Real-time 3D color Doppler allows direct measurement of VC area and may be more accurate for assessment of MR than the conventional VC diameter measurement by 2D color Doppler.

Using a circulatory loop with an incorporated imaging chamber, various pulsatile flow rates of MR were driven through 4 differently sized orifices. In a clinical study of patients with at least mild MR, regurgitation severity was assessed quantitatively using Doppler-derived effective regurgitant orifice area (EROA), and semiquantitatively as recommended by the American Society of Echocardiography. We describe a step-by-step process to accurately identify the 3D-VC area and compare that measure against known orifice areas (in vitro study) and EROA (clinical study).

In vitro, 3D-VC area demonstrated the strongest correlation with known orifice area (r = 0.92, p < 0.001), whereas 2D-VC diameter had a weak correlation with orifice area (r = 0.56, p = 0.01). In a clinical study of 61 patients, 3D-VC area correlated with Doppler-derived EROA (r = 0.85, p < 0.001); the relation was stronger than for 2D-VC diameter (r = 0.67, p < 0.001). The advantage of 3D-VC area over 2D-VC diameter was more pronounced in eccentric jets (r = 0.87, p < 0.001 vs. r = 0.6, p < 0.001, respectively) and in moderate-to-severe or severe MR (r = 0.80, p < 0.001 vs. r = 0.18, p = 0.4, respectively).

Measurement of VC area is feasible with real-time 3D color Doppler and provides a simple parameter that accurately reflects MR severity, particularly in eccentric and clinically significant MR where geometric assumptions may be challenging.

Vortices that form during LV filling have specific geometry and anatomical locations that are critical determinants of directed blood flow during ejection. Therefore, it is clinically relevant to assess the vortex flow patterns to better understand the LV function.

Twenty-five patients (10 normal and 15 patients with abnormal LV systolic function) underwent CE with intravenous contrast agent, Definity (Bristol-Myers Squibb Medical Imaging, Inc., North Billerica, Massachusetts). The velocity vector and vorticity were estimated by particle image velocimetry. Average vortex parameters including vortex depth, transverse position, length, width, and sphericity index were measured. Vortex pulsatility parameters including relative strength, vortex relative strength, and vortex pulsation correlation were also estimated.

Vortex depth and vortex length were significantly lower in the abnormal LV function group (0.443 ± 0.04 vs. 0.482 ± 0.06, p < 0.05; 0.366 ± 0.06 vs. 0.467 ± 0.05, p < 0.01, respectively). Vortex width was greater (0.209 ± 0.05 vs. 0.128 ± 0.06, p < 0.01) and sphericity index was lower (1.86 ± 0.5 vs. 3.66 ± 0.6, p < 0.001) in the abnormal LV function group. Relative strength (1.13 ± 0.4 vs. 2.10 ± 0.8, p < 0.001), vortex relative strength (0.57 ± 0.2 vs. 1.19 ± 0.5, p < 0.001), and vortex pulsation correlation (0.63 ± 0.2 vs. 1.31 ± 0.5, p < 0.001) were significantly lower in the abnormal LV function group.

It was feasible to quantify LV vorticity arrangement by CE using particle image velocimetry in normal subjects and those with LV systolic dysfunction, and the vorticity imaging by CE may serve as a novel approach to depict vortex, the principal quantity to assess the flow structure.

Catecholamine sensitivity is reduced in failing hearts as a result of myocardial abnormalities in the beta-adrenergic receptor signaling pathway. However, little is known about adrenergic myocardial contractile reserve in asymptomatic or mildly symptomatic patients with DCM.

The maximal first derivative of left ventricular pressure (LV dP/dt_max) was determined during infusion of dobutamine (10 µg kg^–1 min^–1) in 46 asymptomatic or mildly symptomatic (New York Heart Association functional class I or II) patients with DCM. The expression of messenger ribonucleic acid (mRNA) for contractile regulatory proteins in endomyocardial biopsy specimens was quantified by reverse transcription and real-time polymerase chain reaction analysis. Plasma norepinephrine levels were measured in all patients and [¹²³I]metaiodobenzylguanidine (MIBG) scintigraphy performed.

