Doppler echocardiography in diastology: 35 years of Japanese contribution to its advancement and utility

Echocardiography is one of the most important and clinically useful techniques in the assessment of diastolic function. Because of the prevalence of this technique, "diastology" and even the concept of diastolic heart failure have become familiar to researchers and physicians. We believe the first description by Kitabatake and his colleagues in 1982 of the use of Doppler technique to assess the transmitral flow velocity pattern in various cardiac diseases was the beginning of this development. Since then, a number of excellent works regarding echocardiographic assessment of diastolic function have emerged from Japan. Here, we review the Japanese contributions to the development of the use of Doppler echocardiography in diastology.

Simulation of blood flow coronary artery with consecutive stenosis and coronary-coronary bypass

INTRODUCTION

In this research the behavior of coronary arteries has been studied with symmetric and asymmetric consecutive stenosis, and grafted vessels.

METHODS

The incompressible Navier-Stokes and energy equations were discretized with second-order upwind method. Assumptions such as Newtonian fluid, wall rigidity and steady-flow were used.

RESULTS

All the calculations showed the same results with Newtonians and non- Newtonian fluids. It was found that the possibility of stenosis be reduced by increasing the graft angle. However, there exists further stenosis possibility. Among the three graft angles 20, 30 ˚ and 40, the 30 ˚ was found to be the reliable ones.

CONCLUSION

Based on these findings, it can be deduced that there would be a high risk of further atherosclerosis when the first stenose has the maximum percentage.

Infective endocarditis presents as isolated splenomegaly

Sub acute left-sided bacterial endocarditis is a serious condition that may be overlooked due to highly variable clinical manifestations. We present the case of a 45-year-old man who presented with complaints of fullness in his abdomen and splenomegaly that referred to the surgery clinic. He underwent diagnostic splenectomy. 3 month after splenectomy endocarditis was diagnosed. We recommend echocardiography in the work up of isolated splenomegaly.

Isolated true parachute mitral valve in an asymptomatic elderly patient

We report the extremely rare case of a 73-year-old asymptomatic patient who has an isolated true parachute mitral valve (PMV). In the echocardiographic examination, the parasternal long-axis view showed a single papillary muscle. The short-axis view revealed the presence of a symmetric mitral valve orifice with all chordae attaching to a large anterolateral papillary muscle. Because detailed examination did not reveal the presence of other complications, this patient was diagnosed as an isolated true PMV.

Two cases of quadricuspid aortic valve

Quadricuspid aortic valve (QAV) is a rare congenital aortic valve anomaly. We present two cases of QAV diagnosed by using echocardiography including transesophageal echocardiography (TEE) and cardiac computed tomography (CT). The first case, QAV with four equal-sized cusps, was identified in a 58-year-old man. The second case, QAV with a small accessory cusp between the right coronary and non-coronary cusp, was identified in a 42-year-old man. TEE and cardiac CT could lead to accurate diagnosis of QAV. QAV in these two patients could be diagnosed before indication for surgery but it is necessary to continue careful follow-up.

Relation between progression of aortic valve sclerosis and carotid intima-media thickening in asymptomatic subjects with cardiovascular risk factors

BACKGROUND

Aortic valve sclerosis (AVS) is the early lesion of calcific aortic valve disease and may subsequently progress toward valvular stenosis. Histopathological and clinical evidence has suggested that AVS and atherosclerosis share similar mechanisms. However, little is known regarding the relation between the early AVS progression and the early atherosclerosis progression. The carotid intima-media thickness (IMT) by carotid ultrasonography has been established as the surrogate marker of the early atherosclerosis. The aim of this study was to examine the association between progression of early AVS and increase of carotid IMT.

METHODS

We retrospectively analyzed the data of 127 asymptomatic subjects (49 ± 8 years, 114 men) with ≥1 cardiovascular (CV) risk factors, without history of CV disease, who underwent echocardiographic and carotid ultrasonographic examinations twice ≥6 months apart. We evaluated aortic valve morphology and function and carotid IMT at the baseline and at follow-up examinations.

RESULTS

During a follow-up of 25 ± 15 months, the number of subjects with AVS was significantly increased (34 vs. 47%, P < 0.0001) and the mean value of carotid IMT was significantly increased (1.16 ± 0.33 vs. 1.29 ± 0.41 mm, P < 0.0001). The progression of AVS was observed in 26 subjects. By logistic regression analysis, the baseline carotid IMT value was an independent predictor of AVS progression (odds ratio = 4.07, P = 0.026).

