Heart Failure Drug May Not Ease Symptoms in Some
In the diastolic form, the left ventricle doesn't relax enough between contractions, which means it cannot fill up with as much blood as it should. But the heart's ejection fraction is actually normal.
Diastolic heart failure is trickier to diagnose, and doctors know less about how to best treat it, said Dr. John Cleland, a cardiologist at Hull York Medical School in Kingston-upon-Hull, England, who co-wrote an editorial published with the study.
He agreed that it's too soon to draw conclusions from the current findings, and that doctors will know more when Shah's study results are in.
"I think the public should wait for TOPCAT," Cleland said, referring to the acronym Shah's trial goes by.
For the current study, researchers led by Dr. Burkert Pieske, of the Medical University Graz, in Austria, recruited 422 patients diagnosed with diastolic heart failure. They randomly assigned half to add spironolactone to their current treatment, while the rest received inactive placebo pills.
Over one year, the drug did lower patients' blood pressure and improve their heart function. Based on echocardiograms, there was less thickening and resistance in the left ventricle.
But the patients did not report any improvements in their symptoms or quality of life. Nor did they perform any better on a treadmill walking test.
Cleland said it's not surprising that the patients would not be feeling better despite the objective improvement in heart function. That's been seen with other drugs, he noted.
Pieske said that the reasons are not fully clear. It's possible that the drug dose was not high enough, he said. Or the changes in heart function that his team saw may just not translate into benefits such as better walking ability.
On top of that, the patients in this study were actually fairly healthy, Shah and Cleland pointed out. So they may not have been sick enough to expect symptoms or walking ability to get noticeably better.
Shah and Cleland both suspect that many study patients may have had diastolic "dysfunction" in their hearts -- but were not sick enough to really have diastolic heart failure.