Left atrial and ventricular systolic and diastolic myocardial mechanics in patients with end-stage renal disease.

BACKGROUND: Diastolic cardiac dysfunction is an important complication of end-stage renal disease (ESRD), but quantification remains a challenge. Given that diastolic dysfunction is reflected in both left atrial (LA) and ventricular (LV) function, we aimed to identify abnormalities in LV and LA volume and function using measures of myocardial mechanics. METHODS: We retrospectively studied 53 incident ESRD patients (46±16 y/o 44% male) and compared them to 85 normal controls. LA phasic volumes and functional parameters were obtained from the apical 4CH view. Global ventricular peak longitudinal and circumferential strain, strain rate (GLS, GL-SR, CS), and rotation were obtained from apical and short-axis views. LA and LV measurements were taken off line using dedicated software (eSie VVI). RESULTS: ESRD patients had abnormal systolic function with lower LV ejection fraction and peak endocardial strain parameters (mean: GLS -16.6% vs -19.9%, GL-SR -0.91 vs -1.04, and CS -25.6% vs 27.9%, P≤.01 for all). Traditional Doppler parameters remained similar between groups, while diastolic mechanics were abnormal in ESRD. Reduced LV-derived diastolic parameters, fractional early reverse rotation, a marker of ventricular relaxation (P<.006), and ratio of early diastolic SR to systolic SR (P<.04) denote significant diastolic dysfunction. Increased LA volumes (P<.001), decreased LA reservoir (P<.001), conduit (P<.0004), and contractile (P<.02) function reflect diastolic dysfunction. CONCLUSION: Myocardial strain measurements quantitated the abnormalities in both LV diastolic and LA function associated with the uremic state. The distinct abnormal diastolic parameters were suggestive of abnormal relaxation and increased filling pressures. Early and accurate assessment of diastolic function may help tailor patient management ESRD.

Velocity vector imaging in the measurement of left ventricular myocardial mechanics on cardiac magnetic resonance imaging: correlations with echocardiographically derived strain values.

BACKGROUND: Regional and global function can be measured by echocardiography using speckle-tracking, a technique that has previously been validated against crystal sonomicrometry. However, the application of Velocity Vector Imaging (VVI) to images obtained from cardiac magnetic resonance (CMR) imaging has never been validated against those values derived from VVI applied to two-dimensional echocardiographic images in the same patient group. The aim of this study was to validate for the first time the application of VVI to retrospectively acquired CMR data sets for the assessment of left ventricular strain and rotation, using echocardiographic strain assessment by VVI as the reference technique. METHODS: Cine steady-state free precession CMR data sets and two-dimensional echocardiographic images obtained on the same day in 36 adult patients with hypertrophic cardiomyopathy were analyzed retrospectively using VVI to quantify global longitudinal and circumferential strain and rotation parameters. RESULTS: The absolute differences in longitudinal strain between the two imaging modalities were -1.1 ± 3.3% (endocardial) and -2.2 ± 3.6% (full thickness). The absolute differences in circumferential strain were -4.7 ± 5.3% (endocardial) and -3.4 ± 3.8% (full thickness). CMR consistently resulted in higher strain values than echocardiography. The absolute differences in twist were -0.2 ± 5.6% (endocardial) and 0.1 ± 5.8% (full thickness). CONCLUSIONS: The application of VVI to CMR data sets allows a feasible and reproducible method for strain analysis in HCM, demonstrating excellent agreement with two-dimensional echocardiography-derived values. Given the superior image quality obtained with CMR in a significant proportion of patients, this technique provides a method for strain assessment without the need for dedicated CMR acquisition and analytic techniques.

Myocardial mechanical remodeling after septal myectomy for severe obstructive hypertrophic cardiomyopathy.

