What is Lenient Rate Control in AF?

Lenient rate control in atrial fibrillation

The debate on rate vs rhythm control in atrial fibrillation is still on, though the evidence was more in favour of rate control, mainly because of adverse effects of rhythm control agents. If ablation is the method of rhythm control, that may be better, though more taxing. There is also a question on lenient vs strict rate control in atrial fibrillation. By lenient rate control, what is aimed at is to maintain the resting heart rate below 110 beats/minute whereas in strict rate control the target is below 80 beats/minute. We are aware that higher rates would increase the chance for tachycardiomyopathy.

A study published earlier in the New England Journal of Medicine by the RACE II Investigators had compared these two strategies [1]. A composite of cardiovascular death, heart failure hospitalization, stroke, bleeding, systemic embolic episodes and life threatening arrhythmic events was the primary outcome measure. The follow up period was between two to three years. The primary composite outcome was lower in the lenient control group with a P<0.001 for non-inferiority between the two strategies. The symptomatic status and frequency of adverse events were similar in the two groups. The authors of the study concluded that lenient rate control is as good as strict rate control in permanent atrial fibrillation and an easier target to achieve.

Reference

1. Isabelle C Van Gelder, Hessel F Groenveld, Harry J G M Crijns, Ype S Tuininga, Jan G P Tijssen, A Marco Alings, Hans L Hillege, Johanna A Bergsma-Kadijk, Jan H Cornel, Otto Kamp, Raymond Tukkie, Hans A Bosker, Dirk J Van Veldhuisen, Maarten P Van den Berg, RACE II Investigators. Lenient versus strict rate control in patients with atrial fibrillation. N Engl J Med. 2010 Apr 15;362(15):1363-73.