Evaluation of left ventricular filling pressure by echocardiography: incremental diagnostic information from left atrial strain

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): South-Eastern Norway Regional Health Authority

Background

Elevated left ventricular (LV) filling pressure is an important diagnostic feature of heart failure.

Objectives

To investigate determinants of left atrial (LA) reservoir and pump strain and if these parameters may serve as markers of LV filling pressure.

Methods

In a multicenter study of 322 patients with cardiovascular disease of different etiologies, LA strain by speckle tracking echocardiography was compared to conventional echocardiographic markers using invasive pressure as reference.

Results

Left ventricular filling pressure correlated well with LA reservoir and pump strain (r-values

‑0.52 and ‑0.57, respectively) (Figure). However, LV global longitudinal strain (GLS) was the strongest determinant of LA reservoir strain (r = 0.64), and correlated well with LA pump strain (r = 0.51).  For both LA strains, association with filling pressure was strongest in patients with reduced LV ejection fraction. In patients with normal GLS (≥18%), atrial strains provided no information regarding filling pressure (Figure). Reservoir strain <18% and pump strain <8% predicted elevated LV filling pressure better (p < 0.05) than the conventional indices LA volume, ratio of mitral early filling velocity/annular velocity and tricuspid regurgitation velocity. Accuracy to classify filling pressure as normal or elevated was 75% for both LA strains . When any one of the conventional indices were missing, and were replaced by LA strains, the combination of indices had accuracy 82% to correctly classify filling pressure.

Conclusions

Left atrial reservoir and pump strain may serve as clinical markers of LV filling pressure, but will be useful predominantly in patients with reduced systolic function.  Due to limited diagnostic accuracy, LA strain should be used in combination with other indices.

Abstract Figure

Intracardiac echocardiographic measurement of left ventricular volume

We tested the utility of intracardiac echocardiography (ICE) in measuring left ventricular (LV) volume. In 4 normal dogs, a 10-F percutaneous sheath was placed inside the LV along its major axis. An ICE catheter (9 F, 9 MHz) was then inserted through the sheath into the LV. The ICE catheter was pulled back in 1-mm intervals starting from the apex, and 2-D tomographic images were continuously acquired. Subsequently, the ICE catheter was replaced in the LV by a conductance catheter to measure single-beat volume signals. Stroke volume was determined by thermodilution for validation. All measurements were made in each dog while pacing the atrium at two different cycle lengths (range=300-500 ms). The endocardium was segmented in the ICE images throughout the cardiac cycle, and LV volume was computed by integrating multiple segments (range=55-70 mm). We found that ICE accurately reconstructed LV 3-D anatomy. Stroke volume by ICE was in excellent agreement with thermodilution (error = 3.8+/-3.0%, r = 0.99, n = 8). Morphology of LV volume signals correlated well with instantaneous volume signals derived by conductance (r=0.93, n=8). In conclusion, ICE accurately reconstructs LV anatomy and volume throughout the cardiac cycle in the normal heart. This approach could facilitate interventional diagnostic and therapeutic procedures.

Echocardiographic predictors of adverse clinical events in children with dilated cardiomyopathy: a prospective clinical study

OBJECTIVES

To compare tissue Doppler (TD) velocities between patients with dilated cardiomyopathy (DCM) and normal controls and to determine whether TD velocities, Tei index, right ventricular fractional area change, and left ventricular ejection fraction (LVEF) predict adverse clinical outcomes in children with DCM.

METHODS

Prospective evaluation of children with DCM.

RESULTS

54 children with DCM and 54 age and sex matched control group participants were studied. Mitral inflow velocities were similar for both groups except for decreased mitral deceleration time in patients with DCM. Systolic and diastolic TD velocities at the mitral annulus (septal and lateral sides) and tricuspid annulus were significantly reduced in children with DCM compared with controls (p < 0.001 for each). By multivariate analysis, after adjustment for Tei index and right ventricular fractional area change, decreased LVEF and tricuspid velocity during early diastole (Ea) were predictors of the primary end point (PEP), a composite end point consisting of need for hospitalisation or the outcome transplantation or death. Tricuspid Ea velocity < 8.5 cm/s had 87% specificity and 60% sensitivity for reaching the PEP. LVEF < 30% had 68% specificity and 74% sensitivity for the PEP. Combined LVEF < 30% and tricuspid Ea < 11.5 cm/s had 100% specificity and 44% sensitivity for the PEP.

CONCLUSIONS

Children with DCM have significantly lower TD velocities than normal controls. In such cases, lower LVEF (< 30%) is more sensitive but less specific than lower tricuspid Ea velocities (< 8.5 cm/s) in predicting which patients are at risk of hospitalisation, transplantation, or death.

Comparison of ethanol septal reduction therapy with surgical myectomy for the treatment of hypertrophic obstructive cardiomyopathy

OBJECTIVES

This study was designed to compare the hemodynamic efficacy of nonsurgical septal reduction therapy (NSRT) by intracoronary ethanol with standard therapy (surgical myectomy) for the treatment of hypertrophic obstructive cardiomyopathy (HOCM).

BACKGROUND

Nonsurgical septal reduction therapy has gained interest as a new treatment modality for patients with drug-refractory symptoms of HOCM; however, its benefits in comparison to surgery are unknown.

METHODS

Forty-one consecutive NSRT patients at Baylor College of Medicine with one-year follow-up were compared with age- and gradient-matched septal myectomy patients at the Mayo Clinic. All patients had left ventricular outflow obstruction with a resting gradient > or =40 mm Hg and none had concomitant procedures.

RESULTS

There were no baseline differences in New York Heart Association class, severity of mitral regurgitation, use of cardiac medications or exercise capacity. One death occurred during NSRT because of dissection of the left anterior descending artery. At one year, all improvements in both groups were similar. After surgical myectomy, more patients were on medications (p < 0.05) and there was a higher incidence of mild aortic regurgitation (p < 0.05). After NSRT, the incidence of pacemaker implantation for complete heart block was higher (22% vs. 2% in surgery; p = 0.02). However, seven of the nine pacemakers in the NSRT group were implanted before a modified ethanol injection technique and the use of contrast echocardiography.

CONCLUSIONS

Nonsurgical septal reduction therapy resulted in a significantly higher incidence of complete heart block, but the risk was reduced with contrast echocardiography and slow ethanol injection. Surgical myectomy resulted in a significantly higher incidence of mild aortic regurgitation. Nonsurgical septal reduction therapy, guided by contrast echocardiography, is an effective procedure for treating patients with HOCM. The hemodynamic and functional improvements at one year are similar to those of surgical myectomy.

Myocardial viability: recent developments in detection and clinical significance

The long-term prognosis of patients with ischemic cardiomyopathy is highly variable, depending on the extent of myocardial viability and the success and completeness of the revascularization techniques used. Other important factors include left ventricular function, extent of coronary artery disease (CAD), and patient age. Chronic left ventricular dysfunction in ischemic cardiomyopathy is the result of a mixture of scarred as well as hibernating myocardium. In fact, most patients have both scarring and hibernation in different regions. Transmural biopsies of dysfunctional segments reveals that recovery of function is inversely proportional to the extent of fibrosis and that endocardial fibrosis extending over 30% of the myocardial thickness precludes recovery of function.Nagueh et al. [1] evaluated the relation of contractile reserve and thallium uptake in hibernating myocardium to myocardial structure in humans. The authors found that segments with postoperative functional recovery had more wall thickening at low-dose dobutamine echocardiography (DE), higher thallium uptake, and less fibrosis (2.0 vs 28%) than those segments without recovery. Also, segments with viability on DE had less fibrosis, less vimentin and fibronectin, more glycogen, and higher thallium uptake, than those segments without viability. Importantly, segments viable by single-photon emission computed tomography (SPECT) and DE had significantly less fibrosis (1%) than those viable by only one of the two techniques. In this review, we discuss recent developments in the detection of myocardial viability, including echocardiography, nuclear cardiac imaging, magnetic resonance imaging (MRI), and other techniques.

A pilot safety trial of prolonged (48 h) infusion of the dual endothelin-receptor antagonist tezosentan in patients with advanced heart failure

STUDY OBJECTIVES

Tezosentan, an IV dual endothelin-receptor antagonist, has demonstrated beneficial hemodynamic effects in patients with advanced heart failure. In addition, no notable differences in safety and tolerability variables were detected between tezosentan-treated and placebo-treated patients when infused over 4 to 6 h. The present study was conducted primarily to assess the safety and tolerability of tezosentan when administered over a prolonged, 48-h treatment period, and secondarily to investigate hemodynamic response.

DESIGN

This randomized, double-blind, active-controlled study of continual IV administration of two dosages of tezosentan (20 mg/h and 50 mg/h; n = 6 each) or dobutamine (5 microg/kg/min; n = 2) over 48 h in patients with advanced heart failure was conducted to assess tolerability, safety, and hemodynamic variables (Doppler echocardiography).

