The influence of elevated Mg2+ concentrations on cardiac electrophysiologic parameters

Cardiovascular Drugs and Therapy
G StarkH A Tritthart

Abstract

This study was performed to evaluate the direct effects of magnesium ions on cardiac conduction velocities and on refractoriness using a modified Langendorff perfusion system and a special ECG recording and stimulation technique. An increase of the MG2+ concentration to 2.3 mM had no detectable effects. Higher concentrations of up to 4.6 mM decreased the spontaneous sinus rate and the conduction velocity through the AV node and the His bundle in a concentration-dependent manner. During stimulation with premature beats, in the presence of 4.6 mM of Mg2+, the effective and relative refractory periods (ERP, RRP) of sinoatrial, AV nodal, and His bundle conduction and the ERP of the ventricular myocardium were significantly prolonged, whereas the ERP of the atrial myocardium remained unaffected. The refractoriness of sinoatrial, AV nodal, and His bundle conduction, and of the ventricular myocardium, were also prolonged during pacing with a stepwise increased pacing rate. These observations suggest a marked rate-dependent inhibitory effect of magnesium on the refractoriness of the His-bundle conduction and of the ventricular myocardium, which might be an important factor in the antiarrhythmic effectiveness of magnesium in ventricular...Continue Reading

References

Nov 14, 1977·Biochimica Et Biophysica Acta·L M Hondeghem, B G Katzung
May 1, 1978·Journal of Molecular and Cellular Cardiology·J Dunnett, W G Nayler
Nov 1, 1977·American Heart Journal·M F Ghani, M Rabah
Jun 1, 1986·Journal of the American College of Cardiology·L A DiCarloT M Annesley
Jul 1, 1985·Journal of the American College of Cardiology·F MoradyR B Krol
Oct 1, 1985·American Heart Journal·L T IseriM A Brodsky
Dec 1, 1974·Circulation·K A CollinsworthD C Harrison
Jan 1, 1972·Cardiovascular Research·Y Watanabe, L S Dreifus
Dec 1, 1980·The American Journal of Cardiology·P D Henry
Jan 1, 1982·Reviews of Physiology, Biochemistry and Pharmacology·P Honerjäger
May 1, 1983·The Journal of General Physiology·B P BeanR W Tsien
Jul 1, 1984·American Heart Journal·L T Iseri, J H French
Feb 1, 1984·The American Journal of Cardiology·D TzivoniS Stern

❮ Previous
Next ❯

Citations

Oct 31, 2006·Medical Hypotheses·Ba X HoangStephen A Levine
Apr 9, 2013·Autonomic Neuroscience : Basic & Clinical·Fumiaki KomakiMikiyasu Shirai
Aug 1, 1994·Annals of Emergency Medicine·J A KlineR M Raymond

❮ Previous
Next ❯

Related Concepts

Related Feeds

Arrhythmia

Arrhythmias are abnormalities in heart rhythms, which can be either too fast or too slow. They can result from abnormalities of the initiation of an impulse or impulse conduction or a combination of both. Here is the latest research on arrhythmias.

Cardiac Conduction System

The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Discover the latest research on the cardiac conduction system here.

Anti-Arrhythmic Drug Therapies

Anti-arrhythmic drugs are used to prevent abnormal heart rhythms. These medications are used in conditions including, ventricular tachycardia, ventricular fibrillation and atrial fibrillation. Discover the latest research on anti-arrhythmic drug therapies here.

Cardiac Electrophysiology

Cardiac electrophysiology is the study of electrical activities of the heart and includes the assessment, diagnosis, and treatment of cardiac events. Find the latest research on cardiac electrophysiology here.

Antiarrhythmic Agents: Mechanisms of Action

Understanding the mechanism of action of antiarrhythmic agents is essential in developing new medications as treatment of cardiac arrhythmias is currently limited by the reduced availability of safe and effective drugs. Discover the latest research on Antiarrhythmic Agents: Mechanism of Action here.