Noninvasive estimation of cardiac systolic function using continuous-wave Doppler echocardiography in dogs with experimental mitral regurgitation

OBJECTIVE

To evaluate the feasibility of noninvasive estimation of cardiac systolic function using transthoracic continuous-wave Doppler echocardiography in dogs with mitral regurgitation.

PROCEDURE

Seven mongrel dogs with experimental mitral regurgitation were used. Left ventriculography and measurement of pulmonary capillary wedge pressure were performed under inhalational anaesthesia. A micromanometer-tipped catheter was placed into the left ventricle and transthoracic echocardiography was carried out. The peak rate of left ventricular pressure rise (peak dP/dt) was derived simultaneously by continuous-wave Doppler and manometer measurements. The Doppler-derived dP/dt was compared with the catheter-measured peak dP/dt in the dogs.

RESULTS

Classification of the severity of mitral regurgitation in the dogs was as follows: 1+, 2 dogs; 2+, 1 dog; 3+, 2 dogs; 4+, 1 dog; and not examined, 1 dog. We were able to derive dP/dt from the transthoracic continuous-wave Doppler echocardiography in all dogs. Doppler-derived dP/dt had a significant correlation with the catheter-measured peak dP/dt (r = 0.90, P < 0.0001).

CONCLUSION

It was demonstrated that transthoracic continuous-wave Doppler echocardiography is a feasible method of noninvasive estimation of cardiac systolic function in dogs with experimental mitral regurgitation and may have clinical usefulness in canine patients with spontaneous mitral regurgitation.

Tissue Doppler imaging: a useful echocardiographic method for the cardiac sonographer to assess systolic and diastolic ventricular function

Tissue Doppler imaging (TDI) has evolved to become a useful noninvasive method that can complement other echocardiographic techniques in the assessment of left ventricular myocardial velocities in a variety of clinical conditions. Color 2-dimensional and color M-mode TDI are used for quantification of systolic myocardial velocities during myocardial ischemia at rest and with pharmacologic stress testing. Spectral pulsed TDI can provide measurements of regional systolic and diastolic myocardial velocities, and it is particularly useful in the identification of abnormalities of left ventricular diastolic relaxation. This review summarizes the clinical applications of TDI to promote understanding of its utility in the evaluation of left ventricular myocardial function.

Maternal left ventricular transverse and long-axis systolic function during pregnancy

OBJECTIVES

Circumferential fiber shortening has been the dominant basis for conventional analysis by echocardiography of left ventricular systolic function during pregnancy. Results in the literature have been conflicting due mainly to the fact that geometric assumptions for the calculation of these indices are made that may not be valid due to changes in left ventricular shape during pregnancy. Left ventricular long-axis displacement is expected to be a useful index of systolic function, independent of the changes in left ventricular geometry. The aim of this study was to compare circumferential to long-axis shortening during left ventricular contraction in pregnant women.

METHODS

This was a cross-sectional study of 125 pregnant women at 9-42 weeks of gestation and 19 non-pregnant female controls. Two-dimensional and M-mode echocardiography of the left ventricle was performed including measurement of left ventricular long-axis displacement and activation time on the lateral, septal, anterior and inferior sides of the mitral annulus. Activation time was assessed as the time from the start of the Q-wave of the electrocardiogram to the onset of left ventricular long-axis shortening.

RESULTS

Mean arterial pressure and activation time decreased during pregnancy, reaching a nadir at about 19 weeks' gestational age of 4% and 13%, respectively, below non-pregnant values; they subsequently increased towards term. Left ventricular long-axis displacement mirrored the changes in mean arterial pressure and activation time and increased with gestational age at all four sites of the atrioventricular plane reaching a peak at about 23 weeks (+ 12% compared to non-pregnant levels). The ejection fraction and fractional shortening remained stable until 30 and 32 weeks, respectively, and then decreased towards term.

CONCLUSION

Changes in left ventricular long-axis performance during pregnancy occur earlier than do measures of transverse function.

Diastolic function in hypertension

Diastolic dysfunction in patients with hypertension may present as asymptomatic findings on noninvasive testing, or as fulminant pulmonary edema, despite normal left ventricular systolic function. Up to 40% of hypertensive patients presenting with clinical signs of congestive heart failure have normal systolic left ventricular function. In this article we review the pathophysiologic factors affecting diastolic function in individuals with diastolic function, current and emerging tools for measuring diastolic function, and current concepts regarding the treatment of patients with diastolic congestive heart failure.

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.

Long axis electromechanics during dobutamine stress in patients with coronary artery disease and left ventricular dysfunction

OBJECTIVE

To dissociate the effect of inotropy from activation change during dobutamine stress on left ventricular long axis function in patients with coronary artery disease (CAD).

METHODS

25 patients with CAD and normal left ventricular cavity size and 30 with cavity dilatation-18 with normal activation (DCM-NA) and 12 with left bundle branch block (DCM-LBBB)-were compared with 20 controls. 12 lead ECG and septal long axis echograms were assessed at rest and peak dobutamine stress. Amplitude, shortening and lengthening velocities, postejection shortening, Q wave to onset of shortening (Q-OS), and A2 to onset of lengthening (A2-OL) were measured. Inotropy was evaluated from peak aortic acceleration.

RESULTS

In controls, amplitude, shortening and lengthening velocities, and peak aortic acceleration increased with stress; QRS, Q-OS, and A2-OL shortened (all p < 0.001); and contraction remained coordinate. In the group of patients with CAD and normal left ventricular cavity size, shortening velocity and peak aortic acceleration increased with stress (p < 0.005). However, amplitude and lengthening velocity did not change, QRS, Q-OS, and A2-OL lengthened (p < 0.01), and incoordination appeared. Results were similar in the group with DCM-NA. In the DCM-LBBB group, shortening velocity and peak aortic acceleration increased modestly with stress (p < 0.01) but amplitude, lengthening velocity, QRS, Q-OS, A2-OL, and incoordination remained unchanged. Overall, change in shortening velocity correlated with that in peak aortic acceleration (r(2) = 0.71), in amplitude with that in lengthening velocity (r(2) = 0.74), and in QRS with both Q-OS (r(2) = 0.69) and A2-OL (r(2) = 0.63).

