P854Reference values for automatic measurements of tissue doppler indices

Abstract

Background: Tissue Doppler imaging is widely used to quantify global left ventricular (LV) longitudinal function. We have developed an algorithm that automatically measures the mitral annular peak velocities in systole (S'), early diastole (e') and late diastole (a'). This algorithm can be implemented on most available echocardiographic scanners, and also future handheld scanners. Automatic measurements and interpretation of findings can speed up work flow for cardiologists and assist inexperienced users when evaluating LV function. Normal reference values of automatic measurements are needed. Purpose: To estimate age- and gender-specific reference values of the automatic measurements. Methods: The study population included 1032 Caucasian volunteers (53% females, mean age (standard deviation (SD)) 49 (14) years), all free from cardiovascular disease, hypertension and diabetes. An experienced cardiologist examined all patients conventionally using a high-end scanner. Apical four-chamber color tissue Doppler recordings were analyzed manually and by the automatic algorithm, and then compared. All measurements were calculated as the average of septal and lateral measurements from three cardiac cycles. Results: Normal reference ranges (mean (SD)) are presented by gender and age in Table 1. Figure 1 shows automatic and manual measurements according to age. There was no significant interaction effect between gender and age on any of the automatic indices (all p≥0.21). There were highly significant differences by age. S' and e' were lower, and a' higher, with higher age (all p≤0.001). Conclusion: Age influenced all indices considerably. The agreement between automatic and manual measurements is comparable to what has been shown in interobserver studies, which suggests that the automatic measurements could assist both experienced and inexperienced users.