Cholesterol drugs may improve abnormal heart rhythm
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A study of a class of commonly used cholesterol-lowering drugs, called statins, used by patients with enlarged hearts (dilated cardiomyopathy) shows that these patients had significant reductions in mortality, which was due in large measure to an anti-arrhythmic effect.
Investigators with the multicenter Defibrillators in Nonischemic Cardiomyopathy Treatment Evaluation (DEFINITE) trial evaluated the survival benefit and effect of statin therapy on sudden cardiac death in 458 patients with cardiomyopathy. Of the total, 229 patients were randomly selected to receive an implantable cardioverter defibrillator to correct their abnormal heart rhythm. These devices are programed to detect these abnormalities, and to then deliver a shock to restore normal heart rhythm.
Overall, 110 patients were taking a statin, while 348 were not. Statins include drugs such as Lipitor, Pravachol and Zocor.
Patients on statin therapy had a 78-percent reduction in mortality rates, Dr. Jeffrey J. Goldberger of Northwestern University in Chicago, reported at the Heart Rhythm Society’s 27th Annual Scientific Sessions in Boston.
After the subjects were monitored for almost 2,000 days, the researchers found that the patients who received a defibrillator and who were on statin therapy were 39-percent less likely to die than the other patients.
There was only 1 sudden death from arrhythmia among the patients who were receiving statins, compared with 18 patients who were not on statins.
Among the patients with defibrillators, those who were on statin therapy were less likely to require a shock to correct an abnormal heartbeat compared with patients who were not on statin therapy.
“It is fairly unlikely that statins’ benefits are due to their cholesterol-lowering effects,” Goldberger said in an interview with Reuters Health. “These patients did not have coronary artery disease, where the cholesterol-lowering effects are the greatest.”
He noted that survival curves for patients on a statin versus who were not on a statin “started to separate almost immediately—another indication that the effects were not from cholesterol-lowering.” he noted.
The benefits of statins may be due to anti-inflammatory effects, antioxidant effects or effects on the nervous system, he speculated. “To be honest, we don’t know how the effects of statins are mediated. This was not the design of the trial.”
Goldberger pointed out that all statins and all doses used were “lumped together” in the DEFINITE analysis.
Further studies of the anti-arrhythmic effects of statins are needed, “and we are talking about that,” the Chicago researcher said. In new trials, we need to evaluate patients with normal cholesterol to minimize the cholesterol-lowering effects of the drugs.
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