Diltiazem is a calcium channel blocker whose effects on left ventricular function (LVF) are controversial. We studied 12 patients with ischemic heart disease (IHD) before starting and 15 and 30 days after having initiated Diltiazem 60 mg t.i.d. LVF was accessed by means of the normalized indexes of the calibrated apexcardiogram: nS for systolic LVF evaluation and nA for diastolic LVF evaluation. Recent works have shown that these indexes have a good correlation with invasive parameters of LVF. We verified that nS did not change and nA decreased significantly (p < 0.05) after Diltiazem. We preliminary concluded that Diltiazem has no deleterious effect on LV systolic function and improves LV diastolic function, by decreasing nA, a parameter which correlates well with LV end diastolic pressure.