Short-term statin therapy and cardiac function and symptoms in patients with idiopathic dilated cardiomyopathy.

and Symptoms in Patients With Idiopathic Dilated Cardiomyopathy To the Editor: With great interest we read the article by Node et al1 concerning short-term statin therapy in patients with idiopathic dilated cardiomyopathy (IDC). The demonstrated improvement of left ventricular ejection fraction (LVEF) by simvastatin therapy is intriguing. The authors speculated on several possible mechanisms, including a decrease in plasma cytokines and neurohormones. Although this may certainly have played a role, we think that another potential mechanism should have been discussed. We hypothesize that improvement of LVEF by simvastatin in the present study might be caused by the beneficial effects on myocardial blood flow (MBF) reserve. In healthy subjects with hypercholesterolemia, statin treatment improves MBF reserve, as measured by positron emission tomography.2 In patients with IDC, MBF reserve is impaired in proportion to the severity of heart failure.3,4 Therefore, it is very likely that a decrease of cholesterol levels in patients with IDC will also lead to an improvement of MBF reserve. Whether such an improvement in MBF reserve in patients with IDC automatically translates into an increase in LVEF may be disputed. Nevertheless, recent work from our institution using positron emission tomography has demonstrated that regional impairment of MBF reserve is associated with decreases in contractile reserve and LVEF.4 The observed improvement in LVEF in the study by Node et al1 may well have been caused by improvement of MBF reserve leading to increased LVEF.