RESULTS

During tezosentan infusion, no episodes of hypotension requiring withdrawal of therapy occurred, and hemodynamic rebound was not observed after abrupt cessation of the infusion. There were no reports of worsening heart failure in tezosentan-treated patients up to 28 days following the infusion. The most common side effect during the infusion was headache (9 of 12 tezosentan-treated patients and both dobutamine-treated patients). Echocardiographic Doppler measurements suggested improvements in cardiac index, pulmonary capillary wedge pressure, and relaxation properties as well as in diastolic and systolic function in all treatment groups.

CONCLUSIONS

Prolonged, 48-h IV dual endothelin-receptor antagonism with tezosentan was well tolerated with no new safety concerns emerging. These data further support the potential role of tezosentan in the treatment of patients with acute heart failure.

Simvastatin induces regression of cardiac hypertrophy and fibrosis and improves cardiac function in a transgenic rabbit model of human hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy is a genetic disease characterized by cardiac hypertrophy, myocyte disarray, interstitial fibrosis, and left ventricular (LV) dysfunction. We have proposed that hypertrophy and fibrosis, the major determinants of mortality and morbidity, are potentially reversible. We tested this hypothesis in beta-myosin heavy chain-Q(403) transgenic rabbits.

METHODS AND RESULTS

We randomized 24 beta-myosin heavy chain-Q(403) rabbits to treatment with either a placebo or simvastatin (5 mg. kg(-1). d(-1)) for 12 weeks and included 12 nontransgenic controls. We performed 2D and Doppler echocardiography and tissue Doppler imaging before and after treatment. Demographic data were similar among the groups. Baseline mean LV mass and interventricular septal thickness in nontransgenic, placebo, and simvastatin groups were 3.9+/-0.7, 6.2+/-2.0, and 7.5+/-2.1 g (P<0.001) and 2.2+/-0.2, 3.1+/-0.5, and 3.3+/-0.5 mm (P=0.002), respectively. Simvastatin reduced LV mass by 37%, interventricular septal thickness by 21%, and posterior wall thickness by 13%. Doppler indices of LV filling pressure were improved. Collagen volume fraction was reduced by 44% (P<0.001). Disarray was unchanged. Levels of activated extracellular signal-regulated kinase (ERK) 1/2 were increased in the placebo group and were less than normal in the simvastatin group. Levels of activated and total p38, Jun N-terminal kinase, p70S6 kinase, Ras, Rac, and RhoA and the membrane association of Ras, RhoA, and Rac1 were unchanged.

CONCLUSIONS

Simvastatin induced the regression of hypertrophy and fibrosis, improved cardiac function, and reduced ERK1/2 activity in the beta-myosin heavy chain-Q(403) rabbits. These findings highlight the need for clinical trials to determine the effects of simvastatin on cardiac hypertrophy, fibrosis, and dysfunction in humans with hypertrophic cardiomyopathy and heart failure.

Tissue Doppler imaging consistently detects myocardial abnormalities in patients with hypertrophic cardiomyopathy and provides a novel means for an early diagnosis before and independently of hypertrophy

BACKGROUND

Left ventricular hypertrophy (LVH), the clinical hallmark of familial hypertrophic cardiomyopathy (FHCM), is absent in a significant number of subjects with causal mutations. In transgenic rabbits that fully recapitulate the FHCM phenotype, reduced myocardial tissue Doppler (TD) velocities accurately identified the mutant rabbits, even in the absence of LVH. We tested whether humans with FHCM also consistently showed reduced myocardial TD velocities, irrespective of LVH.

METHODS AND RESULTS

We performed 2D and Doppler echocardiography and TD imaging in 30 subjects with FHCM, 13 subjects who were positive for various mutations but did not have LVH, and 30 age- and sex-matched controls (all adults; 77% women). LV wall thickness and mass were significantly greater in FHCM subjects (P<0.01 versus those without LVH and controls). There were no significant differences in 2D echocardiographic, mitral, and pulmonary venous flow indices between mutation-positives without LVH and controls. In contrast, systolic and early diastolic TD velocities were significantly lower in both mutation-positives without LVH and in FHCM patients than in controls (P<0.001). Reduced TD velocities had a sensitivity of 100% and a specificity of 93% for identifying mutation-positives without LVH.

CONCLUSIONS

Myocardial contraction and relaxation velocities, detected by TD imaging, are reduced in FHCM, including in those without LVH. Before and independently of LVH, TD imaging is an accurate and sensitive method for identifying subjects who are positive for FHCM mutations.

Echocardiographic evaluation of mitral regurgitation

Accurate evaluation of mitral regurgitation (MR) severity remains a challenging task in clinical cardiology. The importance of proper quantification of regurgitation cannot be underestimated because a delayed decision to replace or repair a defective valve may lead to worsening ventricular function and increased perioperative and long-term mortality. In this review we discuss both recent developments in the quantification of MR as well as new insights into the pathophysiology and progression of this lesion.

Decreased expression of tumor necrosis factor-alpha and regression of hypertrophy after nonsurgical septal reduction therapy for patients with hypertrophic obstructive cardiomyopathy

BACKGROUND

Nonsurgical septal reduction therapy (NSRT) is a novel therapeutic strategy for patients with hypertrophic obstructive cardiomyopathy (HOCM). Although the clinical benefits of this technique appear to be clear, the structural and functional changes that lead to improvements in cardiac function are not completely defined. In these studies, we sought to define the effect of NSRT on myocardial function as well as various markers of hypertrophy including the expression of tumor necrosis factor (TNF)-alpha, a cytokine capable of producing fibrosis, left ventricular hypertrophy (LVH), and cardiomyopathy.

METHODS AND RESULTS

We performed endomyocardial biopsies of the RV side of the septum and echocardiograms on 15 HOCM patients at baseline and after successful NSRT. Comparative analysis on paired myocardial samples were performed to determine the effects of NSRT on LVH, end-diastolic volume and chamber stiffness, myocyte size, collagen content, and TNF-alpha levels. At baseline, myocardial TNF-alpha levels were increased in all patients. After NSRT, myocyte size, collagen content, and TNF-alpha were significantly decreased. These changes were accompanied by an increase in left ventricular volumes and a reduction in LVH and chamber stiffness.

CONCLUSIONS

We suggest that pressure overload in HOCM patients contributes to the development of hypertrophy. These data provide the initial experimental evidence to suggest that TNF-alpha may play a pathogenetic role in the hypertrophy of pressure overload.

Regression of left ventricular hypertrophy after nonsurgical septal reduction therapy for hypertrophic obstructive cardiomyopathy

BACKGROUND

Hypertrophic obstructive cardiomyopathy (HOCM) is characterized by left ventricular hypertrophy (LVH) in the absence of increased external load. Recently, nonsurgical septal reduction therapy (NSRT) with intracoronary ethanol has been introduced to treat severely symptomatic patients with outflow tract obstruction. Its long-term effects on LV mass, however, are unknown.

METHODS AND RESULTS

The LV size, function, and outflow tract gradient of 26 HOCM patients (53+/-15 years old) who underwent NSRT were assessed by echocardiography at baseline and 1 and 2 years after the procedure. LVH was evaluated by wall thickness of individual myocardial segments, planimetered myocardial area, and mass. The outflow gradient decreased from 36+/-6 mm Hg before NSRT to 0+/-3 mm Hg at 2 years (P<0.001), with patients experiencing symptomatic improvement (P<0.05). LV end-diastolic and end-systolic dimensions increased significantly at both 1 and 2 years (P<0.001). All parameters of LVH showed evidence of regression. LV mass decreased (301+/-78 g at baseline, 223+/-5 g at 1 year, and 190+/-58 g at 2 years; P<0.01), with the 2-year reduction in mass related to infarct size and the acute reduction in outflow tract gradient (r=0.48, P<0.05 and r=0.63, P<0.01, respectively).

CONCLUSIONS

NSRT results in LV remodeling that is characterized by an increase in LV size and a decrease in the extent of LVH.

Deceleration time in ischemic cardiomyopathy: relation to echocardiographic and scintigraphic indices of myocardial viability and functional recovery after revascularization

BACKGROUND

In patients with heart failure secondary to left ventricular (LV) systolic dysfunction, a short deceleration time (DT) successfully predicts clinical outcome. The impact of myocardial viability and revascularization on the mitral inflow velocities, however, is unknown.

METHODS AND RESULTS

Forty patients with ischemic cardiomyopathy underwent (201)Tl scintigraphy (SPECT) and 2D, Doppler, and dobutamine echocardiography (DE, to 40 microg. kg(-1). min(-1)) 2 days before CABG. Echocardiography was repeated 3 months after revascularization to determine recovery of function. Significant correlations were present between DT and LV contractile reserve by DE (r=0.72), scar perfusion defect by SPECT (r=-0.69), and the change in ejection fraction (DeltaEF) after surgery (r=0.77) (all P:<0.01). DT >150 ms effectively identified (sensitivity 79%, specificity 81%) patients with DeltaEF >/=5%. The population was divided into 2 groups according to DT: group 1 (DT >150 ms, n=21) and group 2 (DT </=150 ms, n=19). At baseline, NYHA class, LV EF, age, and use of cardiovascular drugs were similar between the 2 groups. The number of viable segments by both DE and SPECT, however, was higher in group 1 (both P:<0.01), and only patients in group 1 had an increase in EF (29+/-4.8% to 40+/-8%, P:<0.01) after surgery. Death and heart transplantation occurred in 7 patients from group 2 and 1 patient from group 1 (P:=0.017).

