Cardioprotective effect of an L/N-type calcium channel blocker in patients with hypertensive heart disease

SummaryBackgroundLeft ventricular (LV) diastolic dysfunction is related to increased cardiac sympathetic activity. We investigated the effect of cilnidipine, an L/N-type calcium channel blocker, on LV diastolic function and cardiac sympathetic activity in patients with hypertensive heart disease (HHD) using radionuclide myocardial imaging.Methods and resultsThirty-two frame electrocardiography (ECG) -gated 99mTc-sestamibi (MIBI) myocardial single photon emission computed tomography (SPECT), and 123I-metaiodobenzylguanidine (MIBG) imaging were performed before and 6 months after drug administration in 32 outpatients with HHD. Sixteen of the patients were treated with cilnidipine and the other 16 were treated with nifedipine retard. The parameters for assessing LV diastolic function evaluated using ECG-gated 99mTc-MIBI SPECT were peak filling rate (PFR), first-third filling rate (1/3FR), and time to peak filling (TPF). Cardiac sympathetic activity was assessed as early and delayed heart to mediastinum (H/M) ratios and a washout rate (WR), using 123I-MIBG imaging. The PFR and 1/3FR significantly increased after 6 months of treatment with cilnidipine (p < 0.05 for both), but did not with nifedipine retard. The H/M ratios significantly increased (p < 0.05 for both) in conjunction with a decreased WR (p < 0.05) in the cilnidipine group. Moreover, a significant positive correlation was seen between the rate of change in PFR and the rate of change in early and delayed H/M ratios in the cilnidipine group (p < 0.05 for both). The same results were obtained for the relationship between the rate of change in 1/3FR and the rate of change in H/M ratios (p < 0.05 for both). However, no such relationship was seen in the nifedipine group.ConclusionThese data indicate that cilnidipine seems to suppress cardiac sympathetic overactivity via blockade of N-type calcium channels and improves LV diastolic function in patients with HHD.