So I was listening to the Medscape Family Medicine Podcast on my way to work and there was a three part episode on atrial fibrillation. The guest was talking about treatment and she said that if the patient is symptomatic, then she would consider rhythm control. she also said that she would try an convert almost anyone at least once because rhythm control gives the patient a better quality of life. Rhythm control can be use for younger patients without co morbid conditions. I felt like that was different than what I had had previously learned. It decide to use my new iPhone app "AFP by topic" and read all the articles on treatment for AFIB. Ill discuss anti-coagulation next time.
Rate control is preferred for patients who are asymptomatic or mildly symptomatic "AFIBers". It improves diastolic filling, coronary perfusion, and decreases myocardial energy demands. So for rate control, we have beta blockers, calcium channel blockers (diltiazem and verapamil) and digoxin. The calcium channel blockers are contraindicated in patients with structural disease. As a side note, these two calcium channel blockersdo have an effect in the glomerulus, similar to ACEI's and ARB's in patients with CKD. Digoxin is not preferred because it is not effective for rate control during exercise. It can have a synergistic effect when used in conjugation with beta blockers.
It is true that rhythm control should be tried at least once because the patient could cardiovert and stay in sinus rhythm for several years without needing medications. This may also be considered if the patient is young, first time AFIBers. The four main antiarrhythmic drugs are dronadarone, flecanide, propafenone and sotolol. Those patients with structural heart disease my need a different therapy [2].I failed to mention amiodarone. This medication is the strongest antiarrhythmic, but there are many bad side effects (lung damage, liver damage, and pulmonary toxicity), thus it is not considered a first line medication for rhythm control. There have been studies that recommend amiodarone in patients with low injection fraction.
There have been several studies comparing rate vs. rhythm in atrial fibrillation. The PIAF (2000) study compared therapy with symptoms (palpitations, dyspnea, and dizziness) and showed no difference between the two therapies. It also showed better exercise tolerance and mor frequent need for hospitalization in the rhythm group. The more hospitalizations were do to the more frequent need to recardiovert patients. The PIAF QOL (2003) study showed no difference in quality of life in either group.
The STAF (2003) study compared the to therapies against "primary endpoint" (The primary endpoint was the combination of death, cardiopulmonary resuscitation, cerebrovascular event, and systemic embolism). Again there was no difference.
The RACE (2002) study compared the two therapies against a primary endpoint of a "composite of death from cardiovascular causes, heart failure, thromboembolic complications, bleeding, implantation of a pacemaker, and severe adverse drug effects [3]". Again there was no difference.
The AFFIRM (2002) trial which again showed "no clinical advantage for rhythm control over rate control". It did however, show that amiodarone was the most effective antiarrhythmic drug. Also, the study reinforced the importance of anticoagulation.
SO what does all this mean? Rate control is safer and cheaper. If you put a gun to my head, then I would treat with rate control measures. But it is really a case by case process, especially in those who are highly symptomatic.
1.Am Fam Physician. 2002 Jul 15;66(2):249-257
2.Can J Cardiol. 2011 May-Jun;27(3):388.
3.Pharmacologic Management of Atrial Fibrillation: Where Do We Currently Stand? , by John Camm, MD
Medscape Cardiology, 2005-02-28
No comments:
Post a Comment