BACKGROUND: Septal myectomy for symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM) is a well-established procedure for symptomatic relief. Myocardial mechanics are abnormal in patients with HOCM, demonstrating low longitudinal strain, high circumferential strain, and high apical rotation compared with healthy subjects. The aim of this study was to determine whether functional improvement after myectomy is associated with improved myocardial mechanics. METHODS: Clinical data and paired echocardiographic studies before and after myectomy (6-18 months) were retrospectively analyzed and compared in 66 patients (mean age, 54 ± 13 years; 64% men) with HOCM. Myocardial mechanics including longitudinal and circumferential strain and rotation were assessed using two-dimensional strain software (Velocity Vector Imaging). RESULTS: Patients had significant symptomatic alleviation (mean New York Heart Association class, 2.8 ± 0.4 at baseline and 1.3 ± 0.5 after myectomy; P < .05). Left ventricular outflow gradient decreased dramatically (from 93 ± 26 to 17 ± 12 mm Hg; P < .05), and left atrial volume index decreased (from 48 ± 16 to 37 ± 13 cm(3)/m(2); P < .05). Low longitudinal strain decreased at the myectomy site, increased in the lateral segments, and remained unchanged globally (-16 ± 4). High circumferential strain decreased (from -31 ± 5 to -25 ± 6, P < .05). High left ventricular twist normalized (from -15.5 ± 6.2° to 12.8 ± 4.2°, P < .05). Independent predictors of symptomatic response included younger age before myectomy, thinner posterior wall, and higher lateral early diastolic velocity (e'). CONCLUSION: In patients with HOCM, surgical myectomy alleviated symptoms, relieved obstruction, and decreased left atrial volume index. Longitudinal strain remained unchanged, but circumferential strain and rotation decreased, demonstrating different mechanical adaptations to chronic elevated afterload seen in patients with severe aortic stenosis undergoing valve replacement. Disease extent (age, posterior wall involvement) and the presence of diastolic dysfunction seem to be related to partial symptomatic response to myectomy.

Hypertrophy pattern and regional myocardial mechanics are related in septal and apical hypertrophic cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is associated with considerable phenotypic heterogeneity. Previous studies have shown a relationship between the degree and location of hypertrophy and the prognosis of patients. The aim of this study was to compare left ventricular (LV) circumferential and longitudinal regional mechanics in patients with septal HCM and apical HCM to study the relationship between hypertrophy and function as assessed by myocardial mechanics. METHODS: Seventy-two patients with HCM (27 with apical HCM, 45 with septal HCM) were compared with 25 clinically normal and age-matched subjects. Myocardial mechanics were assessed using Velocity Vector Imaging, which extracts myocardial motion estimates from B-mode clips by tracking user-defined points and feature tracking. The Velocity Vector Imaging software generated data on global and regional systolic and diastolic longitudinal and circumferential strain, strain rate, and rotational angle velocities. One-way analysis of variance with post hoc multiple comparisons was used among the three groups. RESULTS: Normal subjects had relatively uniform strain and strain rates for all LV segments. Compared with the normal group, patients with septal HCM had decreased LV regional longitudinal strain rates and strain at both the basal and mid septal and lateral segments (all P < .01). Compared with patients with apical HCM, those with septal HCM had higher LV circumferential strain rates and strain at the basal and mid segments (P < .05 to P < .01). There were significant differences in rotational velocities at the mid segments among the three groups (P < .05 to P < .001). CONCLUSIONS: Patients with HCM have abnormalities in myocardial mechanics that are related to the site of abnormal myocardial hypertrophy.

Endothelial function, carotid-femoral stiffness, and plasma matrix metalloproteinase-2 in men with bicuspid aortic valve and dilated aorta.

OBJECTIVES: This study sought to examine the relationship between proximal aortic dilation and systemic vascular function in men with bicuspid aortic valve (BAV). BACKGROUND: Proximal aortic dilation in subjects with BAV is associated with structural and functional abnormalities in the ascending aorta. METHODS: We studied 32 men (median age 31 years [range 28 to 32 years]) with nonstenotic BAV categorized into 2 subgroups according to proximal ascending aorta dimensions (nondilated or=40 mm, respectively). Sixteen healthy men were studied as control subjects. Flow-mediated dilation in response to hyperemia (a marker of endothelial dysfunction) and carotid-femoral pulse wave velocity (an index of aortic stiffness) were assessed, and peripheral blood was sampled for matrix metalloproteinases (MMP-2 and -9) and their tissue inhibitors (TIMP-1 and -2), respectively. Cardiac chamber and aortic dimensions were assessed by echocardiography and cardiac magnetic resonance imaging, respectively. RESULTS: Despite the similar severity of aortic stenosis, left ventricular mass, and function, men with dilated aortas had blunted brachial flow-mediated vasodilation to hyperemia (5% [interquartile range (IQR) 4% to 6%] vs. 8% [IQR 7% to 9%] change, p = 0.001), higher carotid-femoral pulse wave velocity (9.3 cm/s [IQR 9 to 10 cm/s] vs. 7 cm/s [IQR 6.9 to 7.4 cm/s], p = 0.001), and significantly higher plasma levels of MMP-2 (1,523 [IQR 1,460 to 1,674] vs. 1,036 [IQR 962 to 1,167], p = 0.001) compared with men with BAV and nondilated aorta. Values for MMP-9, TIMP-1 and -2 levels, and nitroglycerin-induced (endothelium-independent) vasodilation were similar in all 3 groups. CONCLUSIONS: Young men with BAV and dilated proximal aortas manifest systemic endothelial dysfunction, increased carotid-femoral pulse wave velocity, and higher plasma levels of MMP-2. These observations could introduce new targets for screening and perhaps for therapeutic intervention.