CONCLUSION

In asymptomatic subjects with CV risk factors, progression of AVS and increase of carotid IMT were observed during a mean follow-up period of 25 months. Progression of AVS in asymptomatic subjects with CV risk factors was associated with carotid intima-media thickening.

Exercise echocardiography in the evaluation of severity of functional mitral regurgitation in patients with heart failure

We present two cases with ischemic cardiomyopathy and similar functional mitral regurgitation (fMR) at rest, who represented different outcomes following mitral valve repair. In case 1, fMR was enhanced during exercise echocardiography, and his symptoms were improved following the repair and coronary artery bypass graft (CABG). In case 2, fMR did not change during exercise, and the improvement of his symptoms was small following the operation. Exercise echocardiography evidenced variability of the dynamic changes in fMR in patients with ischemic cardiomyopathy. The variability may be related to the outcome of the mitral valve repair.

Mitral annulus segmentation from 3D ultrasound using graph cuts

The shape of the mitral valve annulus is used in diagnostic and modeling applications, yet methods to accurately and reproducibly delineate the annulus are limited. This paper presents a mitral annulus segmentation algorithm designed for closed mitral valves which locates the annulus in three-dimensional ultrasound using only a single user-specified point near the center of the valve. The algorithm first constructs a surface at the location of the thin leaflets, and then locates the annulus by finding where the thin leaflet tissue meets the thicker heart wall. The algorithm iterates until convergence metrics are satisfied, resulting in an operator-independent mitral annulus segmentation. The accuracy of the algorithm was assessed from both a diagnostic and surgical standpoint by comparing the algorithm's results to delineations made by a group of experts on clinical ultrasound images of the mitral valve, and to delineations made by an expert with a surgical view of the mitral annulus on excised porcine hearts using an electromagnetically tracked pointer. In the former study, the algorithm was statistically indistinguishable from the best performing expert (p=0.85) and had an average RMS difference of 1.81+/-0.78 mm to the expert average. In the latter, the average RMS difference between the algorithm's annulus and the electromagnetically tracked points across six hearts was 1.19+/-0.17 mm .

Heterogeneity of apex-to-base dispersion in diastolic lengthening is related to impaired global left ventricular relaxation in patients with hypertrophic cardiomyopathy

BACKGROUND

The presence of apex-to-base disparity in diastolic left ventricle (LV) endocardial lengthening, based on an electromechanical activation sequence, has been recognized as an important determinant of LV diastolic properties. However, the behavior of LV apical and basal diastolic lengthening and its relationship to LV filling in hypertrophic cardiomyopathy (HCM) are unknown.

METHODS

We obtained basal and apical LV short-axis views in 27 patients with non-obstructive HCM and 25 healthy volunteers. The patients with HCM were subdivided into two groups; those with apical hypertrophy [APH(+)] or those without apical hypertrophy [APH(-)]. Eight equiangular points on the endo-myocardium at end diastole were placed in each view, and the movements of these points were automatically tracked using a two-dimensional echocardiographic tissue tracking system. Time-LV internal diameter curves were obtained and averaged. The time intervals from the aortic valve closure to the point of the first 40% of peak diastolic lengthening (T 40) were measured in each view. The standard deviation of the time to peak systolic circumferential shortening at the base and apex were calculated to assess the heterogeneity of LV contraction.

RESULTS

The time difference in the T 40 between the apex and base (dt-T 40) in the HCM-APH(+) and HCM-APH(-) groups was greater than that in the control group. The heterogeneities in LV apical systolic shortening in the HCM groups were greater than those in the control group. There were good linear correlations between the dt-T 40 and the LV early diastolic echo-parameters and the LV mass index.

CONCLUSIONS

Delayed apical relaxation and filling in patients with HCM is related to LV diastolic dysfunction and systolic dyssynchronous contraction.

Left ventricular-right atrial communication by perforation of the atrioventricular portion of the membranous septum and severe aortic valve regurgitation caused by infective endocarditis

We report the case of acquired left ventricle (LV) to right atrial (RA) communication through an aneurysm of the atrioventricular septum caused by infectious endocarditis. A severe aortic valve regurgitation and destruction of the aortic valve was detected by echocardiography. Transesophageal echocardiography revealed a flail aortic valve with vegetation and abnormal shunt flow from the LV to RA with ruptured aneurysm of the membranous septum. An abscess cavity of the aortic ring was introduced. Because of worsening congestive heart failure, the patient underwent emergency aortic valve replacement and patch closure of the communication of the membranous septum. The patient's postoperative course was uneventful.

