Andrew M. Keller

Assessment of cardiac function by three-dimensional echocardiography compared with conventional noninvasive methods.

BACKGROUND Reliable, serial, noninvasive quantitative estimation of left ventricular ejection fraction is essential for selecting and timing therapeutic interventions in patients with heart disease. Equilibrium radionuclide angiography is widely used for this purpose but has well-recognized limitations. Advantages of echocardiography over equilibrium radionuclide angiography include assessment of wall motion, valvular pathology, and cardiac hemodynamics, in addition to portability, lack of radiation exposure, and substantially lower cost. However, conventional echocardiographic techniques are limited by geometric assumptions, image positioning errors, and use of subjective visual methods. To overcome these limitations, a three-dimensional echocardiographic method was developed. This study compares ejection fraction by three-dimensional echocardiography, quantitative two-dimensional echocardiography, and subjective two-dimensional echocardiographic visual estimation with that by equilibrium radionuclide angiography. METHODS AND RESULTS Fifty-one unselected patients with suspected heart disease underwent left ventricular ejection fraction determination by equilibrium radionuclide angiography and three-dimensional echocardiography using an interactive line-of-intersection display and a new algorithm, ventricular surface reconstruction, for volume computation. In 44 patients, ejection fractions were also estimated visually by experienced observers from two-dimensional echocardiography and by quantitative two-dimensional echocardiography using an apical biplane summation-of-disks algorithm. An excellent correlation was obtained between three-dimensional echocardiography and equilibrium radionuclide angiography (r = .94 to .97, SEE = 3.64% to 5.35%; limits of agreement, 10.3% to 13.3%) without significant underestimation or overestimation. SEE values and limits of agreement were twofold to threefold lower than corresponding values for all two-dimensional echocardiographic techniques. In addition, interobserver variability was significantly lower for the three-dimensional echocardiographic method (10.2%) than for the apical biplane summation-of-disks method (26.1%) and subjective visual estimation (33.3%). CONCLUSIONS Determination of ejection fraction by three-dimensional echocardiography yields results comparable to those obtained by equilibrium radionuclide angiography and is substantially superior to all two-dimensional echocardiographic methods. Therefore, three-dimensional echocardiography may be used for accurate serial quantification of left ventricular function as an alternative to equilibrium radionuclide angiography.

American society of echocardiography recommendations for quality echocardiography laboratory operations

Michael H. Picard, MD, FASE, David Adams, RDCS, FASE, S. Michelle Bierig, RDCS, MPH, FASE, JohnM.Dent,MD,FASE, Pamela S.Douglas,MD,FASE,LindaD.Gillam,MD,FASE,AndrewM.Keller,MD,FASE, David J. Malenka, MD, FASE, Frederick A. Masoudi, MD, MSPH, Marti McCulloch, RDCS, FASE, Patricia A. Pellikka, MD, FASE, Priscilla J. Peters, RDCS, FASE, Raymond F. Stainback, MD, FASE, G.Monet Strachan, RDCS, FASE, andWilliam A. Zoghbi,MD, FASE, Boston, Massachusetts; Durham,North Carolina; St. Louis, Missouri; Charlottesville, Virginia; New York, New York; Danbury, Connecticut; Lebanon, New Hampshire; Denver, Colorado; Houston, Texas; Rochester, Minnesota; Pennsauken, New Jersey; San Diego, California

Left ventricular volume and endocardial surface area by three-dimensional echocardiography: Comparison with two-dimensional echocardiography and nuclear magnetic resonance imaging in normal subjects☆

OBJECTIVES We evaluated a three-dimensional echocardiographic method for ventricular volume and surface area determination that uses polyhedral surface reconstruction. Six to eight nonparallel, unequally spaced, nonintersecting short-axis planes were positioned with a line of intersection display to overcome limitations associated with two-dimensional echocardiography. BACKGROUND Two-dimensional echocardiographic methods of ventricular volume and surface area determination are limited by assumptions about ventricular shape and image plane position. METHODS Left ventricular end-diastolic and end-systolic volumes and endocardial surface areas determined by three-dimensional echocardiography and nuclear magnetic resonance (NMR) imaging were compared in 15 normal subjects (7 men, 8 women, aged 23 to 41 years, body surface area 1.38 to 2.17 m2). Ten of these subjects also underwent two-dimensional echocardiography; and end-diastolic and end-systolic volumes were determined by the apical biplane summation of discs method and compared with results of NMR imaging. RESULTS Interobserver variability was 5% to 8% for three-dimensional echocardiography and 6% to 9% for NMR imaging. Both methods were in close agreement on end-diastolic volume (r = 0.92, SEE = 6.99 ml) and end-systolic volume (r = 0.81, SEE = 4.01 ml) and on end-diastolic surface area (r = 0.84, SEE = 8.25 cm2) and end-systolic surface area (r = 0.84, SEE = 4.89 cm2). Three-dimensional echocardiography and NMR imaging correlated significantly better for end-diastolic volume (r = 0.90, SEE = 7.0 ml) and end-systolic volume (r = 0.88, SEE = 3.1 ml) than did two-dimensional echocardiography and NMR imaging (r = 0.48, SEE = 20.5 ml for end-diastolic volume; r = 0.70, SEE = 5.6 ml for end-systolic volume). CONCLUSIONS Three-dimensional echocardiography is an in vivo method of measuring left ventricular end-diastolic and end-systolic volumes and endocardial surface area with results comparable to those of NMR imaging. Additionally, three-dimensional echocardiography is superior to the two-dimensional echocardiographic apical biplane summation method because the technique eliminates geometric assumptions and image plane positioning error.