Diastolic myocardial mechanics in hypertrophic cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is characterized by myocardial hypertrophy, fiber disarray, and fibrosis interfering with myocardial force generation and relaxation. Because conventional Doppler echocardiographic methods inadequately assess diastolic function in HCM, the aim of this study was to determine local and global left ventricular (LV) relaxation mechanics in patients with HCM. METHODS: Seventy-two patients with HCM and 32 normal controls were studied. Using Velocity Vector Imaging, longitudinal and circumferential strain, strain rate, and rotation at the base, middle, and apex of the septal and lateral LV walls were measured. Differences between patients' functional class subgroups were assessed using analysis of variance, and Tukey's post hoc analysis was used to compare patients in HCM clinical subgroups with normal controls. RESULTS: Longitudinal strain and systolic and early diastolic strain rates were lower than normal in patients with HCM, whereas their circumferential values were higher. This suggests that shortening and relaxation orientation in HCM was more circumferential. The ratio of peak early diastolic to peak systolic strain rate decreased longitudinally and circumferentially in moderately to severely symptomatic (New York Heart Association class III or IV) patients (0.95 +/- 0.35 vs 0.89 +/- 0.35, P < .001). LV untwist was similarly prolonged in all HCM subgroups. LV relaxation assessed using the early apical reverse rotation fraction was significantly lower in patients with worse functional status (34 +/- 14% vs 18 +/- 4% in class I or II vs class III or IV). Left atrial volume increased, paralleling the severity of symptoms and the degree of diastolic dysfunction. CONCLUSIONS: The evaluation of biplane myocardial mechanics offers new insights into the evaluation of diastolic function and its relationship to clinical status.

Retrospective study to identify predictors of the presence and rapid progression of aortic dilatation in patients with bicuspid aortic valves.

BACKGROUND: Aortic dilatation is common among adults with bicuspid aortic valves (BAV). Predictors of risk and progression of aortic dilatation are not well described in this setting. METHODS: We analyzed retrospective data on the presence of dilation in several aortic segments in 156 adult patients with BAV who had serial echocardiograms performed at least 1 year apart. Various risk factors for the presence and progression of aortic dilatation were identified. RESULTS: Mean echocardiographic follow-up was 3.8 +/- 1.4 years, yielding a total of 582 patient-years. Independent predictors of having a dilated aorta at baseline were age (odds ratio [OR] 1.06, 95% CI 1.03-1.09), body surface area (OR 8.78, 95% CI 1.08-71.70) and moderate to severe aortic regurgitation (OR 6.38, 95% CI 2.51-16.20). During echocardiographic follow-up, 16 (15.2%) patients developed dilatation (incidence 4 cases per 100 patient-years). Mean annual rates of progression were estimated at 0.37 mm (95% CI 0.17-0.57), 0.18 mm (95% CI 0.05-0.31), 0.17 mm (95% CI 0.06-0.29) and 0.18 mm (95% CI 0.05-0.31) for the ascending aorta, sinotubular junction, aortic sinus and aortic annulus, respectively. Fusion of the right and left valve leaflets was associated with rapid aortic dilatation (OR 2.92, 95% CI 1.15- 7.41) whereas prior coarctation repair was associated with protection from rapid aortic dilatation (OR 0.13, 95% CI 0.04-0.40). CONCLUSIONS: Patients with BAV and increased age, high body surface area and moderate to severe aortic regurgitation are more likely to have a dilated aorta. Patients with right-to-left leaflet fusion are at increased risk of rapid aortic dilatation.

Outcomes in adults with bicuspid aortic valves.

