Influence of image quality on the accuracy of real time three-dimensional echocardiography to measure left ventricular volumes in unselected patients: a comparison with gated-SPECT imaging.

BACKGROUND: Patient selection, often restricted to those with ideal image quality, and timing of studies in relation to reference methods may limit clinical applicability of cardiac volumes derived from 3D echocardiography. METHODS: To test the influence of image quality on LV volumes by real time 3DE (RT3DE), we compared results obtained by RT3DE to those from gated-SPECT imaging in 64 consecutive patients referred for clinically indicated nuclear perfusion imaging. To minimize hemodynamic effects, RT3DE was performed immediately following G-SPECT. LV volumes by RT3DE were calculated using at least three orthogonal plane pairs. Image quality was rated as good if 75-100% of the endocardial border was visualized, fair if 60-74% was visualized, and poor if 50-60% was visualized. RESULTS: Image quality was good in 25 (39%), fair in 20 (31%), and poor in 13 (20%) patients. Six patients (9%) were excluded for uninterpretable echo images. For the entire cohort, EDV and ESV agreed closely (all P = NS). When stratified by image quality, the EDV and ESV of those with good and fair image quality agreed closely with minimal bias (average 1 +/- 9 mL and 2 +/- 7 mL, respectively). Poor image was associated with less strong agreement and much greater bias for EDV and ESV (7 +/- 25 mL and 7 +/- 20 mL, respectively). CONCLUSIONS: When applied to patients studied in routine clinical practice, LV volumes by RT3DE compare favorably to G-SPECT. RT3DE results are more reliable when >60% of endocardium is visualized.

Direct ultrasound measurement of longitudinal, circumferential, and radial strain using 2-dimensional strain imaging in normal adults.

Current noninvasive techniques used to evaluate left ventricular systolic function are limited by dependence on the angle of insonation (tissue Doppler imaging/TDI) or limited by availability (MRI tagging). We utilized 2-dimensional speckle strain (epsilon) imaging (1) to establish normal values for all three epsilon vectors; (2) to compare circumferential epsilon values with circumferential shortening (midwall fractional shortening (FS(mw)); (3) to examine the relationship between left ventricular epsilon and wall stress; and (4) to compare 2D echocardiographic characteristics by gender. Echocardiography was performed in 60 normal subjects (mean 39 +/- 15 years). Small, but significant regional heterogeneity was seen in circumferential epsilon, but not in radial or longitudinal epsilon. We found an inverse correlation between circumferential epsilon and stress (r =-0.29, p<0.05) as well as longitudinal epsilon and stress (r =-0.11, P < 0.05), though the relationships were not close. We also observed a linear relationship between mean circumferential epsilon and FS(mw) (r = 0.29, P < 0.05). In conclusion, (1) 2-dimensional epsilon imaging permits measurement of regional systolic epsilon values in the majority of normal individuals; (2) epsilon values furnished by this method obey expected stress-shortening relationships; (3) systolic epsilon displays minor regional heterogeneity in the circumferential direction; (4) for the first time, a close relationship between FS(mw) and mean circumferential epsilon was demonstrated; and (5) there are minor gender-related differences in LV geometry and function.

Heart failure in the "oldest old": clinical and echocardiographic insights.

While the incidence and prevalence of heart failure (HF) increase markedly with age, few studies have included data on a large series of patients aged 85 years and older. Clinical and echocardiographic data from 533 patients admitted to a tertiary care hospital for acute HF were obtained. Data from the oldest old (>or=85 years; n=252; mean age, 91.9+/-3.6 years) were compared with data from those aged 65 to 74 years (n=123; mean age, 70.1+/-2.8 years) and 75 to 84 years (n=158; mean age, 79.4+/-2.9 years). Echocardiographic data were consistent with hypertensive remodeling. The proportion of patients with HF and a preserved left ventricular ejection fraction was greatest in the oldest patients (61%) in comparison to patients aged 65 to 74 years (48%) and 75 to 84 years (48%). Approximately three-fourths of the oldest patients were women, and two-thirds of women had a left ventricular ejection fraction >or=50%.

Analysis of left ventricular systolic function using midwall mechanics in patients >60 years of age with hypertensive heart disease and heart failure.

