Observations from cardiac catheterization suggest that coronary artery cross-sectional area (CSA) is increased in patients with left ventricular (LV) hypertrophy and is proportional to LV mass. This hypothesis was tested using computer-based quantitative analysis of LV mass and CSA from angiographic images of the left ventricle and proximal coronary arteries from 19 men and 21 women, aged 23 to 78 years (mean 56). Twenty-seven patients had valvular heart disease, 16 of whom had multivalvular involvement; diagnoses included aortic stenosis in 19, aortic regurgitation in 13 and mitral regurgitation in 12. Thirteen patients had normal valvular and ventricular function. All patients had normal coronary arteries. Significant differences between normal patients and those with valvular disease were noted in LV mass (88 +/- 7 vs 165 +/- 12 g/m2, p less than 0.001) and coronary CSA (26 +/- 2 vs 46 +/- 3 mm2, p less than 0.001). Furthermore, a linear relation between LV mass and coronary CSA was noted (r = 0.788, p less than 0.001). Thus, proximal coronary artery CSA is significantly larger in valvular heart disease patients with LV hypertrophy than in those with normal ventricles, and proximal coronary artery area increases in proportion to LV mass in hypertrophied ventricles.