Fletcher A. Miller

Clinical Utility of Doppler Echocardiography and Tissue Doppler Imaging in the Estimation of Left Ventricular Filling Pressures A Comparative Simultaneous Doppler-Catheterization Study

BackgroundNoninvasive assessment of diastolic filling by Doppler echocardiography provides important information about left ventricular (LV) status in selected subsets of patients. This study was designed to assess whether mitral annular velocities as assessed by tissue Doppler imaging are associated with invasive measures of diastolic LV performance and whether additional information is gained over traditional Doppler variables. Methods and ResultsOne hundred consecutive patients referred for cardiac catheterization underwent simultaneous Doppler interrogation. Invasive measurements of LV pressures were obtained with micromanometer-tipped catheters, and the mean LV diastolic pressure (M-LVDP) was used as a surrogate for mean left atrial pressure. Doppler signals from the mitral inflow, pulmonary venous inflow, and TDI of the mitral annulus were obtained. Isolated parameters of transmitral flow correlated with M-LVDP only when ejection fraction <50%. The ratio of mitral velocity to early diastolic velocity of the mitral annulus (E/E′) showed a better correlation with M-LVDP than did other Doppler variables for all levels of systolic function. E/E′ <8 accurately predicted normal M-LVDP, and E/E′ >15 identified increased M-LVDP. Wide variability was present in those with E/E′ of 8 to 15. A subset of those patients with E/E′ 8 to 15 could be further defined by use of other Doppler data. ConclusionsThe combination of tissue Doppler imaging of the mitral annulus and mitral inflow velocity curves provides better estimates of LV filling pressures than other methods (pulmonary vein, preload reduction). However, accurate prediction of filling pressures for an individual patient requires a stepwise approach incorporating all available data.

Recommendations for Evaluation of Prosthetic Valves With Echocardiography and Doppler Ultrasound. A Report From the American Society of Echocardiography's Guidelines and Standards Committee and the Task Force on Prosthetic Valves, Developed in Conjunction With the American College of Cardiology Cardiovascular Imaging Committee, Cardiac Imaging Committee of the American Heart Association

A Report From the American Society of Echocardiography’s Guidelines and Standards Committee and the Task Force on Prosthetic Valves, Developed in Conjunction With the American College of Cardiology Cardiovascular Imaging Committee, Cardiac Imaging Committee of the American Heart Association, the European Association of Echocardiography, a registered branch of the European Society of Cardiology, the Japanese Society of Echocardiography and the Canadian Society of Echocardiography, Endorsed by the American College of Cardiology Foundation, American Heart Association, European Association of Echocardiography, a registered branch of the European Society of Cardiology, the Japanese Society of Echocardiography, and Canadian Society of Echocardiography

The Frequency of Familial Dilated Cardiomyopathy in a Series of Patients with Idiopathic Dilated Cardiomyopathy

BACKGROUND Dilated cardiomyopathy is characterized by an increase in ventricular size and impairment of ventricular function. Most cases are believed to be sporadic, and familial dilated cardiomyopathy is usually considered to be a rare and distinct disorder. We studied the proportion of cases of idiopathic dilated cardiomyopathy that were familial in a large sequential series of patients whose first-degree relatives were investigated regardless of whether these relatives had cardiac symptoms. METHODS We studied relatives of 59 index patients with idiopathic dilated cardiomyopathy of obtaining a family history and performing a physical examination, electrocardiography, and two-dimensional, M-mode, and Doppler echocardiography. A total of 315 relatives were examined. RESULTS Eighteen relatives from 12 families were shown to have dilated cardiomyopathy. Thus, 12 of the 59 index patients (20.3 percent) had familial disease. There was no difference in age, sex, severity of disease, exposure to selected environmental factors, or electrocardiographic or echocardiographic features between the index patients with familial disease and those with nonfamilial disease. A noteworthy finding was that 22 of 240 healthy relatives (9.2 percent) with normal ejection fractions had increased left ventricular diameters during systole or diastole (or both), as compared with 2 of 112 healthy control subjects (1.8 percent) who were studied separately. CONCLUSIONS Dilated cardiomyopathy was found to be familial in at least one in five of the patients in this study, a considerably higher percentage than in previous reports. This finding has important implications for family screening and provides direction for further investigation into the causes and natural history of dilated cardiomyopathy.

Echocardiographically documented mitral-valve prolapse. Long-term follow-up of 237 patients.