CONCLUSIONS

In patients with ischemic cardiomyopathy, the reduced amount of viable myocardium results in a restrictive mitral inflow pattern, which in turn predicts poor survival.

Stress echocardiography in the diagnosis of coronary artery disease

Stress echocardiography (SE) is currently a widely accepted method for the diagnostic and prognostic assessment of coronary artery disease. This article reviews new concepts in SE, such as new stress techniques, new methods of endocardial border detection, strain, tissue Doppler velocities, and others. Although some of these techniques are in their infancy, we believe that they will become widely accepted.

Echocardiographic insights into the mechanisms of relief of left ventricular outflow tract obstruction after nonsurgical septal reduction therapy in patients with hypertrophic obstructive cardiomyopathy

OBJECTIVES

We sought to evaluate the mechanisms by which nonsurgical septal reduction therapy (NSRT) reduces left ventricular outflow tract (LVOT) obstruction in patients with hypertrophic obstructive cardiomyopathy (HOCM) both acutely and on a long-term basis.

BACKGROUND

NSRT reduces LVOT obstruction in patients with HOCM and leads to symptomatic improvement. The mechanisms involved, however, are not well studied.

METHODS

An initial group of 30 HOCM patients (age 46 +/- 17, 16 women) who underwent NSRT had echocardiographic studies performed at baseline and six months after the procedure. Measurements included LVOT diameter, end-diastolic distance between the anterior mitral leaflet and interventricular septum, septal base function and the angle between LV systolic flow and the protruding mitral leaflets. In addition, pulse Doppler recordings at a point 2.5 cm apical to the mitral valve were acquired and analyzed for peak and mean ejection velocity, peak acceleration rate and the ratio of acceleration time to ejection time (AT/ET).

RESULTS

Significant changes were observed after the procedure, with widening in the LVOT, thinning and akinesis of the septal base, decrease in the angle between LV systolic flow and the protruding mitral leaflets, a decrease in peak acceleration rate and an increase in AT/ET. All of these variables had significant relations with the decrease in LVOT obstruction (r = 0.5 to 0.79, p < 0.01). These correlations were then evaluated in a test group of 15 patients who underwent echocardiographic examinations at baseline, acutely in the catheterization laboratory with ethanol injection and at six weeks post NSRT. Acute changes in peak acceleration rate (r = 0.65) and AT/ET (r = 0.73) related significantly (p < 0.01) to the decrease in LVOT obstruction with ethanol. At six weeks, changes similar to those noted in the initial group were observed in LVOT geometry, the angle between LV systolic flow and the protruding mitral leaflets, peak acceleration rate and AT/ET. In both populations combined, these parameters accounted for 72% to 77% of the variance in gradient reduction.

CONCLUSIONS

Changes in LV ejection dynamics and septal base function account in part for the acute relief of LVOT gradient after NSRT. The long-term relief of obstruction is dependent on remodeling of LVOT as well as the changes in LV ejection.

Hemodynamic determinants of the mitral annulus diastolic velocities by tissue Doppler

OBJECTIVES

Our goal was to identify the hemodynamic determinants of the mitral annulus (MA) diastolic velocities by tissue Doppler.

BACKGROUND

The MA diastolic velocities are promising indexes of left ventricular (LV) diastolic function. However, their hemodynamic determinants have not yet been evaluated.

METHODS

Ten adult mongrel dogs underwent left atrial (LA) and LV pressure measurements by Millar catheters while tissue Doppler was applied to record the MA diastolic velocities at the septal and lateral comers. Conventional transmitral flow was also obtained. Left atrial and LV pressures were modified utilizing fluid administration and caval occlusion, whereas dobutamine and esmolol were used to change LV and LA relaxation. Left ventricular filling pressures were altered during different lusitropic states to evaluate for the possible interaction of preload and LV relaxation on the early diastolic velocity (Ea).

RESULTS

In the majority of dogs, a positive significant relation was observed between Ea and the transmitral pressure gradient (r = 0.57, p = 0.04). The Ea had strong correlations with tau (r = -0.83, p < 0.001), LV -dP/dt (r = 0.8, p < 0.001) and minimal LV pressure (r = -0.76, p < 0.01). However, there was no relation between Ea and the transmitral pressure gradient in experimental stages where tau >50 ms. Furthermore, the late diastolic velocity at both corners of the MA had significant positive relations with LA dP/dt (r = 0.67, p < 0.01) and LA relaxation (r = 0.73, p < 0.01) but an inverse correlation with LV end-diastolic pressure (r = -0.53, p = 0.01).

CONCLUSIONS

Left ventricular relaxation, minimal pressure and preload determine Ea while late diastolic velocity determinants include LA dP/dt, LA relaxation and LV end-diastolic pressure.

Variants of trophic factors and expression of cardiac hypertrophy in patients with hypertrophic cardiomyopathy

Patients with hypertrophic cardiomyopathy (HCM) exhibit variable expression of left ventricular hypertrophy (LVH), a major determinant of mortality and morbidity, which is partly due to the diversity of causal mutations, genetic background (modifier genes), and probably environmental factors. We determined association of functional variants of tumor necrosis factor (TNF)- alpha, interleukin-6 (IL6), insulin-like growth factor-2 (IGF2), transforming growth factor- beta 1 (TGFB1), and aldosterone synthase (CYP11B2) genes, all previously implicated in cardiac hypertrophy, with the severity of LVH in patients with HCM. Two-dimensional echocardiography was performed and demographic variables were recorded in 142 genetically independent patients. Indices of LVH including interventricular septal thickness (IVST), left ventricular mass index (LVMI), and LVH score were measured/calculated. TNF-alpha-308G/A, IL6-174G/C, IGF2 820G/A, TGFB1-509C/T, and CYP11B2-344T/C genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Genotypes were identified by the presence of specific electrophoretic patterns and their distributions were according to the Hardy-Weinberg equilibrium. Demographic variables were not significantly different among the genotypes. Subjects with the AA genotype of TNF-alpha (n=8) were approximately 13 years younger at the time of clinical diagnosis. Despite a younger age, they had a greater mean LVMI than those with the GG (n=94) or GA (n=33) genotypes (191.8+/-59.5 v 139.1+/-47.3 v 132.1+/-34.3, respectively, P=0.004). TNF-alpha-308G/A genotypes accounted for 6.0% of variability of LVMI (P=0.002). Mean IVST, LVEDD, and LVH score were not significantly different. Variants of IL6, IGF2, TGFB1, and CYP11B2 were not associated with indices of LVH. The uncommon allele of TNF-alpha-308G/A polymorphism, known to produce more TNF- alpha, was associated with greater LVMI and clinical diagnosis at a younger age in patients with HCM. Functional variants of other trophic factors, previously implicated in cardiac hypertrophy, were not associated with the indices of LVH. These results suggest that TNF-alpha is a modifier gene for HCM.

Altered adrenergic receptor density in myocardial hibernation in humans: A possible mechanism of depressed myocardial function

BACKGROUND

Alterations in adrenergic receptor densities can potentially contribute to myocardial dysfunction. Their relevance to myocardial hibernation in humans is unknown.

METHODS AND RESULTS

Accordingly, 22 transmural myocardial biopsies were obtained in 11 patients with ischemic ventricular dysfunction during bypass surgery, guided by transesophageal echocardiography. Patients underwent dobutamine echocardiography (DE) and rest scintigraphic studies before revascularization and DE at 3 to 4 months. alpha- and ss-receptor density (ARD and BRD) and extent of fibrosis were quantified from the myocardial biopsies. Of the 22 segments, 16 had abnormal rest function and 6 were normal. Severely hypokinetic or akinetic segments showed a 2.4-fold increase in ARD with a concomitant 50% decrease in BRD compared with normal segments. An increase in ARD, a decrease in BRD to a lesser extent, and thus an increase in ARD/BRD ratio were seen in dysfunctional segments with contractile reserve compared with normal segments and were most pronounced in those without contractile reserve (P:<0.001). Similar findings were observed if recovery of function or scintigraphic uptake was analyzed as a marker for viability. No significant relation between either ARD or BRD and percent myocardial fibrosis was noted (r=0.37 and -0.39, respectively).

CONCLUSIONS

Thus, graded and reciprocal changes in alpha- and ss-adrenergic receptor densities occur in viable, hibernating myocardium and may account in part for the observed depression in resting myocardial function and preserved contractile reserve in this entity.

Tissue Doppler imaging consistently detects myocardial contraction and relaxation abnormalities, irrespective of cardiac hypertrophy, in a transgenic rabbit model of human hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is diagnosed clinically by the presence of left ventricular hypertrophy (LVH). However, LVH is absent in a significant number of genotype-positive patients. Because myocyte dysfunction and disarray are the primary abnormalities in HCM, we reasoned that tissue Doppler imaging could identify contraction and relaxation abnormalities, irrespective of hypertrophy, in a transgenic rabbit model of human HCM.