CONCLUSION

The normal long axis response to dobutamine reflects both inotropy and rapid activation. In CAD, inotropy is preserved with development of ischaemia but the normal increase in amplitude is lost and prolonged activation delays the time course of shortening, causing pronounced incoordination. Overall, shortening rate uniformly reflects inotropy while lengthening rate depends mainly on systolic amplitude rather than primary diastolic involvement, even with overt ischaemia.

Improved outcomes from a comprehensive management system for heart failure

AIMS

Congestive heart failure (CHF) is associated with a high readmission rate after diagnosis. We assessed the ability of a comprehensive management program (CMP) for CHF to reduce readmissions with secondary endpoints of improving quality of life, exercise capacity and targeted drug doses.

METHODS AND RESULTS

Patients (pts) with: New York Heart Association Class (NYHA) III or IV CHF; left ventricular ejection fraction <40%; and stable outpatient therapy were assigned to a CMP of cardiology assessment intensive education and referral to a tailored exercise program. Forty-two pts (35 M, 7 F, mean age 54 years, S.D. 12 years) were enrolled. Two pts were transplanted, two died during follow-up and two were lost to follow-up. Hospital admissions were reduced by 87.2%, (mean 1.05, S.D. 0.98, admissions per pt to mean 0.08, S.D. 0.28, admissions per pt at 6-month follow-up; P<0.0001). ACE-inhibitor dose increased by 42% (P<0.0008) and beta-blocker dose increased by 61% (P<0.0001). NYHA Class, 6-min walk and quality of life scores all improved significantly (P<0.0001).

CONCLUSION

A CMP improves QOL and exercise capacity as well as substantially reducing hospital admissions in CHF pts. This study validates the benefit of intensive outpatient care of CHF.

Analysis of systolic and diastolic time intervals during dobutamine-atropine stress echocardiography: diagnostic potential of the Doppler myocardial performance index

Systolic and especially diastolic Doppler time intervals may be early markers of myocardial ischemia inducible by dobutamine-atropine stress echocardiography (DASE). We postulated that the Doppler myocardial performance index (MPI) may help differentiate ischemic from nonischemic responses. Hemodynamic and Doppler echocardiography variables were measured prospectively at every stress level of DASE in 32 patients (mean age 67 +/- 13 years). Adequate recordings were obtained in 27 patients; 13 had an ischemic response (group I) and 14 a nonischemic response (group II). Heart rate differed between groups at baseline. At equivalent peak stress, left ventricular wall motion score index was significantly greater and ejection fraction lower in group I patients. Of the Doppler variables, only the MPI consistently differed between groups, irrespective of the number of stress levels compared. The Doppler MPI may be a useful adjunct to wall motion analysis in the detection of myocardial ischemia during DASE.

Atrioventricular plane displacement correlates closely to circulatory dimensions but not to ejection fraction in normal young subjects

AIMS

Mitral atrioventricular plane displacement (AVPD) provides information about left ventricular systolic function. M-mode of systolic annulus amplitude or tissue Doppler imaging of systolic annulus velocity are the current methods of evaluating AVPD. A correlation to ejection fraction (EF) has been demonstrated in patients with coronary artery disease and left ventricular dysfunction. Our aim was (i) to investigate the mitral AVPD of normal subjects with different physical work capacities and (ii) to further evaluate AVPD as an index of left ventricular systolic function.

METHODS AND RESULTS

Twenty-eight healthy men mean age 28 years (20-39) were included: endurance trained (ET) (n=10), strength trained (ST) (n=9) and untrained (UT) (n=9). The systolic AVPD was recorded at four sites, septal, lateral, anterior and posterior, using M-mode. Left ventricular volumes were calculated according to Simpson's rule. Systolic AVPD was higher in endurance trained, 16.9 +/- 1.5 mm, as compared with both strength trained, 13 +/- 1.6 (P<0.001) and untrained, 14 +/- 1.6 (P<0.001). Left ventricular systolic AVPD correlated strongly with end-diastolic volume (r=0.82), stroke volume (r=0.80) and maximal oxygen consumption per body weight (r=0.72). The correlation between AVPD and EF was poor (r=0.22).

CONCLUSION

In the subjects studied, with a range of normal cardiac dimensions, AVPD correlated to stroke volume, end-diastolic volume and maximal oxygen consumption per body weight, but not to EF. On theoretical grounds, it also seems reasonable that a dimension like AVPD is related to other cardiac dimensions and volumes, rather than to a fraction, like EF. AVPD is one parameter that is useful for evaluation of left ventricular systolic function but is not interchangeable with other measurements such as EF.

Noninvasive assessment of left ventricular isovolumic contraction and relaxation with continuous wave Doppler aortic regurgitant velocity signals: an in vivo validation study

The purpose of this study was to provide fundamental in vivo validation of a method with the use of aortic regurgitant (AR) jet signals recorded with continuous wave (CW) Doppler for assessing left ventricular (LV) isovolumic contraction and relaxation. Preliminary studies have suggested that analysis of CW Doppler AR velocity signals permits the estimation of LV positive and negative dP/dt. We studied 19 hemodynamically different states in 6 sheep with surgically induced chronic aortic regurgitation. CW AR velocity spectra and high-fidelity LV and aortic pressures were recorded simultaneously. Rates of LV pressure rise and fall (RPR and RPF) were calculated by determining the time interval between points at 1 m/s and 2.5 m/s in the deceleration and acceleration slopes of the CW Doppler AR velocity envelope (corresponding to a pressure change of 21 mm Hg). RPR and RPF calculated by CW Doppler analysis for each state were compared with the peak positive dP/dt and negative dP/dt, obtained from the corresponding high-fidelity LV pressure curve, respectively. The LV peak positive and negative dP/dt derived by catheter ranged from 817 to 2625 mm Hg/s and from 917 to 2583 mm Hg/s, respectively. Multiple regression analysis showed that Doppler RPR correlated well with catheter peak positive dP/dt (r = 0.93; mean differences, -413 +/- 250 mm Hg/s). There was also good correlation and agreement between Doppler RPF and the catheter peak negative dP/dt (r = 0.89; mean difference, -279 +/- 239 mm Hg/s). Both Doppler-determined RPR and RPF underestimated their respective LV peak dP/dt. CW Doppler AR spectra can provide a reliable noninvasive estimate of LV dP/dt and could be helpful in the serial assessment of ventricular function in patients with aortic regurgitation.

