Effects of Diltiazem and Nitroglycerin on Left Ventricular Diastolic Properties in Patients with Coronary Artery Disease

Abstract

To determine the effects of diltiazem (DTZ) and nitroglycerin (NTG) on left ventricular (LV) diastolic relaxation and filling in patients with coronary artery disease (CADpts), LV graphy and time constant (Tc) of LV isovolumic pressure decay were studied before and 5min after intravenous DTZ (10mg) in 16 CADpts and sublingual NTG (0.3mg) in 11 CADpts. Diastolic regional ventricular filling dynamics were quantitated by segmental areatime curves during early-, mid- and late-filling periods. After NTG, LV systolic pressure (LVSP), end-diastolic pressure (EDP) and end-diastolic volume (EDV) decreased. Early-filling rate (EFR) decreased (165±82 to 122±61ml/sec/m²) due to a decrease in the regional early-filling rate in the normokinetic area and late-filling rate (LFR) increased (95±38 to 145±45ml/sec/m²), while LV peak positive dp/dt, peak LVSP/end-systolic volume (ESV) ratio, Tc and mid-filling rate (MFR) were unchanged. After DTZ, LVSP decreased and EDV increased. EFR increased. EFR increased (127±54 to 166±60ml/sec/m²) due to an enhanced regional early-filling rate in the mildly hypokinetic area, while EDP, LV peak positive dp/dt, peak LVSP/ESV ratio, Tc, MFR and LFR were unchanged. From these results, it was postulated that NTG caused a decrease in LV early filling and an increase in LV late filling, probably due to LV preload reduction. In contrast, DTZ caused significant improvement of LV early filling particularly in the mild hypokinetic area. Thus, DTZ but not NTG was able to relieve local myocardial dysfunction secondary to a stenosed coronary artery during the fillingperiod, resulting in clinical improvement in CADpts.