[Heart frequency control in chronic and paroxysmal atrial fibrillation. Critical evaluation of traditional therapy concepts].

BACKGROUND

The loss of the "atrial kick" associated with atrial fibrillation results in a diminished cardiac output. With normal atrial pressures, this latter may decrease initially by 20 to 30%, and an increase in the ventricular rate fails to achieve full compensation, while the irregular rhythm may be felt as bothersome palpitations.

RELEVANT STUDIES: The results of all the studies investigating the role of ventricular rate control are inconsistent and contradictory. Despite its widespread use, the value of digitalis remains controversial. Although it is the drug of choice in atrial fibrillation associated with congestive heart failure, it is unsuitable for ventricular rate control during physical effort. Nor is there any solid evidence in favour of its prophylactic use after cardiac surgery; indeed, in paroxysmal atrial fibrillation, it may even prolong attacks and aggravate symptoms. Generally applicable optimal control of the ventricular rate at rest or during effort does not exist, but the latter needs to be higher in atrial fibrillation than in sinus rhythm.

CONCLUSION

Patients symptoms are the most important guide for the need of rate control in atrial fibrillation. This can be achieved by beta-blockers, calcium antagonists and digitalis but often without objective improvement in exercise capacity. In the individual case it should be determined early on whether cardioversion is possible and sinus rhythm can be preserved over the long term.