METHODS AND RESULTS

M-mode, 2D, Doppler echocardiography and tissue Doppler imaging were performed in nontransgenic (n=24), wild-type beta-myosin heavy chain-arginine(403) (n=14), and mutant beta-myosin heavy chain-glutamic acid(403) (n=24) transgenic rabbits. Mean septal thicknesses were 2.0+/-0.3, 2.0+/-0.25, and 2.75+/-0.3 mm in the 3 groups, respectively (P:=0.001). LVH was absent in 9 of the 24 mutant rabbits. Left ventricular dimensions, systolic function, heart rate, mitral inflow velocities, and time intervals were similar in the groups. However, the difference between atrial reversal and transmitral A wave duration was increased in the mutant rabbits (P:<0.001). More importantly, systolic and early diastolic tissue Doppler velocities were significantly lower in all mutant rabbits (7.45+/-2.2 versus 10.8+/-2.3 cm/s in nontransgenic and 9. 0+/-0.76 cm/s in wild-type; P:<0.001), including the 9 without LVH. A systolic velocity <8.5 cm/s had an 86% sensitivity and 100% specificity in identifying the mutant transgenic rabbits.

CONCLUSIONS

Myocardial contraction and relaxation were reduced in the mutant beta-myosin heavy chain-glutamic acid(403) transgenic rabbit model of human HCM, irrespective of the presence or absence of LVH. In addition, tissue Doppler imaging is more sensitive than conventional echocardiography for HCM screening.

Nonsurgical septal reduction therapy for hypertrophic obstructive cardiomyopathy: one-year follow-up

OBJECTIVE

The objective of this study is to evaluate the one-year outcome of the first 50 patients who underwent nonsurgical septal reduction for symptomatic hypertrophic obstructive cardiomyopathy at our institution.

BACKGROUND

Left ventricular outflow tract obstruction is an important determinant of clinical symptoms in patients with hypertrophic obstructive cardiomyopathy. Nonsurgical septal reduction is a new therapy that has been shown to result in left ventricular outflow tract gradient reduction and resolution of symptoms immediately after the procedure and on midterm follow-up.

METHODS

Fifty patients with hypertrophic obstructive cardiomyopathy who underwent nonsurgical septal reduction at our institution and completed 1-year follow-up are described. Complete history, physical examination, two-dimensional echocardiography with Doppler and exercise treadmill testing have been analyzed.

RESULTS

The mean age of the study group was 53 +/- 17 years. All patients had refractory symptoms before enrollment. Ninety-four percent had class III or IV New York Heart Association class symptoms at baseline compared to none at 1 year (p < 0.001). The exercise duration increased by 136 s at 1 year (p < 0.021). Only 20% of patients were either receiving beta-blockers or calcium-channel blockers on follow-up. The resting left ventricular outflow tract gradient decreased from 74 +/- 23 mm Hg to 6 +/- 18 mm Hg (p < 0.01) and from 84 +/- 28 mm Hg to 30 +/- 33 mm Hg (p < 0.01) in patients with dobutamine-provoked gradient at one year. These changes are associated with decreased septal thickness and preserved systolic function.

CONCLUSION

Nonsurgical septal reduction therapy is an effective therapy for symptomatic patients with hypertrophic obstructive cardiomyopathy with persistence of the favorable outcome up to one year after the procedure.

Relation of tissue Doppler derived myocardial velocities to myocardial structure and beta-adrenergic receptor density in humans

OBJECTIVES

We sought to evaluate the relation of segmental tissue Doppler (TD) velocities to both the regional amount of interstitial fibrosis and the myocyte beta-adrenergic receptor density in humans.

BACKGROUND

The systolic myocardial velocity (Sm) and early diastolic myocardial velocity (Em) acquired by TD are promising new indexes of left ventricular function. However, their structural and functional correlates in humans are still unknown.

METHODS

Ten patients with coronary artery disease underwent echocardiographic examination including TD imaging, along with transmural endomyocardial biopsy at the time of coronary bypass surgery (two biopsies per patient for a total of 20 specimens). The specimens were analyzed for percent interstitial fibrosis and beta-adrenergic receptor density.

RESULTS

Normal segments (n = 8) had a higher beta-adrenoceptor density (2,280 +/- 738 vs. 1,373 +/- 460, p = 0.03) and a lower amount of interstitial fibrosis (13 +/- 3.3% vs. 28 +/- 11.5%, p = 0.002) than dysfunctional segments (n = 12). Myocardial systolic velocity and Em were also significantly higher (9.5 +/- 2.7 vs. 5.9 +/- 1.8 cm/s, p = 0.025 and 11.3 +/- 2.8 vs. 6.4 +/- 2.1 cm/s, p = 0.002, respectively) in normal segments. A significant relationship was present between Em and the beta-adrenergic receptor density (r = 0.78, p < 0.001) and percent interstitial fibrosis (r = -0.7, p = 0.0026), which together accounted for 81% of the variance observed in Em. Likewise, a significant relationship was present between Sm and the beta-adrenergic receptor density (r = 0.68, p < 0.001) and the percent interstitial fibrosis (r = -0.66, p = 0.004) and together accounted for 62% of the variance observed in Sm.

CONCLUSIONS

Systolic myocardial velocity and Em are strongly dependent on both the number of myocytes and the myocardial beta-adrenergic receptor density.

End-diastolic wall thickness as a predictor of recovery of function in myocardial hibernation: relation to rest-redistribution T1-201 tomography and dobutamine stress echocardiography

OBJECTIVES

The study assessed whether end-diastolic wall thickness (EDWT), measured with echocardiography, is an important marker of myocardial viability in patients with suspected myocardial hibernation, and it compared this index to currently established diagnostic modalities of dobutamine stress echocardiography (DSE) and rest-redistribution thallium-201 (T1-201) scintigraphy.

BACKGROUND

Because myocardial necrosis is associated with myocardial thinning, preserved EDWT may provide a simple index of myocardial viability that is readily available from the resting echocardiogram.

METHODS

Accordingly, 45 patients with stable coronary artery disease and ventricular dysfunction underwent rest 2D echocardiograms, DSE and rest-redistribution T1-201 tomography before revascularization and a repeat resting echocardiogram > or =2 months later.

RESULTS

Global wall motion score index decreased from 2.38 +/- 0.73 to 1.94 +/- 0.82 after revascularization (p < 0.001). Thirty-eight percent of severely dysfunctional segments recovered resting function. Compared to segments without recovery of resting function, those with recovery had greater EDWT (0.94 +/- 0.18 cm vs. 0.67 +/- 0.22 cm, p < or = 0.0001) and a higher T1-201 uptake (78 +/- 13% vs. 59 +/- 21%; p < 0.0001). An EDWT >0.6 cm had a sensitivity of 94% and specificity of 48% for recovery of function. Similarly, a T1-201 maximal uptake of > or =60% had a sensitivity of 91% and specificity of 50%. Receiver operating characteristic curves for prediction of recovery of regional and global function were similar for EDWT and maximum T1-201 uptake. Combination of EDWT and any contractile reserve during DSE for recovery of regional function improved the specificity to 77% without a significant loss in sensitivity (88%).

CONCLUSIONS

End-diastolic wall thickness is an important marker of myocardial viability in patients with suspected hibernation, and it can predict recovery of function similar to T1-201 scintigraphy. Importantly, a simple measurement of EDWT < or =0.6 cm virtually excludes the potential for recovery of function and is a valuable adjunct to DSE in the assessment of myocardial viability.

Comparison of global and regional left ventricular function assessed by gated-SPECT and 2-D echocardiography

Left ventricular (LV) function and volumes have major diagnostic and prognostic importance in patients with heart diseases. Those measurements are most commonly obtained with echocardiographic techniques. Recently, with the use of electrocardiographic gating during the acquisition of myocardial perfusion scintigraphy, it has become possible to simultaneously assess LV perfusion, function and volumes. Both technetium-99m labeled agents and thallium-201, the most commonly used tracers for perfusion scintigraphy, can be used for gated perfusion purposes. Many authors compared gated perfusion images to echocardiography, in regard to LV global and segmental wall motion as well as volumes. We performed gated single photon emission computed tomography (SPECT) and echocardiography in 109 consecutive patients (53 male, 56 female, mean age 63 +/- 14 years) within 15 days of each other. Gated tomographic data, including LV volumes, LV ejection fraction and segmental wall motion, were processed using an automatic algorithm whereas echocardiography used standard techniques. To obtain interobserver and intraobserver variability of regional wall motion, we randomly re-analyzed 34 of the 109 gated SPECT studies. The correlations between gated tomography and echocardiography with respect to end-diastolic volume, end-systolic volume and left ventricular ejection fraction were good to excellent (all p < 0.001, r values > or = 0.68) regardless of the use of post-stress or rest/redistribution images, thallium-201 or technetium-99m tracers. The agreement between both techniques, regarding segmental wall motion analysis were also good. Intraobserver and interobserver variability for regional wall motion were good to excellent, with an agreement of 90% and 88%, respectively. Other authors also had similar results in different studies with different populations, tracers, imaging acquisition and processing protocols. Thus, quantitative gated SPECT, using a variety of protocols and with either Tl-201 or Tc-99m tracers, has a good correlation with echocardiography for the measurements of absolute LV volumes and LV global and regional function. This technique is highly reproducible and can be used clinically for those measurements, with the additional advantage that the ventricular performance parameters are obtained from the perfusion images. Furthermore, contrary to echocardiographic techniques used to assess LV volumes and LV function, which are quite labor intensive and more observer-dependent, the gated SPECT technique is nearly totally automatic, and highly reproducible.