Normal ejection fraction (EFs) is often equated with normal systolic function. However, midwall mechanics reveal systolic dysfunction in hypertensive heart disease accompanied by hypertrophic remodeling. Midwall mechanics are unstudied in patients with acute diastolic heart failure (HF). This study analyzed left ventricular (LV) midwall stress-shortening relations in 61 patients aged >60 years with hypertensive heart disease, HF, and normal EF. Sixty-one hypertensive patients (mean age 78 +/- 10 years) who presented with HF, each with an EF >50%, underwent echocardiography. Midwall mechanics were compared with those of 79 controls (mean age 75 +/- 8 years) without structural heart disease. Relative wall thickness (0.63 +/- 0.11 vs 0.46 +/- 0.10 mm) and LV mass (237 +/- 67 vs 177 +/- 57 g) were significantly greater in patients with HF compared with controls. Mean EFs were similar in patients with HF and controls (64 +/- 9% vs 67 +/- 9%). Although mean endocardial fractional shortening (35 +/- 7% vs 37 +/- 7%) was not significantly different, midwall shortening in patients with HF was significantly less compared with controls (16 +/- 2% vs 19 +/- 3%, p <0.05). Eighteen of the 61 patients with HF (30%) had midwall shortening that was <95% confidence intervals of the normal midwall stress-shortening relations. By this criterion, these patients had systolic dysfunction despite normal EF; they had smaller LV chambers (in dimension and volume), greater relative wall thickness, and smaller stroke volumes. In conclusion, almost 1/3 of patients hospitalized with diastolic HF had systolic dysfunction, characterized by abnormal midwall stress-shortening relations.

Paradoxical changes in brain natriuretic peptide levels and loading conditions after intravenous conscious sedation.

BACKGROUND: Elevated filling pressure and wall stress have been proposed as stimuli for elevated brain natriuretic peptide (BNP) levels. Narcotic and benzodiazepine sedation, such as is used for transesophageal echocardiography (TEE), is known to decrease filling pressures. We hypothesized that lower filling pressure and wall stress associated with intravenous conscious sedation (IVCS) would lead to lower BNP levels. METHODS: We studied BNP levels, blood pressure, and echocardiographic indices of filling pressure and wall stress before and after IVCS and TEE. RESULTS: When data before and after IVCS and TEE were compared, mean blood pressure decreased (149 +/- 24/83 +/- 14 mm Hg vs 126 +/- 29/69 +/- 14; P < .01), as did mitral Doppler E wave velocity (82 +/- 23 cm/s vs 76 +/- 22; P < .05), right ventricular/atrial gradient (31 +/- 10 mm Hg vs 29 +/- 13; P < .05), and wall stress. However, BNP levels increased (195 +/- 407 pg/mL vs 238 +/- 458; P < .01). CONCLUSIONS: In a series of patients undergoing clinically indicated TEE, BNP levels increase above baseline after IVCS. The increase in BNP occurs despite lower blood pressure, lower mitral Doppler E velocity, lower right ventricular/atrial gradient, and lower wall stress compared with baseline. The mechanism of the paradoxical increase in BNP is not entirely clear, but it may conceivably be a result of counterregulatory hormone release caused by acute decrease in blood pressure.

Brain natriuretic peptide levels fall rapidly after cardioversion of atrial fibrillation to sinus rhythm.

BACKGROUND: Brain natriuretic peptide (BNP) levels have been reported to fall following cardioversion of atrial fibrillation (AF). The mechanism for the fall in BNP has not been elucidated and the potential confounding effects of sedation have not been investigated. Sedation may alter BNP levels via its effects on loading conditions. Accordingly, we studied whether BNP levels change shortly after cardioversion and attempted to control for possible effects of sedation. METHODS: BNP levels were obtained before and after cardioversion in patients with AF and in a control group of patients undergoing intravenous conscious sedation for transesophageal echocardiography. RESULTS: BNP levels dropped (260 +/- 255 vs. 190 +/- 212 pg/ml, p < 0.05) 40 min after cardioversion, decreasing in 33 of 41 subjects who achieved sinus rhythm. By contrast, mean BNP did not fall in subjects in whom cardioversion was not successful. The change in BNP level was not related to the degree of change in heart rate. No control subject experienced a change in cardiac rhythm; BNP levels increased (195 +/- 407 vs. 238 +/- 458 pg/ml, p < 0.05) in 18/22 subjects after sedation. Baseline BNP levels were elevated in subjects with AF, and BNP levels were elevated in parallel with heart failure symptoms. CONCLUSIONS: The rapid fall in BNP after cardioversion (1) may reflect prompt hemodynamic improvement associated with rhythm change and (2) does not appear to be due to the effects of sedation.

The utility of newly derived Doppler echocardiographic variables in the diagnosis and management of patients with heart failure.

Doppler echocardiography, because of its noninvasive nature, is an ideal tool to evaluate patients with heart failure (HF), offering the potential to improve early identification and management of these patients. Although traditional Doppler indices have allowed characterization of diastolic filling abnormalities associated with various HF states, important limitations are recognized. More refined Doppler techniques such as analysis of color M-mode flow propagation velocity, tissue Doppler imaging, and strain parameters can add to the ability of the noninvasive laboratory to improve the identification and management of this group of patients. These newer techniques as well as the traditional Doppler assessment of transmitral left ventricular inflow and pulmonary venous inflow velocities are reviewed as methods to improve the diagnosis and management of patients with HF.