We determined the long-term prognosis for patients with mitral-valve prolapse documented by echocardiography by following 237 minimally symptomatic or asymptomatic patients for a mean of 6.2 years (range, 1 to 10.4). The actuarial eight-year probability of survival was 88 per cent, which is not significantly different from that for a matched control population. An initial left ventricular diastolic dimension exceeding 60 mm was the best echocardiographic predictor of the subsequent need for mitral-valve replacement (17 patients). Of the 97 patients with redundant mitral-valve leaflets identified echocardiographically, 10 (10.3 per cent) had sudden death, infective endocarditis, or a cerebral embolic event; in contrast, of the 140 patients with nonredundant valves, only 1 (0.7 per cent) had such complications (P less than 0.001). Most patients with echocardiographic evidence of mitral-valve prolapse have a benign course, but subsets at high risk for the development of progressive mitral regurgitation, sudden death, cerebral embolic events, or infective endocarditis can be identified by echocardiography.

Doppler Echocardiography: Theory, Instrumentation, Technique, and Application

A Doppler examination is a valuable adjunct to a complete echocardiographic examination. It has the capability of measuring normal and abnormal velocities of blood flow noninvasively. For the first time, this procedure allows noninvasive quantitation of stenotic gradients, intracardiac pressures, and blood flow as well as semiquantitative assessment of regurgitant lesions. With this procedure, the operator must progress through a learning curve in order to gain a complete understanding of the examination techniques, the limitations of the instruments, and the Doppler physics principles before applications can be made to clinical practice. Evaluation of other aspects of Doppler echocardiography, such as color-flow mapping and assessment of diastolic events, portends great promise for the role of this procedure in the future.

Outcome after normal exercise echocardiography and predictors of subsequent cardiac events : Follow-up of 1,325 patients

OBJECTIVES This study sought to examine the outcome of a large group of patients after normal exercise echocardiography and to identify potential predictors of subsequent cardiac events. BACKGROUND Earlier studies suggested that prognosis after normal exercise echocardiography is favorable, with a low subsequent cardiac event rate. These studies involved a small number of patients and did not have sufficient statistical power to stratify risk. METHODS The outcomes of 1,325 patients who had normal exercise echocardiograms were examined. End points were overall and cardiac event-free survival. Cardiac events were defined as cardiac death, nonfatal myocardial infarction and coronary revascularization. Patient characteristics were analyzed in relation to time to first cardiac event in a univariate and multivariate manner to determine which, if any, were associated with an increased hazard of subsequent cardiac events. RESULTS Overall survival of the study group was significantly better than that of an age- and gender-matched group obtained from life tables (p < 0.0001). The cardiac event-free survival rates at 1, 2 and 3 years were 99.2%, 97.8% and 97.4%, respectively. The cardiac event rate per person-year of follow-up was 0.9%. Subgroups with an intermediate or high pretest probability of having coronary artery disease also had low cardiac event rates. Multivariate predictors of subsequent cardiac events were angina during treadmill exercise testing (risk ratio [RR] 4.1, 95% confidence interval [CI] 1.5 to 11.0), low work load (defined as < 7 metabolic equivalents [METs] for men and < 5 METs for women; RR 3.2, 95% CI 1.4 to 7.6), echocardiographic left ventricular hypertrophy (RR 2.6, 95% CI 1.1 to 6.3) and advancing age (RR 1.04/year, 95% CI 1.0 to 1.1). CONCLUSIONS The outcome after normal exercise echocardiography is excellent. Subgroups with an intermediate or high pretest probability of having coronary artery disease also have a favorable prognosis after a normal exercise echocardiogram. Characteristics predictive of subsequent cardiac events (i.e., patient age, work load, angina during exercise testing and echocardiographic left ventricular hypertrophy) should be considered in the clinical interpretation of a normal exercise echocardiogram.

Multiplane transesophageal echocardiography: image orientation, examination technique, anatomic correlations, and clinical applications.

Multiplane transesophageal echocardiography (TEE) consists of a single ultrasound array or imaging sector that can be rotated around the long axis of the ultrasound beam typically in a 180 degrees arc. This capability produces a circular (conical) continuum of tomographic two-dimensional images. The principal advantage of multiple TEE is that the transducer can be rotated to an image-specific orientation and critically optimized. Thus, manipulation of the transducer is less complex than with the biplane technique, and user adaptation is considerably enhanced. The logical image notation (that is, degrees of rotation) and orientation are described in this report. A step-by-step approach to the multiplane TEE examination, which evolved from our initial experience with 400 consecutive patients, is correlated with accompanying tomographic anatomic corroboration. The unique clinical applications are discussed and related to the amplification of diagnostic information. Although the multiplanar TEE transducer is relatively large, all adult patients who weigh 40 kg or more can be examined. No major complications occurred in our initial experience with this promising new technology.

