Tim - My response to you about magnesium and dehydration was incomplete. (Sorry)…. I should have also mentioned the importance of magnesium's action in the sodium/potassium ion pump mechanism and the essential function of potassium in relation to sodium in the body... important for everyone but especially critical for afibbers. Without magnesium, those pumps can’t function and the critical balance of potassium to sodium is the bottom line for afibbers.
Spend time reviewing at least the introduction to Conference Room Session 72 [
www.afibbers.org] – posted below for convenience. The discussion that follows at that link also provides invaluable information on this topic and serves to help us understand the critical need for afibbers to have the proper intake as well as reserves of these essential electrolytes. This all fits together; it can't be any other way.
Jackie
Proceedings of 72nd Session
February 7, 2011 – June 11, 2011
SUBJECT: Potassium/Sodium Ratio in Atrial Fibrillation
Sodium and potassium! Biophysicist Richard D. Moore explains:
"For purely physical reasons (connected with the law of osmotic equilibrium), inside the cell the sum of sodium and potassium must be constant. This means that... sodium and potassium are unalterably linked together like two children on a teeter totter. You can’t change one without changing the other.
"Thus, in the perspective of biophysics, it makes no sense to talk about either sodium or potassium alone - these two substances always affect each other in a reciprocal relation. Hence their ratio... reflects the state of the living cell more completely than either sodium or potassium alone... It is not only a simplifying concept, but a much more scientifically valid measure of the state of health of the living cell.
"Reflecting the action in the cell, potassium and sodium always work in a reciprocal manner in the whole body... This means that increased consumption of potassium will drive sodium out of the body through the kidneys. Thus, potassium has been called "nature’s diuretic"... This is an example of the fact that elevation of sodium inside our body cells must always be accompanied by a decrease in the potassium level." [1, 11]
From the article Paleolithic Nutrition Revisited: A twelve-year retrospective on its nature and implications: [2]
"The nutritional needs of today's humans arose through a multimillion year evolutionary process during nearly all of which genetic change reflected the life circumstances of our ancestral species. But, since the appearance of agriculture 10,000 years ago and especially since the Industrial Revolution, genetic adaptation has been unable to keep pace with cultural progress. Natural selection has produced only minor alterations during the past 10,000 years, so we remain nearly identical to our late Paleolithic ancestors and, accordingly, their nutritional pattern has continuing relevance. The pre-agricultural diet might be considered a possible paradigm or standard for contemporary human nutrition."
Sodium (Na) and potassium (K) are critical nutrients, but today’s typical diet might supply 5 times the amount of Na, and only 1/4th the amount of K that we evolved with. In our evolutionary past the kidneys became configured to optimize the body's cellular Na and K levels by conserving the sodium available and by discarding excessive potassium. Our kidneys have essentially not changed since then, but the typical diet is now upside down, with disease-causing consequences for all cells and systems.
Our bodies are 'The Body Electric'.[3] Each of the body's cells is like a battery (10, 20 trillion?), charged to their functional voltage by the enzyme Na/K-ATPase, commonly called 'Na/K pump', or 'sodium pump'. "Depending on cell type, there are between 800,000 and 30 million [Na/K] pumps on the surface of cells. They may be distributed fairly evenly, or clustered in certain membrane domains, as in the basolateral membranes of polarized epithelial cells in kidney and intestine".[4]
Na/K pumps span the cell membrane, and generate the electrical voltage (potential) to charge the cell/battery by continuously pumping ~3 Na+ ions out of the cell in exchange for ~2 K+ ions pumped in.[5, 6] In cardiac muscle a 'trans-membrane potential' of about 90 millivolts (mV) is generated (negative inside), which provides for the cell's electrical requirements: voltage-gated ion channels, calcium pumps, etc. To attain this functional voltage requires the intracellular K/Na ratio to be at least 20 to 1 [7], which in turn requires the dietary K/Na ratio to be at least 4 to 1.[1] The kidneys ideally maintain serum K and Na at the levels they were evolved to maintain, but the high intracellular K/Na ratio can not be attained if intracellular Na is too high (as Dr. Moore explains, above).
