A novel method to assess systolic ventricular function using atrioventricular plane displacement--a study in young healthy males and patients with heart disease.

Analysis of atrioventricular plane displacement (AVPD) is a well established method for assessment of both systolic and diastolic ventricular function. For several years, AVPD has been a clinical tool and there are many current, as well as potential, areas of application. However, clinical work has shown that the traditional method for evaluation of systolic ventricular function, called total AVPD, does not temporally reflect true systole. Systolic AVPD is a new approach for measuring AVPD to assess ventricular systolic function. We wished to apply this new model in healthy subjects and in patients with different common heart diseases. Twenty-eight young healthy males and 30 patients (aortic stenosis, left sided regurgitant lesions, postmyocardial infarction) were enrolled. AVPD was obtained at the four standard sites by M-mode. Total AVPD was measured in the conventional way and systolic AVPD by identifying true systole, by means of mitral- and aortic valve closure respectively. Ventricular volumes were calculated according to biplane Simpson's rule. The systolic AVPD measurements were significantly lower than the total measurements, at both atrioventricular planes in all groups (P<0.001). This discrepancy was greater at the mitral than at the tricuspid annulus in the patients 24.2% vs. 15.5% (P<0.001), but did not differ in the healthy subjects. At the mitral annulus, this discrepancy also seemed to be more pronounced in the patients than in the healthy subjects 24.2% vs. 10.7%. When assessing ventricular systolic function by AVPD, the conventional method overestimates the amplitude in relation to true systolic function in both patients with heart disease and in young healthy males. Thus, there are uncertainties regarding earlier estimations of AVPD in terms of expression of systolic function and regarding previously presented reference values. We recommend the proposed methodology.

The feasibility of ultrasonic regional strain and strain rate imaging in quantifying dobutamine stress echocardiography.

BACKGROUND: Ultrasonic strain rate and strain can characterize regional one-dimensional myocardial deformation at rest. In theory, these deformation indices could be used to quantify normal or abnormal regional function during a dobutamine stress echo test. AIMS: The aims of our pilot study were threefold: (1) to determine the percentage of segments in which interpretable strain rate/strain data could be obtained during routine dobutamine stress echo, (2) to establish whether either the increase in heart rate or artefacts induced by respiration during dobutamine stress echo would influence analysis by degrading the data and (3) to determine the optimal frame rate vs image sector angle settings for data acquisition. Furthermore, although the detection of ischaemia was not to be addressed specifically in this study, we would describe the findings on the potential clinical role of regional deformation vs velocity imaging in detecting ischaemia-induced changes. METHODS: A standard dobutamine stress echo protocol was performed in 20 consecutive patients with a history of chest pain (16 with angiographic coronary artery disease and four with normal coronary angiograms). DMI velocities were acquired at baseline, low dose, peak dose, and recovery. To evaluate radial function (basal segment of the left ventricle posterior wall segment), parasternal LAX, SAX views were used. For long axis function data were acquired (4-CH, 2-CH views) from the septum; lateral, inferior and anterior left ventricle walls. Data was acquired using both 15 degrees (>150 frames per second (fps) and 45 degrees (115fps) sector angles. During post-processing each wall was divided into three segments: basal, mid and apical. Strain rate/strain values were averaged over three consecutive heart cycles. RESULTS: Data was obtained from 1936 segments, of which only 54 had to be excluded from subsequent analysis (2.8%) because of suboptimal quality. An increase in heart rates (up to 150/min) was not associated with a significant reduction in the number of interpretable segments. There was a significant correlation between maximal systolic strain rate/strain values obtained at narrow and at wide sector angles (e.g. a correlation for the septal segments: r=0.73,P <0.001 for strain rate, and r=0.71; P<0.001 for strain). The correlation for the timing of events obtained from narrow and wide sector angles was weaker. This would indicate that there was the insufficient temporal resolution for the latter acquisition method. Normal and abnormal regional strain rate/strain responses to an incremental dobutamine infusion were defined. In normal segments, maximal systolic strain rate values increased continuously from baseline, reaching the highest values at the peak dose of dobutamine. The segmental strain response was different. For strain, there was an initial slight increase at low dose of dobutamine (5, 10 microg/kg/min), but no further increase with increasing dose. A pattern representing an ischaemic response was identified and described. CONCLUSIONS: The feasibility study would suggest that with appropriate data collection and post-processing methodologies, strain rate/strain imaging can be applied to the quantification of dobutamine stress echo. However, appropriate post-processing algorithms must be introduced to reduce data analysis time in order to make this a practical clinical technique.