Resolution of thrombus in left ventricular outflow tract pseudoaneurysm mimicking periaortic abscess

Prosthetic valve complications are not uncommon after valve replacement. In this paper we report a female patient who presented with aortic prosthetic valve endocarditis and echocardiographic appearance of periaortic abscess. After 6 weeks of antibiotic therapy, echocardiographic examination revealed resolution of abscess cavity and replacement with a clear blood-filled anechoic sac. Diagnosis was made by cardiac computed tomography, which showed a left ventricular outflow tract (LVOT) pseudoaneurysm rather than an abscess, located just below the sewing ring of the prosthetic aortic valve. We assumed that either resolution of thrombus in LVOT pseudoaneurysm following effective warfarin therapy or clearance of infective content in pseudoaneurysm after co-administered antibiotics gave rise to change in echocardiographic characteristics in the perivalvular area.

Quantification of global myocardial oxygenation in humans: initial experience

PURPOSE

To assess the feasibility of our newly developed cardiovascular magnetic resonance (CMR) methods to quantify global and/or regional myocardial oxygen consumption rate (MVO2) at rest and during pharmacologically-induced vasodilation in normal volunteers.

METHODS

A breath-hold T2 quantification method is developed to calculate oxygen extraction fraction (OEF) and MVO2 rate at rest and/or during hyperemia, using a two-compartment model. A previously reported T2 quantification method using turbo-spin-echo sequence was also applied for comparison. CMR scans were performed in 6 normal volunteers. Each imaging session consisted of imaging at rest and during adenosine-induced vasodilation. The new T2 quantification method was applied to calculate T2 in the coronary sinus (CS), as well as in myocardial tissue. Resting CS OEF, representing resting global myocardial OEF, and myocardial OEF during adenosine vasodilation were then calculated by the model. Myocardial blood flow (MBF) was also obtained to calculate MVO2, by using a first-pass perfusion imaging approach.

RESULTS

The T2 quantification method yielded a hyperemic OEF of 0.37 +/- 0.05 and a hyperemic MVO2 of 9.2 +/- 2.4 micromol/g/min. The corresponding resting values were 0.73 +/- 0.05 and 5.2 +/- 1.7 micromol/g/min respectively, which agreed well with published literature values. The MVO2 rose proportionally with rate-pressure product from the rest condition. The T2 sensitivity is approximately 95% higher with the new T2 method than turbo-spin-echo method.

CONCLUSION

The CMR oxygenation method demonstrates the potential for non-invasive estimation of myocardial oxygenation, and should be explored in patients with altered myocardial oxygenation.

Diastolic flow velocity pattern of the left anterior descending coronary artery in hypertrophied heart, with special reference to the difference between hypertrophic cardiomyopathy and hypertensive left ventricular hypertrophy

BACKGROUND

This study aimed to clarify the characteristics of diastolic flow velocity pattern of the left anterior descending coronary artery (LAD) in patients with left ventricular hypertrophy (LVH), and the difference in diastolic LAD flow velocity pattern between hypertensive LVH and hypertrophic cardiomyopathy (HCM).

METHODS

The flow velocity pattern was recorded at the mid-portion of the LAD by high-frequency transthoracic Doppler echocardiography in 22 patients with HCM, 10 hypertensive patients with LVH [LVH(+)HT], and 9 hypertensive patients without LVH [LVH(-)HT]. The diastolic flow pattern was analyzed. Standard two-dimensional echocardiogram and apexcardiogram (ACG) were also recorded.

RESULTS

The interventricular septal thickness (IVST) and the sum of the IVST and LV posterior wall thickness (PWT) (IVST + PWT) were greater in HCM than in HT (p < 0.01) patients. Early diastolic upstroke time (D-UT) of the LAD flow velocity wave was longest in HCM, and was longer in LVH(+)HT than in LVH(-)HT (p < 0.01) patients. Direct correlation was found between D-UT and IVST, IVST + PWT in patients with LVH(+)HT and LVH(-)HT (r = 0.80, 0.79, respectively; p < 0.01), but no correlation was found between these parameters in HCM. Late-diastolic step (LDS) formation of the LAD flow velocity wave was observed in 68% of HCM, 20% of LVH(+)HT, but none of the LVH(-)HT patients. The A wave ratio of ACG was higher in patients with LDS than in those without (p < 0.01). The LDS occurred coincidently with the A wave of ACG.

