Figure 2.

Example of a normal PW-TDI spectral curve: note the immediate representation of the mechanical events in the various phases of the cardiac cycle. It is possible to measure time intervals using the traces of the ECG and/or the phonocardiogram as reference (see the panel below). Sm = positive wave of systolic contraction; Em = negative early diastolic wave; Am = negative end-diastolic wave; IVCT = isovolumetric contraction time or precontraction; IVRT = isovolumetric relaxation time.