RESUMO
The objectives of this study were to assess whether 2-dimensional strain (2DS) can detect left ventricular (LV) segmental dysfunction and to compare the diagnostic accuracy of various 2DS parameters. Multiple segmental longitudinal 2DS parameters were measured in 54 patients with a first myocardial infarction and single vessel coronary artery disease (age: 56 ± 11 years, 74% men, LV ejection fraction: 47 ± 10%, left anterior descending artery occlusion in 63%) and 14 age-matched subjects. 2DS parameters were compared to visual assessment of segmental function by multiple observers. Using receiver-operating characteristics analysis, the area under the curve (AUC) for peak systolic strain in diagnosing segmental dysfunction (akinetic or hypokinetic LV segments) and for diagnosing akinetic segments was 0.85 (95% confidence interval 0.83-0.88) and 0.88 (0.85-0.90), respectively (all P values < 0.001). Other 2DS strain parameters had similar (peak strain, peak strain rate) or lower (post-systolic shortening, time-to-peak strain, diastolic 2DS parameters) AUC values. An absolute value of peak systolic strain <16.8% (25th percentile in normal subjects) had high sensitivity (0.89) and negative predictive values (0.88), but low specificity (0.55) and positive predictive values (0.59) for diagnosing segmental dysfunction. Similar findings were observed using a cutoff of <13.3% (absolute value of 10th percentile) for diagnosing akinetic segments. Diagnostic accuracy was significantly worse for segments in which visual segmental assessment was discordant between observers. In conclusion, 2DS can be used to diagnose segmental LV dysfunction with high sensitivity but limited specificity. The diagnostic limitation of 2DS is partially related to the visual echocardiographic definition of segmental abnormality.
