G. Hamilton Baker

Transthoracic real-time three-dimensional echocardiography in the diagnosis and description of noncompaction of ventricular myocardium.

Background: Numerous modalities have been used to diagnose and characterize noncompaction of ventricular myocardium (NCVM) including magnetic resonance imaging, two‐dimensional echocardiography (2DE), contrast‐enhanced 2DE, and angiography. The current case series examines the use of real‐time three‐dimensional transthoracic echocardiography (RT‐3DE) in four such cases of NCVM. Methods: From December 2003 to March 2004, we performed RT‐3DE using a Philips Sonos 7500 echocardiographic scanner equipped with a 2–4 MHz 3D matrix array transthoracic probe, to evaluate four patients with NCVM. The real‐time 3D transthoracic probe allows for dataset acquisition in an ultrasound wedge, which can be manipulated instantaneously. In addition, complete 3D volume rendering is acquired, allowing for volumetric imaging. Results: The age range of the patients was 2 months to 42 years. One patient had the codiagnoses of coarctation of the aorta and bicuspid aortic valve. In all four patients, RT‐3DE enabled diagnosis and provided detailed characterization of the affected myocardium. Entire trabecular projections and intertrabecular recesses were easily visualized simultaneously, and endocardial borders were clearly demarcated. Wall motion abnormalities of the affected myocardium were clearly visualized. The compacted and noncompacted portions of the myocardium could be differentiated well. Conclusions: Our study provides preliminary data highlighting the utility and feasibility of RT‐3DE in the clinical characterization of NCVM. The complex 3D nature of this disorder and the endocardial hypertrabeculation were more readily visualized than with 2DE.

Usefulness of Live Three-Dimensional Transesophageal Echocardiography in a Congenital Heart Disease Center

Three-dimensional (3D) transesophageal echocardiography (TEE) has numerous potential applications in the care of patients with congenital heart disease (CHD). However, there were few data examining its utility in this setting. The aim was to describe the initial experience and feasibility of this modality at a tertiary CHD center. Twenty-seven 3D-TEE studies using the x7-2t live 3D matrix TEE transducer with an iE33 echocardiographic scanner (Philips Medical Systems, Bothell, Washington) were attempted. The utility of this method was examined in the 3 settings of interventional catheterizations (n = 16), intraoperative studies (n = 4), and diagnostic studies (n = 7). The probe was successfully inserted in 26 of 27 patients (weight 22.6 to 110 kg). In conclusion, the current matrix-array 3D-TEE probe was found to have a wide variety of clinical applications in a CHD center.

Intervention for Recoarctation in the Single Ventricle Reconstruction Trial Incidence, Risk, and Outcomes

Background— Recoarctation after the Norwood procedure increases risk for mortality. The Single Ventricle Reconstruction (SVR) trial randomized subjects with a single right ventricle undergoing a Norwood procedure to a modified Blalock-Taussig shunt or a right ventricle–pulmonary artery shunt. We sought to determine the incidence of recoarctation, risk factors, and outcomes in the SVR trial. Methods and Results— Recoarctation was defined by intervention, either catheter based or surgical. Univariate analysis and multivariable Cox proportional hazard models were performed with adjustment for center. Of the 549 SVR subjects, 97 (18%) underwent 131 interventions (92 balloon aortoplasty, 39 surgical) for recoarctation at a median age of 4.9 months (range, 1.1–10.5 months). Intervention typically occurred at pre–stage II catheterization (n=71, 54%) or at stage II surgery (n=38, 29%). In multivariable analysis, recoarctation was associated with the shunt type in place at the end of the Norwood procedure (hazard ratio, 2.0 for right ventricle–pulmonary artery shunt versus modified Blalock-Taussig shunt; P=0.02), and Norwood discharge peak echo-Doppler arch gradient (hazard ratio, 1.07 per 1 mm Hg; P<0.01). Subjects with recoarctation demonstrated comorbidities at pre–stage II evaluation, including higher pulmonary arterial pressures (15.4±3.0 versus 14.5±3.5 mm Hg; P=0.05), higher pulmonary vascular resistance (2.6±1.6 versus 2.0±1.0 Wood units·m2; P=0.04), and increased echocardiographic volumes (end-diastolic volume, 126±39 versus 112±33 mL/BSA1.3, where BSA is body surface area; P=0.02). There was no difference in 12-month postrandomization transplantation-free survival between those with and without recoarctation (P=0.14). Conclusions— Recoarctation is common after Norwood and contributes to pre–stage II comorbidities. Although with intervention there is no associated increase in 1-year transplantation/mortality, further evaluation is warranted to evaluate the effects of associated morbidities. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00115934.