Estimation of mean right atrial pressure using tissue Doppler imaging

Sixty-two patients underwent simultaneous right atrial pressure measurement and Doppler echo including tissue Doppler to evaluate the utility of this technique in the estimation of right ventricular filling pressure. Mean right atrial pressure related weakly to the ratio of tricuspid peak early inflow velocity to annular early diastolic velocity (r = 0.75, p <0.0001), with a mean difference between Doppler and catheter pressures of 0.3 +/- 3.7 mm Hg.

Gated myocardial perfusion tomography for the assessment of left ventricular function and volumes: comparison with echocardiography

The purpose of this study was to evaluate left ventricular volumes and function by gated SPECT using different tracers and protocols in comparison with quantitative echocardiography. Gated myocardial perfusion scintigraphy permits simultaneous assessment of left ventricular perfusion, function and volumes. Information is scanty regarding the accuracy of absolute left ventricular volumes measurements by this technique.

METHODS

We performed gated SPECT and echocardiography within 15 d of each other in 109 consecutive patients (53 men, 56 women; mean age 63 +/- 14 y). Gated tomographic data, including left ventricular volumes and ejection fraction, were processed using an automatic algorithm, whereas echocardiography used standard techniques.

RESULTS

The correlations between gated tomography and echocardiography with respect to end-diastolic volume, end-systolic volume and left ventricular ejection fraction were good to excellent (all P < 0.001, r values > or = 0.68), regardless of the use of poststress or rest/redistribution images, 201Tl or 99mTc tracers. End-systolic volume was similar with gated tomography and echocardiography (P = ns), but end-diastolic volume and left ventricular ejection fraction were significantly higher with echocardiography (P < or = 0.05).

CONCLUSION

Quantitative gated tomography, using either 201Tl or 99mTc tracers, has a good correlation with echocardiography for the assessment of left ventricular volumes and ejection fraction. These results support the clinical use of this new technique.

Changes in left ventricular filling and left atrial function six months after nonsurgical septal reduction therapy for hypertrophic obstructive cardiomyopathy

OBJECTIVES

The purpose of this study was to evaluate changes in left ventricular (LV) filling, left atrial (LA) volumes and function six months after nonsurgical septal reduction therapy (NSRT) for hypertrophic obstructive cardiomyopathy (HOCM).

BACKGROUND

Patients with HOCM frequently have enlarged left atria, which predisposes them to atrial fibrillation. Nonsurgical septal reduction therapy results in significant reduction in left ventricular outflow tract (LVOT) obstruction and symptomatic improvement. However, its effect on LV passive filling volume, LA volumes and function is not yet known.

METHODS

Thirty patients with HOCM underwent treadmill exercise testing as well as 2-dimensional and Doppler echocardiography before and six months after NSRT. Data included clinical status, exercise duration, LVOT gradient, mitral regurgitant (MR) volume, LV pre-A pressure and LA volumes. Left atrial ejection force and kinetic energy (KE) were computed noninvasively and were compared with 12 age-matched, normal subjects.

RESULTS

New York Heart Association (NYHA) class was lower and exercise duration was longer (p < 0.05) six months after NSRT. The LVOT gradient, MR volume and LV pre-A pressure were all significantly reduced. HOCM patients had larger atria, which had a higher ejection force and KE, compared with normal subjects (p < 0.01). After NSRT, LV passive filling volume increased (p < 0.01), whereas LA volumes, ejection force and KE decreased (p < 0.01). Reduction in LA maximal volume was positively related to changes in LV pre-A pressure (r = 0.8, p < 0.05) and MR volume (0.4, p < 0.05). Changes in LA ejection force were positively related to changes in LA pre-A volume (r = 0.7, p < 0.01) and KE (r = 0.81, p < 0.01). The increase in exercise duration paralleled the increase in LV passive filling volume (r = 0.85, p < 0.05).

CONCLUSIONS

Nonsurgical septal reduction therapy results in an increase in LV passive filling volume and a reduction in LA size, ejection force and KE.

Relation of the contractile reserve of hibernating myocardium to myocardial structure in humans

BACKGROUND

Although dobutamine echocardiography (DE) is widely used to assess myocardial viability in humans, little is known about the relation between contractile reserve and myocardial structure.

METHODS AND RESULTS

We evaluated 20 patients with coronary disease (64+/-13 years old, ejection fraction 28+/-7.5%) with DE (up to 40 micrograms . kg(-1). min(-1)), rest-redistribution (201)Tl single photon emission CT, and quantitative angiography before bypass surgery. During surgery, patients underwent transmural myocardial biopsies (n=37) guided by transesophageal echocardiography to determine the extent of interstitial fibrosis and intracellular and interstitial proteins by histopathology and immunohistochemistry. Among the 37 segments biopsied, 16 recovered function as assessed 2 to 3 months later. Segments with postoperative functional recovery had more wall thickening at low-dose DE (28% versus 3%, P<0.001), higher thallium uptake (69% versus 48%, P=0.03), and less interstitial fibrosis (2% versus 28%, P<0.001). Quantitative angiographic parameters did not predict recovery of function. Segments with DE viability (contractile reserve and/or ischemia) had less fibrosis (2.7% versus 28%, P<0.001), less vimentin and fibronectin (both P<0.01), more glycogen (P=0.016), and higher thallium uptake (64% versus 35.5%, P<0.05) than those without viability. Viable segments by both DE and thallium had less fibrosis (1%) than those viable by 1 of the 2 techniques (9%) or not viable by both (28%, P=0.005). Thickening at low-dose DE correlated well with the extent of interstitial fibrosis (r=-0.83, P<0.01).

CONCLUSIONS

Contractile reserve during DE correlates inversely with the extent of interstitial fibrosis and the amount of fibronectin and vimentin and directly with rest-redistribution thallium uptake.

Assessment of myocardial viability with stress echocardiography

Over the past two decades, there has been an increased realization that systolic myocardial dysfunction, outside of the setting of acute ischemia, does not necessarily imply irreversible myocardial injury. Echocardiographic techniques, particularly dobutamine stress echocardiography, have emerged as important diagnostic modalities that can identify residual viable myocardium in patients following acute myocardial infarction and in those with suspected myocardial hibernation. Dobutamine echocardiography can also help risk stratify patients with coronary artery disease and depressed ventricular function and identify patients who would benefit best from revascularization procedures.

Noninvasive evaluation of hemodynamics by Doppler echocardiography

Doppler echocardiography plays an invaluable role in the diagnosis and management of patients with heart disease. Noninvasive measurements of cardiac output, pulmonary artery pressures, and left and right ventricular filling pressures can be obtained with reasonable accuracy at baseline and at intervals to assess the response to therapy. Furthermore, simple measurements of Doppler-acquired mitral inflow parameters provide independent and incremental prognostic data in patients with restrictive heart disease and in patients with left ventricular systolic dysfunction and heart failure.

Supine bicycle versus post-treadmill exercise echocardiography in the detection of myocardial ischemia: a randomized single-blind crossover trial

OBJECTIVES

We sought to determine the comparative accuracy of supine bicycle exercise echocardiography (SBE) and posttreadmill exercise echocardiography (TME) in detecting myocardial ischemia in patients with known or suspected coronary artery disease (CAD).

BACKGROUND

Supine bicycle echocardiography and TME have been used for evaluation of CAD. However, the comparative accuracy of these modalities in the detection of ischemia in the same patients is not known.

METHODS

Seventy-four patients (age 59 +/- 9 years [mean +/- SD]) referred for evaluation of coronary disease underwent SBE (starting at 25 to 50 W with 25-W increment every 3 min) and post-TME (Bruce protocol) in a random sequence. Digitized images at baseline and maximal exercise were interpreted in a random and blinded fashion.

RESULTS

Maximal heart rate was higher during TME, whereas systolic blood pressure was higher during SBE, resulting in a similar double product. At quantitative angiography (n = 67), 57 patients had coronary stenosis (>50%). During SBE, ischemia was detected in 47 patients compared with 38 patients by TME (p < 0.001). Wall motion score index at maximal exercise was higher with SBE than with TME (1.48 +/- 0.51 vs. 1.38 +/- 0.43; p < 0.001). The extent of myocardial ischemia (number of ischemic segments) was higher during SBE compared with TME (3.3 +/- 3.4 vs. 2.3 +/- 2.9 segments; p = 0.004), whereas severity of abnormal wall motion was similar. The sensitivity of SBE and TME for CAD was 82% and 75% with a specificity of 80% and 90%, respectively. Image quality was similar with both techniques. Patients and sonographers favored SBE over TME.

