Home About us Contact
|
Home About us Contact | ||
|
|
||
Segment Model (segment + model)
Selected AbstractsRisk Stratification and Prognosis in Octogenarians Undergoing Stress Echocardiographic StudyECHOCARDIOGRAPHY, Issue 8 2007F. A. C. C., Farooq A. Chaudhry M.D. Background: The prognostic value of stress echocardiography (SE) for the diagnosis and risk stratification of coronary artery disease in octogenarians is not well defined. Methods: Follow-up of 5 years (mean 2.9 ± 1.0 years) for confirmed nonfatal myocardial infarction (n = 17) and cardiac death (n = 37) was obtained in 335 patients, age ,80 years (mean age 84 ± 3 years, 44% male), undergoing SE (33% treadmill, 67% dobutamine). Left ventricular (LV) regional wall motion was assessed by a consensus of two echocardiographers and scored as per standard five-point scale, 16-segment model of wall motion analysis. Ischemic LV wall segment was defined as deterioration in the thickening and excursion during stress (increase in wall-motion score index (WMSI) ,1). Results: By univariate analysis, inducible ischemia (chi-square = 38.4, P < 0.001), left ventricular ejection fraction (chi-square = 41.2, P < 0.001), a history of previous myocardial infarction (chi-square = 22.3, P < 0.01), hypertension (chi-square = 33, P < 0.01), and age (chi-square = 27.7, P < 0.01) were significant predictors of future cardiac events. WMSI, an index of inducible ischemia, provided incremental prognostic information when forced into a multivariable model where clinical and rest echocardiography variables were entered first. WMSI effectively stratified octogenarians into low- and high-risk groups (annualized event rates of 1.2 versus 5.8%/year, P < 0.001). Conclusions: Stress echocardiography yields incremental prognostic information in octogenarians and effectively stratifies them into low- and high-risk groups. Precise therapeutic decision making in very elderly patients should incorporate combined clinical and stress echocardiography data. [source] Visual Quantitative Estimation: Semiquantitative Wall Motion Scoring and Determination of Ejection FractionECHOCARDIOGRAPHY, Issue 5 2003M.D., Steven J. Lavine Ejection fraction (EF) is the most commonly used parameter of left ventricular (LV) systolic function and can be assessed by echocardiography. Quantitative echocardiography is time consuming and is as accurate as visual estimation, which has significant variability. We hypothesized that each echocardiographer has developed a mental set of guidelines that relate to how much individual segment shortening constitutes normal function or hypokinesis of varying extents. We determined the accuracy of applying these guidelines to an accepted technique of EF determination using a retrospective analysis of consecutive two-dimensional echocardiographic studies performed on patients who had radioventriculography (RVG) within 48 hours. Using a 12 segment model, we scored each segment at the base and mid-ventricular level based on segmental excursion and thickening. The apex was scored similarly but with 1/3 of the value based on a cylinder-cone model. EF was determined from the sum of segment scores and was estimated visually. We termed this approach visual quantitative estimation (VQE). We correlated the EF derived from VQE and visual estimation with RVG EF. In the training set, VQE demonstrated a strong correlation with RVG(r = 0.969), which was significantly greater than visual estimation(r = 0.896, P < 0.01). The limits of agreement for VQE (+12% to ,7%) were similar to the limits of RVG agreement with contrast ventriculography (+10% to ,11%) with similar intraobserver and interobserver variabilities. Similar correlation was noted in the prediction set between VQE and RVG EF(r = 0.967, P < 0.001). We conclude that VQE provides highly correlated estimates of EF with RVG. (ECHOCARDIOGRAPHY, Volume 20, July 2003) [source] Palpable Cardiac Impulse Predicts Adequate Acoustic WindowsECHOCARDIOGRAPHY, Issue 1 2000F.A.C.C., JAMES P. EICHELBERGER M.D. In this study, we sought to determine the usefulness of palpating an apical cardiac impulse on physical examination in predicting adequate echocardiographic images for stress echocardiography. A variety of stress tests using either echocardiographic imaging or nuclear imaging are available to referring physicians. Deciding which test is best for a given patient is often dificult. In the case of stress echocardiography, the most significant limitation is poor image quality i n a small portion of patients. We enrolled 136 consecutive outpatients referred for echocardiography. The presence or absence of a palpable cardiac apex on physical examination was recorded by two independent and blinded examiners. Data, including age, sex, weight, prior chest surgery, and smoking, were also collected. Echocardiographic imaging of the left ventricle was scored according to the number of adequately visualized wall segments in a standard 16-segment model. One