Dobutamine stress echocardiography for preoperative cardiac risk stratification in patients undergoing orthotopic liver transplantation

This study attempts to evaluate the efficacy of dobutamine stress echocardiography for preoperative cardiac risk stratification in patients undergoing orthotopic liver transplantation. Two hundred twenty consecutively submitted patients were evaluated in preparation for orthotopic liver transplantation. Dobutamine stress echocardiography was performed in 80 patients with known or suspected coronary artery disease. Follow-up information was available in 40 patients in the form of cardiac catheterization and/or outcome from liver transplantation to validate the dobutamine stress echo findings. The prevalence of coronary artery disease in this cohort was 5% and was closely associated with the presence of diabetes mellitus. Dobutamine stress echocardiography, when interpreted as abnormal in the presence of wall motion abnormalities only, is associated with a sensitivity, specificity, and positive and negative predictive value of 100%. Dobutamine stress echocardiography is highly efficacious and should be the screening study of choice to detect coronary artery disease in patients undergoing orthotopic liver transplantation.

New modalities of regional and global left ventricular function analysis: state of the art

Study of left ventricular (LV) regional and global function represents a main point of the cardiologic evaluation. This article presents an overview of the state of the art in quantitative analysis of ventricular wall motion and describes the different techniques available in clinical settings; we also present the personal experience of the authors in comparing conventional 2-dimensional (2D) echocardiography with other recently developed, more sophisticated techniques. Conventional 2D echocardiography mainly depends on the operator's ability. Moreover, the physiologic regional pattern of myocardial wall motion in different segments of left ventricle is still not completely known as well as the heart's rotational and translational movements. Qualitative and quantitative transesophageal echocardiography allows a better and more accurate evaluation of regional wall motion, and improves the on-line border detection feasibility even in patients with poor transthoracic echocardiographic window. The automated system for on-line endocardial border detection, color kinesis, and the power Doppler are, at the moment, promising techniques. Using magnetic resonance imaging as a "gold standard" for the study of global and regional left ventricular function, the investigators describe personal experiences with tissue Doppler imaging and a new computerized system for tissue Doppler images postprocessing analysis.

Treatment of chronic mitral regurgitation

BACKGROUND

Chronic, severe mitral regurgitation is a common clinical entity that can lead to progressive, irreversible left ventricular dysfunction. New information on the natural history of this condition, coupled with advances in surgical technique, have changed the roles of medical and surgical therapies.

METHODS

The current medical and surgical literature regarding chronic mitral regurgitation is critically reviewed.

RESULTS

There is no well-defined role for medical therapy in chronic mitral regurgitation. The goal of the treating physician is therefore to choose the optimal timing for surgical intervention. This process begins with noninvasive quantification of the degree of regurgitation. If severe, a careful search for signs or symptoms of impending left ventricular dysfunction should follow. Recent advances in surgical techniques for mitral valve repair allow for correction of the valvular defect with minimal mortality risk and improved preservation of ventricular function and are an impetus for early operative intervention. Mitral valve repair may also be beneficial in the setting of severe dilated cardiomyopathy.

CONCLUSIONS

The development of techniques for mitral valve repair has altered the treatment paradigm for severe mitral regurgitation. Surgical intervention before the onset of left ventricular dysfunction is recommended.

Hemodynamic basis of mitral E transmission in the left ventricular cavity and its relation to the left ventricular relaxation process

Mitral E-wave transit time to the left ventricular outflow tract was measured as an E-Er interval in 30 subjects undergoing cardiac catheterization. The E-Er interval (range 30 to 190 ms) correlated with left ventricular peak negative dP/dt (r = -0.62, p = 0.0003) and tau (r = 0.74, p <0.0001) but not with left ventricular minimum, pre-A-wave, or end-diastolic pressures. We conclude that the E-Er interval is an easily obtainable Doppler measurement that reflects the left ventricular relaxation process.

Rates of left ventricular isovolumic pressure rise and fall from the aortic regurgitation velocity signal: description of the method and validation in human beings

BACKGROUND

Aortic regurgitation results from a pressure gradient across the aortic valve during left ventricular (LV) isovolumic relaxation, LV filling, and isovolumic contraction periods. Assuming the applicability of the simplified Bernoulli equation to this pressure-flow relation and constancy of aortic pressure during LV isovolumic relaxation and contraction periods, one can theoretically obtain estimates of the rates of LV isovolumic pressure fall and rise (deltaP/delta t) from the aortic regurgitation (AR) velocity signal.