Patients were classified into 3 groups based on the percentage increase in LV dP/dt_max induced by dobutamine (LV dP/dt_max) and on LV ejection fraction (LVEF) at baseline: group I (n = 18): LV dP/dt_max >100% and LVEF >25%; group IIa (n = 17): LV dP/dt_max ≤100% and LVEF > 25%; and group IIb (n = 11): LV dP/dt_max ≤100% and LVEF ≤25%. The amounts of beta₁-adrenergic receptor, sarcoplasmic reticulum Ca²⁺-adenosine triphosphatase, and phospholamban mRNA were significantly smaller in groups IIa and IIb than in group I. The plasma norepinephrine level was increased and the delayed heart/mediastinum count ratio in MIBG scintigraphy was decreased in both groups IIa and IIb.

Dobutamine stress testing is a useful diagnostic tool for identifying reduced adrenergic myocardial contractile reserve related to altered myocardial expression of beta₁-adrenergic receptor, sarcoplasmic reticulum Ca²⁺-adenosine triphosphatase, and phospholamban genes even in asymptomatic or mildly symptomatic patients with DCM.

The CS–GCV has become an anatomical structure of interest because it provides a way of access to the heart for a number of interventional procedures. Previous reports demonstrate that the postulated close anatomical proximity of the CS–GCV to the MVA does not always hold true in patients, both in autopsy specimens and in vivo by computed tomography.

In 31 participants (24 volunteers and 7 patients; 15 men; 42 ± 19 years), cardiovascular magnetic resonance was performed for noninvasive evaluation of the coronary sinus and of the coronary arteries using whole-heart imaging and intravascular contrast agents. Three-dimensional reconstructions, standard orthogonal planes, and unprocessed raw data were used to assess CS–GCV anatomy and its relation to the MVA and the LCX along their entire course.

The CS–GCV was located behind the left atrium in all examined participants, at a minimum distance of 8.6 ± 3.9 mm from the MVA. In 80% of the participants, the LCX crossed the CS–GCV inferiorly, between the CS–GCV and the MVA. The CS–GCV and the LCX had a parallel course for 26.2 ± 23.0 mm, with great variability of location and length. In several participants, the CS–GCV had a long parallel course, but in other participants, the LCX crossed below the CS–GCV at a discrete point.

In all participants, the CS–GCV coursed behind the left atrium rather than behind the MVA. In the majority of the participants, the LCX coursed between the CS–GCV and the MVA. These anatomical relationships should be kept in mind when referring a patient for interventional procedures requiring the access to the CS–GCV, and cardiovascular magnetic resonance might provide important information for the selection of candidates for these procedures.

Although it is generally thought that the aorta becomes tortuous with aging, there has been no systematic study to date in healthy adults to determine if this is so. Such age-related aortic elongation may be a confounding factor for the PWV measurement in elderly people.

Arterial lengths were computed by the 3-dimensional transverse magnetic resonance image arterial tracing of the aorta and carotid and iliac arteries in 256 apparently healthy adults (age 19 to 79 years).

The ascending aorta was greater with advancing age (r = 0.72), whereas the lengths of the descending aorta and carotid and iliac arteries were not associated with age. The elongation of the ascending aorta was associated with the corresponding increases in aortic PWV (beta = 0.50) and brachial/aortic pulse pressure ratio (beta = 0.24), which is an index of pulse wave amplification. The straight distance between carotid and femoral sites (car-fem), the most popular arterial length measurement, overestimated the aortic length measured with the magnetic resonance image by ~25%. The most accurate arterial length estimation was the distance obtained by subtracting carotid length from the car-fem, with <5% difference from the magnetic resonance image-measured length. Because the ascending aorta was omitted or subtracted from the length estimation in PWV, the impact of age-related elongation of the aorta on PWV was small.