CONTEXT: Bicuspid aortic valve is the most common congenital cardiac anomaly in the adult population. Cardiac outcomes in a contemporary population of adults with bicuspid aortic valve have not been systematically determined. OBJECTIVE: To determine the frequency and predictors of cardiac outcomes in a large consecutive series of adults with bicuspid aortic valve. DESIGN, SETTING, AND PARTICIPANTS: Cohort study examining cardiac outcomes in 642 consecutive ambulatory adults (mean [SD] age, 35 [16] years; 68% male) with bicuspid aortic valve presenting to a Canadian congenital cardiac center from 1994 through 2001 and followed up for a mean (SD) period of 9 (5) years. Frequency and predictors of major cardiac events were determined by multivariate analysis. Mortality rate in the study group was compared with age- and sex-matched population estimates. MAIN OUTCOME MEASURES: Mortality and cause of death were determined. Primary cardiac events were defined as the occurrence of any of the following complications: cardiac death, intervention on the aortic valve or ascending aorta, aortic dissection or aneurysm, or congestive heart failure requiring hospital admission during the follow-up period. RESULTS: During the follow-up period, there were 28 deaths (mean [SD], 4% [1%]). One or more primary cardiac events occurred in 161 patients (mean [SD], 25% [2%]), which included cardiac death in 17 patients (mean [SD], 3% [1%]), intervention on aortic valve or ascending aorta in 142 patients (mean [SD], 22% [2%]), aortic dissection or aneurysm in 11 patients (mean [SD], 2% [1%]), or congestive heart failure requiring hospital admission in 16 patients (mean [SD], 2% [1%]). Independent predictors of primary cardiac events were age older than 30 years (hazard ratio [HR], 3.01; 95% confidence interval [CI], 2.15-4.19; P<.001), moderate or severe aortic stenosis (HR, 5.67; 95% CI, 4.16-7.80; P<.001), and moderate or severe aortic regurgitation (HR, 2.68; 95% CI, 1.93-3.76; P<.001). The 10-year survival rate of the study group (mean [SD], 96% [1%]) was not significantly different from population estimates (mean [SD], 97% [1%]; P = .71). At last follow-up, 280 patients (mean [SD], 45% [2%]) had dilated aortic sinus and/or ascending aorta. CONCLUSIONS: In this study population of young adults with bicuspid aortic valve, age, severity of aortic stenosis, and severity of aortic regurgitation were independently associated with primary cardiac events. Over the mean follow-up duration of 9 years, survival rates were not lower than for the general population.

Systolic myocardial mechanics in hypertrophic cardiomyopathy: novel concepts and implications for clinical status.

In hypertrophic cardiomyopathy (HCM), malfunctioning sarcomeric protein, myocyte hypertrophy, fiber disarray, and interstitial fibrosis interfere with systolic myocardial mechanics despite clinically hyperdynamic systolic function. We evaluated local left ventricular (LV) mechanics in 72 patients with HCM and 32 control subjects using 2-dimensional velocity vector imaging. Patients had higher circumferential strain (-34 +/- 9 vs -29 +/- 8, P < .05) and lower longitudinal strain (-16 +/- 4 vs -21 +/- 4, P < .05) compared with control subjects. Biplanar strain vector magnitude was similar (-38% +/- 8 vs -36 +/- 7) in both groups, but was circumferentially oriented in HCM (27 +/- 10 vs 39 +/- 9 degrees, P < .05). Mid LV rotation was clockwise (opposite to normal). LV outflow tract obstruction and clinical status were related to more circumferentially directed strain and reduced apical biplanar strain. Patients with HCM have more circumferential myocardial strain and apically displaced systolic twist. Functional status and LV outflow tract obstruction were related to decreased strain vector angle and apical mechanics. These findings provide insights into the pathophysiology of HCM.

Myocardial mechanics explains the time course of benefit for septal ethanol ablation for hypertrophic cardiomyopathy.

We hypothesized that the time course of left ventricular (LV) outflow tract gradient reduction during septal ethanol ablation for patients with symptomatic hypertrophic obstructive cardiomyopathy is related to changes in myocardial mechanics. A total of 21 patients with hypertrophic obstructive cardiomyopathy undergoing septal ethanol ablation were analyzed. LV outflow tract gradient decreased with septal balloon occlusion, further decreased postethanol injection, and partially rebounded at discharge (5-6 days postprocedure). During balloon occlusion longitudinal and circumferential strain significantly decreased in all analyzed segments, significantly improved with alcohol injection only at sites distant to infarction, and normalized at all segments except infarcted ones at discharge. LV twist significantly improved with ethanol injection and remained high at discharge. Myocardial mechanics suggest that the decrease in LV outflow tract gradient during septal ethanol ablation coincides with global LV dysfunction despite only local ischemia during septal balloon occlusion. Global dysfunction is transient and the gradient rebounds when dysfunction is limited to the basal septum.