Differentiation between pathologic and physiologic left ventricular hypertrophy by tissue Doppler assessment of long-axis function in patients with hypertrophic cardiomyopathy or systemic hypertension and in athletes

To identify new echocardiographic indexes of long-axis function that might differentiate between pathologic and physiologic left ventricular (LV) hypertrophy, we compared 60 subjects with different types of LV hypertrophy (group I: 15 patients with hypertrophic cardiomyopathy, group II: 15 patients with systemic hypertension, and group III: 30 athletes) with 20 normal subjects (group IV). The peak velocities of mitral annular motion at 4 sites were measured from the apex by tissue Doppler echocardiography. There were no differences in mean age and global ejection fraction between groups. Groups I and II had lower long-axis systolic and early diastolic velocities than the athletes (p <0.01) for all 4 sites. The best differentiation of pathologic from physiologic hypertrophy was provided by a mean systolic annular velocity <9 cm/s (sensitivity 87%, specificity 97%). Heterogeneity of annular velocities discriminated between group I and group II. Thus, long-axis systolic and early diastolic velocities are decreased in patients with pathologic hypertrophy, but preserved in athletes. These simple new echocardiographic parameters can differentiate between pathologic and physiologic hypertrophy.

The mode of left ventricular pumping: is there an outer contour change in addition to the atrioventricular plane displacement?

The outer contour of the heart has in some studies been shown to be constant during the heart cycle and the epicardial apex almost stationary whilst the base of the ventricles moves towards apex during systole. The base of the left ventricle has been regarded as a cylinder with constant cross-sectional area with changes in height during the heart cycle, the latter corresponding to the amplitude of mitral annulus motion (MAM). In this echocardiographic study, including 20 healthy adults, the stroke volume calculated by the cylinder model was significantly lower than by a reference method (modified Simpson's rule). MAM explained 82% of the stroke volume and 18% must, therefore, be explained by an inward motion of the outer left ventricular wall. A mean outer diameter shortening of about 3% (about 2 mm) was calculated.

Effects of atrial pacing on QT dispersion in patients with coronary artery disease without angina pectoris and ST segment depression

The aim of this study was to investigate QT dispersion during atrial pacing in patients with coronary artery disease (CAD) without clinical ischemia, such as angina pectoris and ST segment depression. Thirteen patients with normal coronary arteries and 42 patients with CAD (12 with single-vessel, 16 with two-vessel and 14 with three-vessel disease) having no angina pectoris or ST segment depression during atrial pacing with maximum rate of 120/minute were enrolled in the study. Twelve-lead surface ECGs were recorded at 100 mm/second paper speed before pacing, at maximum pacing rate, and during the recovery period for measurement of QT interval parameters. Corrected QTd (QTcd) increased from 43.4 +/- 8.1 to 49.3 +/- 9.5 ms (p < 0.05) in the control group, from 46.1 +/- 8.1 to 74.3 +/- 7.7 ms (p < 0.0001) in the single-vessel disease group, from 48.5 +/- 10.4 to 93.8 +/- 22.1 ms in the two-vessel disease group (p < 0.0001), and from 49.7 +/- 13.6 to 128.5 +/- 31 ms (p < 0.0001) in the three-vessel disease group at peak atrial pacing period. A positive correlation was found between the severity of CAD and QTcd (r = 0.49, p < 0.0001). It was found that pacing-induced QTc dispersion identifies coronary disease extent, even when there is no ST depression or T wave inversion during pacing.

Tissue Doppler imaging enables the identification of diastolic dysfunction of pseudonormal pattern in Chagas' disease

The Doppler pseudonormal pattern of left ventricular (LV) diastolic function filling, characterized by apparent normal transmitral flow velocities, indicates advanced diastolic dysfunction with abnormal relaxation and compliance. Left ventricular diastolic dysfunction has been shown to occur in the early stages of the outcome of Chagas cardiopathy, and its identification may potentially contribute to the management of those patients. The aim of this study was to evaluate the usefulness of tissue Doppler imaging (TDI) in identifying LV diastolic dysfunction in patients with Chagas' disease with pseudonormal transmitral flow. For this purpose, 89 patients with Chagas' disease (48 men) who had no other pathology and showed normal (n = 79) or pseudonormal (n = 10) patterns of diastolic function by pulsed wave Doppler were submitted to TDI. A significant LV systolic impairment in terms of the dimensions (P = .00001), ejection fraction (P = .000001), and wall motion score (P = .000002) was observed in patients with diastolic dysfunction when compared with the group with normal LV diastolic function. Tissue Doppler imaging enabled the recognition of a pseudonormal type of transmitral flow velocity with high statistical significance through early (P = .000008) and late (P = .0003) expansion waves. The sensitivity and specificity in detecting LV diastolic dysfunction with TDI in the septal, anterior, inferior, posterior, and lateral walls were 90% and 87.3%, 87.3% and 90%, 87.3% and 90%, 84.8% and 90%, and 84.8 and 90%, respectively. In conclusion, TDI enabled the differentiation of patients with Chagas' disease with normal LV diastolic function and those with the pathologic LV pseudonormal pattern with high statistical significance. Moreover, this article shows the potential in demonstrating the occurrence of major alterations in the LV performance of patients with Chagas' disease with LV diastolic dysfunction, as well as the occurrence of signs of an increased LV filling pressure in those patients.

Pulmonary venous flow in large, uncomplicated atrial septal defect

BACKGROUND

The pulmonary venous flow velocity pattern (PVFVP) in atrial septal defect (ASD) has not been previously studied in detail. Normally, PVFVP is primarily determined by the left heart performance. We hypothesized that the impact of left-sided heart dynamics on PVFVP is diminished in patients with ASD because of the presence of a left-to-right shunt into the low-resistance right side of the heart.

METHODS AND RESULTS

Transesophageal echocardiography was performed in 19 adults and 3 children with a large, uncomplicated secundum ASD (maximum diameter 0.6 to 3.0 cm). All patients were in normal sinus rhythm with an average heart rate of 78 bpm in adults and 116 bpm in children. In 21 subjects the antegrade PVFVP lacked distinct systolic (S) and diastolic (D) waves. Instead, we observed a single continuous antegrade wave extending from the beginning of systole to the onset of atrial contraction. Furthermore, the amplitude of the atrial reversal (AR) wave was smaller than in historical controls. In 3 patients in whom ASD was surgically repaired, we observed an immediate return of distinct S and D waves postoperatively. This confirmed that PVFVP abnormality was indeed the result of the ASD. Also a large increase in the AR wave amplitude (46 + 15 cm/s) was noted postoperatively.

