Atrial fibrillation, a condition affecting three million to six million Americans, is caused by irregular contractions of the heart and results in an increased risk of stroke and death. Over the past two decades, cardiologists have increasingly treated it with a procedure called catheter ablation, in which small plastic catheters are used to create scars in the damaged heart tissue to prevent the aberrant electrical signals from spreading. Many have touted catheter ablation, which can cost well above $20,000, as a “cure” for atrial fibrillation.

Yet a new randomized controlled trial, the gold standard of clinical research, has produced disappointing results. The study, called the Cabana trial, found that the procedure was no more effective than much cheaper medications at reducing mortality, cardiac arrest, major bleeding and stroke.

These results come on the back of another prominent trial published last year, which showed that stents used to relieve blockages in patients with stable chest pain provided no benefit over medications.

In the furor over the Cabana results, which have been presented at a scientific conference but not yet published, many have argued that the underlying data suggests that catheter ablation does help some people. But a different kind of study will be needed to confirm that. The fact is that years after catheter ablation hit the market, we shouldn’t have this many questions about it.