Effect of Sodium Intake

[Gunter]

About three years ago a I started having occasional symptoms of atrial fibrillation. The cardiologist put me on Lanoxin and Aspirin. I continued to have events, however, where, on the outside of my chest, it felt like two mice were having a wrestling match. As is generally recommended, I was on a very low salt diet. During an extended trip, where I could not adhere to the low salt regimen, these events did not occur. Subsequently I increased my salt intake and I have had no further events as described above. My fibrillations have turned chronic, but I still get a lower pulse rate and less turbulent activities by the heart with a high salt intake. I also recall the media reporting on a paper published about two years ago which indicated that patients with a higher salt intake had fewer heart attacks. Unfortunately I did not catch the exact reference.

1.) Can the increase in sodium intake assist the digoxin, which inhibits the ATPase enzyme to increase the intracellular concentration of sodium and thereby increases the intracellular concentration of calcium?

2.) Does the apparent beneficial effect of increased sodium give any clues concerning the treatment options for my fibrillations: Tambacor did not work at all, Betapace seemed to restore sinus rythm for a week or so, Procainamide restored Sinus rythm initially, then failed, then worked for a few days on a second attempt, but then failed again.

3.) Somebody mentioned that Procaidamine has different short term and long term chemical interaction with the heart. Is this a fact and does this possibly tie in with the above observations?

Thanks for the help!

[Cleveland Clinic, MD]

A thoughtful and insightful question.  However, the dietary intake of sodium (salt) does not play a role in the cellular mechanisms of these drugs.  Plasma and cellular sodium is very tightly regulated by the adrenal-renal system and must be within a very narrow range to be compatable with life.  Dietary intake of sodium is important in reducing blood pressure and is related to water retention rather than plasma levels.  Hope this helps clarify things.  Remember afib is a chronic condition and not everyone can be maintained in sinus rhythm although that is the goal.  There are many different drugs and sometimes it is a matter of trial and error to find the right one.  Good luck.

[Gunter]

Thanks for your comments Dr. CRC. Do you have any hypothesis why increased sodium intake reduces my AF symptoms? Any comments on the short term and long term chemistry and effects of Procaidamine?

Thanks!

[Cleveland Clinic, MD]

????? why the sodium decreases the AF symptoms.  As long as your blood pressure is OK it is probably alright to continue.  Procainamide is a good drug but is not tolerated by many people due to nausea and the potential for lupus-like side effects.