[Accuracy and clinical applicability of the echocardiographic automated endocardial boundary detection system: correlation and bias analysis]. / Precisión y aplicabilidad clínica del sistema ecocardiográfico de detección automática de bordes endocárdicos: análisis de correlación y de sesgo.

INTRODUCTION AND OBJECTIVES: Automated edge detection of endocardial borders is a new echo system that permits on-line delineation and tracking of blood-tissue interface and offers promise for measuring cyclic changes in cavity area and the assessment of left ventricular function on-line. Its accuracy has only been analyzed by linear regression and its applicability in unselected patients is not clearly established. METHODS: We analyzed the accuracy and clinical applicability of the system in 150 patients. Its accuracy was assessed not only by linear regression but also by bias analysis by comparing the results of the system with those obtained by manual tracing from parasternal short-axis and apical 4 chamber views. RESULTS: We obtained satisfactory studies with this system in at least one of the two echo views in 66% of patients: 47% from 4-chambers view, 43% from parasternal short-axis view and 24.6% from both echo views. A visual semiquantitative assessment of left ventricular function could be performed in 88.6% of patients (p < 0.001). On-line and hand-traced left ventricular areas there well correlated, but fractional area change values from both methods correlated less closely. 95% limits of agreement between both methods were: 2.8 +/- 5.5 cm2 (end-diastolic area), 1 +/- 4.4 cm2 (end-systolic area) and 1.2 +/- 23% (fractional area change) in short-axis parasternal view; in apical 4-chambers view these limits were: 1.16 +/- 6.4 cm2,--1.1 +/- 6 cm2 and 7.3 +/- 16%, respectively. CONCLUSIONS: Although the correlations between left ventricular areas from both methods were close the limits of agreement exceeded our acceptable range of reproducibility. Fractional area change showed only moderate correlations and a lack of agreement with off-line method. Poor image quality of the conventional echo still limits the clinical applicability of the current automated edge detection system.

[The progression of a postinfarct interventricular communication: an echocardiographic follow-up]. / Progresión de una comunicación interventricular postinfarto: seguimiento ecocardiográfico.

An 80-year-old female patient presented rupture of the interventricular septum as complication of acute anteroseptal myocardial infarction. Serial echocardiographic studies documented progressive increase in size of the apical defect over 16 hours. This observation highlights a potential hazard if surgical repair is deferred to "stabilize" hemodynamically the patient before the intervention.

Right ventricular systolic time intervals determined by means of a pulmonary artery catheter.

OBJECTIVES: To evaluate the right ventricular systolic time interval as an index of right ventricular function and also to ascertain whether the right ventricular ejection fraction may be determined by means of a conventional pulmonary artery catheter. DESIGN: Prospective study. SETTING: Intensive care unit. PATIENTS: Eight, consecutive critically ill adult patients. METHODS: Simultaneous blind measurements, performed by two investigators, of the right ventricular systolic time interval and right ventricular ejection fraction, determined by means of a pulmonary artery catheter. Two studies, separated by an interval of 24 hrs, per patient. Linear regression analysis. Multiple regression test. RESULTS: Of the 16 studies performed, two determinations of right ventricular systolic time intervals were technically inadequate. In the remaining 14 valid studies, we found one close linear correlation between the right ventricular ejection fraction and the preejection period/ejection time quotient measured using the simultaneous display of the electrocardiogram (EKG) and pulmonary arterial pressure curve (r2 = .90, p < .001, right ventricular ejection fraction = 68.96-60.59 x [right ventricular preejection period/right ventricular ejection time]). The method proved to be simple, very accurate, with little interobserver variation (8.09 +/- 10.6% interobserver variation for right ventricular preejection period/right ventricular ejection time) and provided adequate information regarding situations in which the performance of the right ventricle is modified in a given patient. The right ventricular preejection period/right ventricular ejection time quotient was the only variable that displayed a significant relationship with the right ventricular ejection fraction in the multivariate analysis (p < .001). CONCLUSIONS: Right ventricular systolic time intervals, measured using the simultaneous display of the pulmonary artery catheter curve and EKG, provide adequate information regarding right ventricle performance in critically ill patients. The close linear correlation between the right ventricular preejection period/right ventricular ejection time quotient and the right ventricular ejection fraction enables the investigator to estimate, with a high degree of accuracy, the right ventricular ejection fraction and the values derived from the preload of the right ventricle, without the need for a modified pulmonary artery catheter.