CONCLUSIONS

This previously unrecognized PVFVP comprising a single continuous antegrade wave and a diminished AR wave sheds new light on the hemodynamics of ASDs. Its presence may also alert the echocardiographer to the possibility of an ASD when the septal defect cannot be visualized directly.

The relation of the peak Doppler E-wave to peak mitral annulus velocity ratio to diastolic function

Previous observations (Garcia et al. 1998; Sohn et al. 1997; Nagueh et al. 1997) indicate that mitral annulus velocity may be viewed as a "load-independent" index of filling and that wedge pressure is linearly related to the transmitral flow velocity (V(E)) to mitral annulus velocity (V(MA)) ratio (V(E)/V(MA)) measured at maximum velocity. In healthy subjects, the mean value observed for [V(E)](max)/[V(MA)](max) was 1:0.23 approximately 4. No prior physiologic or physical explanation for the basis of, or for the magnitude of, the ratio has been proposed. We propose a physiologic, model-based, quantitative explanation for these observations and test our simplified model's prediction in an invasive (n = 30) and noninvasive (n = 34) test groups of subjects. The simplified geometric model is based on the known constant volume (within a few percentage points) attribute of the four-chambered heart. Accordingly, left-atrial and left-ventricular volumes reciprocate so that their sum is constant throughout the cardiac cycle. The model predicts that: 1. the ratio (V(E)/V(MA)) is a constant approximately 3 in healthy hearts; and 2. V(E)/V(MA) should be linearly proportional to left ventricular end-diastolic pressure (LVEDP). Model prediction was tested using V(E) and V(MA) echocardiographic data from 34 subjects (noninvasive group), and simultaneous echocardiographic and high-fidelity hemodynamic (LVEDP) data in 30 subjects (invasive group). Excellent agreement was observed between model prediction and observed data. For the noninvasive (healthy) group, [V(E)](max)/[V(MA)](max) = 4.20 +/- 1.11. For the invasive group, [V(E)](max)/[V(MA)](max) was observed to be linearly related to LVEDP, [V(E)](max)/[V(MA)](max) = 0.19 (LVEDP) + 1.54, r = 0.92. Hence, [V(E)](max)/[V(MA)](max) is a legitimate flow-derived index of diastolic function because it is a derivable consequence of the heart's constant-volume pump attribute.

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.

Usefulness of dobutamine stress tests for detection of cardiac abnormalities in dogs with experimentally induced early left ventricular dysfunction

OBJECTIVE

To determine whether dobutamine stress tests (DST) can be used to detect cardiac dysfunction in dogs with early left ventricular dysfunction (ELVD) induced by rapid right ventricular pacing (RRVP).

ANIMALS

7 adult male Beagles.

PROCEDURE

A pacemaker was surgically implanted in each dog at the level of the right ventricular apex. Electrocardiography, Doppler sphygmomanometry, and Doppler echocardiography were performed before and during a DST prior to activation of the pacemaker and every 3 to 4 days during the period of RRVP. Dobutamine stress tests were performed by infusing dobutamine at incremental dosages ranging from 12.5 to 42.5 microg/kg of body weight/min.

RESULTS

Clinical signs of congestive heart failure were not observed during the pacing period. However, all dogs developed ELVD associated with significant changes in values for most Doppler echocardiographic variables obtained prior to DST Adverse cardiac effects were not detected during DST. Most Doppler echocardiographic indices of cardiac function were significantly altered in response to dobutamine infusion during the pacing period, compared with prepacing values. However, a dobutamine-induced 2-fold increase in cardiac output was maintained.

CONCLUSIONS AND CLINICAL RELEVANCE

Dobutamine stress tests can be safely performed in dogs with experimentally induced ELVD. Dobutamine stress tests may be a sensitive, noninvasive diagnostic method, complementary to standard clinical examinations, for detection of early cardiac dysfunction in dogs asymptomatic for dilated cardiomyopathy.

Left ventricular pseudoaneurysm as a complication of electrophysiologic study

We have described a patient who developed a small submitral pseudoaneurysm of the left ventricle during electrophysiologic mapping aimed at ablating a concealed accessory pathway. The patient was asymptomatic, and the lesion was detected on a routine postprocedure echocardiographic study. Spontaneous healing occurred, and the lesion was no longer seen on a repeated echocardiographic examination performed a month later.

A new coronary artery disease index of treadmill exercise electrocardiograms based on the step-up diagnostic method

Treadmill exercise electrocardiography (ECG) is one of the most common noninvasive methods for detecting ischemic heart disease. However, this method has problems due to false-positive and false-negative results in a significant number of patients. The aim of this study was to determine whether the diagnostic accuracy of treadmill exercise ECG for detecting significant coronary stenosis can be improved by employing a step-up diagnostic method using multiple diagnostic indicators. We studied 273 consecutive patients (mean age, 56 +/- 9 years; 190 men and 83 women) without a history of myocardial infarction who underwent treadmill exercise ECG and coronary angiography for ischemic chest pain. Of these, 146 patients had no significant coronary stenosis, 61 had single-vessel disease, 56 had multivessel disease, and 10 patients had left main truncus disease. A multivariate logistic regression analysis was used to select 3 treadmill exercise electrocardiographic parameters that were independent predictors of the presence or absence of significant coronary stenosis: exercise-induced maximum ST-segment depression, QT dispersion immediately after exercise, and Athens QRS score. Significant coronary stenosis was diagnosed with a sensitivity of 84% and a specificity of 90% when a step-up diagnostic method using these 3 indicators was employed. These results were better than those obtained for each indicator alone (exercise-induced maximum ST-segment depression: sensitivity, 66%, and specificity, 73%; QT dispersion immediately after exercise [> or =60 ms positive]: sensitivity, 76%, and specificity, 86%; and Athens QRS score [< or =5 mm positive]: sensitivity, 72%, and specificity, 72%). We conclude that this step-up diagnostic method, using multiple diagnostic indicators, is a clinically useful predictor of the presence or absence of significant coronary stenosis.

