A new study published in the American Journal of Medicine shows that for patients with the most common arrhythmia (irregular heartbeat), atrial fibrillation (A-fib), trying to convert the heartbeat to regularity gives poorer clinical outcomes than merely controlling the heart rate.
A group of researchers based in multiple medical centers in the U.S. and Europe, led by Dr. Nasir Shariff of the University of Pittsburgh, undertook the task of determining whether the higher-risk procedures and medications involved in attempting to convert A-fib to normal sinus rhythm was worth it, as compared to administering medications to control the heart rate. Normal rate is in the 55-80 beats per minute range. Patients with A-fib can develop irregular rates that can be either dangerously fast, or slow, either of which compromise cardiac output and lead to disabling symptoms. The procedure of administering medications and DC-electroshock cardioversion has been relied upon by cardiologists most commonly to get the patient back into a regular rhythm and rate. But these procedures and medications can take a toll, and the reversion to normal beat is often temporary.
Medications to keep the heart rate within acceptable limits, on the other hand, are much less risky, and their effects can be easily monitored. So the researchers studied 2,248 patients with A-fib who were between 70 and 80 years of age, and divided them into two almost-equal groups: one rate control, the other rhythm control. In a case-control study, it was found that (over a 3.4 year course) the rate-control group had a 23 percent better all-cause death rate, and a 24 percent less hospitalization rate.
The authors summarized their findings thusly: ...until further evidence emerges, older adults with atrial fibrillation may be best served by traditional rate-control rather than rhythm-control strategies.
ACSH s Dr. Gilbert Ross added this: The data here seem fairly conclusive. Of course, in the ideal situation, normal sinus rhythm is best, since the ineffective flutterings of the atria the small upper heart chambers promote the development of small blood clots, which can embolize to the major arteries, especially the cerebral vessels. Strokes are the result, and to reduce that risk, patients with A-fib must stay on anti-coagulants blood thinners indefinitely, with their attendant risks. Still, the complexity and risks of converting older patients to normal rhythm is not worth it, according to this well-designed study.