Megan Yamat

3D Echocardiographic Location of Implantable Device Leads and Mechanism of Associated Tricuspid Regurgitation

OBJECTIVES This study sought to: 1) determine the feasibility of using 3-dimensional transthoracic echocardiography (3D TTE) in patients with implantable cardiac resynchronization devices, pacemakers, and defibrillators to visualize the device leads in the right heart and their position relative to the tricuspid valve leaflets; 2) determine the prevalence of different lead positions; and 3) study the relationship between lead location and tricuspid regurgitation (TR) severity. BACKGROUND Pacemaker, defibrillator, and cardiac resynchronization device implantation is currently guided by fluoroscopy, not allowing targeted lead positioning relative to the tricuspid valve leaflets. These leads have been reported to cause TR of variable degrees, but echocardiography is not routinely used to elucidate the mechanisms of lead interference with tricuspid valve leaflets in individual patients. METHODS 3D TTE full-volume images of the right ventricle and/or zoomed images of the tricuspid valve were obtained in 121 patients with implanted devices. Images were viewed offline to determine the position of the device-lead relative to the tricuspid valve leaflets. Severity of TR was estimated on the basis of vena contracta measurements. RESULTS 3D TTE clearly depicted lead position in 90% of patients. The right ventricular lead was impinging on either the posterior (20%) or septal (23%) leaflet or was not interfering with leaflet motion (53%) when positioned near the posteroseptal commissure or in the central portion of the tricuspid valve orifice. In the remaining patients, leads were impinging on the anterior leaflet (4%) or positioned in either the anteroposterior or anteroseptal commissure (3%). Leads interfering with normal leaflet mobility were associated with more TR than nonimpinging leads (vena contracta: median 0.62 cm [1st and 3rd quartiles: 0.51, 0.84 cm] vs. 0.27 cm [1st and 3rd quartiles: 0.00, 0.48 cm]; p < 0.001). CONCLUSIONS 3D TTE showed a clear association between device lead position and TR. To minimize TR induced by device-leads, 3D TTE guidance should be considered for placement in a commissural position.

Right Ventricular Strain in Pulmonary Arterial Hypertension: A 2D Echocardiography and Cardiac Magnetic Resonance Study

Right ventricular (RV) strain is a potentially useful prognostic marker in patients with pulmonary arterial hypertension (PAH). However, published reports regarding the accuracy of two‐dimensional echocardiography (2DE)‐derived RV strain against an independent reference in this patient population are limited. The aims of this study were: (1) to study the relationship between 2DE RV longitudinal strain and cardiovascular magnetic resonance (CMR)‐derived RV ejection fraction (RVEF) in patients with PAH; (2) to compare 2DE‐derived and CMR‐derived RV longitudinal strain in these patients; and (3) to determine the reproducibility of these measurements.

Impact of Implantable Transvenous Device Lead Location on Severity of Tricuspid Regurgitation

BACKGROUND Implantable device leads can cause tricuspid regurgitation (TR) when they interfere with leaflet motion. The aim of this study was to determine whether lead-leaflet interference is associated with TR severity, independent of other causative factors of functional TR. METHODS A total of 100 patients who underwent transthoracic two-dimensional and three-dimensional (3D) echocardiography of the tricuspid valve before and after lead placement were studied. Lead position was classified on 3D echocardiography as leaflet-interfering or noninterfering. TR severity was estimated by vena contracta (VC) width. Logistic regression analysis was used to identify factors associated with postdevice TR, including predevice VC width, right ventricular end-diastolic and end-systolic areas, fractional area change, right atrial size, tricuspid annular diameter, TR gradient, device lead age, and presence or absence of lead interference. Odds ratios were used to describe the association with moderate (VC width ≥ 0.5 cm) or severe (VC width ≥ 0.7 cm) TR, separately, using bivariate and stepwise multivariate logistic regression analysis. RESULTS Forty-five of 100 patients showed device lead tricuspid valve leaflet interference. The septal leaflet was the most commonly affected (23 patients). On bivariate analysis, preimplantation VC width, right atrial size, tricuspid annular diameter, and lead-leaflet interference were significantly associated with postdevice TR. On multivariate analysis, preimplantation VC width and the presence of an interfering lead were independently associated with postdevice TR. Furthermore, the presence of an interfering lead was the only factor associated with TR worsening, increasing the likelihood of developing moderate or severe TR by 15- and 11-fold, respectively. CONCLUSION Lead-leaflet interference as seen on 3D echocardiography is associated with TR after device lead placement, suggesting that 3D echocardiography should be used to assess for lead interference in patients with significant TR.