Non-invasive cardiac assessment in beta-thalassaemia major.

Iron deposition in the heart occurs in beta-thalassaemia major and contributes to cardiac dysfunction. Eighteen patients with beta-thalassaemia major were assessed clinically and had non-invasive investigations. They were young (15.5 +/- 3.6 years). Two patients had clinical heart failure. Doppler echocardiography demonstrated higher transmitral peak flow velocity in early and late diastole compared with controls (e: p<0.05, a: p<0.01). Transtricuspid peak late diastolic flow velocity was higher in patients (p<0.005). Isovolumic relaxation time was shortened (p<0.001). Pulmonary venous flow velocity was higher in diastole than systole (S: 0.51 +/- 0.11 m/s, D: 0.62 +/- 0.08 m/s). Reversal of pulmonary venous flow during atrial systole was seen in eight patients. These diastolic filling abnormalities did not significantly change with blood transfusion. Left ventricular ejection fraction was normal in patients. Two patients had cardiomegaly on chest X-ray. In beta-thalassaemia with iron overload, there is a restrictive pattern of diastolic dysfunction. This is not altered by recent blood transfusion. Left ventricular function remains relatively intact.

Age-dependent changes in regional diastolic function evaluated by color Doppler myocardial imaging: a comparison with pulsed Doppler indexes of global function.

The goals of this study were to evaluate possible normal age-related changes in regional myocardial relaxation as detected by color Doppler myocardial imaging (CDMI) velocities and to compare the extent of any such changes with age-induced changes in global diastolic function. In 80 healthy subjects (aged 21 to 72 years, equally subdivided by decades) the mitral flow velocities in early diastole (E) and atrial contraction (A) were recorded as were the velocities of left ventricular (LV) motion of early (EDV) and late diastole (LDV) in the 16 standard LV segments, and their ratios were calculated. In healthy persons younger than 40 years, all segments showed an EDV/LDV ratio > 1, whereas in healthy persons aged 40 years or older the mean EDV of all segments decreased, and the mean LDV increased, resulting in a significant decrease of the mean EDV/LDV ratio with age. Values of EDV/LDV ratios were higher than E/A ratios (P <.0001), but their changes with age correlated well with each other (r = 0.805). With increasing age, an EDV/LDV ratio <1 was observed more often in basal segments (P <.001, compared with mid and apical segments) and less often in segments of anteroseptal and posterior walls viewed from the parasternal window. The presence of >50% segments with an EDV/LDV ratio <1 was associated with an E/A ratio <1. Regional diastolic function indexes as evaluated by CDMI changed with increasing age in a heterogeneous way and influenced global diastolic function parameters.

Quantification of the spectrum of changes in regional myocardial function during acute ischemia in closed chest pigs: an ultrasonic strain rate and strain study.

The objectives of this study were to define the spectrum of regional myocardial function changes during acute ischemia in closed chest animals by using newly developed ultrasonic strain rate and strain indexes derived from regional color Doppler myocardial imaging (CDMI) velocity data. Myocardial ischemia was induced in 18 pigs either with acute total 20-second occlusions (group 1, n = 12) or graded hypoperfusion (40 to 0 mL/min, group 2, n = 6) of the circumflex coronary artery. In addition, a dobutamine challenge (5 to 10 microg/kg per minute) was performed during sustained subtotal ischemia (10 mL/min) in group 2. CDMI acquisitions with parasternal views monitored the myocardial posterior wall function. Regional radial strain rate and strain (epsilon(r)) were measured for systole, isovolumic relaxation, early diastole, and atrial filling, respectively. During total and graded ischemia, epsilon(r) profiles were consistently modified, showing a delayed onset and a decrease in regional systolic thickening as well as increased postsystolic thickening. Radial strain rate and epsilon(r) indexes decreased consistently during systole and early diastole and increased during isovolumic relaxation. End-systolic epsilon(r) could differentiate total ischemia from severe hypoperfusion (10 mL/min), decreasing from 32% +/- 8% to 16% +/- 5% (versus 60% +/- 10% at baseline). During dobutamine infusion (10 microg/kg per minute), end-systolic epsilon(r) tended to decrease from 27% +/- 5% to 18% +/- 11%, whereas postsystolic thickening increased by 2-fold (P <.05). The combined analysis of regional deformation characteristics and global cardiac event timing derived from CDMI data can identify and quantify regional function changes induced by experimental acute ischemia in closed chest pigs. This would appear to be a potentially promising new noninvasive approach to the clinical evaluation of ischemia-induced changes in segmental myocardial function.