Mitral annulus motion as determined by M-mode echocardiography in normal dogs and dogs with cardiac disease

M-mode echocardiography was used to assess apical mitral annulus motion (MAM) in 103 normal dogs and 101 dogs with cardiac disease, to obtain information on systolic left ventricular long axis function. In normal dogs, a close relationship was found between MAM and body weight (r = 0.80, P < 0.001). There was a weak correlation between MAM and heart rate (r = -0.25, P < 0.05), but no correlation between MAM and age or left ventricular shortening fraction (P > 0.05). Mean MAM (95% confidence intervals) were established for normal dogs of differing body weight, and were 0.70 cm (0.65 to 0.75) in dogs < 15 kg, 1.08 cm (1.03 to 1.13) in dogs weighing 15 to 40 kg, and 1.51 cm (1.21 to 1.81) in dogs > 40 kg. "Cut-off" values to define decreased MAM for normal dogs of differing body weight were 0.45 cm (dogs < 15 kg), 0.80 cm (dogs 15-40 kg), and 1.20 cm (dogs > 40 kg). In dogs with cardiac disease, median MAM was normal in mitral valve endocardiosis or aortic stenosis, but significantly decreased (P < 0.05) in dilated cardiomyopathy. All dogs with mitral valve endocardiosis (n = 54) or aortic stenosis (n = 26) had MAM above the above-mentioned "cut-off" values, suggesting normal or increased left ventricular longitudinal systolic shortening, whereas 81% (17/21) of dogs with dilated cardiomyopathy had MAM below the "cut-off" value, indicating decreased long axis systolic function. It is concluded that MAM may be used to evaluate systolic left ventricular long axis performance in dogs and may add useful information on global left ventricular contraction dynamics.

Predictors of self-care in persons with heart failure

OBJECTIVE

The objective of this study was to test a model of individual patient characteristics, covering symptom severity, comorbidity, social support, education, age, socioeconomic status, and gender, derived from Connelly's Model of Self-Care in Chronic Illness as predictors of self-care in heart failure.

DESIGN

This was a nonexperimental correlational study.

SETTING

The study took place in 6 hospitals in southern California.

PATIENTS

The study included 209 patients diagnosed with heart failure by their physicians. The typical study participant was age 73 years, Class III, married, grade-school educated, and earning an income of less than $20,000 per year. The genders were almost equally represented.

OUTCOME MEASURE

Self-care was measured by the Evaluating the Change subscale of the Self-Management of Heart Failure Instrument.

RESULTS

The model of 7 variables, analyzed by using multiple regression analysis, explained 10.3% of the variance in self-care. Only 2 of the variables were significant predictors of self-care: education (P =.009) and symptom severity (P =.046); 89.7% of the variance remained unexplained.

CONCLUSIONS

Persons with higher education and those who are symptomatic may be more likely to engage in self-care than those who are poorly educated or asymptomatic. Further research is needed to confirm these Results and identify other predictors of self-care.

QT dispersion in single coronary artery disease: is there a relation between QT dispersion and diseased coronary artery or lesion localization?

It has been shown that QT dispersion (QTD) increases during episodes of myocardial ischemia or infarction. However, no extensive data on the relation between the diseased coronary artery or the localization of stenosis and the QTD are available. The aim of the study was to examine the relation between QTD and diseased coronary artery and lesion localization during exercise stress test in patients with single coronary artery disease without prior myocardial infarction. One hundred nineteen patients with single coronary artery disease and 53 patients with normal coronary arteries were enrolled in study. All patients underwent exercise stress test with modified Bruce protocol, and QT interval parameters were measured at rest and at minute 2 of the recovery (rec-2) period. QT dispersion at rest was found higher in all single-vessel disease groups compared with that in the control group, and corrected QT dispersion at rec-2 period was also markedly higher in left anterior descending, circumflex, and right coronary artery groups compared with that in the control group. No relation was found between QT dispersion and diseased coronary artery or the lesion localization. In conclusion, no qualitative difference was found between QT dispersion and diseased coronary artery or proximal or distal lesion localization. However, it was observed that patients with single-vessel disease had wider baseline QT dispersion as compared with that in the control group, which further increased significantly with exercise. This finding supports the idea that severity of localized ischemia rather than extent of coronary artery disease would be expected to have a greater effect on inducible QT dispersion.

Assessment of left ventricular long axis contraction can detect early myocardial dysfunction in asymptomatic patients with severe aortic regurgitation

OBJECTIVE

To identify variables that could be applied at rest to diagnose subclinical ventricular dysfunction in asymptomatic patients with severe aortic regurgitation.

DESIGN

Cross sectional study.

PATIENTS

Left ventricular long axis contraction was studied using tissue Doppler and M mode echocardiography in 21 patients with no symptoms (New York Heart Association (NYHA) functional class </= 2a) but severe aortic regurgitation (jet area/left ventricular outflow tract area > 40%).

MAIN OUTCOME MEASURES

Left ventricular ejection fraction (LVEF) at baseline and peak exercise (Weber protocol), cardiopulmonary function, and left ventricular long axis function at rest (peak systolic velocity and excursion of the mitral annulus).

RESULTS

In 11 patients, ejection fraction increased or did not change (from mean (SD) 55 (5)% to 58 (4)%, p < 0.05) (group I); in 10 patients it decreased by > 5% (from 54 (4)% to 42 (5)%, p < 0.001) (group II). Exercise ejection fraction was < 50% in all patients in group II. At rest, there were no differences between the groups in ejection fraction, left ventricular diameter indices, wall stress, and short axis contraction. However, patients in group II had reduced long axis contraction compared with group I: peak systolic velocity 8.6 (0.6) v 11.9 (2.2) cm/s (p < 0.001); excursion 11 (2) v 14 (2) mm (p < 0.01). A resting velocity of < 9.5 cm/s was the best indicator of poor exercise tolerance (sensitivity 90%, specificity 100%).

CONCLUSIONS

Markers of reduced long axis contraction may provide simple and reliable indices of subclinical left ventricular dysfunction in asymptomatic patients with severe aortic regurgitation.

