Hans Larsen

Researchers at the Johns Hopkins University School of Medicine have just released a major study aimed at determining the effectiveness of heart drugs in converting atrial fibrillation to sinus rhythm and in maintaining sinus rhythm in AF patients. They looked at the results of 36 major clinical trials and reached the conclusion that ibutilide/dofetilide and flecainide (Tambocor) are the most effective drugs when it comes to converting AF to sinus rhythm. Ibutilide/dofetilide was 29 times more effective than placebo and flecainide 25 times more effective. Verapamil, diltiazem (Cardizem) and digoxin (Lanoxin) were all found to be essentially useless; that is, no better than placebo. So while these drugs may be helpful in slowing the heartbeat, they are ineffective in converting it to normal sinus rhythm. Propafenone (Rythmol) and quinidine (Biquin) were much less effective and sotalol (Sotacor, Betapace) actually had a negative effect. None of the drugs evaluated were particularly effective in maintaining sinus rhythm; that is, preventing another attack. Quinidine, disopyramide (Rythmodan), flecainide, propafenone, and sotalol all showed some positive effect while verapamil, diltiazem and digoxin had no beneficial effects. The researchers point out that all the drugs tested can have serious side effects and there have been reports of increased mortality with flecainide.[1]

Considering that LAF is a disorder of the autonomic nervous system it is not really surprising that heart drugs won’t cure it although they may temporarily suppress the overt symptom of fibrillation.

Researchers at the University of Michigan Medical Center have recently confirmed that not only is digoxin (Lanoxin) useless in the treatment of LAF, but it may actually worsen the condition. They conclude that digoxin might promote atrial fibrillation not only in patients with the vagal type, but among all atrial fibrillation patients.[2]

So if you have LONE atrial fibrillation and are taking digoxin ask your doctor to help you discontinue it.

Professor Philippe Coumel of the Hopital Lariboisiere in Paris, France was the first electrophysiologist to propose that LAF is a disorder of the autonomic nervous system. Dr. Coumel suggested that there are two forms of LAF – an adrenergic form and a vagal form.

LAF of the adrenergic variety occurs exclusively during daytime and is often preceded by exercise or emotional stress. Frequent urination (every 20 minutes or so) often occurs during the early phase of an attack. This type of LAF can also be a symptom of hyperthyroidism or pheochromocytoma.

LAF of the vagal origin is often observed in athletes and people with digestive problems and is most common among men aged 40 to 50 years. The commonest feature is that of weekly episodes, lasting from a few minutes to several hours. The essential feature is the occurrence of attacks at night, often ending in the morning. Rest, digestive periods (particularly after dinner), and alcohol consumption are also predisposing factors. Exercise or emotional stress does not trigger the arrhythmia. On the contrary, on feeling the sensation of an oncoming episode (repeated atrial premature beats), many patients have observed that they can prevent an attack by exercising, but the relaxation period that follows an effort or an emotional stress frequently coincides with the onset of vagal LAF.

The means of preventing reoccurrence of the two forms are quite different. While beta-blockers like atenolol (Tenormin) and propranolol (Inderal) may be quite effective in preventing adrenergic type attacks they, as well as digoxin, will worsen the vagal form.[2,3,4,5]

It has been known for some time that diet can influence the autonomic nervous system in diabetics. Some very recent research has found that the effects of diet on the nervous system may also be quite profound in normal, healthy people. In other words, relatively poor glycemic control can lead to a dysfunction of the autonomic nervous system. Could such a dysfunction in turn lead to an attack of LAF? We shall explore this and other fascinating links between autonomic system dysfunction and LAF in the next issue of the The Afib Report. Stay tuned!

References

1. Miller, Marlene, et al. Efficacy of agents for pharmacologic conversion of atrial fibrillation and subsequent maintenance of sinus rhythm – a meta-analysis of clinical trials. The Journal of Family Practice, Vol. 49, November 2000, pp. 1033-46 [59 references]
2. Sticherling, Christian, et al. Effects of digoxin on acute, atrial fibrillation – induced changes in atrial refractoriness. Circulation, Vol. 102, November 14, 2000, pp. 2503-08
3. Coumel, Philippe. Paroxysmal atrial fibrillation: a disorder of autonomic tone? European Heart Journal, Vol. 15 Suppl A, April 1994, pp. 9-16
4. Hohnloser, SH, et al. Atrial fibrillation and the autonomic nervous system. Z Kardiol, Vol. 83, Suppl 5, 1994, pp. 21- 7
5. Prystowsky, Eric N. Management of patients with atrial fibrillation - a statement for healthcare professionals from the subcommittee on electrocardiography and electrophysiology, American Heart Association. Circulation, Vol. 93, March 15, 1996, pp. 1262-77 [155 references]

ATRIAL FIBRILLATION

It is estimated that about 700,000 new cases of lone (paroxysmal) atrial fibrillation (LAF) are diagnosed every year in the United States alone. LAF is a very frustrating disorder – although not life-threatening it is debilitating and can really play havoc with your life – and the medical profession has no cure for it.

E.A. Butler, the author of Atrial Fibrillation: My Heart, The Doctors and Me, is well acquainted with the treadmill of fruitless visits to GPs, cardiologists, and electrophysiologists. He has personally experienced the frustration of trying one powerful heart drug after another only to find that they did not help and, in some cases, made things worse. Mr. Butler is a retired management consultant and columnist for the Chicago Tribune and his writing is eloquent and easy to follow. Besides relating his own experience with LAF the author also clearly presents the results of his impressive research into the various drug and surgery options and the role of stress, diet and lifestyle in the development and progression of LAF. He concludes that “afibbers" must take charge of their own health if they are to get better and provides a wealth of information and advice to make their task easier. The author has now reduced his frequency of LAF attacks from as many as three a week to just two a year through a program of stress reduction, exercise, appropriate diet, and supplements in combination with a beta-blocker and the heart drug flecainide. His book does not provide the ultimate solution to the LAF puzzle, but it certainly is an excellent starting point for the journey to full recovery. A MUST READ for anyone diagnosed with lone atrial fibrillation. You can order Atrial Fibrillation: My Heart, The Doctors and Me at our website www.afibbers.org.