Although impaired ventricular function has been shown to improve after aortic valve replacement, there are few data on hemodynamic changes after balloon aortic valvuloplasty based on follow-up catheterization. Of 71 patients surviving 6 months after balloon aortic valvuloplasty, 41 agreed to late recatheterization. All patients had pre- and postvalvuloplasty and 6 month catheterization data measured with high fidelity micromanometer pressure recordings and simultaneous digital subtraction left ventriculography. The hemodynamic result immediately after valvuloplasty included a reduction in the aortic valve gradient and a moderate increase in aortic valve area (0.51 ± 0.14 to 0.81 ± 0.19 cm2, p < 0.0001). Ejection fraction increased slightly (52 ± 18 to 55 ± 17%, p < 0.0001) despite a decrease in peak positive rate of rise of left ventricular pressure (dP/dt 1,650 ± 460 to 1,500 ± 490 mm Hg/s, p < 0.05). There was also a decrease in left ventricular afterload and a small decrease in preload. At 6 month recatheterization, the mean aortic valve gradient and area were similar to baseline values, with 31 (76%) of 41 patients demonstrating valvular restenosis. At 6 months many left ventricular hemodynamic variables, including peak positive dP/dt and stroke work, also resembled prevalvuloplasty values. However, left ventricular end-diastolic volume was reduced (111 ± 40 ml at 6 months versus 136 ± 52 ml before valvuloplasty, p < 0.01). The mean left ventricular ejection fraction was unchanged from prevalvuloplasty values in the study group of 41 patients, but was significantly improved in 9 of 15 patients with a baseline ejection fraction <50%. Thus, recatheterization at 6 months demonstrates left ventricular remodeling and a modest improvement in ventricular performance, with the left ventricle being less dilated while maintaining stroke work and cardiac output. These changes occur despite a high incidence of valve restenosis, indicating that balloon aortic valvuloplasty should be reserved for patients unable to tolerate surgical valve replacement. © 1990.