scholarly journals Rescuing cardiac automaticity in L-type Cav1.3 channelopathies and beyond

2016 ◽  
Vol 594 (20) ◽  
pp. 5869-5879 ◽  
Author(s):  
Pietro Mesirca ◽  
Isabelle Bidaud ◽  
Matteo E. Mangoni
Keyword(s):  
Cardiac Automaticity

Intoxication by large amounts of barium nitrate overcome by early massive K supplementation and oral administration of magnesium sulphate

2010 ◽  
Vol 30 (1) ◽  
pp. 34-37 ◽  
Author(s):  
Christine Payen ◽  
Arnaud Dellinger ◽  
Corine Pulce ◽  
Vincent Cirimele ◽  
Vincent Carbonnel ◽  
...  
Keyword(s):  
Magnesium Sulphate ◽  
Laboratory Data ◽  
Muscular Activity ◽  
Acute Poisoning ◽  
Barium Nitrate ◽  
Uneventful Recovery ◽  
Compound A ◽  
Adverse Health Effects ◽  
Ventricular Premature Complexes ◽  
Cardiac Automaticity

Suicide by ingestion of barium is exceptionally rare. Adverse health effects depend on the solubility of the barium compound. Severe hypokalemia, which generally occurs within 2 hours after ingestion, is the predominating feature of acute barium toxicity, subsequently leading to adverse effects on muscular activity and cardiac automaticity. We report one case of acute poisoning with barium nitrate, a soluble barium compound. A 75-year-old woman was hospitalized after suicidal ingestion of a burrow mole fumigant containing 12.375 g of barium nitrate. About 1 hour post-ingestion, she was only complaining of abdominal pain. The ECG recording demonstrated polymorphic ventricular premature complexes (VPCs). Laboratory data revealed profound hypokalemia (2.1 mmol/L). She made a complete and uneventful recovery after early and massive potassium supplementation combined with oral magnesium sulphate to prevent barium nitrate absorption.

Abstract 247: Dose-dependent Role of Inwardly Rectifying Potassium Current on Cardiac Automaticity of Human Embryonic Stem Cell-derived Cardiomyocytes

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Jidong Fu ◽  
Adrienne Dennis
Keyword(s):  
Action Potential ◽  
Potassium Current ◽  
Human Embryonic Stem Cell ◽  
Embryonic Stem ◽  
Ventricular Cells ◽  
Fire Action Potential ◽  
Cardiac Automaticity ◽  
Inwardly Rectifying ◽  
Dose Dependent

The inwardly rectifying potassium current (IK1), encode by Kir2 family, is responsible for maintaining the negative resting potential, and contributes to phase 3 repolarization of the cardiac action potential. IK1 was generally thought to suppress cardiac automaticity, while the suppression of IK1 in adult ventricular cardiomyocytes (CMs) could engineer bio-artificial pacemaker-like cells to spontaneously fire action potential. Our studies also showed that overexpressed the gene of Kir2.1 could facilitate the electrophysiological maturing of mouse and human embryonic stem cell-differentiated CMs (ESC-CMs), which have the high degree of automaticity with nearly 50% of cells that can spontaneously fire action potential. In this study, we extensively analyzed the electrophysiology of mouse and human ESC-CMs, and found that the maximum diastolic potential in spontaneously firing ESC-CMs, -72.1±1.3 mV in atrial cells and -75.0±2.1 mV in ventricular cells, were significantly more hyperpolarized than that in quiescent ESC-CMs (-64.4±2.1 mV in atrial cells and -67.1±3.2 mV in ventricular cells). Applying a small amount of IK1 to hyperpolarize the membrane potential could enable those quiescent ESC-CMs to spontaneously fire action potential, indicating the enhancement of cardiac automaticity, while a large amount of IK1 could quiet those spontaneously firing cells down. By combining computational and experimental analyses, we confirmed that the synergistic interaction of IK1 and pacemaker current (If) could efficiently regulate cardiac automaticity during the differentiation. Our studies disclosed a dose-dependent role of IK1 on cardiac automaticity that a small amount of IK1 enhances and a large amount of IK1 suppresses cardiac automaticity in ESC-CMs during differentiation.

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