Figure 4. Effect of afterload reduction on septal curvature. Short-axis MR images on which curvature was evaluated before (left) and after (right) administration of 10 mg of nifedipine. Images were acquired at the exact same anatomic location, both 425 msec after R wave triggering. Note difference in shape of interventricular septum. Heart rate was not affected by the drug. Pulse sequence: steady-state free precession, flip angle of 50°, acquisition matrix of 153 x 256 pixels, field of view of 270 x 340 mm, section thickness of 5 mm, 3.2/1.6.