Negative inotropes improve LV obstruction by decreasing LV ejection acceleration and hydrodynamic forces on the mitral valve. Disopyramide's particular efficacy is due to its potent negative inotropic effects; in head-to-head comparison, it is more effective for gradient reduction than either beta-blocker or verapamil. Disopyramide is most often administered with beta-blockade. When used in patients resistant to beta-blockade, disopyramide is effective in 60% of cases, reducing symptoms and gradient to the extent that invasive procedures such as surgical septal myectomy are not required.