Quantification of Right Ventricular Size and Function from Contrast-Enhanced Three-Dimensional Echocardiographic Images

Background: Three‐dimensional (3D) echocardiography directly assesses right ventricular (RV) volumes without geometric assumptions, despite the complex shape of the right ventricle, and accordingly is more accurate and reproducible than the two‐dimensional methodology, which is able to measure only surrogate parameters of RV function. Volumetric analysis has been hampered by frequent inability to clearly visualize RV endocardium, especially the RV free wall, in 3D echocardiographic images. The aim of this study was to test the hypothesis that RV contrast enhancement during 3D echocardiographic imaging would improve the accuracy of RV volume and function analysis. Methods: Thirty patients with a wide range of RV size and function and image quality underwent transthoracic 3D echocardiography with and without contrast enhancement and cardiovascular magnetic resonance imaging on the same day. RV end‐diastolic and end‐systolic volumes and ejection fraction were measured from contrast‐enhanced and nonenhanced 3D echocardiographic images and compared with cardiovascular magnetic resonance reference values using linear regression and Bland‐Altman analyses. Blinded repeated measurements were performed to assess measurement variability. Results: RV contrast enhancement was feasible in all patients. RV volumes obtained both with and without contrast enhancement correlated highly with cardiovascular magnetic resonance (end‐diastolic volume, r = 0.90 and r = 0.92; end‐systolic volume, r = 0.92 and r = 0.94, respectively), but the correlation for ejection fraction was better with contrast (r = 0.87 vs r = 0.70). Biases were smaller with contrast for all three parameters (end‐diastolic volume, −16 ± 23 vs −36 ± 25 mL; end‐systolic volume, −10 ± 16 vs −23 ± 18 mL; ejection fraction, −0.7 ± 5.5% vs −2.7 ± 8.1% of the mean measured values), reflecting improved accuracy. Also, measurement reproducibility was improved by contrast enhancement. Conclusions: Contrast enhancement improves the visualization of RV endocardial borders, resulting in more accurate and reproducible 3D echocardiographic measurements of RV size and function. This approach may be particularly useful in patients with suboptimal image quality. HighlightsWe hypothesized that contrast enhancement during 3D echocardiographic imaging would improve the accuracy of RV volume and function analysis.This hypothesis was tested by comparing measurements obtained from nonenhanced and contrast‐enhanced images against cardiac magnetic resonance reference images.Contrast enhancement improved the visualization of RV endocardial borders, resulting in more accurate and more reproducible measurements.This approach may be particularly useful in patients with suboptimal image quality. Abbreviations: 2D = Two‐dimensional; 3D = Three‐dimensional; CMR = Cardiovascular magnetic resonance; EDV = End‐diastolic volume; ESV = End‐systolic volume; LV = Left ventricular; RV = Right ventricular; RVEF = Right ventricular ejection fraction; RVOT = Right ventricular outflow tract.

Diagnosis of Isolated Cleft Mitral Valve Using Three-Dimensional Echocardiography