CONCLUSIONS

The diastolic LAD flow velocity pattern in hypertrophied heart is characterized by slow acceleration and LDS formation, reflecting impaired relaxation and increased stiffness of the LV, respectively. These abnormalities correlate with the degree of hypertrophy in hypertensive heart, but do not correlate with that in HCM.

Myocardial deformation in acute myocarditis with normal left ventricular wall motion--a cardiac magnetic resonance and 2-dimensional strain echocardiographic study

BACKGROUND

The aim of our study was to assess longitudinal (L), circumferential (C) and radial (R) strain (S) of the left ventricle (LV) in patients with acute myocarditis and preserved LV wall motion.

METHODS AND RESULTS

Of the 26 male patients that were enrolled, 13 patients (26+/-8 years) suffered from acute myocarditis and 13 (25+/-2 years) were healthy participants (controls). Both patients and controls underwent cardiac magnetic resonance (CMR) and 2-dimensional S imaging (2D-S) echocardiography on the same day. Myocardial strains (RS, LS and CS) were quantified by 2D-S. In patients with myocarditis, a delayed enhancement (DE) CMR study was performed to identify damaged myocardial segments. In the myocarditis group there was a significant LS reduction compared with controls (-25+/-7 vs -20+/-7, P<0.0001), whereas no difference was found between the 2 groups concerning CS and RS. Subepicardial DE areas were found in 12 of 13 patients. Segments with DE showed a significantly lower LS in comparison with segments without DE (-19+/-4 vs -23+/-6, P<0.0001). In contrast, no difference in CS and RS was found when comparing segments with DE vs segments without DE.

CONCLUSIONS

In patients with acute myocarditis, evidence of subepicardial damage and no wall motion abnormalities, longitudinal deformation is diffusely impaired, whereas circumferential impairment is regionally sited in the areas of subepicardial damage.

Regular exercise training prevents aortic valve disease in low-density lipoprotein-receptor-deficient mice

BACKGROUND

Regular exercise training (ET) slows the progression of atherosclerotic lesions, reduces oxidative stress, and increases nitric oxide bioavailability, all of which may be expected to improve degenerative aortic valve disease.

METHODS AND RESULTS

Four-week-old low-density lipoprotein-receptor-deficient mice (n=94) were randomly divided into 4 groups: Group 1 (control group), normal diet plus sedentary activity; group 2 (cholesterol group), cholesterol diet plus sedentary activity; group 3 (regular ET group), cholesterol diet plus regular ET (60 min/day, 5 days/week) for 16 weeks; and group 4 (occasional exercise group), cholesterol diet plus occasional ET (1 day/week) for 16 weeks. At 20 weeks of age, histological analysis was performed. A significant increase in aortic valve thickness was evident in the cholesterol group compared with the control group. Importantly, regular but not occasional ET significantly reduced aortic valve thickness compared with the cholesterol group (control 31.3+/-3.0 mum, cholesterol 50.1+/-3.4 mum, regular exercise 30.4+/-1.2 mum, and occasional exercise 48.9+/-3.2 mum). Immunohistochemistry revealed that a cholesterol diet disrupted and regular ET preserved endothelial integrity on the aortic valve surface. Furthermore, serum myeloperoxidase, accumulation of macrophages and oxidized low-density lipoprotein, in situ superoxide, activated myofibroblasts/osteoblast phenotypes, and mineralization were increased in the cholesterol group but were decreased by regular ET. Polymerase chain reaction revealed increased messenger RNA expression for alpha-smooth muscle actin, bone morphogenetic protein-2, runt-related transcription factor-2, and alkaline phosphatase in the cholesterol group, whereas these were diminished by regular ET. Moreover, regular ET significantly increased circulating levels of fetuin-A compared with the cholesterol group.

CONCLUSIONS

In the low-density lipoprotein-receptor-deficient mouse, regular ET prevents aortic valve sclerosis by numerous mechanisms, including preservation of endothelial integrity, reduction in inflammation and oxidative stress, and inhibition of the osteogenic pathway.

