Digitalis has been used to aid in the diagnosis of heart failure. Patients in failure often have a clinical response to digitalis within a few days. The reason for the failure may not be elucidated, but the diagnosis is supported. Do ACE inhibitors produce a similar quick response? If so, how long does it take?
—EUGENE GUAZZO, MD, Chaptico, Md.

I’m not sure I can totally agree with Dr. Guazzo’s premise about testing a heart failure (HF) diagnosis with digitalis. First of all, the response to digitalis preparations in HF is predicated on the heart failure’s being systolic in nature (i.e., reduced left ventricular [LV] ejection fraction), usually with concomitant cardiac dilation (Circulation. 2004;109:2942-2946). Patients with diastolic dysfunction and normal-sized hearts do not respond as well to this drug. The “quick response” Dr.Guazzo notes also depends on the time course of the digitalization loading dose and whether diuretics are also being given. Today, ACE inhibitors (plus diuretics) are the first-line drugs for treatment of systolic LV dysfunction, with digitalis added if necessary. Responses are often noted after only a few days of treatment.
—Peter F. Cohn, MD (118-8)