Background: The prevalence of isolated cleft mitral valve (MV; no concomitant congenital heart disease or degenerative MV disease) with significant mitral regurgitation (MR) diagnosed using two‐dimensional echocardiography (2DE) has been reported to be very low. Three‐dimensional echocardiography (3DE) has enabled a more comprehensive visualization of the MV and detailed understanding of the mechanisms of MR and can potentially reveal isolated cleft MV that is not recognized with 2DE. The aim of this study was to determine, using 3DE, the prevalence, location, and associated MV annular and left ventricular characteristics of isolated cleft MV, in the absence of associated congenital heart disease, in patients with significant MR. Methods: A total of 1,092 patients with unexplained moderate or greater MR on two‐dimensional transthoracic echocardiography who were referred for three‐dimensional transesophageal echocardiography between 2005 and 2017 (n = 626) were retrospectively studied. Left ventricular dimensions and function were determined, and quantitative MR assessment and three‐dimensional analysis of the MV annulus was performed. Results: Twenty‐one patients (prevalence 3.3%) were diagnosed with isolated cleft MV using three‐dimensional transesophageal echocardiography but not 2DE. The majority of these patients (n = 16) were noted to have anterior cleft MVs, with most located in the mid‐A1 (n = 10) or mid‐A3 (n = 5) scallops. Posterior clefts were less common (n = 5) and occurred at the site of the natural scallop indentations (three between P1 and P2 and two between P2 and P3). Among patients with either anterior or posterior MV cleft, there were no differences in left ventricular ejection fraction or three‐dimensional MV geometry (annular distance, height, circumference, and area). There was a trend toward worse MR severity in patients with anterior cleft MV. Conclusions: In patients with otherwise unexplained significant MR referred for transesophageal echocardiography, 3DE uncovered a considerably higher prevalence of isolated cleft MV than previously reported by 2DE, with the majority located in the anterior MV. Although the annular geometry was similar between patients with anterior and posterior cleft MVs, a trend toward more severe MR in anterior clefts may reflect underlying abnormalities in the embryologic development of the anterior MV leaflet. Evaluation of MV pathology is improved by 3DE, which should be used routinely in the setting significant MR. HIGHLIGHTSUsing 3DE, isolated cleft MV is more prevalent than previously reported.The majority of isolated cleft MV are located on the anterior MV leaflet.Patients with isolated cleft MV on the anterior leaflet tend to have more MR.3DE should be utilized when evaluating patients with MR of unclear etiology.

Load Dependency of Left Atrial Strain in Normal Subjects

Background: Left atrial (LA) longitudinal strain is a novel parameter used for the evaluation of LA function, with demonstrated prognostic value in several cardiac diseases. However, the extent of load dependency of LA strain is not well known. The aim of this study was to evaluate the impact of acute changes in preload on LA strain, side by side with LA volume, in normal subjects. Methods: Twenty‐five healthy volunteers (13 men; mean age, 31 ± 2 years) were prospectively enrolled, who underwent two‐dimensional and three‐dimensional echocardiographic imaging during acute stepwise reductions in preload using a tilt maneuver: baseline at 0°, followed by 40° and 80°. Left ventricular and LA size and function parameters were measured using standard methodology, and LA strain‐time curves were obtained using speckle‐tracking software (TomTec), resulting in reservoir, conduit, and contractile strain components. All parameters were compared among the three loading conditions using one‐way analysis of variance for repeated measurements. Results: Although there were no significant changes in blood pressure, heart rate increased significantly with tilt. As expected, LA volumes, left ventricular volumes, and left ventricular ejection fraction, as well as E wave, A wave, and e′ significantly decreased with progressive inclination. In parallel, LA reservoir, conduit, and contractile strain values decreased with reduction in preload (reservoir: 42.9 ± 3.9% to 27.5 ± 3.8%, P < .001; conduit: 29.3 ± 2.7% to 20.2 ± 5.0%, P < .001; contractile: 13.6 ± 2.9% to 7.3 ± 3.5%, P < .001). Paired post hoc analysis showed that all LA strain values were significantly different among all three tilt phases. Of note, percentage change in LA reservoir strain was significantly smaller than that in LA maximum volume. Conclusions: In normal subjects, LA strain is preload dependent but to a lesser degree than LA volume. This difference underscores the relative advantage of LA strain over maximum volume, when LA assessment is used as part of the diagnostic paradigm. HIGHLIGHTSWe studied the impact of preload changes on LA strain and volume in normal subjects.LA strain is preload dependent, but to a lesser degree than LA volume.Left atrial strain should be interpreted while taking into account loading conditions.