Doppler myocardial imaging in the assessment of normal and ischemic myocardial function--past, present and future.

Myocardial ischemia is associated with impaired regional myocardial function. Echocardiography is a suitable technique for the assessment of regional myocardial function as it is easily applicable and commonly available. However, most of the currently used echo-techniques are based on 2D images or M-mode traces. Therefore, they are limited either to the assessment of myocardial segments that can be insonated at 90 degrees or are based on visually assessed wall motion scoring which is semiquantitative at best. Doppler myocardial imaging (DMI) is a new ultrasound technique which assesses the velocity of myocardial motion. Different parameters can be derived from this velocity information such as velocity time integrals, intramural velocity gradients and strain/strain-rate information. Moreover, DMI provides information of the timing of regional motion related to myocardial contraction and relaxation. These parameters are all assessed quantitatively, therefore, DMI is a promising technique to quantify myocardial function, avoiding the disadvantages of observer-dependant judgement of myocardial contraction.

Can natural strain and strain rate quantify regional myocardial deformation? A study in healthy subjects.

Strain rate (SR) and strain (epsilon) have been proposed as new ultrasound (US) indices for quantifying regional wall deformation, and can be measured from color Doppler myocardial data by determining the local spatial velocity gradient. The aim of this study was to define normal regional SR/epsilon values for both radial and longitudinal myocardial deformation. SR/epsilon profiles were obtained from 40 healthy volunteers. For radial deformation, posterior left ventricular (LV) wall SR/epsilon were calculated. For longitudinal, they were determined for basal, mid- and apical segments of the 1. septum; 2. lateral, 3. posterior and 4. anterior LV walls and for the 5. right ventricular (RV) lateral wall. SR/epsilon values describing radial deformation were higher than the corresponding SR/epsilon values obtained for longitudinal deformation. Longitudinal SR/epsilon were homogeneous throughout the septum and all LV walls. This was in contrast to the normal base-apex velocity gradient. The RV segmental SR/epsilon values were higher than those obtained from the corresponding LV wall and inhomogeneous (higher in the apical segments). SR/epsilon imaging appears to be a robust technique for quantifying regional myocardial deformation.

Changes in systolic and postsystolic wall thickening during acute coronary occlusion and reperfusion in closed-chest pigs: Implications for the assessment of regional myocardial function.

The aim of the study was to characterize the impact of short-lived total coronary occlusions in closed-chest pigs on radial wall thickening within the "at-risk" myocardial segment by using gray-scale M-mode echocardiography. Twelve pigs underwent a series of 20-second total circumflex coronary artery occlusions with an angioplasty balloon. Myocardial thickening/thinning indexes were continuously monitored before ischemia, during ischemia, and on reperfusion by high-resolution M-mode recordings of the posterior wall obtained from parasternal views. The timing of regional events was compared with global systolic time intervals derived from the color Doppler myocardial imaging velocity data. Each occlusion induced a rapid decrease in end-systolic thickening (epsilon(ES)), closely paralleled by an increase in postsystolic thickening in the ischemic segment. After 20 seconds of ischemia, epsilon(ES) decreased by -86% and postsystolic thickening increased by +100%, whereas maximal thickening decreased only by -34% in comparison with preocclusion values. All wall thickening parameters returned to baseline after 15 seconds of reperfusion. During acute total ischemia in a closed-chest animal model, the changes in regional myocardial function were best characterized by the combined analysis of systolic and postsystolic thickening abnormalities and by their respective timings relative to global cardiac events markers.

Does atrioventricular ring motion always distinguish constriction from restriction? A Doppler myocardial imaging study.