Prognostic value of myocardial perfusion contrast echocardiography in patients with suggested or known ischemic heart disease.

OBJECTIVE: We sought to determine the prognostic value of myocardial contrast echocardiography (MCE) in patients with known or suggested coronary artery disease compared with technetium-99m sestamibi single photon emission computed tomography (SPECT)-myocardial perfusion imaging (MPI). BACKGROUND: The prognostic value of SPECT-MPI is well established for patients with coronary artery disease. It is less well defined by MCE. METHODS: In all, 51 consecutive patients with suggested coronary artery disease prospectively underwent MCE and SPECT-MPI at baseline and after dipyridamole infusion. MCE and SPECT-MPI were independently analyzed for myocardial perfusion. Cardiac events during the follow-up period were determined, and event-free survival was calculated for MCE and SPECT-MPI techniques separately. RESULTS: MCE (log rank P < .005) and SPECT-MPI (log rank P < .05) demonstrated equivalent event-free survival. The negative predictive value for events for both MCE and SPECT-MPI was 100%. CONCLUSION: MCE accurately classifies patients at risk for cardiac events and provides prognostic information comparable with validated SPECT-MPI techniques.

Enlarged left atrial volume in hypertrophic cardiomyopathy: a marker for disease severity.

BACKGROUND: Patients with hypertrophic cardiomyopathy and left atrial (LA) enlargement have increased morbidity and mortality. We analyzed the clinical and echocardiographic factors related to LA enlargement, particularly the degree of left ventricular (LV) hypertrophy and diastolic function. METHODS: A total of 104 patients with hypertrophic cardiomyopathy (age 53 +/- 15 years, 64% men) were divided into two groups based on the indexed LA volume (LAVI) (mL/m2) measured by echocardiography: group A (or smaller LAVI group, n = 43) was defined as LAVI < or = 34 mL/m2; and group B (or larger LAVI group, n = 61) as LAVI > 34 mL/m2. Detailed clinical and echocardiographic data were obtained. LV wall thickness was measured at 15 sites at 3 levels (base, mid, and apex). Diastolic function was assessed from mitral and pulmonary venous inflow velocities and Doppler tissue imaging. RESULTS: Both groups were similar in terms of sex, functional class (1.6 +/- 0.8 vs 1.5 +/- 0.8, group B vs A, P = .64), and incidence of atrial fibrillation (13% vs 5%, P = .19). However, patients of group B had a significantly higher incidence of serious cardiovascular events (16.4% vs 2.3%, group B vs A, P = .024). Both groups had a similar degree of resting LV outflow tract obstruction (19 +/- 30 vs 12 +/- 13 mm Hg, group B vs A, P = .06). However, those in group B had a higher incidence of at least moderate mitral regurgitation (25% vs 5%, group B vs A, P = .007), more LV hypertrophy at 6 LV nonapical wall segments (P < .05-P < .001), and a higher hypertrophy (Wigle) score (6.2 +/- 2.2 vs 4.5 +/- 2.1, group B vs A, P < .001). In addition, patients of group B had a higher incidence of abnormal diastolic filling (57% vs 28%, group B vs A, P = .003), a higher early diastolic velocity/early diastolic mitral annular velocity (10.2 +/- 4.9 vs 7.5 +/- 2.9, group B vs A, P = .003), and a higher calculated LA pressure (14.8 +/- 6.5 vs 11.1 +/- 3.4 mm Hg, group B vs A, P = .0011). CONCLUSIONS: Patients with hypertrophic cardiomyopathy and LA enlargement had more serious cardiovascular events and demonstrated greater LV hypertrophy, more diastolic dysfunction, and higher filling pressures.

Usefulness of myocardial contrast echocardiographic quantification of risk area for predicting postprocedural complications in patients undergoing septal ethanol ablation for obstructive hypertrophic cardiomyopathy.