The aorta lengthens with age, even in healthy humans, due primarily to the elongation of the ascending aorta. Age-related aortic elongation has little impact on PWV measurements, as the ascending aorta, which undergoes lengthening with age, is not included in the arterial length measurements.

Intracoronary optical coherence tomography (OCT) is a catheter-based optical imaging modality that is capable of providing microscopic (~7-µm axial resolution, ~30-µm transverse resolution), cross-sectional images of the coronary wall. Although the use of OCT has shown substantial promise for imaging coronary microstructure, blood attenuates the OCT signal, necessitating prolonged, proximal occlusion to screen long arterial segments. OFDI is a second-generation form of OCT that is capable of acquiring images at much higher frame rates. The increased speed of OFDI enables rapid, 3-dimensional imaging of long coronary segments after a brief, nonocclusive saline purge.

Volumetric OFDI images were obtained in 3 patients after intracoronary stent deployment. Imaging was performed in the left anterior descending and right coronary arteries with the use of a nonocclusive saline purge rates ranging from 3 to 4 ml/s and for purge durations of 3 to 4 s. After imaging, the OFDI datasets were segmented using previously documented criteria and volume rendered.

Good visualization of the artery wall was obtained in all cases, with clear viewing lengths ranging from 3.0 to 7.0 cm at pullback rates ranging from 5 to 20 mm/s. A diverse range of microscopic features were identified in 2 and 3 dimensions, including thin-capped fibroatheromas, calcium, macrophages, cholesterol crystals, bare stent struts, and stents with neointimal hyperplasia. There were no complications of the OFDI procedure.

Our results demonstrate that OFDI is a viable method for imaging the microstructure of long coronary segments in patients. Given its ability to provide microscopic information in a practical manner, this technology may be useful for studying human coronary pathophysiology in vivo and as a clinical tool for guiding the management of coronary artery disease.

Nesiritide, a recombinant human B-type natriuretic peptide is approved for the treatment of acute decompensated HF and has been shown to exert favorable hemodynamic, neurohormonal, and symptomatic effects. The renal effect of nesiritide in HF patients has not been well defined.

In 15 patients with acute decompensated HF, intravascular Doppler and quantitative angiography of the renal artery were used to assess the effect of nesiritide on renal artery diameter and velocity time integral as well as renal blood flow and vascular resistance. Nesiritide was administered intravenously at a standard dose of 2 µg/kg bolus followed by a continuous infusion at a rate of 0.01 µg/kg/min. Assessment of nesiritide effect was made at 15 min.

Nesiritide infusion was associated with a significant central hemodynamic effect including a fall in mean pulmonary artery pressure (36 ± 12 mm Hg to 31 ± 13 mm Hg, p < 0.001), mean pulmonary capillary wedge pressure (21 ± 2 mm Hg to 15 ± 10 mm Hg, p < 0.001), and systemic vascular resistance (1,995 ± 532 dynes·s·cm^–5 to 1,563 ± 504 dynes·s·cm^–5, r < 0.001), and an increase in cardiac output from 3.9 ± 1.2 l/min to 4.6 ± 1.6 l/min (p = 0.001). Nesiritide was also associated with a significant vasodilatory effect on the large conductance renal arteries resulting in an increase in renal artery diameter from 6.2 ± 0.7 mm to 6.7 ± 0.8 mm (p < 0.001). At the same time, there was a concomitant fall in mean renal artery pressure (99 ± 17 mm Hg to 89 ± 13 mm Hg, p = 0.002) and renal blood flow velocity time integral (27 ± 15 cm/beat to 23 ± 15 cm/beat, p = 0.008) and, therefore, no significant change in renal blood flow or renal vascular resistance.

The nesiritide effect on the renal circulation in patients with HF is complex, with a marked vasodilatory action on the large, conductance renal arteries but a concomitant fall in velocity time integral and no effect on renal vascular resistance or renal blood flow. Lack of increase in renal blood flow may be due to a fall in renal blood pressure or an intrarenal vasoconstrictive effect.