Myocardial deformation in patients with Beta-thalassemia major: a speckle tracking echocardiographic study

BACKGROUND

Increasing data suggest that parameters of myocardial deformation are strong indices of ventricular systolic and diastolic function. We sought to determine myocardial deformation of the left ventricle and assess relationship of deformation rates with myocardial iron load in patients with beta-thalassemia major.

METHODS

The left ventricular longitudinal, circumferential, and radial myocardial deformation was determined using speckle tracking echocardiography in 42 thalassemia patients aged 24.4 +/- 6.4 years. The results were compared with those of 38 age-matched controls. The rates of longitudinal and circumferential deformation were correlated with cardiac T2* magnetic resonance findings.

RESULTS

Compared with controls, patients had significantly greater global systolic radial strain (P = 0.001), but similar global systolic longitudinal (P = 0.12) and circumferential strain (P = 0.84). On the other hand, patients had significantly lower longitudinal systolic strain rate (SR) (P = 0.019), longitudinal early diastolic SR (P = 0.036), and circumferential early diastolic SR (P = 0.04) than controls. The cardiac T2* findings correlated positively with longitudinal (r = 0.44, P = 0.004) and circumferential early diastolic SR (r = 0.37, P = 0.019), but not with the respective systolic SRs and left ventricular ejection fraction (all P > 0.05). Patients with iron overload (T2*< 20 msec), compared to those without, had significantly lower longitudinal (1.45 +/- 0.33/sec vs. 1.76 +/- 0.27/sec, P = 0.002) and circumferential (1.01 +/- 0.31/sec vs. 1.22 +/- 0.31/sec, P = 0.03) early diastolic SR.

CONCLUSIONS

Patients with beta-thalassemia major have reduced longitudinal systolic SR, longitudinal early diastolic SR, and circumferential early diastolic SR. The rates of diastolic deformation in the longitudinal and circumferential dimensions are inversely related to myocardial iron overload.

Heterogeneous contraction of the left ventricle demonstrated by 2-dimensional strain imaging

BACKGROUND

Tissue Doppler imaging (TDI) is useful in quantifying regional myocardial function, but has a significant limitation of Doppler angle dependency. The recently developed 2-dimensional strain imaging (2DS), based on speckle tracking imaging (STI) technology, enables us to evaluate myocardial function independent of ultrasound beam direction. The aim of this study was to assess the mode of contraction of the left ventricle.

METHODS

Circumferential, radial and longitudinal strains were measured in 18 segments (anteroseptal, anterior, anterolateral, inferolateral, inferior and inferoseptal walls at the base, mid-ventricle and apex) from apical and short-axis views using 2DS in 24 healthy subjects (mean age, 33 ± 5 years). We divided the left ventricle into 2 sites: septum (anterior, anteroseptal and inferoseptal walls) and free walls (anterolateral, inferolateral and inferior walls). We then compared the mode of contraction between the septum and free walls.

RESULTS

At the base and mid-ventricular levels, circumferential strain was larger in the septum (-22.6 ± 3.6 vs. -18.3 ± 4.1% and -24.1 ± 4.8 vs. -18.4 ± 5.7%, respectively; p < 0.0001 each), and radial strain was larger in the free walls (33.4 ± 12.4 vs. 38.7 ± 14.5% and 37.8 ± 12.6 vs. 43.0 ± 11.6%, respectively; p < 0.001 each) at the basal and mid-ventricular levels, whereas both were relatively homogeneous at the apex. The longitudinal strain did not differ among walls.

CONCLUSIONS

Heterogeneous contraction is seen in the left ventricle. The septum mainly contracts circumferentially, whereas the free walls contract radially. 2DS is helpful in understanding the mode of 3-dimensional myocardial contraction.

Prognostic implications of left atrial dilation evaluated by echocardiographic volume in patients with normal left atrial antero-posterior dimensions

BACKGROUND

The purpose of this study was to clarify the clinical characteristics and prognostic implications of left atrial (LA) dilation evaluated echocardiographic volume in patients with normal LA dimension (LAD).

METHODS

A total of 140 consecutive patients (81 men, mean age: 57 ± 18 years) with normal LAD (<39 mm for women and <41 mm for men) who underwent conventional echocardiography and tissue Doppler imaging were enrolled. LA volume (LAV) ≥29 ml/m(2) was defined as abnormal LAV. Hospitalization for heart failure (HF) and cardiac death were defined as cardiac events.

