关键词: 超声心动图, 动力型左室腔流出梗阻, R指数

Abstract:

Objective: To summarize the echocardigraphic characteristics of dynamic intraventricular obstruction (DIVO) of the left ventricle by traditional echocardiography at rest and to design a new index(R index,V_IVR/V_E) according to its characteristics,and to explore the value of R index in quantitative evaluation on DIVO. Methods: One hundred and twelve patients with DIVO were chosen as obstruction group. All patients had chest pain or dyspnea.A total of 50 healthy volunteers were used as healthy control group.The left ventricular end-systolic diameter (LVESD),left ventricular end-diastolic diameter(LVEDD),upper interventricular septum thickness (U-IVS),middle interventricular septum thickness (M-IVS) and left ventricular ejection fraction(LVEF) were obtained by two-dimensional echocardiogram.The maximal systolic velocities and gradients at the left ventricular outflow tract (LVOT),mid-ventricle and the apex of left ventricle were obtained at rest in all patients using color Doppler ultrasound.The myocardial movement and the flow of left ventricle were observed at different aspects.Then the velocity of E wave,the narrowest inner diameter,the systolic velocity,the velocity of isovolumic relaxation (VIVR) and R index of the narrowest part were obtained.The receiver operating characteristic (ROC) curve was builded and the area under curve(AUC) was calculated.An index about confirmed the diagnosis of R index point was obtained.Moreover,the specificity and sensitivity of R index for the diagnosis of DIVO of the left ventricle at rest was explored. Results: The heart rate of patients with DIVO in obstruction group was faster than that in healthy control group and the blood pressure was higher than that in healthy control group (P<0.01).The 2D echocardigraphic characteristics of the DIVO patients showed that the myocardial movement of left ventricle was enhanced.The left ventricle diameter of the DIVO patients in obstruction group was smaller than that in healthy control group,and the shape of the left ventricle was irregular.As for Doppler,the normal flow velocity gradient in the left ventricular of the patients with DIVO was changed.A Doppler spectrum with peak value moving forward was found in obstruction group,and a IVR wave was seen,and the velocity of IVR wave was faster than healthy control group(P<0.01) and the R index was enlarged obviously(P<0.01). Conclusion: The R index of DIVO patients enlarges significantly,and R index ≥1 is the specific diagnosis indicator of the DIVO patients at rest.

Key words: echocardiography, dynamic intraventricular obstruction, R index