Constrictive pericarditis and restrictive cardiomyopathy can be difficult to differentiate on clinical examination. Cardiac ultrasonography is increasingly being used as the noninvasive method of choice for confirming the specific morphologic and hemodynamic abnormalities associated with either condition. Interrogation of atrioventricular valve plane motion by Doppler myocardial imaging (DMI) has been suggested as a valuable new approach that can help differentiate one from the other. We report the color DMI, pulsed DMI, and strain rate findings in 2 cases of constrictive pericarditis in which consideration of the annular motion pattern alone would not have allowed such differentiation.

Doppler myocardial imaging in the assessment of regional myocardial function in longitudinal direction pre- and post-PTCA.

AIMS: Doppler myocardial imaging is potentially a sensitive tool to assess regional myocardial velocities pre- and post-percutaneous transluminal coronary angioplasty (PTCA) as a marker of contractility to evaluate short- to medium-term information on functional myocardial recovery following the release of ischaemia. METHODS: Thirty patients with single vessel disease were studied to assess regional myocardial peak systolic velocity, systolic velocity time integral and mitral valve plane excursion in longitudinal direction one day pre-, one day post- and 3 months post-PTCA. The patients were assigned to group A with coronary stenoses >70% and group B with stenoses < 70%. RESULTS: In group A pre-PTCA the ischaemic segments showed a significantly lower peak systolic velocity and velocity time integral compared with the values one day after PTCA (5.8 +/- 1.4 vs 7.7 +/- 1.4cm.s(-1); 1.06 +/- 0.22 vs 1.23 +/-0.28cm;P< 0.03). In contrast, mitral valve plane excursion in this group remained unchanged after PTCA for both the ischaemic and non-ischaemic left ventricular wall. In group B no changes of these parameters and no differences in mitral valve plane excursion of the ischaemic and the non-ischaemic left ventricular wall could be seen. CONCLUSION: With Doppler myocardial imaging it was possible to quantify a number of indices which changed due to the successful release of ischaemia.

A comparison of regional myocardial velocity information derived by pulsed and color Doppler techniques: an in vitro and in vivo study.

The objective was to compare velocity information derived from either a tissue mimicking phantom or normal contracting myocardium by both pulsed wave and color Doppler myocardial imaging (PWDMI and CDMI). Both CDMI and PWDMI allow quantitative assessment of regional myocardial contraction and relaxation velocities, but their potential clinical applications have not yet been investigated. Moreover, no information is available as to whether they can be used interchangeably for regional velocity assessment. For the in vitro study, a rotating, circular-shaped, tissue-mimicking sponge driven by a motor at speeds of 15, 30, 60, 90 rpm was used to derive velocity data from the same eight points of interest by using PWDMI or CDMI techniques. For the in vivo study, 25 normal subjects were examined at rest using parasternal and apical approaches. Velocity profiles were derived from the same 26 areas of interest (18 left ventricular segments, 3 right ventricular segments, and 5 measurement points for the tricuspid and mitral annuli) for each technique. Peak maximal velocities were detected by PWDMI and peak mean velocities were measured using CDMI. The results of the in vitro study phantom showed excellent correlation (r = 0.99, P < 0. 001) and satisfactory agreement (0.04 cm/sec; 3.3 cm/sec) between both Doppler techniques. PWDMI velocities were higher than CDMI velocities by up to 20% and overestimated the real velocity value (0. 37 +/- 0.29 cm/sec) while CDMI underestimated predicted velocity by 1.35 +/- 0.36 cm/sec. Good correlation (r = 0.87, P < 0.001), but poor agreement (-2.1 cm/sec; 5.4 cm/sec) was shown in vivo for all segments with regard to peak systolic and diastolic velocities. Both Doppler techniques cannot be used interchangeably for comparing peak velocities in the clinical situation. However, with adequate temporal resolution, they can be used interchangeably for velocity profile recording and for timing of events.

Quantitation of left-ventricular asynergy by cardiac ultrasound.