The degree of mechanical dyssynchrony has been suggested as a predictor of response to cardiac resynchronization therapy. There have been no published reports of dyssynchrony assessment with the use of CT.

Thirty-eight subjects underwent electrocardiogram-gated contrast-enhanced 64-slice multidetector CT. The left ventricular endocardial and epicardial boundaries were delineated from short-axis images reconstructed at 10% phase increments of the cardiac cycle. Global and segmental CT dyssynchrony metrics that used changes in wall thickness, wall motion, and volume over time were assessed for reproducibility. We defined a global metric using changes in wall thickness as the dyssynchrony index (DI).

The DI was the most reproducible metric (interobserver and intraobserver intraclass correlation coefficients ≥0.94, p < 0.0001) and was used to determine differences between the 3 groups: HF-wide QRS group (ejection fraction [EF] 22 ± 8%, QRS 163 ± 28 ms), HF-narrow QRS (EF 26 ± 7%, QRS 96 ± 11 ms), and age-matched control subjects (EF 64 ± 5%, QRS 87 ± 9 ms). Mean DI was significantly different between the 3 groups (HF-wide QRS: 152 ± 44 ms, HF-narrow QRS: 121 ± 58 ms, and control subjects: 65 ± 12 ms; p < 0.0001) and greater in the HF-wide QRS (p < 0.0001) and HF-narrow QRS (p = 0.005) groups compared with control subjects. We found that DI had a good correlation with 2-dimensional (r = 0.65, p = 0.012) and 3-dimensional (r = 0.68, p = 0.008) echocardiographic dyssynchrony.

Quantitative assessment of global CT-derived DI, based on changes in wall thickness over time, is highly reproducible and renders significant differences between subjects most likely to have dyssynchrony and age-matched control subjects.

Multidetector computed tomography (MDCT) permits study of cardiac chamber size, function, and mass. Age- and gender-specific mean values are not available.

A total of 103 normotensive, nonobese adults (43% women, age 51 ± 14 years) who presented consecutively to 2 medical centers for clinically indicated MDCTs with neither history of nor MDCT evidence of significant cardiovascular disease were studied for left ventricular (LV) and right ventricular (RV) end-systolic (ES) and end-diastolic (ED) linear dimensions and volumes; LV and RV ejection fraction (EF), and LV mass (LVM); and left atrial (LA) and right atrial (RA) end-systolic volumes (LAESV and RAESV, respectively) by 1-dimensional (1D), 2-dimensional (2D), and 3-dimensional (3D) measurements.

The LV volumes using 3D techniques were lower than 2D techniques (LVEDV mean 144 ± 71 ml vs. 150 ± 70 ml), with higher LVEF (63 ± 15% vs. 57 ± 13%) (p < 0.001 for both). Mean LVM/height^2.7 was 24.3 ± 11.0 g/m^2.7 and mean relative wall thickness was 0.16 to 0.44. Evaluation by 20 versus 10 cardiac phases resulted in higher LVEF (mean difference: 3.4 ± 9.0%, p < 0.001). For LVEDV, interobserver (r = 0.99, p < 0.001) and intraobserver (r² = 0.97, p < 0.001) correlations were high. Mean RVEDV was 82 ± 57 ml and RVEF was 58 ± 16. The LAESV determined by 3D techniques was higher than by that determined by 2D methods (102 ± 48 ml vs. 87 ± 57 ml, p = 0.0003). The RAESV determined by 3D techniques was 111.9 ± 29.1 ml. The LV size and LVM were greater in men than in women (p < 0.01). The LV size declined with age (p < 0.01), but LVM did not.

This study establishes age- and gender-specific values for LV, RV, LA, and RA size, function, and mass in adults free of cardiovascular disease, hypertension, and obesity using 1D, 2D, and 3D methods. These data can be used as a reference for future MDCT studies.