Na/K pumps are proteins, synthesized within the cells, each consisting of many hundreds of the 20 different amino acids in chain-like linkage, assembled in accordance with nuclear DNA codes, then folded and configured for their specific function. Code errors (genetic or by damage) or lack of required amino acids (genetic or dietary) can result in dysfunctional Na/K pumps (channelopathies) possibly resulting in low cell voltage. Having sufficient cellular amino acids available for protein synthesis is essential.[9] There are excellent computer-generated images of the Na/K pump protein structure at the Protein Data Base website.[5]
Na/K pumps are powered by the energy molecule adenosine-triphosphate (ATP), which for function requires an attached magnesium ion (Mg-ATP). ATP is synthesized from oxygen and food molecules in a process requiring Coenzyme Q10, carnitine, magnesium, ribose, phosphate, and many co-factors. In body cells the continuous pumping of K and Na consumes about 25% of the ATP produced, while in high energy-demand heart, brain, and neurons the consumption is as much as 70%.[4] Therefore, if ATP and magnesium are deficient, and if the intracellular ratio of K to Na is low, the cells' voltage will be low. Low cell voltage may express as abnormalities in cells and systems throughout, as in blood pressure, kidney function, electrically excitable tissues of the heart and brain.
In heart muscle cells the resting membrane potential (phase 4 of the cardiac cycle)[8] is the voltage of the cell while resting before being excited to de-polarize (discharge) and contract. Low resting voltage can trigger AF, and can be an explanation for the cyclical nature of paroxysmal AF. From the web page Cardiac Action Potential: [10]
"Phase 0 is the rapid depolarization phase. The slope of phase 0 represents the maximum rate of depolarization of the cell and is known as dV/dt max. This phase is due to the opening of the fast Na+ channels causing a rapid increase in the membrane conductance to Na+ (GNa) and thus a rapid influx of Na+ ions (INa) into the cell - a Na+ current. The ability of the cell to open the fast Na+ channels during phase 0 is related to the membrane potential at the moment of excitation. If the membrane potential is at its baseline (about -85 mV), all the fast Na+ channels are closed, and excitation will open them all, causing a large influx of Na+ ions. If, however, the membrane potential is less negative [lower voltage], some of the fast Na+ channels will be in an inactivated state, insensitive to opening, thus causing a lesser response to excitation of the cell membrane and a lower Vmax. For this reason, if the resting membrane potential becomes too positive [lower voltage], the cell may not be excitable, and conduction through the heart may be delayed, increasing the risk for arrhythmias."
This means that a slower depolarization (discharging) of the atrial muscle cells' voltage results in shortening of phase 2 of the action potential and the cells’ refractory period (the time period during which cells are at zero volts and can’t be excited), which increases the risk for AF.
Therefore, if atrial cell voltage is generally low, for reasons above, NSR might be on a proverbial razor's edge. If voltage drops just a bit lower AF might result, especially if there are other predisposing conditions, such as fibrosis [12] or electrical remodeling. AF induced release of sodium-lowering hormones such as ANP and BNP results in increasing the intracellular K/Na ratio, thus the cells' voltage, and NSR might return. In this case all body cells will have higher voltage, and one's body-mind might well experience well-being until the next cycle, as all cells and functions will have benefited by having higher voltage.
Erling
References
1. Richard D. Moore, MD, PhD. The High Blood Pressure Solution (2001)
2. Paleolithic nutrition revisited: A twelve-year retrospective on its nature and implications [
www.nature.com]
-- Herb Boynton, Mark F. McCarty, Richard D. Moore. The Salt Solution (2001)
-- Paleolithic Diet [
en.wikipedia.org]
-- Paleolithic diet v. standard diet potassium/sodium ratios
[
www.afibbers.org]
3. Robert Becker, Gary Selden. The Body Electric: Electromagnetism and the Foundation of Life (1998)
4. The Na/K-ATPase (Sodium Pump) [
www.vivo.colostate.edu]
5. Na/K pump [
www.pdb.org]
-- Na/K pump structure [
www.pdb.org]
6. Na/K pump animation
[
www.brookscole.com]
p.html
7. Burton B. Silver, PhD. For K/Na ratio see [
www.afibbers.org]
8. Understanding the cardiac cycle [
www.afibbers.org]
9. Eric R. Braverman, MD, The Healing Nutrients Within (2003)
10. Cardiac action potential [
en.wikipedia.org]
11. The Strategy – Metabolic Cardiology [
www.afibbers.org]
12. K. Shivakumar, MD [
www.afibbers.org]