Three-dimensional echocardiography: In vitro and in vivo validation of left ventricular mass and comparison with conventional echocardiographic methods

OBJECTIVES This study aimed to validate a method for mass computation in vitro and in vivo and to compare it with conventional methods. BACKGROUND Conventional echocardiographic methods of determining left ventricular mass are limited by assumptions of ventricular geometry and image plane positioning. To improve accuracy, we developed a three-dimensional echocardiographic method that uses nonparallel, nonintersecting short-axis planes and a polyhedral surface reconstruction algorithm for mass computation. METHODS Eleven fixed hearts were imaged by three-dimensional echocardiography, and mass was determined in vitro by multiplying the myocardial volume by the density of each heart and comparing it with the true mass. Mass at diastole and systole by three-dimensional echocardiography and magnetic resonance imaging (MRI) was compared in vivo in 15 normal subjects. Ten subjects also underwent imaging by one- and two-dimensional echocardiography, and mass was determined by Penn convention, area-length and truncated ellipsoid algorithms. RESULTS In vitro results were r = 0.995, SEE 2.91 g, accuracy 3.47%. In vivo interobserver variability for systole and diastole was 16.7% to 27%, 14% to 18.1% and 6.3% to 12.8%, respectively, for one-, two- and three-dimensional echocardiography and was 7.5% for MRI at end-diastole. The latter two agreed closely with regard to diastolic mass (r = 0.895, SEE 11.1 g) and systolic mass (r = 0.926, SEE 9.2 g). These results were significantly better than correlations between MRI and the Penn convention (r = 0.725, SEE 25.6 g for diastole; r = 0.788, SEE 28.7 g for systole), area-length (r = 0.694, SEE 24.2 g for diastole; r = 0.717, SEE 28.2 g for systole) and truncated ellipsoid algorithms (r = 0.687, SEE 21.8 g for diastole; r = 0.710, SEE 24.5 g for systole). CONCLUSIONS Image plane positioning guidance and elimination of geometric assumptions by three-dimensional echocardiography achieve high accuracy for left ventricular mass determination in vitro. It is associated with higher correlations and lower standard errors than conventional methods in vivo.

In vivo measurement of myocardial mass using nuclear magnetic resonance imaging.

To examine the accuracy of nuclear magnetic resonance imaging in measuring left ventricular mass, measurements of left ventricular mass made using this technique were compared with left ventricular weight in 10 mongrel dogs. Left ventricular myocardial volume was measured from five short-axis end-diastolic images that spanned the left ventricle. Left ventricular mass was calculated from left ventricular myocardial volume and compared with the left ventricular weight determined after formalin immersion-fixation. Linear regression analysis yielded the following relation in grams: left ventricular mass determined using nuclear magnetic resonance imaging = (0.94) (left ventricular weight) + 9.1 (r = 0.98, SEE = 6.1 g). The small overestimation of left ventricular weight by nuclear magnetic resonance imaging was judged to be secondary to both difficulty with proper border definition and partial volume effects. Hence, this imaging technique can be used to obtain accurate measurements of left ventricular mass in dogs in vivo.

Three-dimensional Echocardiography

Conventional two-dimensional echocardiography is limited in its ability to illustrate complex cardiac structural relationships arid by the need for assumptions about image plane positioning and ventricular geometry when quantitation is performed. Three-dimensional echocardiography, the coupling of cardiac ultrasound images with a system that locates the images in space with reference to an external coordinate system, can address these limitations. Three dimensional systems currently in use have demonstrated the ability to provide unique views of the heart; for example, a “surgeons view” of the mitral valve from the left atrium. Three-dimensional echocardiography is also proving to be more accurate than conventional two-dimensional echocardiography for the measurement of left ventricular volume, mass, and ejection fraction and shows promise for the measurement of these parameters of right ventricular structure and function. Three-dimensional echocardiography will be increasingly clinically applicable, because it provides new and improved means of noninvasively visualizing and quantitating cardiac structure and function.

2016 ACC/ASE/ASNC/HRS/SCAI Health Policy Statement on Integrating the Healthcare Enterprise

Richard J. Kovacs, MD, FACC, Chair Deepak Bhatt, MD, FACC Ralph Brindis, MD, MPH, MACC Paul N. Casale, MD, MPH, FACC Edward T.A. Fry, MD, FACC Paul A. Heidenreich, MD, FACC Jeffrey P. Jacobs, MD, FACC James L. Januzzi, Jr, MD, FACC Amy L. Miller, MD, PhD, FACC Athena Poppas, MD, FACC

Impact of troponin testing in noncardiac admissions.

BACKGROUND There is little data to support Troponin I (TNI) use in the management of noncardiac patients. We studied the use of TNI in patients on our gastroenterology service, to determine whether there was a change in management as a result of TNI testing. METHODOLOGY Patients admitted from September 2011 to June 2012 to our gastroenterology service who had TNI performed were included. Data collected included symptoms, cardiovascular risk factors, medical treatment, and testing. RESULTS Sixty-three of 295 patients had a positive TNI. The mean length of stay was significantly longer with a positive troponin (180 vs. 108 hours, P<0.001). Age, hypertension, diabetes, coronary artery disease, and chronic kidney disease were associated with a positive TNI. Cardiac consultation and echocardiography were performed in a higher proportion of TNI positive patients (P<0.0001). There were no statistically significant changes in treatment with clopidogrel, beta-blockers, angiotensin converting enzyme inhibitors, or statins between both groups. CONCLUSIONS TNI testing in patients admitted to the gastroenterology service was associated with increased length of stay and echocardiography, without any change in management. This study supports adherence to national guidelines for the use of TNI, to reduce TNI testing and length of hospital stay.