An apparatus for assessing cardiovascular status of a mammal comprises a system for locally applying a pressure to an artery capable of restricting blood flow through said artery, a wideband external pulse transducer having an output and situated to measure suprasystolic signals proximate to said artery, and a computing device receiving said output for calculating vascular compliance values. The method described is particularly useful for determining cardiac output, assessing whether a pregnant female has preeclampsia or a patient has cardiac insufficiency, or assessing cardiac arrhythmia.