Residual native left ventricular function optimization using quantitative 3D echocardiographic assessment of rotational mechanics in patients with left ventricular assist devices

Preservation of native left ventricular (LV) function in patients supported with LV assist device (LVAD) may be beneficial to attain optimal hemodynamics and enhance potential recovery. Currently, LVAD speed optimization is based on hemodynamic parameters, without considering residual native LV function. We hypothesized that alternatively, LV rotational mechanics can be quantified by 3D echocardiography (3DE), and may help preserve native LV function while optimizing LVAD speed. The goal of this study was to test the feasibility of quantifying the effects of LVAD implantation on LV rotational mechanics and to determine whether conventional speed optimization maximally preserves native LV function. We studied 55 patients with LVADs, who underwent 3DE imaging and quantitative analysis of LV twist. Thirty patients were studied before and after LVAD implantation. The remaining 25 patients were studied during hemodynamic ramp studies. The pump speed at which LV twist was maximal was compared with the hemodynamics‐based optimal speed. LV twist decreased following LVAD implantation from 4.2 ± 2.7 to 2.3 ± 1.9° (P < 0.01), reflecting the constricting effects on native function. With lower pump speeds, no significant changes were noted in LV twist, which peaked at a higher speed. In 11/25 (44%) patients, the conventional hemodynamic/2DE methodology and 3DE assessment of maximal residual function did not indicate the same optimal conditions, suggesting that a higher pump speed would have better preserved native function. In conclusion, quantitative 3DE analysis of LV rotational mechanics provides information, which together with hemodynamics may help select optimal pump speed, while maximally preserving native LV function.

Three-dimensional echocardiography based evaluation of right ventricular remodeling in patients with pressure overload

Although 3D echocardiography (3DE) allows imaging of right ventricular (RV) morphology, regional RV remodeling has not been evaluated using 3DE. We developed a technique to quantify regional RV shape and tested its ability to characterize RV shape in normal subjects and in patients with RV pressure overload. Transthoracic 3DE images were acquired in 54 subjects (39 patients with pulmonary artery hypertension, PAH, and 15 normal controls, NL). 3D RV surfaces were reconstructed at end-diastole and end-systole (ED, ES) and analyzed using custom software to calculate 3D mean curvature of the inflow and outflow tracts, apex and body (both divided into free-wall and septum). Septal segments in NLs were characterized by concavity (curvature<;O) in ED and slight convexity (curvature>O) in ES. Conversely, the septum remained convex throughout the cardiac cycle in P AH. In the NL group, the body free-wall transitioned from a convex surface to a more flattened surface during contraction, while the convexity of the apex free-wall increased. In contrast, in PAH, both RV free-wall segments remained equally convex throughout the cardiac cycle. Curvature analysis using 3DE allows quantitative evaluation of RV remodeling, which could be used to track diferential changes in regional RV shape, as a way to assess disease progression or regression.

Malcoaptation of the pulmonary valve diagnosed using transthoracic 3D echocardiography

A 41-year-old woman with a history of type II diabetes, congestive heart failure, and pulmonary embolism was admitted for accidental burns on both her lower extremities due to severe peripheral neuropathy. During her hospitalization, a transthoracic echocardiogram (TTE) was ordered to evaluate a murmur heard on physical examination. The echocardiogram revealed a dilated cardiomyopathy with a …

IMPACT OF LEAD LOCATION AS DETERMINED BY 3D ECHOCARDIOGRAPHY ON TRICUSPID REGURGITATION SEVERITY POST IMPLANTABLE DEVICE PLACEMENT

methods: We studied 75 patients (67±16 yrs) with device leads who had 2D and 3D transthoracic echocardiographic images of the right ventricle (RV) and tricuspid valve preand post device lead placement (DLP). Lead position was determined on cropped 3D images and classified as either impinging or non-impinging on a leaflet. TR severity was estimated by vena contracta (VC). Logistic regression analyses were used to identify factors associated with post-DLP TR among: RV end-diastolic and end-systolic area, fractional area change, tricuspid annular diameter, TR gradient, device lead age, lead impingement and pre-DLP VC.