Direct measurement of vena contracta area by real-time 3-dimensional echocardiography for assessing severity of mitral regurgitation.

We tested the hypothesis that the vena contracta (VC) cross-sectional area in patients with mitral regurgitation (MR) can be reproducibly measured by real-time 3-dimensional (3D) echocardiography and correlates well with the volumetric effective regurgitant orifice area (EROA). Earlier MR repair requires accurate noninvasive measures, but practically, the VC area is difficult to image in 2-dimensional views, which are often oblique to it. 3D echocardiography can provide an otherwise unobtainable true cross-sectional view. In 45 patients with mild or greater MR, 44% eccentric, 2-dimensional and 3D VC areas were measured and correlated with the EROA derived from the regurgitant stroke volume. Real-time 3D echocardiography of the VC area correlated and agreed well with the EROA for both central and eccentric jets (r(2) = 0.86, SEE 0.02 cm(2), difference 0.04 +/- 0.06 cm(2), p = NS). For eccentric jets, 2-dimensional echocardiography overestimated the VC width compared with 3D echocardiography (p = 0.024) and correlated more poorly with the EROA (r(2) = 0.61 vs 0.85, p <0.001), causing clinical misclassification in 45% of patients with eccentric MR. The interobserver variability for the 3D VC area was 0.03 cm(2) (7.5% of the mean, r = 0.95); the intraobserver variability was 0.01 cm(2) (2.5% of the mean, r = 0.97). In conclusion, real-time 3D echocardiography accurately and reproducibly quantified the vena contracta cross-sectional area in patients with both central and eccentric MR. Rapid acquisition and intuitive analysis promote practical clinical application of this central, directly visualized, measure and its correlation with outcome.

Assessment of right ventricular function by real-time three-dimensional echocardiography improves accuracy and decreases interobserver variability compared with conventional two-dimensional views.

AIMS: Two-dimensional echocardiographic (2DE) assessment of right ventricular (RV) function is difficult, often resulting in inconsistent RV evaluation. Real-time three-dimensional echocardiography (RT3DE) allows the RV to be viewed in multiple planes, which can potentially improve RV assessment and limit interobserver variability when compared with 2DE. METHODS AND RESULTS: Twenty-five patients underwent 2DE and RT3DE. Views of 2DE (RV inflow, RV short axis, and apical four-chamber) were compared with RT3DE views by four readers. RT3DE data sets were sliced from anterior-posterior (apical view) and from base to apex (short axis) to obtain six standardized planes. Readers recorded the RV ejection fraction (RVEF) from 2DE and RT3DE images. RVEF recorded by RT3DE (RVEF(3D)) and 2D (RVEF(2D)) were compared with RVEF by disc summation (RVEF(DS)), which was used as a reference. Interobserver variability among readers of RVEF(3D) and RVEF(2D) was then compared. Overall, mean RVEF(DS), RVEF(3D), and RVEF(2D) were 37 +/- 11%, 38 +/- 10%, 41 +/- 10%, respectively. The mean difference of RVEF(3D)-RVEF(DS) was significantly less than RVEF(2D)-RVEF(DS) (3.7 +/- 4% vs. 7.1 +/- 5%, P = 0.0066, F-test). RVEF(3D) correlated better with RVEF(DS) (r = 0.875 vs. r = 0.69, P = 0.028, t-test). RVEF(3D) was associated with a 39% decrease in interobserver variability when compared with RVEF(2D) [standard deviation of mean difference: 3.7 vs. 5.1, (RT3DE vs. 2DE), P = 0.018, t-test]. CONCLUSIONS: RT3DE provides improved accuracy of RV function assessment and decreases interobserver variability when compared with 2D views.

Assessing mitral valve area and orifice geometry in calcific mitral stenosis: a new solution by real-time three-dimensional echocardiography.

BACKGROUND: Planimetry of mitral valve area (MVA) is difficult in calcific mitral stenosis (CaMS) in which limiting orifice is near the annulus, and unlike rheumatic mitral stenosis (RhMS), does not present an area for planimetry at the leaflet tips. Moreover, pressure half time (PHT)-derived MVA (MVA(PHT)) has limitations in patients with CaMS in whom there are coexisting conditions that affect LV chamber compliance. We tested the hypothesis that real-time 3-dimensional echocardiography (RT3D) can guide measurement at the narrowest orifice in CaMS. METHODS: In 34 patients with CaMS, MVA by RT3D (MVA(RT3D)) was obtained using a color-defined planimetry technique performed "en face" at the smallest annular orifice cross-section (diastolic maximum). MVA(RT3D) and MVA(PHT) were compared with an independent standard: MVA by continuity equation (MVA(CEQ)). In a subgroup of 10 patients with CaMS or RhMS, the 3-dimensional shape of the stenotic mitral valve was examined, guided by color flow mapping. RESULTS: MVA(PHT) overestimated the mitral orifice area compared with MVA(CEQ) (2.01 +/- 0.52 cm(2) vs 1.75 +/- 0.46 cm(2); P = .037), whereas there was no significant difference in MVA(RT3D) and MVA(CEQ) (1.83 +/- 0.52 cm(2) vs 1.75 +/- 0.46 cm(2), respectively, P = .61). MVA(RT3D) had a greater correlation with MVA (CEQ) than MVA(PHT) (R = 0.86 vs 0.59 MVA(RT3D) vs MVA(PHT), respectively). There was better agreement between MVA by RT3D and MVA by continuity equation than MVA by PHT and MVA by continuity equation (difference in MVA: 0.23 +/- 0.15 cm(2) vs 0.43 +/- 0.29 cm(2); P < .0001, MVA(RT3D) - MVA(CEQ) vs MVA(PHT) - MVA(CEQ,) respectively). In CaMS, there was a tubular geometry to the valve shape. In contrast, RhMS had a doming funnel-shaped geometry. CONCLUSION: RT3D provides an accurate measurement of MVA in CaMS. In contrast with the doming valve shape present in RhMS, the limiting anatomic orifice area occurs at the annulus in CaMS as measured by RT3D and reflects the effective orifice area as present in a tubular valve geometry.