Usefulness of QT dispersion immediately after exercise as an indicator of coronary stenosis independent of gender or exercise-induced ST-segment depression

Several recent studies suggest that QT dispersion on a standard 12-lead electrocardiogram is a clinically useful indicator of significant coronary stenosis. In this study, we compared the diagnostic accuracy of QT dispersion immediately after exercise as an indicator of coronary stenosis in men and women, and in the presence or absence of exercise-induced significant ST-segment depression. The subjects were 273 consecutive patients (mean age 56 +/- 9 years; 190 men and 83 women) without a history of myocardial infarction who underwent treadmill exercise electrocardiography and coronary angiography for evaluation of angina. Of these, 146 patients had no significant coronary stenosis, 61 had single-vessel disease, 56 had multivessel disease, and 10 had left main coronary artery disease. QT dispersion immediately after exercise was significantly greater in patients with significant coronary stenosis than in those without (64 +/- 14 vs 39 +/- 14 ms, p <0.01). QT dispersion immediately after exercise was significantly more sensitive in men (sensitivity 75%; specificity 85%) and significantly more specific in women (sensitivity 77%, specificity 88%) than exercise-induced significant ST-segment depression (men: sensitivity 62%, specificity 74%; women: sensitivity 81%, specificity 68%) as an indicator of significant coronary stenosis. The addition of factors such as gender and the presence or absence of exercise-induced significant ST-segment depression did not significantly alter the sensitivity and specificity of QT dispersion immediately after exercise for detecting significant coronary stenosis (patients with significant ST-segment depression: sensitivity 77%, specificity 88%; patients without significant ST-segment depression: sensitivity 72%, specificity 86%). In conclusion, QT dispersion immediately after exercise is a clinically useful indicator of significant coronary stenosis independent of gender or the presence or absence of exercise-induced significant ST-segment depression.

Strain rate imaging by ultrasonography in the diagnosis of coronary artery disease

Regional strain rate in the left ventricle can be assessed in real time and color mapped. The method is termed strain rate imaging (SRI), and findings correspond well with 2-dimensional echocardiography. This study addresses SRI as a method for localizing coronary lesions, compared with standard echocardiography. Twenty patients with acute myocardial infarction who underwent coronary angiography for clinical reasons were examined with SRI and standard echocardiography. Wall motion was graded by SRI color and separately by wall thickening. Strain rate imaging and 2-dimensional echocardiography results agreed well. An infarct-related artery was identified from angiograms combined with electrocardiograms. Both methods identified an infarct-related artery in 19 possible cases and had equal sensitivity and specificity for wall segments affected by lesion. Combining the information from both methods did not change accuracy. The study validates SRI as a method for assessing regional wall function in coronary artery disease. The advantages of SRI are discussed and measurements of strain rates are given.

Dobutamine stress myocardial perfusion imaging

In patients with limited exercise capacity and (relative) contraindications to direct vasodilators such as dipyridamole or adenosine, dobutamine stress nuclear myocardial perfusion imaging (DSMPI) represents an alternative, exercise-independent stress modality for the detection of coronary artery disease (CAD). Nondiagnostic test results (absence of reversible perfusion defects with submaximal stress) do occur in approximately 10% of patients. Serious side effects during DSMPI are rare, with no death, myocardial infarction or ventricular fibrillation reported in three DSMPI safety reports for a total of 2,574 patients. On the basis of a total number of 1,014 patients reported in 20 studies, the sensitivity, specificity and accuracy of the test for the detection of CAD were 88%, 74% and 84%, respectively. Mean sensitivities for one-, two- and three-vessel disease were 84%, 95% and 100%, respectively. The sensitivity for detection of left circumflex CAD (50%) was lower, compared with that for left anterior descending CAD (68%) and right CAD (88%). The sensitivity of predicting multivessel disease by multiregion perfusion abnormalities varied widely, from 44% to 89%, although specificity was excellent in all studies (89% to 94%). In direct diagnostic comparisons, DSMPI was more sensitive, but less specific, than dobutamine stress echocardiography and comparable with direct vasodilator myocardial perfusion imaging. In the largest prognostic study, patients with a normal DSMPI study had an annual hard event rate less than 1%. An ischemic scan pattern provided independent prognostic value, with a direct relationship between the extent and severity of the perfusion defects and prognosis. In conclusion, DSMPI seems a safe and useful nonexercise-dependent stress modality to detect CAD and assess prognosis.

Atrioventricular filling dynamics, diastolic function and dysfunction

Left ventricular diastolic dysfunction is associated with slowing of LV relaxation and a decrease in LV chamber compliance. This impairment of function leads to changes in filling velocities as measured by pulsed wave Doppler echocardiography in the pulmonary veins and across the mitral valve, and in intraventricular flow propagation velocity as measured by color M-mode Doppler. This paper explores some of the physiology of LV filling in a clinical context.

Validated risk stratification model accurately predicts low risk in patients with unstable angina

BACKGROUND

In the mid 1990s, two unstable angina risk prediction models were proposed but neither has been validated on separate population or compared.

OBJECTIVES

The purpose of this study was to compare patient outcome among high, medium and low risk unstable angina patients defined by the Agency for Health Care Policy and Research (AHCPR) guideline to similar risk groups defined by a validated model from our institution (RUSH).

METHODS

Four hundred sixteen patients consecutively admitted to the hospital with unstable angina between January 1, 1995, and December 31, 1997, were prospectively evaluated for risk factors. The presence of major adverse events such as myocardial infarction (MI), death and heart failure was assessed for each patient by chart review.

RESULTS

The composite end point of heart failure, MI or death occurred in 3% and 5% of the RUSH and AHCPR low risk categories, respectively, and in 8% and 10% of AHCPR and RUSH high risk categories, respectively. Recurrent ischemic events were best predicted by the RUSH model (high: 24% vs. medium: 12% and low: 10%, p = 0.029), but not by the AHCPR model (high: 14% vs. medium: 13% and low: 9%, p = 0.876). The RUSH model identified five times more low risk patients than the AHCPR model.

CONCLUSIONS

Both models identify patients with low and high event rates of MI, death or heart failure. However, the RUSH model allowed for five times more patients to be candidates for outpatient evaluation (low risk) with a similar observed event rate to the AHCPR model; also, the RUSH model more successfully predicted ischemic complications. We conclude that the RUSH model can be used clinically to identify patients for early noninvasive evaluation, thereby improving cost effectiveness of care.

Acute regional myocardial ischemia identified by 2-dimensional multiregion tissue Doppler imaging technique

BACKGROUND AND OBJECTIVE

Tissue Doppler echocardiography (TDE) is a promising method for the assessment of regional myocardial function, but pulsed TDE does not provide quantitative data from multiple regions simultaneously. This feature is important for the objective assessment of regional differences in myocardial function. In the present study, we investigated a new off-line TDE method that provides quantitative pulsed velocity data from an unlimited number of regions selected within a 2-dimensional (2D) image. The goal of the study was to determine the ability of this new approach to quantify regional myocardial function during acute myocardial ischemia induced by balloon angioplasty.

