Instantaneous rates of left ventricular wall motion in infants and children - Computer-assisted determination from single-cycle echocardiograms

To assess their usefulness as indexes of left ventricular (LV) function, peak rates of decrease and increase in LV diameter were determined from single-cycle echocardiograms in 136 infants and children using a digitizer linked to a computer. The subjects included 62 normal children, 15 patients with congestive cardiomyopathy (CCM), 29 with aortic stenosis (AS), and 30 with patent ductus arteriosus (PDA). The results were compared with the conventional echocardiographic measurements of fractional change in LV diameter (percent ΔLVD) and mean velocity of circumferential fiber shortening (Vcf). The peak shortening rate (PSR) was directly related to LV diameter (r=0.7; standard error of the estimate [SEE], 17.4 mm/sec, p<0.001). Peak Vcf was directly related to heart rate (r=0.48, SEE 0.48 circumferences per second [circ/sec], p<0.001) and ranged from 0.87 to 3.57 circ/sec. Peak Vcf was decreased in CCM (p<0.001) and was normal in AS and PDA. The peak relaxation rate (PRR) was not significantly correlated with diastolic diameter or heart rate. It was decreased in CCM (p<0.001) and normal in AS and PDA. All patients with CCM had decreased percentages of ΔLVD and eight of ten had decreased mean Vcf. The single-cycle peak rates of shortening and relaxation of the LV wall are influenced by heart rate and LV diameter. We did not find them superior to conventional echographic indexes in distinguishing normals from patients with CCM, AS, or PDA.