RESULTS

Eighty-seven (62%) of the patients had LA dilation, defined as a normal LAD but an abnormal LAV. Patients with LA dilation were significantly older and had a significantly higher left ventricular (LV) mass index (LVMI) and incidences of hypertension and HF than did patients with both normal LAD and normal LAV. Logistic regression analysis revealed that increased LVMI was an independent (p < 0.01) determinant of LA dilatation. During a follow-up period of 16 ± 10 months, ten patients had cardiac events. Patients with cardiac events had a higher incidence of LA dilation than those without cardiac events (100 vs. 59%, p < 0.05). A Kaplan-Meier survival curve showed that patients with LA dilation had a significantly lower survival rate than those with both normal LAD and normal LAV (log rank 6.1, p = 0.014).

CONCLUSIONS

LV hypertrophy is an independent determinant of LA dilation in patients with normal LAD. Assessment of LA morphology using LAV can contribute to risk stratification in patients with normal LAD.

Fever of unknown origin as a primary presentation of chronic aortic dissection

Fever of unknown origin is rare as a primary presentation of aortic dissection. We describe a 69-year-old female presenting with a sustained fever. A diagnosis of chronic type A aortic dissection was established by computed tomography. Replacements of the ascending aorta and part of the aortic arch were performed. Ten days after the operation, the patient had recurrent pyrexia. A large effusion in the left pleural cavity was found. After puncture aspiration and antibiotic treatment, she recovered. She was doing well at the 5(1/2)-year follow-up.

Increased mid-left ventricular rotation in patients with Duchenne muscular dystrophy using two-dimensional speckle tracking echocardiography

BACKGROUND

In patients with Duchenne muscular dystrophy (DMD), cardiomyopathy initially occurs during adolescence. In routine echocardiographic examination, we often recognize increased rotational movement of the left ventricle in DMD patients even if their conventional echocardiographic finding is normal. Two-dimensional speckle tracking echocardiography can assess left ventricular (LV) rotation. The aim of this study was to analyze the mid-LV rotation and to investigate the clinical implication of this abnormal movement.

METHODS

Nineteen DMD patients (age 15.5 ± 3.1 years) and 22 age-matched healthy subjects were recruited. The two-dimensional speckle tracking method was used to determine the mid-LV rotation at the papillary muscle level. The mid-LV rotation and rotational velocity were calculated and were compared with other echocardiographic data and indices of autonomic function.

RESULTS

Total rotation was greater in the DMD group than in the normal group (7.3 ± 1.4° versus 5.2° ± 1.3°, p < 0.05). Both peak diastolic clockwise and counterclockwise rotational velocity were greater in the DMD group (p < 0.005 and p < 0.05, respectively). Time from the second heart sound to peak diastolic clockwise rotation (% diastolic duration) was greater in the DMD group (p < 0.005). Total rotation and percentage of adjacent normal R-R intervals more than 50 ms different showed a negative correlation (r = -0.72) in the DMD group.

CONCLUSION

In DMD patients, cases diagnosed with normal LV fractional shortening showed an increase in mid-LV rotation that might be due to relative increase of sympathetic nervous function before global cardiac function decreases.

Detection of coronary artery disease using delayed strain imaging at 5 min after the termination of exercise stress: head to head comparison with conventional treadmill stress echocardiography

BACKGROUND

Prolongation of the time to peak strain (TPS) is a sensitive marker of myocardial ischemia. The purpose of this study was to evaluate whether delayed strain imaging obtained at 5 min after the termination of exercise stress can detect patients with significant coronary artery disease (CAD).

METHODS

A total of 45 patients who underwent treadmill stress echocardiography and coronary angiography were studied. Patients with abnormal wall motion at rest were excluded. Digital echocardiographic images were recorded at baseline and immediately after the termination of treadmill stress. Exercise-induced wall motion abnormality was considered as a marker of myocardial ischemia. Tissue velocity images were also recorded at baseline and 5 min after the termination of treadmill stress, and TPS was measured. TPS ratio was calculated as the ratio between TPS at delayed post-exercise and TPS at baseline.

RESULTS

Coronary angiography revealed that 30 of the 45 patients had significant CAD > or =50% diameter stenosis. The receiver operating characteristics curve demonstrated that cut-off value of TPS ratio 1.10 provides best diagnostic accuracy for vessel-based detection of significant CAD. The sensitivity, specificity, and diagnostic accuracy of the conventional exercise stress echocardiography for detecting patients with CAD were 87%, 80%, and 84%, respectively. The sensitivity, specificity, and accuracy of delayed strain imaging for identifying patients with CAD were 93%, 73%, and 87%, respectively.