CONCLUSIONS

During SBE and TME exercise, patients achieve a similar double product. During SBE, however, the detection of ischemia is more frequent and more extensive which, along with patient and sonographer preference, makes supine bicycle exercise a valuable stress echocardiographic modality.

Changes in left ventricular diastolic function 6 months after nonsurgical septal reduction therapy for hypertrophic obstructive cardiomyopathy

BACKGROUND

Nonsurgical septal reduction therapy (NSRT) decreases left ventricular outflow tract (LVOT) gradient and improves symptoms in patients with hypertrophic obstructive cardiomyopathy (HOCM). NSRT effects on LV/left ventricular diastolic function are currently unknown.

METHODS AND RESULTS

HOCM patients (n=29) had Doppler echocardiography at baseline and 6 months after NSRT to evaluate changes in LV volume, pre-A-wave pressure, early diastolic mitral annulus velocity (Ea) by tissue Doppler, and tau. At 6 months, a significant reduction in LVOT gradient (from 53.6+/-15 to 6+/-5 mm Hg; P<0.001) was accompanied by improvement in exercise duration (from 284+/-147 to 408+/-178 seconds; P=0.04) and New York Health Association class (from III to I; P<0.001). Pre-A pressure (18+/-6 to 14+/-5 mm Hg; P<0.01) and tau (62+/-8 to 51+/-8 ms; P<0.01) decreased, whereas Ea (5.8+/-1.8 to 8+/-1.8 cml/s; P<0.01) and LV end-diastolic volume (117+/-16 to 130+/-22 mL; P<0.01) increased.

CONCLUSIONS

NSRT improves LV relaxation and compliance, which contributes to the symptomatic relief seen at 6 months.

Doppler estimation of left ventricular filling pressures in patients with hypertrophic cardiomyopathy

BACKGROUND

Conventional Doppler parameters are unreliable for estimating left ventricular (LV) filling pressures in hypertrophic cardiomyopathy (HCM). This study was undertaken to evaluate flow propagation velocity by color M-mode and early diastolic annular velocity (Ea) by tissue Doppler 2 new indices of LV relaxation, combined with mitral E velocity for estimation of filling pressures in HCM.

METHODS AND RESULTS

Thirty-five HCM patients (52+/-15 years) underwent LV catheterization simultaneously with 2-dimensional and Doppler echocardiography. Pulsed Doppler echocardiography of mitral and pulmonary venous flows was obtained along with flow propagation velocity and Ea. LV preA pressure had weak or no relations with mitral, pulmonary venous velocities and atrial volumes. In contrast, preA pressure related strongly to E velocity/flow propagation velocity (r=0.67; SEE=4) and E/Ea (r=0.76; SEE=3.4). In 17 patients with repeat measurements, preA pressure changes were well detected by measuring E velocity/flow propagation velocity (r=0.68; P=0.01) or E/Ea (r=0.8; P<0.001). PreA pressure estimation with these 2 methods was tested prospectively in 17 additional HCM patients with good results (E velocity/flow propagation velocity, r=0.76; E/Ea, r=0.82).

CONCLUSIONS

LV filling pressures can be estimated with reasonable accuracy in HCM patients by measuring E velocity/flow propagation velocity or E/Ea. These ratios also track changes in filling pressures.

Differentiating thrombus from pannus formation in obstructed mechanical prosthetic valves: an evaluation of clinical, transthoracic and transesophageal echocardiographic parameters

OBJECTIVES

We sought to determine the clinical and echocardiographic parameters that differentiate thrombus from pannus formation as the etiology of obstructed mechanical prosthetic valves.

BACKGROUND

Distinction of thrombus from pannus on obstructed prosthetic valves is essential because thrombolytic therapy has emerged as an alternative to reoperation.

METHODS

We analyzed clinical, transthoracic and transesophageal echocardiography (TEE) data in 23 patients presenting with 24 obstructed prosthetic valves and compared the findings to pathology at surgery.

RESULTS

Fourteen valves had thrombus and 10 had pannus formation. Patients with thrombus had a shorter duration from time of valve insertion to malfunction, shorter duration of symptoms, but similar New York Heart Association functional class at the time of operation. Patients with thrombus had a lower rate of adequate anticoagulation (21% vs. 89%; p=0.0028). Pannus formation was more common in the aortic position (70% vs. 21%; p=0.035). Abnormal prosthetic valve motion was detected by TEE in all cases with thrombus formation but in 60% with pannus (p=0.0198). Thrombi were larger than pannuses (total length 2.8+/-2.47 cm vs. 1.17+/-0.43 cm; p=0.038). This was mostly due to extension of thrombi into the left atrium in prosthetic mitral valves. Thrombi appeared as a soft mass on the valve in 92% of cases, whereas 29% of pannuses had a soft echo density (p= 0.007). Ultrasound video intensity ratio, derived as the videointensity of the mass to that of the prosthetic valve, was lower in the thrombus group (0.46+/-0.14 vs. 0.71+/-0.17, p=0.006). A videointensity ratio of <0.70 had a positive predictive value of 87% and a negative predictive value of 89% for thrombus. Duration from onset of symptoms to reoperation of <1 month separated thrombus from pannus formation. The best objective clinical parameter for prediction of thrombus was inadequate anticoagulation, whereas the best TEE parameters were qualitative and quantitative ultrasound intensity of the mass. The presence of either inadequate anticoagulation or a soft mass by TEE improved the predictive power of either parameter alone and was similar to that of ultrasound videointensity ratio.

CONCLUSIONS

Duration of symptoms, anticoagulation status and qualitative and quantitative ultrasound intensity of the mass obstructing a mechanical prosthetic valve can help differentiate pannus formation from thrombus and may therefore be of value in refining the selection of patients for thrombolytic therapy of prosthetic valve obstruction.

Echocardiography-guided ethanol septal reduction for hypertrophic obstructive cardiomyopathy

BACKGROUND

Left ventricular outflow tract (LVOT) obstruction is frequently responsible for symptoms in hypertrophic obstructive cardiomyopathy (HOCM). Medical therapy is often not sufficient to control these symptoms, and surgical myotomy-myomectomy is required.

METHODS AND RESULTS

We enrolled 33 symptomatic patients with HOCM and obstruction (>/=40 mm Hg gradient at rest or >/=60 mm Hg dobutamine-provoked). By contrast echocardiography, the bulging septum was localized and infarcted by injection of 2 to 5 mL of absolute ethanol into the septal artery(ies) supplying the hypertrophied area. Baseline echocardiograms with Doppler, myocardial perfusion tomograms, and treadmill exercise or pharmacological testing were compared with those at 6 weeks and 6 months. The mean rise in creatine kinase was 1964+/-796 U. All patients experienced symptomatic relief; NYHA class decreased from 3. 0+/-0.5 to 0.9+/-0.6 (P<0.001). Exercise time increased from 286+/-193 to 421+/-181 seconds (P=0.03). The resting and dobutamine-provoked gradient decreased from 49+/-33 and 96+/-34 mm Hg to 9+/-19 (P<0.001) and 24+/-31 mm Hg (P<0.001), respectively. Echocardiograms repeated at 6 weeks after the procedure showed a 28% reduction in septal thickness and 17% reduction in left ventricular mass. Myocardial perfusion imaging showed a "septal amputation pattern," with scarring in the upper and middle septal areas. Complete heart block developed in 11 patients, who then required permanent pacemaker implantation.

CONCLUSIONS

Echocardiography-guided ethanol septal reduction in patients with HOCM is a safe, minimally invasive procedure that provides symptomatic relief with improved hemodynamic and left ventricular parameters.

Doppler estimation of left ventricular filling pressure in sinus tachycardia. A new application of tissue doppler imaging

BACKGROUND

Doppler echocardiography is frequently used to predict filling pressures in normal sinus rhythm, but it is unknown whether it can be applied in sinus tachycardia, with merging of E and A velocities. Tissue Doppler imaging (TDI) can record the mitral annular velocity. The early diastolic velocity (Ea) behaves as a relative load-independent index of left ventricular relaxation, which corrects the influence of relaxation on the transmitral E velocity.

METHODS AND RESULTS

We evaluated 100 patients 64+/-12 years old with simultaneous Doppler and invasive hemodynamics. Mitral inflow was classified into 3 patterns: complete merging of E and A velocities (pattern A), discernible velocities with A dominance (B), or E dominance (C). The Doppler data were analyzed at the mitral valve tips for E, acceleration and deceleration times of E, and isovolumic relaxation time. In patterns B and C, the A velocity, E/A ratio, and atrial filling fraction were derived. Pulmonary venous flow velocities were also measured, and TDI was used to acquire Ea and Aa. Weak significant relations were observed between pulmonary capillary wedge pressure (PCWP) and sole parameters of mitral flow, pulmonary venous flow, and annular measurements. These were better for patterns A and C. E/Ea ratio had the strongest relation to PCWP [r=0.86, PCWP=1.55+1.47(E/Ea)], irrespective of the pattern and ejection fraction. This equation was tested prospectively in 20 patients with sinus tachycardia. A strong relation was observed between catheter and Doppler PCWP (r=0.91), with a mean difference of 0.4+/-2.8 mm Hg.