Progressive nature of chronic mitral regurgitation and the role of tissue Doppler-derived indexes.

The aim of this study was to determine whether severe mitral regurgitation (MR) is progressive and whether tissue-Doppler (TD)-derived indexes can detect early left ventricular (LV) dysfunction in chronic severe MR. Percutaneous rupture of mitral valve chordae was performed in pigs (n = 8). Before MR (baseline), immediately after MR (post-MR), and at 1 and 3 mo after MR, cardiac function was assessed using conventional and TD-derived indexes. The severity of MR was quantified using regurgitant fraction and effective regurgitant orifice area (EROA). In all animals, MR was severe. On follow-up, the LV dilated progressively over time, but LV ejection fraction did not decrease. With the increase in LV dimensions, the forward stroke volume remained unchanged, but the mitral annular dimensions, EROA, and regurgitant fraction increased (EROA = 41 +/- 2 and 51 +/- 2 mm(2) post-MR and at 3 mo, respectively, P < 0.01). Peak systolic myocardial velocities, strain, and strain rate increased acutely post-MR and remained elevated at 1 mo but declined by 3 mo (anterior strain rate = 2.9 +/- 0.1 and 2.4 +/- 0.2 s(-1) post-MR and at 3 mo, respectively, P < 0.001). Therefore, in a chronic model of MR, serial echocardiography demonstrated that MR begets MR and that those TD-derived indexes that initially increased post-MR decreased to baseline before any changes in LV ejection fraction.

Myocardial adaptation and efficiency in response to intensive physical training in elite speedskaters.

BACKGROUND: Physiological cardiac adaptations to exercise training resulting in the 'athlete's heart' are well known. Most of these studies, however, were included either those who exercise to exhaustion, non-elite athletes or those who participate primarily in sports requiring extensive weight training. Studies utilizing conventional and tissue Doppler echocardiographic studies in highly competitive elite athletes whose training includes both aerobic and weight training are limited. AIMS AND METHODS: 1) To identify baseline cardiovascular structural and physiologic adaptations present in elite athletes who participate in both endurance aerobic and weight training programs and to compare them to similarly aged sedentary controls. The population includes 24 speedskaters participating in the 2006 Olympic Games and 15 sedentary young subjects. 2) To evaluate possible structural and physiologic cardiac changes following short duration, vigorous exercise. We repeated the baseline echocardiographic protocol in the athletes following a 3000 m sprint conducted at race pace. RESULTS: Compared to non-athletes, the atrial and left ventricular (LV) volumes at rest were larger in elite athletes. There was enhanced LV diastolic function as manifested by higher early annular (septal and lateral) tissue Doppler velocities (E'): 12.7+/-2.3 vs 11.3+/-1.1 cm/s and 17.4+/-4.7 vs 14.4+/-1.2 cm/s, P=0.025 and 0.020 respectively. Evidence of right ventricular (RV) remodeling included larger basal RV dimensions (38+/-5 vs 32+/-4 mm, P=0.001), attenuated RV systolic function at rest (RV area change 35+/-13% in athletes vs 47+/-11% in controls, P=0.006) and lower RV systolic strain rate (SSR) 1.9+/-0.5 vs 2.9+/-1.1/s, P<0.001). However, there was better right ventricular (RV) diastolic function at rest, E': 13.5+/-3.6 vs 11.1+/-1.5 cm/s (P=0.016). Following exercise, the athletes exhibited augmentation of RV systolic function with increased RV fractional area change (increasing to 43+/-10%, P=0.007) and SSR (2.5+/-1.2/s post-exercise, P=0.038). CONCLUSION: Participation by world-class speedskaters in a vigorous training regimen results in cardiovascular anatomic and physiologic adaptations. These changes, including cardiac chamber dilatation, enhanced ventricular diastolic function and attenuated resting RV systolic function, are likely adaptive and allow for more efficient energy use at rest and a robust response to demands of exercise.