CONCLUSION

Delayed strain imaging obtained at 5 min after the termination of exercise stress can accurately detect patients with significant CAD.

Clinical significance of anterior mitral leaflet fibrillation in patients with nonvalvular atrial fibrillation: comparison with blood flow and wall motion of the left atrial appendage

BACKGROUND AND PURPOSE

Diastolic fibrillation of the anterior mitral leaflet (AML) is seen in patients with atrial fibrillation (AF). However, its clinical significance has been unclear. On the other hand, reduced blood flow velocity in the left atrial appendage (LAA) may be associated with LA thrombus formation. In this study, we investigate the relationship between the flow velocity and the wall motion velocity of the LAA and diastolic fibrillation of the AML in patients with nonvalvular AF.

METHODS

We performed transthoracic echocardiography (TTE) in 45 consecutive patients with chronic nonvalvular AF. The LAA flow velocity was measured by pulsed Doppler echocardiography with the sample volume positioned at the center of the LAA. The LAA wall motion velocity was measured by pulsed Doppler tissue imaging (DTI) with the sample volume at the medial wall of the LAA. The AML fibrillation velocity was measured by pulsed DTI with the sample volume at the AML tip.

RESULTS

The AML fibrillation velocity could be measured in 44 patients (97.8%), and the LAA flow and wall motion velocities were measurable in 35 (77.8%) and 42 (93.3%) patients, respectively. The AML fibrillation velocity had a range from 4 to 21 cm/s and showed significant positive correlation with the LAA flow velocity (r = 0.82, P < 0.001) and the wall motion velocity (r = 0.80, P < 0.001) of the LAA. An AML fibrillation velocity of ≤7 cm/s predicted patients having a tendency to LA thrombus formation (LAA flow velocity ≤20 cm/s) with high sensitivity (87.5%) and specificity (88.9%).

CONCLUSION

The AML fibrillation velocity seems to be a viable substitute for the LAA flow velocity in the detection of flow stagnation in the LA.

Inverted Takotsubo cardiomyopathy masking acute myocardial infarction

We report a case of inverted Takotsubo cardiomyopathy masking acute myocardial infarction. In this case, echocardiography on admission showed left ventricular mid and basal akinesis and apical hyperkinesis compatible with an inverted Takotsubo contractile pattern. In the subacute phase, however, he was suspected of having acute myocardial infarction by serial changes of cardiac enzymes. After 8 days of admission, echocardiography showed normalization of the left ventricular contraction, except the inferior wall which was compatible with inferior myocardial infarction. Subsequent myocardial scintigraphy confirmed the diagnosis. It is important to recognize that inverted Takotsubo cardiomyopathy may mask acute myocardial infarction when they occur simultaneously.

Accuracy of three-dimensional echocardiography in patients with prior anteroseptal myocardial infarction

BACKGROUND

Echocardiography is the most feasible modality for monitoring cardiac volume and function. However, conventional two-dimensional echocardiography (2DE) is frequently not accurate in measuring cardiac performance in cases of abnormal left ventricular wall motion, because of the geometric assumptions. Quantitative gated scintigraphy and magnetic resonance imaging are reliable modalities, but are expensive and not feasible for repetitive use. Real-time three-dimensional echocardiography (RT3DE) has been proved to be applicable in daily practice. The purpose of this study was to confirm the superiority of RT3DE to 2DE in assessing cardiac volume and function in patients with abnormal wall motion.

METHODS

The subjects were 41 patients with old anteroseptal myocardial infarction who underwent left ventricular volume and functional measurement by RT3DE, 2DE, and left ventriculography (LVG). End-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) from RT3DE and 2DE were measured and compared with results from LVG.

RESULTS

RT3DE correlated well with LVG in measurements of EDV, ESV, and EF (r = 0.815, 0.940, and 0.812, respectively; P < 0.001 each). Likewise, 2DE correlated with LVG, but underestimated left ventricular volume, particularly EDV (r = 0.652, 0.909, and 0.761, respectively; P < 0.001 each).

CONCLUSION

Values derived from RT3DE were closer to those from LVG than were values derived from 2DE. RT3DE provides important information on cardiac function in patients with prior anteroseptal myocardial infarction.

Echocardiographic evaluation of mitral geometry in functional mitral regurgitation

Objectives

We sought to evaluate the geometric changes of the mitral leaflets, local and global LV remodeling in patients with left ventricular dysfunction and varying degrees of Functional mitral regurgitation (FMR).