CONCLUSIONS

The ratio of transmitral E velocity to Ea can be used to estimate PCWP with reasonable accuracy in sinus tachycardia, even with complete merging of E and A velocities.

Assessment of valvular regurgitation with Doppler echocardiography

Echocardiography is routinely performed for the evaluation of valvular regurgitation. Different applications of Doppler echocardiography have been successfully applied to detect and quantify valvular regurgitation. Recent advances in color Doppler made possible the study of the dynamic behavior of the regurgitant orifice and, along with continuous wave Doppler, can provide data on the regurgitant volume and fraction. Doppler echocardiography can also be used to follow serial changes in these hemodynamically important parameters after medical or surgical therapy.

Estimation of left and right ventricular filling pressures after heart transplantation by tissue Doppler imaging

Current Doppler methods have been unreliable in estimating filling pressures in heart transplants. Tissue Doppler imaging is a technique that permits evaluation of myocardial relaxation; combined with transvalvular E velocity, it could improve estimation of these pressures. To investigate this possibility, we evaluated 50 patients by right-sided cardiac catheterization and Doppler echocardiography simultaneously. Their mean +/-SD age was 53+/-15 years and the mean age of donor hearts was 30+/-12.5 years. The mitral E velocity was combined with the early myocardial relaxation (Ea) velocity by tissue Doppler at the lateral border of the mitral annulus. Likewise, the tricuspid E velocity was combined with Ea at the lateral corner of the tricuspid annulus. Mean wedge pressure related weakly to mitral inflow variables but strongly to E/Ea [r=0.8; wedge pressure=2.6+1.46(E/Ea)]. In 25 repeat right-sided cardiac catheterizations, changes in mean wedge pressure were well detected by Doppler, with a mean difference of -0.7+/-3 mm Hg. Mean right atrial pressure related weakly to routine tricuspid inflow variables but strongly to tricuspid E/Ea [r=0.79; n=38; right atrial pressure=1.76(E/Ea) - 3.7]. In 18 repeat right-sided cardiac catheterizations, changes in mean right atrial pressure were well detected by Doppler, with a mean difference of 0+/-3.45 mm Hg. Mean wedge pressure and mean right atrial pressure can be estimated in heart transplants with reasonable accuracy using the ratio of E/Ea. Furthermore, this method can accurately track changes in filling pressures.

Role of myocardial contrast echocardiography during nonsurgical septal reduction therapy for hypertrophic obstructive cardiomyopathy

OBJECTIVES

This study was undertaken to evaluate the ability of myocardial contrast echocardiography (MCE) to guide the targeted delivery of ethanol during nonsurgical septal reduction therapy (NSRT) and to assess the relation between the MCE risk area and infarct size determined by enzymatic and radionuclide methods.

BACKGROUND

NSRT with intracoronary ethanol is a new promising treatment for patients with hypertrophic obstructive cardiomyopathy (HOCM). Proper localization and quantification of the septal infarct before ethanol injection are highly desirable. MCE can provide accurate delineation of the vascular territory of the coronary arteries.

METHODS

Twenty-nine patients with HOCM and maximal medical therapy underwent NSRT. The left ventricular outflow tract (LVOT) gradient by Doppler echocardiography at baseline was 53 +/- 16 mm Hg (mean +/- SD). Before NSRT, MCE was performed in all patients with intracoronary sonicated albumin (Albunex). Diluted sonicated albumin (Albunex) was selectively injected into the septal perforator arteries during simultaneous transthoracic imaging. Immediately after MCE, ethanol was injected into the same vessel. Plasma total creatine kinase (CK), total CK-MB fraction and CK-MB fraction subforms were measured at baseline and serially for 36 h.

RESULTS

LVOT gradient decreased to 12 +/- 6 mm Hg (p < 0.001) after NSRT. Accurate mapping of the vascular beds of the septal perforators was successfully attained in all patients by MCE. Furthermore, the MCE risk area correlated well with peak CK (r = 0.79, p < 0.001). Six weeks after NSRT, 23 patients underwent myocardial perfusion studies performed with single-photon emission computed tomography (SPECT). Mean SPECT septal perfusion defect size involved 9.5 +/- 6% of the left ventricle and correlated well with MCE area (r = 0.7), with no statistically significant difference between the risk area estimated by MCE and that by SPECT.

CONCLUSIONS

Estimation of the size of the septal vascular territory with MCE is accurate, safe and feasible in essentially all patients during NSRT. MCE can delineate the perfusion bed of the septal perforators and can predict the infarct size that follows ethanol injection.

Effects of adenosine on left ventricular filling dynamics in patients with and without coronary artery disease: a Doppler echocardiographic study

OBJECTIVES

Adenosine, a potent coronary vasodilator is used as a pharmacologic stress agent for the assessment of coronary artery disease. A paucity of data exists on its effects on filling dynamics. Accordingly, this study was undertaken to evaluate the effects of adenosine on left ventricular filling as assessed by Doppler echocardiography.

METHODS AND RESULTS

We studied 69 patients (45 men, 24 women, aged 61+/-11 years) referred for evaluation of coronary artery disease. Two-dimensional echocardiography and pulsed-Doppler recordings at the mitral valve tips and annulus were performed at baseline and at maximal adenosine infusion of 140 microg/kg/min. During adenosine infusion, an increase in heart rate occurred (70+/-14 beats/min to 85+/-16 beats/min), with a mild decrease in blood pressure (130/75+/-26/13 mm Hg vs 119/66+/-25/13 mm Hg); both p < 0.02. Changes in filling dynamics included an increase in peak early inflow velocity, E/A ratio, and normalized peak filling rate. Of the patients investigated, 23 had one-vessel coronary artery disease, 29 had coronary disease in two vessels or more by angiography, and 17 had no significant disease. Patients without coronary artery disease (controls) had mild changes in E/A ratio (mean 7%). Patients with coronary artery disease had a more heterogeneous change in filling dynamics (range 43% to 369%, mean 26%), with a significant overlap with controls. However, changes in E/A ratio during adenosine infusion that exceeded the confidence limits of normal (-20% to +30%) were specific for coronary artery disease, with a positive predictive value of 84%.

CONCLUSIONS

Normally, adenosine induces significant increases in early filling as assessed by Doppler. The changes in patients with coronary stenosis are more variable. When these changes fall outside the confidence limits of normal, they are predictive of coronary artery disease.

Doppler tissue imaging: a noninvasive technique for evaluation of left ventricular relaxation and estimation of filling pressures

OBJECTIVES

This investigation was designed 1) to assess whether the early diastolic velocity of the mitral annulus (Ea) obtained with Doppler tissue imaging (DTI) behaves as a preload-independent index of left ventricular (LV) relaxation; and 2) to evaluate the relation of the mitral E/Ea ratio to LV filling pressures.

BACKGROUND

Recent observations suggest that Ea is an index of LV relaxation that is less influenced by LV filling pressures.

METHODS

One hundred twenty-five study subjects were classified into three groups according to mitral E/A ratio, LV ejection fraction (LVEF) and clinical symptoms: 34 asymptomatic subjects with a normal LVEF and an E/A ratio > or =1; 40 with a normal LVEF, an E/A ratio <1 and no heart failure symptoms (impaired relaxation [IR]); and 51 with heart failure symptoms and an E/A ratio >1 (pseudonormal [PN]). Ea was derived from the lateral border of the annulus. A subset of 60 patients had invasive measurement of pulmonary capillary wedge pressure (PCWP) simultaneous with Doppler echocardiographic DTI.

RESULTS

Ea was reduced in the IR and PN groups compared with the group of normal subjects: 5.8 +/- 1.5 and 5.2 +/- 1.4 vs. 12 +/- 2.8 cm/s, respectively (p < 0.001). Mean PCWP (20 +/- 8 mm Hg) related weakly to mitral E (r = 0.68) but not to Ea. The E/Ea ratio related well to PCWP (r = 0.87; PCWP = 1.24 [E/Ea] + 1.9), with a difference between Doppler and catheter measurements of 0.1 +/- 3.8 mm Hg.

CONCLUSIONS

Ea behaves as a preload-independent index of LV relaxation. Mitral E velocity, corrected for the influence of relaxation (i.e., the E/Ea ratio), relates well to mean PCWP and may be used to estimate LV filling pressures.

Dobutamine echocardiography versus nuclear cardiac imaging for evaluation of myocardial viability

The presence of myocardial viability is an important determinant of functional recovery after revascularization. Radionuclide and echocardiographic techniques are highly valuable in the identification of viable myocardium. Several clinical studies have compared the two modalities. Dobutamine echocardiography appears to have a higher specificity and a lower sensitivity in comparison with single-photon emission computed tomographic imaging. Importantly, both myocardial perfusion and inotropic reserve are capable of identifying the patients with the large increments in ejection fraction after successful revascularization.

Pathologic correlates of aortic plaques, thrombi and mobile "aortic debris" imaged in vivo with transesophageal echocardiography

OBJECTIVES

This study sought to evaluate the pathologic correlates of aortic atheromas, thrombi and mobile "aortic debris" imaged in vivo by transesophageal echocardiography (TEE).