Septal ethanol ablation (SEA) is an alternative to surgical myectomy in patients who have drug-refractory obstructive hypertrophic cardiomyopathy. However, permanent atrioventricular conduction block is seen more frequently with SEA. To determine whether septal infarction risk area (SIRA) predicts outcome in patients who have obstructive hypertrophic cardiomyopathy and are undergoing SEA, we evaluated 51 patients (mean age 60 +/- 16, 53% women) who had a successful SEA at Toronto General Hospital (November 1998 to June 2003). Intracoronary myocardial contrast echocardiography that targeted the contact area between the septum and the anterior mitral leaflet was performed before ethanol injection. End-systolic myocardial contrast echocardiographic frames were color coded for better delineation of contrast borders, and myocardial contrast echocardiographic area was calculated by planimetry. Patients were assigned to 1 of 2 groups by median SIRA value (3.51 cm(2), range 0.4 to 7.8). The 2 groups did not differ significantly in age, medication before SEA, electrocardiographic characteristics, left ventricular function, left atrial diameter, volume of intracoronary ethanol injected, peak creatine kinase after ablation, and baseline and follow-up left ventricular outflow tract gradients at rest. Patients in the large SIRA group had greater hypertrophy and a larger septal artery than did patients in the small SIRA group. In the small SIRA group, 3 patients (11.5%) had pacemaker implantation; in the large SIRA group, 12 patients (48.0%) had complications after SEA (pacemaker in 5 patients, implantable defibrillator in 5 patients, death in 2 patients; p = 0.008). We conclude that patients who have hypertrophic cardiomyopathy with a small, well-localized SIRA benefit similarly from SEA as patients who have a larger SIRA but with significantly fewer serious complications.

Incremental value of parametric quantitative assessment of myocardial perfusion by triggered Low-Power myocardial contrast echocardiography.

OBJECTIVES: The purpose of this study was to compare the assessment of myocardial perfusion by myocardial parametric quantification (MPQ) with technetium-99m sestamibi single-photon emission computed tomographic (SPECT) imaging in humans. BACKGROUND: Accurate visual interpretation of myocardial contrast echocardiographic (MCE) images is qualitative and requires considerable experience. Current computer-assisted quantitative perfusion protocols are tedious and lack spatial resolution. Myocardial parametric quantification is a novel method that quantifies, color encodes, and displays perfusion data as a set of myocardial parametric images according to the relative degree of perfusion. METHODS: Forty-six consecutive patients underwent prospective stress/rest technetium-99m sestamibi gated-SPECT imaging and MCE using intravenous Optison or Definity. Apical two- and four-chamber cine loops at rest and after dipyridamole (0.56 mg/kg) stress were acquired. For each patient, the following assessments of myocardial perfusion were performed: 1). visual cine-loop assessment (VIS); 2). MPQ assessment; and 3). combined VIS + MPQ assessment. RESULTS: The segmental rates of agreement for myocardial perfusion with SPECT were 83%, 89%, and 92% (kappa = 0.46, 0.58, and 0.68) for VIS, MPQ, and VIS + MPQ, respectively. Similar trends were seen for the classification of the presence or absence of a moderate to severe perfusion defect, with the agreement for VIS, MPQ, and VIS + MPQ being 92%, 97%, and 97%, respectively. CONCLUSIONS: Myocardial parametric quantification demonstrates good agreement with SPECT and incremental agreement with VIS. Analysis strategies that incorporate MPQ demonstrate better agreement with SPECT than visual analysis alone.

Determination of left ventricular ejection fraction using intravenous contrast and a semiautomated border detection algorithm.

Manual endocardial tracing using Simpson's method (MANUAL SIMP) provides an accurate assessment of left-ventricular ejection fraction (LVEF). We have previously demonstrated in patients who are difficult to image: (1) the incremental accuracy of contrast-enhanced power harmonic imaging and MANUAL SIMP in the calculation of LVEF; and (2) the use of intravenous contrast-combined MANUAL SIMP was the most accurate method of LVEF determination. However, MANUAL SIMP is time-consuming, requires accurate planimetry of the endocardial borders, and is difficult to apply routinely in the clinical situation. The current study prospectively studied the accuracy of intravenous contrast and a semiautomated endocardial border detection algorithm in the determination of LVEF in 51 patients with suboptimal images. LVEF was also calculated using contrast-enhanced power harmonic imaging and MANUAL SIMP. We demonstrated that there was good agreement between LVEF determined using both MANUAL SIMP and semiautomated endocardial border detection, and radionuclide angiography (standard of comparison).