Background

Functional mitral regurgitation (FMR) occurs as a consequence of systolic left ventricular (LV) dysfunction caused by ischemic or nonischemic cardiomyopathy. Mitral valve repair in ischemic MR is one of the most controversial topic in surgery and proper repairing requires an understanding of its mechanisms, as the exact mechanism of FMR are not well defined.

Methods

136 consecutive patients mean age of 55 with systolic LV dysfunction and FMR underwent complete echocardiography and after assessing MR severity, LV volumes, Ejection Fraction, LV sphericity index, C-Septal distance, Mitral valve annulus, Interpapillary distance, Tenting distance and Tenting area were obtained.

Results

There was significant association between MR severity and echocardiogarphic indices (all p values < 0.001). Severe MR occurred more frequently in dilated cardiomyopathy (DCM) patients compared to ischemic patients, (p < 0.001). Based on the model, only Mitral valve tenting distance (TnD) (OR = 22.11, CI 95%: 14.18 – 36.86, p < 0.001) and Interpapillary muscle distance (IPMD), (OR = 6.53, CI 95%: 2.10 – 10.23, p = 0.001) had significant associations with MR severity.

Mitral annular dimensions and area, C-septal distance and sphericity index, although greater in patients with severe regurgitation, did not significantly contribute to FMR severity.

Conclusion

Degree of LV enlargement and dysfunction were not primary determinants of FMR severity, therefore local LV remodeling and mitral valve apparatus deformation are the strongest predictors of functional MR severity.

Imaging and estimation of tissue elasticity by ultrasound

Ultrasound (US) elasticity imaging is an extension of the ancient art of palpation and of earlier US methods for viewing tissue stiffness such as echopalpation. Elasticity images consist of either an image of strain in response to force or an image of estimated elastic modulus. There are 3 main types of US elasticity imaging: elastography that tracks tissue movement during compression to obtain an estimate of strain, sonoelastography that uses color Doppler to generate an image of tissue movement in response to external vibrations, and tracking of shear wave propagation through tissue to obtain the elastic modulus. Other modalities may be used for elasticity imaging, the most powerful being magnetic resonance elastography. With 4 commercial US scanners already offering elastography and more to follow, US-based methods may be the most widely used for the near future. Elasticity imaging is possible for nearly every tissue. Breast mass elastography has potential for enhancing the specificity of US and mammography for cancer detection. Lesions in the thyroid, prostate gland, pancreas, and lymph nodes have been successfully imaged using elastography. Evaluation of diffuse disease including cirrhosis and transplant rejection is also possible using both imaging and nonimaging methods. Vascular imaging including myocardium, blood vessel wall, plaque, and venous thrombi has also shown great potential. Elasticity imaging may also be important in assessing the progress of ablation therapy. Recent work in assessing porous materials using elastography suggests that the technique may be useful in monitoring the severity of lymphedema.

Effect of systemic blood pressure on microcollateral circulation evaluated by real-time contrast echocardiography

BACKGROUND

In acute myocardial infarction, residual collateral-derived myocardial blood flow (CBF) within the ischemic area is one of the major determinants of infarct size. Management of systemic blood pressure (sBP) related to maintain collateral circulation is still difficult. The aim of this study was to reveal the influence of sBP on the rescue of area at risk by collateral circulation.

METHODS

Real-time myocardial contrast echocardiography just after the onset of complete occlusion of the left circumflex coronary artery was performed in collateral-rich open-chest dogs. The video intensity of the ischemic area was evaluated during the occlusion and the CBF (A x beta) was calculated from a replenishment curve: y = A (1 - e(-beta t)). To analyze the effect of sBP on the collateral circulation, sBP was altered by infusion of nitroglycerin or etilefrine hydrochloride. To evaluate the defect size (%DS), every end-systolic myocardial contrast echocardiography image after left circumflex coronary artery occlusion was converted into binary images using custom offline software.

RESULTS

The %DS increased and CBF slightly decreased at low sBP. The %DS decreased and CBF increased at high sBP. At excessively high sBP, %DS increased and CBF decreased again.

CONCLUSION

Real-time myocardial contrast echocardiography, which is a useful noninvasive method to evaluate the collateral perfusion quantitatively, has a crucial role in the decision of patient treatment and management strategy of acute myocardial infarction.