After administration of a single intravenous (i.v.) dose of 1.0 mg of AS to 17-25-kg mongrel dogs, the principal exponential decline of plasma AS concentration began 20-60 min after the injection and had a mean half-life (T
½
) of 83 ± 19 min (
sd
). Mean total urinary excretion of AS was 13.3 ± 4.8% of the i.v. dose and occurred with a mean T
½
of 79 ± 10 min. Biliary excretion of AS accounted for only 1.5-2.1% of the i.v. dose. After i.v. administration of 1.0 mg of AS to seven human subjects, the principal exponential decline of plasma AS concentration began 10-30 min after the infusion and had a mean T
½
of 2.3 ± 0.2 hours. Urinary excretion of AS, studied in two patients, accounted for an average of 21.8% of the i.v. dose and occurred with a mean T
½
of 2.4 hours. Thus the plasma level T
½
of AS in human subjects is about tenfold shorter than the 22-hour T
½
previously observed for the relatively short-acting cardiac glycoside ouabain, in agreement with the known brief duration of pharmacologic effects of acetyl strophanthidin.
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