BACKGROUND

Atherosclerotic plaques with various complexity, thrombi and debris are frequently identified by TEE during imaging of the aorta. However, pathologic data to characterize these lesions imaged in vivo are lacking.

METHODS

Intraoperative TEE was performed prospectively in 31 patients undergoing repair of aortic aneurysm or dissection. TEE was used to guide the surgeon to mark aortic areas of interest that were sent for pathologic examination. A four-point scoring system was used for both TEE and pathologic evaluation to grade the degree of involvement of the aortic wall with atheroma. Ultrasound video intensity of the aortic wall lesions was measured and compared with quantitative measures of wall composition at pathologic examination. The presence of thrombi and mobile aortic debris by TEE was noted and compared with pathologic findings.

RESULTS

Histologic-TEE correlations were possible in 62 aortic segments. There was 73% exact agreement between TEE and pathologic grading. Discrepancies were mostly in the inability of TEE to detect superficial ulcerations. However, separation of normal aorta and minimal intimal thickening (grades I and II) from more complex atheromas (grades III and IV) was observed in 93%. For identification of thrombus, TEE had a sensitivity of 91% (29 of 32 segments) and a specificity of 90% (27 of 30 segments). Mobile aortic debris were identified in six aortic segments and were confirmed at pathologic examination to be thrombi. Ultrasound video intensity increased with worsening complexity of atheroma and related significantly to aortic plaque composition at pathologic evaluation (r = 0.80, p < 0.0001). Ultrasound intensity of thrombi and mobile debris was similar and was lower than that of complex atheromas.

CONCLUSIONS

Thus, in the evaluation of aortic pathologic segments, TEE can assess aortic plaque complexity and identify thrombus formation, findings that may have important therapeutic implications.

Nicotine patch therapy in smoking cessation reduces the extent of exercise-induced myocardial ischemia

OBJECTIVES

We sought to determine the effects of nicotine patch therapy, when used to promote smoking cessation, on myocardial ischemia in patients with coronary artery disease.

BACKGROUND

Nicotine patches substantially increase quit rates among cigarette smokers, but their safety in patients with myocardial ischemia who are attempting to quit smoking is unknown.

METHODS

This is a prospective study using exercise thallium-201 single-photon emission computed tomography (SPECT) to assess serial changes in the total and ischemic myocardial perfusion defect size at baseline while patients were smoking and during treatment with 14- and 21-mg nicotine patches. Entry criteria required that patients 1) smoked > or = 1 pack of cigarettes per day; 2) had known coronary artery disease; and 3) had myocardial ischemia (i.e., > or = 5% reversible perfusion defect) on SPECT. All patients performed symptom-limited treadmill exercise, and the baseline SPECT study served as its own control. We interpreted and computer quantified the SPECT images with no knowledge of the testing sequence.

RESULTS

Thirty-six of the 40 enrolled patients had exercise SPECT at baseline and during treatment with at least 14-mg nicotine patches. These patients had an initial perfusion defect size of 17.5 +/- 10.6% while smoking an average of 31 +/- 11 cigarettes per day for 40 +/- 12 years. A significant reduction in the total perfusion defect size (p < 0.001) was observed from baseline (17.5 +/- 10.6%) to treatment with 14-mg (12.6 +/- 10.1%) and 21-mg (11.8 +/- 9.9%) nicotine patches. This reduction occurred despite an increase in treadmill exercise duration (p < 0.05) and higher serum nicotine levels (p < 0.001). There was a significant correlation between the reduction in defect size and exhaled carbon monoxide levels (p < 0.001) because patients reduced their smoking by approximately 74% during the trial.

CONCLUSIONS

Nicotine patches, when used to promote smoking cessation, significantly reduce the extent of exercise-induced myocardial ischemia as assessed by exercise thallium-201 SPECT.

Identification of hibernating myocardium: comparative accuracy of myocardial contrast echocardiography, rest-redistribution thallium-201 tomography and dobutamine echocardiography

OBJECTIVES

We sought to evaluate the comparative accuracy of myocardial contrast echocardiography (MCE), quantitative rest-redistribution thallium-201 (Tl-201) tomography and low and high dose (up to 40 microg/kg body weight per min) dobutamine echocardiography (DE) in identifying myocardial hibernation.

BACKGROUND

Myocardial contrast echocardiography can assess myocardial perfusion and may therefore be useful in predicting myocardial hibernation. However, its accuracy in comparison to myocardial perfusion scintigraphy and to that of high dose DE remains to be investigated.

METHODS

Eighteen patients (aged [+/- SD] 57 +/- 10 years) with stable coronary artery disease and ventricular dysfunction underwent the above three modalities before coronary revascularization. Myocardial contrast echocardiography was achieved with intracoronary Albunex. Rest echocardiographic and Tl-201 studies were repeated > or = 6 weeks after revascularization.

RESULTS

Of 109 revascularized segments with severe dysfunction, 46 (42%) improved. Left ventricular ejection fraction increased from 38 +/- 14% to 45 +/- 13% at follow-up (p = 0.003). Rest Tl-201 uptake and the ratio of peak contrast intensity of dysfunctional to normal segments with MCE were higher (p < 0.01) in segments that recovered function compared with those that did not. Myocardial contrast echocardiography, thallium scintigraphy and any contractile reserve during DE had a similar sensitivity (89% to 91%) with a lower specificity (43% to 66%) for recovery of function. A biphasic response during DE was the most specific (83%) and the least sensitive (68%) (p < 0.01). The best concordance with MCE was Tl-201 (80%, kappa 0.57). Changes in ejection fraction after revascularization related significantly to the number of viable dysfunctional segments by all modalities (r = 0.54 to 0.65).

CONCLUSIONS

In myocardial hibernation, methods evaluating rest perfusion (MCE, Tl-201) or any contractile reserve have a similar high sensitivity but a low specificity for predicting recovery of function. A limited contractile reserve (biphasic response) increases the specificity of DE. Importantly, the three techniques identified all patients who had significant improvement in global ventricular function.

Dobutamine echocardiography and quantitative rest-redistribution 201Tl tomography in myocardial hibernation. Relation of contractile reserve to 201Tl uptake and comparative prediction of recovery of function

BACKGROUND

The purposes of this study were to evaluate the comparative accuracy of dobutamine echocardiography and quantitative rest-redistribution 201Tl tomography in the prediction of recovery of function after revascularization and to assess the relation of contractile reserve to thallium uptake.

METHODS AND RESULTS

Thirty-four patients with stable coronary disease and regional dysfunction underwent dobutamine echocardiography (2.5 up to 40 micrograms.kg-1.min-1) and rest-redistribution 201Tl tomography 1 day before revascularization. Resting echocardiography and scintigraphy were repeated at > or = 6 weeks. Before revascularization, resting 201Tl uptake was similar in segments demonstrating biphasic or sustained improvement and was higher than in those exhibiting no change or worsening function during dobutamine. After revascularization, 201Tl uptake increased only in segments that showed a biphasic response (from 66 +/- 12% to 78 +/- 13%; P < .05). Biphasic response had a sensitivity of 74% and specificity of 89% for prediction of recovery. The use of biphasic or sustained improvement responses increased the sensitivity to 86% with a decrease in specificity to 68%. Qualitative thallium assessment provided a high sensitivity (98%) but poor specificity (27%). Quantification of thallium uptake, however, improved its accuracy: a maximal uptake (at rest or redistribution) of > or = 60% yielded a 90% sensitivity and a 56% specificity.

CONCLUSIONS

In patients with myocardial hibernation, biphasic response during dobutamine is less sensitive but more specific for recovery of function, whereas indexes of 201Tl scintigraphy are in general more sensitive and less specific, the least accurate being a qualitative assessment of thallium uptake. The sensitivity and specificity of both methods, however, can be altered depending on the quantitative criteria of thallium uptake or combination of responses of the myocardium to dobutamine.

Prognostic value of stress echocardiography in stable angina or after myocardial infarction

Stress echocardiography is increasingly used for the assessment of coronary artery disease and is valuable in the treatment of patients with known disease as well. Although several studies are available on the accuracy of stress echocardiography in the detection of coronary artery disease and evaluation of its severity, studies on the use of this technique for evaluation of prognosis are just now emerging. Over the past decade, few studies have investigated its prognostic value in different patient populations. The versatility and advantage of stress echocardiography lie in the fact that it provides information on both resting ventricular function and stress-induced ischemia, two important determinants of cardiac events. Exercise echocardiography with the bicycle or posttreadmill approach is used in subjects who can exercise and provides important additional prognostic data from physiologic exercise variables. In patients unable to exercise, pharmacologic stress echocardiography with dobutamine or vasodilators is used. Stress echocardiography has been shown to identify different populations of patients at risk of cardiac events, including those with stable or suspected coronary artery disease, those with acute myocardial infarction, and those scheduled for major noncardiac surgery. In the early postinfarct setting, exercise and vasodilator stress have been used more often, whereas dobutamine echocardiography has been used predominantly at low doses for the assessment of residual myocardial viability. This review focuses on recently published investigations evaluating the prognostic effect of stress echocardiography in patients with stable coronary artery disease or acute myocardial infarction.