To determine if symptoms and electrocardiographic abnormalities relate to left ventricular mass, volume, and mass/volume ratio in children with aortic stenosis and/or insufficiency, we examined 42 patients (aged 11±6 years) with cross-sectional and Doppler echocardiography. Clinical symptoms included exertional chest pain, shortness of breath, exercise intolerance, congestive heart failure and syncope. Electrocardiographic abnormalities were defined as the presence of both left ventricular hypertrophy and ST-T wave changes. Left ventricular volumes and mass were measured from echocardiograms using paired orthogonal apical views and biplane Simpson's and truncated ellipsoid models, respectively. The peak and mean pressure gradients across the aortic valve, the aortic valvar area, and the degree of aortic insufficiency were determined using echo/Doppler techniques. Eighteen patients (ages 10±7 years) had pure aortic stenosis (peak gradient 52±29 mm Hg, mean gradient 28±18 mm Hg, and valve area 0.86±.46 cm2/m2). Of these 18, seven had symptoms and seven had an abnormal electrocardiogram. Twenty-four patients (aged 12±6 years) had aortic stenosis and aortic insufficiency (peak gradient 36±18 mm Hg, mean gradient 19±9 mm Hg, 18 with 1−2+ aortic insufficiency and six with 3−4+ aortic insufficiency). Of these 24, 10 had symptoms and 10 had an abnormal electrocardiogram. When symptomatic and asymptomatic patients were compared using an unpaired Student's t-test, symptomatic patients with pure aortic stenosis and combined aortic stenosis and insufficiency had left ventricular hypertrophy and inappropriately increased mass/volume ratios. However, due to differences in left ventricular volume, symptoms and electrocardiographic abnormalities occurred at a higher mass/ volume ratio in pure aortic stenosis (2.7±0.6) than in combined aortic stenosis and insufficiency (1.7±0.3).