METHODS

Twenty-two patients undergoing angioplasty of the left anterior descending coronary artery (LAD) were studied. Left ventricular longitudinal wall motion was assessed by 2D TDE from the apical 4-chamber view before, during, and after angioplasty. Images were sampled at a rate of 69 +/- 15 frames/s, and the off-line analysis allowed simultaneous measurement of velocities in multiple myocardial segments.

RESULTS

There were 3 major alterations in the systolic velocity pattern during LAD occlusion. Peak early systolic velocities along the apical septum were significantly reduced during LAD occlusion (2.8 +/- 1.2 cm/s to 0.6 +/- 1.7 cm/s, P <.001). Myocardial velocities in mid systole suggested paradoxical wall motion (1.0 +/- 1.2 cm/s to -0.8 +/- 0.9 cm/s, P <.001). When comparing the ischemic regions of the left ventricle with the nonischemic regions, each patient demonstrated lower myocardial systolic velocities in the ischemic region. Furthermore, during early diastole, the wall motion of the ischemic segments showed a postsystolic contraction pattern with velocities changing from -0.9 +/- 1.0 cm/s to 1.9 +/- 1.3 cm/s (P <.001).

CONCLUSION

This new 2D TDE approach is able to quantify detailed myocardial velocity profiles from multiple regions simultaneously. Single-beat comparisons of ischemic and nonischemic regions might enhance the sensitivity for diagnosing ischemic heart disease. Reversed systolic wall motion during midsystole and marked positive velocity during early diastole might be new and important markers of myocardial wall ischemia.

Doppler-derived dP/dt and -dP/dt predict survival in congestive heart failure

OBJECTIVES

The purpose of this study was to evaluate the ability of novel Doppler indices of left ventricular (LV) systolic and diastolic function to predict survival in patients with congestive heart failure (CHF).

BACKGROUND

Congestive heart failure is associated with an increased risk of death or cardiac transplantation, yet techniques to predict survival are limited.

METHODS

Doppler-derived dP/dt and - dP/dt were determined prospectively from the continuous-wave Doppler spectrum of the mitral regurgitation jet (dP/dt = 32/time between 1 and 3 m/s; -dP/dt = 32/time between 3 and 1 m/s) in 56 patients with chronic CHF (age, 60 +/- 15 years; LV ejection fraction, 23 +/- 9%). Baseline clinical and echocardiographic variables were also obtained, and clinical follow-up was performed in all patients.

RESULTS

Twenty-four patients experienced a primary event of cardiac death (n = 15), United Network for Organ Sharing status I (inotrope-dependent) heart transplant (n = 3) or urgent implantation of a LV assist device (n = 6). Doppler-derived dP/dt (dichotomized to > or = or <600 mm Hg/s; p = 0.0002) and -dP/dt (trichotomized to <450, 450 to 550 and >550 mm Hg/s; p = 0.0001) predicted event-free survival, as did Doppler-derived risk groups determined by the combination of the two (low risk, dP/dt > or = 600; intermediate risk, dP/dt < 600 and -dP/dt > or = 450; high risk, dP/dt < 600 and -dP/dt < 450; p = 0.0001). Multivariable analysis revealed Doppler-derived risk groups, intravenous inotrope requirement and blood urea nitrogen as significant independent predictors of outcome.

CONCLUSION

New Doppler indices of dP/dt, - dP/dt and risk groups defined by the combination of dP/dt and -dP/dt predict event-free survival in patients with CHF.

Left ventricular wall motion velocities in healthy children measured by pulsed wave Doppler tissue echocardiography: normal values and relation to age and heart rate

Left ventricular wall motion velocities were measured by pulsed wave Doppler tissue (PWDT) echocardiography in 131 healthy children (mean age 7.5 +/- 5.5 years) at the interventricular septum and the posterior wall in the left ventricular short-axis view, and at the interventricular septum and the lateral wall in the 4-chamber view. The systolic wave (Sw) consisted of 2 components, and the difference between the 2 components was greater in the lateral wall than in the other walls. The peak early diastolic wave (Ew) velocity was also highest in the lateral wall. Most variables during systole correlated with age. The ratio of peak atrial systolic wave (Aw) velocity to peak Ew velocity (Aw/Ew) correlated with heart rate. The Aw/Ew in each wall correlated with the ratio of late (A) to early (E) peak mitral flow, although regression slopes differed among different wall segments. In younger children with increased heart rates, the Aw/Ew ratio increased because the Ew velocity decreased, although the A/E ratio increased because of an increased A velocity. Normal values for the PWDT variables change with heart rate and age in the pediatric population. The data reported in this study can be used as normal values for left ventricular function for PWDT echocardiography.

Systolic anterior motion begins at low left ventricular outflow tract velocity in obstructive hypertrophic cardiomyopathy

OBJECTIVES

The purpose of this study was to determine whether the dynamic cause for mitral systolic anterior motion (SAM) is a Venturi or a flow drag (pushing) mechanism.

BACKGROUND

In obstructive hypertrophic cardiomyopathy (HCM), if SAM were caused by the Venturi mechanism, high flow velocity in the left ventricular outflow tract (LVOT) should be found at the time of SAM onset. However, if the velocity was found to be normal, this would support an alternative mechanism.

METHODS

We studied with echocardiography 25 patients with obstructive HCM who had a mean outflow tract gradient of 82 +/- 6 mm Hg. We compared mitral valve M-mode echocardiogram tracings with continuous wave (CW) and pulsed wave (PW) Doppler tracings recorded on the same study. A total of 98 M-mode, 159 CW, and 151 PW Doppler tracings were digitized and analyzed. For each patient we determined the LVOT CW velocity at the time of SAM onset. This was done by first determining the mean time interval from Q-wave to SAM onset from multiple M-mode tracings. Then, CW velocity in the outflow tract was measured at that same time interval following the Qwave.

RESULTS

Systolic anterior motion began mean 71 +/- 5 ms after Q-wave onset. Mean CW Doppler velocity in the LVOT at SAM onset was 89 +/- 8 cm/s. In 68% of cases SAM began before onset of CW and PW Doppler LV ejection.

CONCLUSIONS

Systolic anterior motion begins at normal LVOT velocity. At SAM onset, though Venturi forces are present in the outflow tract, their magnitude is much smaller than previously assumed; the Venturi mechanism cannot explain SAM. These velocity data, along with shape, orientation and temporal observations in patients, indicate that drag, the pushing force of flow, is the dominant hydrodynamic force that causes SAM.

