3.Pharmacological action (1)decrease myocardiac oxygen consumption dilate venous decrease blood returning to heart decrease ventricular end-diastolic volume and pressure (large dose)dilate arterial decrease peripheral resistance decrease afterload *(2)increase blood supply to ischemia area3. Pharmacological action (1) decrease (1) decrease myocardiac myocardiac oxygen consumption consumption dilate venous decrease blood returning dilate venous decrease blood returning to heart decrease ventricular end to heart decrease ventricular end -diastolic diastolic volume and pressure volume and pressure (large dose) dilate arterial decrease (large dose) dilate arterial decrease peripheral resistance decrease peripheral resistance decrease afterload afterload (2) increase blood supply to ischemia (2) increase blood supply to ischemia area