The clinical evaluation of regional delays in myocardial motion (myocardial asynchrony) has proved problematic, yet it remains an important functional parameter to evaluate. Prior attempts to quantify regional asynergy have met with limited success, often thwarted by the low temporal resolution of imaging-system data acquisition. If a delay in onset of motion of 30-40 msec is clinically important to measure, then data acquisition at frame rates of 50-100 per second is required. This is out of the current temporal resolution of angiographic, nuclear, or magnetic resonance studies. Only cardiac ultrasound can currently achieve the necessary frame rates. Furthermore, quantitative studies into the accuracy with which a trained observer can identify computed regional myocardial asynchrony in a left-ventricular 2-dimensional (2-D) image have shown that regional delays of < 80 msec are not normally recognized in a moving image. This may be improved to 60 msec when either training is undertaken or comparative image review is used. However, this is still out of the temporal resolution required in clinical practice. Thus, visual interpretation of asynchrony is not sufficiently accurate. Two ultrasound data sets based on either integrated backscatter or Doppler myocardial imaging data may provide the solution. Doppler myocardial imaging is a new ultrasound technique which, in either its pulsed or color Doppler format, can achieve the required temporal resolution (with temporal resolutions of 8 msec and 16 msec, respectively). In contrast, color Doppler myocardial imaging, in its curved M-mode format, can display the timing of events during the cardiac cycle for all in-plane myocardial segments. This should allow the quantitation of regional delay for all systolic and diastolic events. Potentially, asynchrony due to regional ischemia, bundle branch block, ventricular premature beats, and ventricular preexcitation could all be identified and the degree of delay quantified. This overview will aim to establish the potential role of these new ultrasound methodologies in the recognition and quantitation of left-ventricular asynergy and how they might best be introduced into clinical practice.

Assessment of regional longitudinal myocardial strain rate derived from doppler myocardial imaging indexes in normal and infarcted myocardium.

Myocardial deformation properties may be characterized by regional strain rates (SRs) calculated from Doppler myocardial velocity data. In 10 control subjects and 12 patients with established transmural infarcts, longitudinal median segmental SR, strain, and myocardial velocity were analyzed and compared with the corresponding wall motion score. All segments in control subjects and normal segments in infarct patients showed no significant difference in either systolic or diastolic SR (systolic: -1.27+/-0.39 s(-1) versus -1.23+/-0.24 s(-1), not significant [NS]; and isovolumic relaxation [IVR]: 1.23+/-0.38 s(-1) versus 1.95+/-0.62 s(-1), NS; respectively) and strain (-0.21+/-0.06 versus -0.19+/-0.06, NS). In infarcted segments, peak systolic SR, systolic strain, and early diastolic SR showed the most pronounced reduction (hypokinetic and akinetic) or even inversion (dyskinetic segments: 0.10+/-0.26 s(-1), 0.00+/-0.03, and -1.78+/-0.67 s(-1), respectively; P<.001). In this study, new myocardial deformation indexes were shown to quantitatively describe the function of normal and chronically infarcted regions.

Results of the Ross operation in rheumatic versus non-rheumatic aortic valve disease.

BACKGROUND AND AIM OF THE STUDY: A total of 213 patients underwent the Ross operation at our institution between January 1990 and January 1999. Outcome was assessed in rheumatic (RH) patients and compared with that in patients with other etiology (non-RH). METHODS: After exclusion of 69 patients with a follow up of <18 months, the study group comprised 144 patients (119 RH, 25 non-RH). Patients were studied clinically and by echo-Doppler cardiography preoperatively, within 2 months and 6-8 months after surgery, and yearly afterwards. Preoperative assessment included age, gender, body surface area (BSA), type of aortic valve lesion and additional valve disease, left and right ventricular outflow tract (LVOT, RVOT) dimensions, and left ventricular (LV) size, function and mass. Postoperatively, patients were studied for presence and severity of autograft regurgitation, mitral regurgitation, LV size, function and mass, and incidence and timing of reoperation. RESULTS: On average, RH patients were older and had higher BSA, more aortic regurgitation than stenosis, more additional mitral valve disease (mostly regurgitation), larger LV size and poorer LV function. Mitral valve repair was performed in 24% of RH patients versus 0% of non-RH patients. Postoperatively, differences in LV size, function and mass remained present, but diminished during follow up. The autograft reoperation incidence was 22% (26/119) in RH patients versus 8% (2/25) in non-RH patients (p = NS). Preoperative predictors for reoperation in the RH group were severe concomitant mitral regurgitation (MR), followed by male gender and large indexed LVOT (all p<0.001 by discriminant analysis). CONCLUSION: Marked differences were present in patient characteristics between rheumatic and nonrheumatic patients who underwent the Ross operation. Rheumatic patients had a higher incidence of autograft reoperation. Severe concomitant MR was the most important predictor for reoperation in rheumatic patients.