The relation between mitral annulus motion and ejection fraction: a nonlinear function

In previous studies of the relation between mitral annulus motion (MAM) and left ventricular ejection fraction (EF), a linear relationship has been suggested. In this meta-analysis of 434 patients, we show that the relation is nonlinear and that a linear regression model overestimates EF in the lower range of MAM. The relation is better described by an S function and is influenced by age and heart size.

Effects of oral L-arginine supplementation on exercise-induced QT dispersion and exercise tolerance in stable angina pectoris

We assessed the effects of L-arginine (an endogenous precursor of nitric oxide) on the magnitude of exercise-induced QT dispersion in patients with coronary artery disease. The study had a randomized double-blind cross-over design. Twenty-five patients with stable coronary artery disease underwent two separate exercise tests: after oral administration of L-arginine (6 g/24 h for 3 days) or placebo. Indications for cessation of exercise included: pulse limit, exhaustion, chest pain, ST segment depression >2 mm. We found that arginine significantly increased exercise duration from 604+/-146 to 647+/-159 s (P<0.03). However, it had no effect on the sum of exercise-induced ST segment depressions (1.9+/-2.3 and 2.4+/-3.3 on and off arginine, respectively, NS). Exercise shortened QT interval to a similar extent in patients treated with placebo or arginine. QT dispersion changed during exercise from 55+/-21 to 60+/-19 ms (NS) and from 60+/-21 to 53+/-17 ms (NS), respectively. We conclude that, in patients with coronary artery disease, oral supplementation of L-arginine does not affect exercise-induced changes in QT interval duration, QT dispersion or the magnitude of ST segment depression. However, it significantly increases exercise tolerance, most likely due to improved peripheral vasomotion. These results may be of clinical and therapeutic importance.

Myocardial longitudinal motion by tissue velocity imaging in the evaluation of patients with myocardial infarction

Left ventricular (LV) longitudinal shortening plays an important role in cardiac contraction and is invariably affected by the presence of coronary artery disease. Third-generation tissue velocity imaging (TVI) color-maps cardiac movement by obtaining mean velocities of LV segments from the same set of beats. The goals of this study were to characterize patterns of longitudinal myocardial motion velocity in healthy subjects and to use these patterns to evaluate abnormal segments of patients with myocardial infarction (MI). Included were 20 healthy subjects and 16 patients with MI who underwent a 2-dimensional Doppler echocardiography study. Myocardial velocity profiles were taken at the anulus, basal, mid, and apical segments of the septal and lateral walls in the apical view. Segmental velocity patterns from healthy subjects were compared with abnormal segments in patients with MI. Both lateral and septal walls of healthy subjects showed significant basal-apical myocardial velocity reductions in systolic shortening (Sm) and early and late diastolic lengthening (Em and Am) and a basal-apical increase in the Em/Am ratio. The lateral wall had greater Sm and Em velocities than the septal wall. The Sm and Em velocities and the Em/Am ratio were significantly reduced in the abnormal segments in patients with MI. Latent lateral wall ischemia may have been detected in 5 of 9 patients with septal infarction, showing reduced Sm velocity in apparently normal lateral walls. In conclusion, TVI objectively quantifies directional and incremental changes in myocardial movement that are useful in evaluating global and regional myocardial function, and it may play a role in the detection of early myocardial ischemia.

Tissue Doppler echocardiography

Tissue Doppler echocardiography (TDE) is a relatively recent addition to the diagnostic ultrasonographic examination. This is similar to routine Doppler ultrasonography to assess blood flow, but technologic features focus on lower velocity frequency shifts. Two techniques are used to assess myocardial function: pulsed TDE and color-coded TDE. A great deal of data has been generated on TDE over the last 5 years, and this review allows for only a small portion of these emerging data to be discussed. One clinical application is to assess peak systolic mitral annular velocity from the apical windows as an index of global ventricular function. The six-site average for peak systolic mitral annular velocity by the color-coded TDE method of greater than 5.4 cm/sec is predictive of an ejection fraction greater than 50% with an 88% sensitivity and a 97% specificity. An emerging application is to use pulsed-TDE to assess ventricular filling pressures. The mitral annular to inflow ratio (E/Ea) greater than 10 is predictive of a mean pulmonary capillary wedge pressure greater than 15 mm Hg with a 92% sensitivity and 80% specificity. Another application is to use peak early diastolic velocity to help differentiate constrictive pericarditis from restrictive cardiomyopathy. Peak early diastolic velocity is blunted with restrictive cardiomyopathy and preserved with constrictive pericarditis. These are just a few of the many evolving clinical applications of this new quantitative diagnostic ultrasonographic method.

Assessment of regional left ventricular function during exercise test with pulsed tissue Doppler imaging

To investigate whether mitral annular velocity, measured by tissue Doppler imaging (TDI), is able to get a feasible quantitative evaluation of global and regional left-ventricular function during exercise test, 29 patients with previous uncomplicated myocardial infarction were studied by exercise echocardiography. All patients underwent coronary arteriography within 10 days of stress echocardiography. All of them were in sinus rhythm and had no right or left bundle branch block or significant mitral regurgitation as observed by left ventriculography. A total of 12 patients had anteroseptal and/or posteroseptal wall asynergies and left anterior descending involvement; 9 patients had lateral and/or posteroinferior asynergies and left circumflex coronary artery involvement; 8 patients had inferior and posteroseptal wall asynergies and right coronary artery involvement. Twelve subjects of same age and sex with normal cardiovascular findings were selected as a control group. TDI sample volumes were set on the mitral annuli corresponding to anteroseptal, posterior, posteroseptal, lateral, anterior, and inferior wall in 4-chamber, 2-chamber, and long-axis views. There was a significant correlation between the left-ventricular ejection fraction (0.41 +/- 0.8) and the means of the systolic (S) values (6.1 +/- 0.9 cm/sec, r = 0.83, p < 0.01). The mean S at the sites corresponding to the infarct regions (5.5 +/- 0.4 cm/sec) was significantly lower than the control group (11 +/- 0.8 cm/sec, p < 0.001). After stress, in patients with multivessel disease, S values corresponding to remote regions were significantly lower (p < 0.01) compared with control subjects. Thus, the parameters obtained from mitral annular velocities with pulsed TDI in patients with previous myocardial infarction reflect left ventricular asynergy corresponding to the infarct regions and reversible regional dysfunction after exercise.