Left Ventricular Torsion by Two-Dimensional Speckle Tracking Echocardiography in Patients with Diastolic Dysfunction and Normal Ejection Fraction

BACKGROUND Left ventricular torsion (LVtor) and subsequent untwisting play an important role in diastolic filling. There is, however, limited information about how LVtor and untwisting are related to the severity of diastolic dysfunction. The aim of this study was to assess LVtor and untwisting in the progressive severity of diastolic dysfunction. METHODS We studied 148 subjects (116 with diastolic dysfunction, 32 healthy controls). Apical and basal short-axis rotations were measured by 2-dimensional speckle tracking echocardiography. LVtor was defined as the instantaneous net difference of the basal and apical rotation. Patients were divided into 3 groups according to diastolic dysfunction grade and their underlying disease, such as hypertension, hypertrophic cardiomyopathy, and amyloidosis. RESULTS Age, gender, and ejection fraction were similar in the 3 groups and control. Mitral annulus early diastolic velocity was reduced by design in all 3 groups. Peak LVtor was significantly greater in mild diastolic dysfunction (n = 45; 29.7 +/- 9.0 degrees) compared with control (n = 32: 15.6 +/- 4.0 degrees) and then normalized in moderate (n = 49; 19.3 +/- 4.8 degrees) and severe diastolic dysfunction (n = 22; 17.3 +/- 9.3 degrees). The twisting and untwisting rates were significantly higher in mild diastolic dysfunction group. CONCLUSION Systolic torsion and diastolic untwisting are significantly increased in patients with mild diastolic dysfunction. In patients with advanced diastolic dysfunction with increased filling pressure, they are normalized or reduced. Whether increased LVtor is a compensatory mechanism for reduced myocardial relaxation or a consequence of reduced filling in the early stage of diastolic dysfunction requires further investigation. Analysis of LVtor with speckle tracking echocardiography should be further explored to elucidate the role of torsion in patients with diastolic dysfunction.

Right Ventricular Strain for Prediction of Survival in Patients With Pulmonary Arterial Hypertension

BACKGROUND Pulmonary arterial hypertension (PAH) is a devastating illness of pulmonary vascular remodeling, right-sided heart failure, and limited survival. Whether strain-based measures of right ventricular (RV) systolic function predict future right-sided heart failure and/or death is untested. METHODS RV longitudinal systolic strain and strain rate were evaluated by echocardiography in 80 patients with World Health Organization group 1 pulmonary hypertension (PH) (72% were functional class [FC] III or IV). Survival status was assessed over 4 years. RESULTS All patients had a depressed RV systolic strain (-15% ± 5%) and strain rate (-0.80 ± 0.29 s(-1)). Of the parameters assessed, average RV free wall systolic strain worse than -12.5% identified a cohort with greater severity of disease (82% were FC III/IV), greater RV systolic dysfunction (RV stroke volume index 26 ± 9 mL/m(2)), and higher right atrial pressure (12 ± 5 mm Hg). Patients with an RV free wall strain worse than -12.5% were associated with a greater degree of disease progression within 6 months, a greater requirement for loop diuretics, and/or a greater degree of lower extremity edema, and it also predicted 1-, 2-, 3-, and 4-year mortality (unadjusted 1-year hazard ratio, 6.2; 2.1-22.3). After adjusting for age, sex, PH cause, and FC, patients had a 2.9-fold higher rate of death per 5% absolute decline in RV free wall strain at 1 year. CONCLUSIONS Noninvasive assessment of RV longitudinal systolic strain and strain rate independently predicts future right-sided heart failure, clinical deterioration, and mortality in patients with PAH.

Stress Echocardiography. Part II. Dobutamine Stress Echocardiography: Techniques, Implementation, Clinical Applications, and Correlations

OBJECTIVE To describe the rationale, methods, and clinical applications for dobutamine stress echocardiography. DESIGN We review our experience with the first 1,000 Mayo Clinic patients who underwent this procedure and discuss studies from the literature that have assessed the accuracy of dobutamine stress echocardiography in determining the presence and extent of coronary artery disease. MATERIAL AND METHODS The Mayo protocol for dobutamine stress echocardiography is presented, and the indications for use of this test and comparisons of sensitivity and specificity with other tests are summarized. RESULTS Although exercise stress testing is the usual noninvasive method for the detection and assessment of coronary artery disease, a substantial number of patients are unable to perform adequate exercise because of physical limitations. In these patients, dobutamine stress echocardiography has emerged as a feasible, safe, and accurate method for the evaluation of coronary artery disease. The test has been proved to be valuable in the noninvasive diagnosis of coronary artery disease and to have an accuracy comparable to that of tomographic perfusion imaging. Other indications for dobutamine stress echocardiography include risk stratification before noncardiac surgical procedures, risk stratification after myocardial infarction, and identification of viable myocardium in patients with left ventricular dysfunction. CONCLUSION Dobutamine stress echocardiography is an accurate, safe, cost-effective, and portable procedure for the noninvasive diagnosis of coronary artery disease and for the preoperative assessment of patients with such disease, especially those who are unable to perform adequate exercise tests.