ACCURACY OF THE IMPEDANCE CARDIOGRAM IN THE MEASUREMENT OF CARDIAC OUTPUT IN THE ELDERLY

: The cardiac output has been determined by radionuclide angiocardiography and by impedance cardiography in 93 elderly patients. The agreement between the two methods was excellent in patients in sinus rhythm, without regurgitant valvular lesions, and without severe airways obstruction or right bundle branch block. In atrial fibrillation the lack of correlation may be due to differences in heart rate during the two measurements, in regurgitant valvular lesions to the fact that impedance cardiography measures stroke output, whether forward or backward, in airways obstruction to high values for the basal thoracic impedance, and in right bundle branch block perhaps to the abnormal impedance wave-form often present.