hundred eleven patients (82%) had adequate visualization of at least 14 of 16 wall segments. Ninety-eight patients (72%) had a palpable cardiac impulse, of whom 90 (92%) also had adequate acoustic image quality versus only 21 (55%) of the 38patients in whom an apex was not palpable (P < 0.0001). Other variables that were measured were not significantly related to image quality, with the exception of weight; patients with adequate images weighed a mean of 75 kg versus 91 kg i n those with inadequate images (P < 0.0006). However, multivariate analysis showed a palpable apex to be the only independent predictor after controlling for other variables. A physical examination assessment for a palpable apical impulse is useful to predict adequate echocardiographic image quality for stress echocardiography. When used in conjunction with other parameters, this may lead to more appropriate referral to augmented stress testing. (ECHOCARDIOGRAPm, Volume 17, January 2000) [source] Clinical Application of PET/CT Fusion Imaging for Three-Dimensional Myocardial Scar and Left Ventricular Anatomy during Ventricular Tachycardia AblationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 6 2009JING TIAN M.D., Ph.D. Background: Image integration has the potential to display three-dimensional (3D) scar anatomy and facilitate substrate characterization for ventricular tachycardia (VT) ablation. However, the current generation of clinical mapping systems cannot display 3D left ventricle (LV) anatomy with embedded 3D scar reconstructions or allow display of border zone and high-resolution anatomic scar features. Objective: This study reports the first clinical experience with a mapping system allowing an integrated display of 3D LV anatomy with detailed 2D/3D scar and border zone reconstruction. Methods: Ten patients scheduled for VT ablation underwent contrast-enhanced computed tomography (CT) and Rubidium-82 perfusion/F-18 Fluorodeoxyglucose metabolic Positron Emission Tomography (PET) imaging to reconstruct 3D LV and scar anatomy. LV and scar models were co-registered using a 3D mapping system and analyzed with a 17-segment model. Metabolic thresholding was used to reconstruct the 3D border zone. Real-time display of CT images was performed during ablation. Results: Co-registration (error 4.3 ± 0.7 mm) allowed simultaneous visualization of 3D LV anatomy and embedded scar and guided additional voltage mapping. Segments containing homogenous or partial scar correlated in 94.4% and 85.7% between voltage maps and 3D PET scar reconstructions, respectively. Voltage-defined scar and normal myocardium had relative FDG uptakes of 40 ± 13% and 89 ± 30% (P < 0.05). The 3D border zone correlated best with a 46% metabolic threshold. Real-time display of registered high-resolution CT images allowed the simultaneous characterization of scar-related anatomic changes. Conclusion: Integration of PET/CT reconstruction allows simultaneous 3D display of myocardial scar and border zone embedded into the LV anatomy as well as the display of detailed scar anatomy. Multimodality imaging may enable a new image-guided approach to substrate-guided VT ablation. [source] Magnetic Resonance Imaging is Superior to Cardiac Scintigraphy to Identify Nonresponders to Cardiac Resynchronization TherapyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2009MIKI YOKOKAWA M.D. Background: Left ventricular (LV) postero-lateral scar and total scar burden are factors responsible for a poor response to cardiac resynchronization therapy (CRT). Contrast-enhanced magnetic resonance imaging (CMR) and 99mTc-2-methoxy isobutyl isonitrile single photon emission computed tomography (SPECT) perfusion imaging are widely used to detect myocardial scar tissue; however, their ability to detect regional scars and predict a positive response to CRT has not been fully evaluated. Methods: CMR and SPECT were performed in 17 patients with dilated cardiomyopathy (DCM) and seven patients with ischemic cardiomyopathy (ICM) before CRT. All images were scored, using a 17-segment model. To analyze the LV scar regions by CMR, we assessed the transmural delayed enhancement extent as the transmural score in each segment (0 = no scar, 4 = transmural scar). Similarly, a perfusion defect score was assigned to each segment by SPECT (0 = normal uptake, 4 = defect). Results: By both SPECT and CMR imaging, the total scar score was significantly higher in the ICM than in the DCM group. An LV postero-lateral wall scar region was detected using both imaging modes. By SPECT imaging, the percentage of regional scar score in the LV inferior wall was significantly higher in the DCM than in the ICM group. Conclusions: By SPECT imaging in the DCM group, severe perfusion defects, due to attenuation artifacts, were frequently observed in the LV inferior wall, resulting in the overestimation of scar tissue. CMR identified nonresponders to CRT more reliably than SPECT in patients with DCM. [source] | ||||||||||