Myocardial injury and ventricular dysfunction related to training levels among nonelite participants in the Boston marathon.

BACKGROUND: Multiple studies have individually documented cardiac dysfunction and biochemical evidence of cardiac injury after endurance sports; however, convincing associations between the two are lacking. We aimed to determine the associations between the observed transient cardiac dysfunction and biochemical evidence of cardiac injury in amateur participants in endurance sports and to elicit the risk factors for the observed injury and dysfunction. METHODS AND RESULTS: We screened 60 nonelite participants, before and after the 2004 and 2005 Boston Marathons, with echocardiography and serum biomarkers. Echocardiography included conventional measures as well as tissue Doppler-derived strain and strain rate imaging. Biomarkers included cardiac troponin T (cTnT) and N-terminal pro-brain natriuretic peptide (NT-proBNP). All subjects completed the race. Echocardiographic abnormalities after the race included altered diastolic filling, increased pulmonary pressures and right ventricular dimensions, and decreased right ventricular systolic function. At baseline, all had unmeasurable troponin. After the race, > 60% of participants had increased cTnT > 99th percentile of normal (> 0.01 ng/mL), whereas 40% had a cTnT level at or above the decision limit for acute myocardial necrosis (> or = 0.03 ng/mL). After the race, NT-proBNP concentrations increased from 63 (interquartile range [IQR] 21 to 81) pg/mL to 131 (IQR 82 to 193) pg/mL (P<0.001). The increase in biomarkers correlated with post-race diastolic dysfunction, increased pulmonary pressures, and right ventricular dysfunction (right ventricular mid strain, r=-0.70, P<0.001) and inversely with training mileage (r=-0.71, P<0.001). Compared with athletes training > 45 miles/wk, athletes who trained < or = 35 miles/wk demonstrated increased pulmonary pressures, right ventricular dysfunction (mid strain 16+/-5% versus 25+/-4%, P<0.001), myocyte injury (cTnT 0.09 versus < 0.01 ng/mL, P<0.001), and stress (NT-proBNP 182 versus 106 pg/mL, P<0.001). CONCLUSIONS: Completion of a marathon is associated with correlative biochemical and echocardiographic evidence of cardiac dysfunction and injury, and this risk is increased in those participants with less training.

Myocardial adaptation to short-term high-intensity exercise in highly trained athletes.

We aimed to clarify the myocardial adaptation to short-term high-intensity exercise among trained athletes. We screened 17 participants in the 2004 World Indoor Rowing Championships before and after a 2000-m sprint. Echocardiography included standard measurements and tissue Doppler-derived strain (epsilon), strain rate, and 2-dimensionally derived speckle-tracking imaging for left ventricular (LV) torsion. LV volumes and ejection fraction were unchanged after exercise. There was a reduction in early and an increase in late diastolic filling velocities and a decrease in the flow propagation velocity. Annular systolic velocities, slope of the systolic acceleration, septal and lateral epsilon, and speckle tracking-derived torsion were increased. The increased LV torsion was a result of increased basal and apical rotation. Right ventricular apical epsilon decreased. In conclusion, maximal intensity short-duration exercise was associated with attenuation of LV diastolic function, augmentation of LV systolic function, and a reduction in apical right ventricular contractility.

Geometric determinants of functional tricuspid regurgitation: insights from 3-dimensional echocardiography.

BACKGROUND: Tricuspid regurgitation (TR) is an important predictor of morbidity and mortality in heart failure. We aimed to examine the 3D geometry of the tricuspid valve annulus (TVA) in patients with functional TR, comparing them with patients with normal tricuspid valve function and relating annular geometric changes to functional TR. METHODS AND RESULTS: TVA shape was examined by real-time 3D echocardiography in 75 patients: 35 with functional TR and 40 with normal tricuspid valve function (referent group). The 3D shape of the TVA was reconstructed from rotated 2D planes, and the annular plane was computed by least-squares fitting. Annular area and mediolateral, anteroposterior, and high (superior)-low (inferior) distances were calculated. TR was assessed by vena contracta width. The normal TVA has a bimodal pattern (high-low distance=7.23+/-1.05 mm). High points were located anteroposteriorly, and low points were located mediolaterally. With moderate or greater TR (vena contracta width 5.80+/-2.62 mm), the TVA became dilated (17.24+/-4.75 versus 9.83+/-2.18 cm2, P<0.0001, TR versus referent), more planar with decreased high-low distance (4.14+/-1.05 mm), and more circular with decreased ratio of mediolateral/anteroposterior (1.11+/-0.09 versus 1.32+/-0.09, P<0.0001, TR versus referent). CONCLUSIONS: The normal TVA has a bimodal shape with distinct high points located anteroposteriorly and low points located mediolaterally. With functional TR, the annulus becomes larger, more planar, and circular. These changes in annular shape with TR have potentially important mechanistic and therapeutic implications for tricuspid valve repair.