How successful is successful? Aortic arch shape after successful aortic coarctation repair correlates with left ventricular function

Objectives: Even after successful aortic coarctation repair, there remains a significant incidence of late systemic hypertension and other morbidities. Independently of residual obstruction, aortic arch morphology alone may affect cardiac function and outcome. We sought to uncover the relationship of arch 3‐dimensional shape features with functional data obtained from cardiac magnetic resonance scans. Methods: Three‐dimensional aortic arch shape models of 53 patients (mean age, 22.3 ± 5.6 years) 12 to 38 years after aortic coarctation repair were reconstructed from cardiac magnetic resonance data. A novel validated statistical shape analysis method computed a 3‐dimensional mean anatomic shape of all aortic arches and calculated deformation vectors of the mean shape toward each patients arch anatomy. From these deformations, 3‐dimensional shape features most related to left ventricular ejection fraction, indexed left ventricular end‐diastolic volume, indexed left ventricular mass, and resting systolic blood pressure were extracted from the deformation vectors via partial least‐squares regression. Results: Distinct arch shape features correlated significantly with left ventricular ejection fraction (r = 0.42, P = .024), indexed left ventricular end‐diastolic volume (r = 0.65, P < .001), and indexed left ventricular mass (r = 0.44, P = .014). Lower left ventricular ejection fraction, larger indexed left ventricular end‐diastolic volume, and increased indexed left ventricular mass were identified with an aortic arch shape that has an elongated ascending aorta with a high arch height‐to‐width ratio, a relatively short proximal transverse arch, and a relatively dilated descending aorta. High blood pressure seemed to be linked to gothic arch shape features, but this did not achieve statistical significance. Conclusions: Independently of hemodynamically important arch obstruction or residual aortic coarctation, specific aortic arch shape features late after successful aortic coarctation repair seem to be associated with worse left ventricular function. Analyzing 3‐dimensional shape information via statistical shape modeling can be an adjunct to long‐term risk assessment in patients after aortic coarctation repair.

Looks Do Matter! Aortic Arch Shape After Hypoplastic Left Heart Syndrome Palliation Correlates With Cavopulmonary Outcomes

BACKGROUND Aortic arch reconstruction after hypoplastic left heart syndrome (HLHS) palliation can vary widely in shape and dimensions between patients. Arch morphology alone may affect cardiac function and outcome. We sought to uncover the relationship of arch three-dimensional shape features with functional and short-term outcome data after total cavopulmonary connection (TCPC). METHODS Aortic arch shape models of 37 patients with HLHS (age, 2.89 ± 0.99 years) were reconstructed from magnetic resonance data before TCPC completion. A novel, validated statistical shape analysis method was used to compute a three-dimensional anatomic mean shape from the cohort and calculate the deformation vectors of the mean shape toward each patients specific anatomy. From these deformations, three-dimensional shape features most related to ventricular ejection fraction, indexed end-diastolic volume, and superior cavopulmonary pressure were extracted by partial least-square regression analysis. Shape patterns relating to intensive care unit and hospital lengths of stay after TCPC were assessed. RESULTS Distinct deformation patterns, which result in an acutely mismatched aortic root and ascending aorta, and a gothic-like transverse arch, correlated with increased indexed end-diastolic volume and higher superior cavopulmonary pressure but not with ejection fraction. Specific arch morphology with pronounced transverse arch and descending aorta mismatch also correlated with longer intensive care unit and hospital lengths of stay after TCPC completion. CONCLUSIONS Independent of hemodynamically important arch obstruction, altered aortic morphology in HLHS patients appears to have important associations with higher superior cavopulmonary pressure and with short-term outcomes after TCPC completion as highlighted by statistical shape analysis, which could act as adjunct to risk assessment in HLHS.

Interpreting measurements of cardiac function using vendor‐independent speckle tracking echocardiography in children: a prospective, blinded comparison with catheter‐derived measurements

Adult studies demonstrate that echocardiographic measurements of cardiac function using speckle tracking correlate with invasive measurements, but such data in the pediatric population are sparse. Our aim was to compare speckle‐derived measures of cardiac function to measurements routinely obtained by cardiac catheterization in children.