Double-chambered right ventricle in 73 patients: spectrum of the disease and surgical results of transatrial repair.

OBJECTIVE: To review the spectrum of double-chambered right ventricle (DCRV) and the outcome of surgical repair in patients diagnosed between February 1988 and March 1999. DESIGN: The charts of patients with DCRV were studied. SETTING: Tertiary care hospital. PATIENTS AND METHODS: A total of 73 patients were identified. Sixty-nine underwent surgical repair, while four are awaiting surgery. The repair was through a transatrial approach in 61 patients, while in eight an additional ventriculotomy was performed. MAIN RESULTS: An associated ventricular septal defect (VSD) was present in 56 of 73 patients (77%). These patients were significantly younger (P<0.05) than the 17 patients without a VSD. Among patients with a VSD, the 31 requiring patch closure were significantly younger than the 25 patients having direct closure. Five older patients among those with intact septum had impaired right ventricular (RV) function as well as higher intraventricular gradients. At surgery the intraventricular obstruction was relieved by myomectomy. There was no hospital or late mortality. Following surgery, at a mean follow-up of 13.6 months, no increase in the intraventricular gradient was detected by Doppler echocardiography. CONCLUSIONS: The development of DCRV is associated with VSD in early life. The probability of the presence of a VSD decreases with age. The disease is progressive, resulting in increased intracavitary gradient within the RV and in RV impairment if it is not treated in a timely fashion. Transatrial repair is safe with excellent midterm results. In the presence of high gradients within the RV, a ventriculotomy may be necessary to obtain acceptable results.

Normal regional right ventricular function and its change with age: a Doppler myocardial imaging study.

BACKGROUND: Doppler Myocardial Imaging (DMI) is a new technique currently being studied for the assessment of regional systolic and diastolic left ventricular (LV) function. No normal values or data on age-related changes in regional myocardial right ventricular (RV) velocities are available. METHODS AND RESULTS: Color DMI was used in 32 healthy volunteers (aged 16-76 years) to derive regional velocities from basal, medial, and apical segments of the RV free wall in the apical 4-chamber view, and from distal segments as well as from the tricuspid annulus in the parasternal long-axis view. Both mitral annular and regional LV velocities (4-chamber, long-axis parasternal view) were also recorded and compared with corresponding RV regional velocities. The M-mode displacement of the cardiac base was measured. Corresponding RV and LV DMI data sets were compared. For longitudinal function, RV free wall systolic velocities were consistently higher than velocities recorded in corresponding LV segments (analysis of variance, P <.05). Older subjects (40-76 years; 13 men, 2 women) had lower RV long-axis regional velocities than younger subjects (16-39 years; 15 men, 2 women), but had higher short-axis RV systolic velocities. For diastolic velocities, a negative correlation between age and the ratio of regional early diastolic to late diastolic velocity was shown for all RV free wall segments (eg, basal segment: r = -0.63, P <.0001). CONCLUSIONS: The right ventricle has higher long-axis regional velocities, a greater excursion of its lateral atrioventricular valve ring, and reduced circumferential shortening velocities compared with the left ventricle. Right ventricular longitudinal shortening is dominant over short-axis function in healthy young subjects. Normal age-related changes of diastolic velocities for each segment of the normal RV free wall have been defined.

Regional strain and strain rate measurements by cardiac ultrasound: principles, implementation and limitations.

The non-invasive quantification of regional myocardial function is an important goal in clinical cardiology. Myocardial thickening/thinning indices is one method of attempting to define regional myocardial function. A new ultrasonic method of quantifying regional deformation has been introduced based on the principles of 'strain' and 'strain rate' imaging. These new imaging modes introduce concepts derived from mechanical engineering which most echocardiographers are not familiar with. In order to maximally exploit these new techniques, an understanding of what they measure is indispensable. This paper will define each of these modalities in terms of physical principles and will give an introduction to the principles of data acquisition and processing required to implement ultrasonic strain and strain rate imaging. In addition, the current status of development of the technique and its limitations will be discussed, together with examples of potential clinical applications.