Longitudinal measures of deformation are associated with a composite measure of contractility derived from pressure–volume loop analysis in children

Aims The relationship between echocardiographic measures of left ventricular (LV) systolic function and reference-standard measures have not been assessed in children. The objective of this study was to assess the validity of echocardiographic indices of LV systolic function via direct comparison to a novel composite measure of contractility derived from pressure-volume loop (PVL) analysis. Methods and results Children with normal loading conditions undergoing routine left heart catheterization were prospectively enrolled. PVLs were obtained via conductance catheters. A composite invasive composite contractility index (ICCI) was developed using data reduction strategies to combine four measures of contractility derived from PVL analysis. Echocardiograms were performed immediately after PVL analysis under the same anesthetic conditions. Conventional and speckle-tracking echocardiographic measures of systolic function were measured. Of 24 patients, 18 patients were heart transplant recipients, 6 patients had a small patent ductus arteriosus or small coronary fistula. Mean age was 9.1 ± 5.6 years. Upon multivariable regression, longitudinal strain was associated with ICCI (β = -0.54, P = 0.02) while controlling for indices of preload, afterload, heart rate, and LV mass under baseline conditions. Ejection fraction and shortening fraction were associated with LV mass and load indices, but not contractility. Conclusion Speckle-tracking derived longitudinal strain is associated ICCI in children with normal loading conditions. Longitudinal measures of deformation appear to accurately assess LV contractility in children.

Echocardiographic Detection of Increased Ventricular Diastolic Stiffness in Pediatric Heart Transplant Recipients: A Pilot Study

Background: Pediatric heart transplant recipients are at risk for increased left ventricular (LV) diastolic stiffness. However, the noninvasive evaluation of LV stiffness has remained elusive in this population. The objective of this study was to compare novel echocardiographic measures of LV diastolic stiffness versus gold‐standard measures derived from pressure‐volume loop (PVL) analysis in pediatric heart transplant recipients. Methods: Patients undergoing left heart catheterization were prospectively enrolled. PVLs were obtained via conductance. The end‐diastolic pressure‐volume relationship was obtained via balloon occlusion. The stiffness constant, &bgr;, was calculated. Echocardiographic measures of diastolic function were derived from spectral and tissue Doppler and two‐dimensional speckle‐tracking. Ventricular volumes were measured using three‐dimensional echocardiography. The novel echocardiographic estimates of ventricular stiffness included E:e′/end‐diastolic volume (EDV) and E:early diastolic strain rate/EDV. Results: Of 24 children, 18 were heart transplant recipients. Six control patients had hemodynamically insignificant patent ductus arteriosus or coronary fistula. The mean age was 9.1 ± 5.6 years. Median end‐diastolic pressure was 9 mm Hg (interquartile range, 8–13 mm Hg). Lateral E:e′/EDV (r = 0.59, P < .01), septal E:e′/EDV (r = 0.57, P < .01), and (E:circumferential early diastolic strain rate)/EDV (r = 0.54, P < .01) correlated with &bgr;. Lateral E:e′/EDV displayed a C statistic of 0.93 in detecting patients with abnormal LV stiffness (&bgr; > 0.015 mL−1). A lateral E:e′/EDV of >0.15 mL−1 had 89% sensitivity and 93% specificity in detecting an abnormal &bgr;. Conclusions: Echocardiographic estimates of ventricular stiffness may be accurate compared with the gold standard in pediatric heart transplant recipients. The clinical usefulness of these noninvasive measures in assessing LV stiffness merits further study in children.

PRESSURE VOLUME LOOP ANALYSIS IN PATIENTS WITH SINGLE VENTRICLES: COMPARISON OF PRESSURE-VOLUME LOOP AND NON-INVASIVE MEASURES OF SYSTOLIC FUNCTION

Non-invasive measurements of systolic function in the single ventricle population are performed using measures whose accuracy and reliability have not been fully assessed. We sought to validate non-invasive measures of systolic function with invasive measures of systolic function derived from

Feasibility of conductance catheter-derived pressure-volume loops to investigate ventricular mechanics in shunted single ventricles

We present pressure–volume loops obtained from two patients with single-ventricle physiology, one with a modified Blalock–Taussig shunt and one with a right ventricle-to-pulmonary artery shunt. The dissimilarities in pressure–volume loop contour and related indices highlight potentially important differences in ventricular mechanics between the shunt types.