METHODS AND RESULTS

Mitral regurgitation (MR) and AR signals were recorded by using the continuous wave Doppler technique in 26 patients with combined mitral and aortic regurgitant lesions. The LV negative deltaP/delta t was obtained by dividing the time taken for the AR velocity to rise from 1 m/sec to 2.5 m/sec into 21 mm Hg, which is the estimated LV pressure drop between these points. In a similar fashion, the LV positive deltaP/delta t was obtained between 2.5 m/sec and 1 m/sec of the fast decelerating portion of the AR signal. The LV negative deltaP/delta t by the AR method ranged from 420 to 3500 mm Hg/sec and correlated well with that obtained by the MR method obtained in a blinded fashion (r = 0.95, p < 0.0001). The mean (SD) difference between the two methods was 30 (129) mm Hg/sec. Similarly, the LV positive deltaP/delta t by the AR method (range 420 to 2625 mm Hg/sec) correlated closely with that obtained by the MR method (r = 0.93, p < 0.0001), with the mean (SD) difference between the two methods being 38 (138) mm Hg/sec.

CONCLUSIONS

Preliminary data presented in this study indicate the feasibility of obtaining a reliable estimate of LV positive and negative deltaP/delta t from the AR velocity profile. Thus the examination of the AR signal may give valuable insights into both LV systolic and diastolic functions.

Abnormal ventricular activation and repolarisation during dobutamine stress echocardiography in coronary artery disease

OBJECTIVE

To assess possible ECG changes caused by dobutamine stress and their relation to wall motion disturbances in patients with coronary artery disease.

DESIGN

Prospective recording and analysis of 12 lead ECG at rest and during each stage of dobutamine stress echocardiography, and correlation with wall motion changes.

SETTING

A tertiary referral centre for cardiac disease equipped with non-invasive facilities for pharmacological stress tests.

SUBJECTS

27 patients, mean (SD) age 60 (8) years, with documented evidence of coronary artery disease in whom dobutamine stress echo was clinically indicated, and 17 controls of similar age.

RESULTS

In controls, all ECG intervals shortened with increasing heart rate but in the patient group only PR and QT intervals shortened while QRS duration broadened and QTc interval prolonged progressively. In the 27 patients, 16 developed chest pain, 15 with reduced left ventricular long axis systolic excursion (p < 0.001), and all showed reduced peak lengthening rate; ST segment shift appeared in 16, 13 of whom developed chest pain, but did not correlate with reduction of either systolic long axis excursion or peak lengthening rate; QRS duration broadened in 20, 16 with reduction of long axis excursion (p < 0.02) which was more often seen at the septum (p < 0.005); QTc interval prolonged in 19, all of whom had associated reduction of peak long axis lengthening rate (p < 0.02).

CONCLUSIONS

QRS duration and QTc interval both normally shorten with dobutamine stress, while in coronary artery disease they both lengthen: changes in QRS duration correlate with systolic and QTc interval with diastolic left ventricular wall motion disturbances. ST segment shift also occurred in most patients, but without consistent correlation with wall motion abnormalities. It was thus less discriminating than the other two abnormalities in this respect.

Impaired systolic blood pressure response to dobutamine stress testing: a marker of more severe functional abnormalities in patients with myocardial infarction

Dobutamine-induced hypotension has been disregarded as a marker of more severe functional abnormalities in patients with suspected coronary artery disease. However, its functional significance in patients with myocardial infarction has not been studied. The aim of this study was to define the predictors of systolic blood pressure (SBP) response to dobutamine in patients with previous myocardial infarction. Dobutamine stress (up to 40 microg/kg per minute) echocardiography was performed in 326 patients with prior myocardial infarction referred for evaluation of myocardial ischemia. A 16-segment, four-grade score model was used to assess left ventricular function. Wall motion score index was derived by summation of wall motion score divided by 16. SBP and heart rate increased from rest to peak dobutamine stress (127 +/- 22 vs 134 +/- 27 mm Hg and 72 +/- 14 vs 122 +/- 24 bpm, p < 0.00001 in both). An increase of SBP > or = 30 mm Hg occurred in 50 patients (15%). By multivariate analysis, independent predictors of failure of SBP increase were higher peak wall motion score index (p < 0.001), higher resting SBP (p < 0.01), and medication with calcium channel blockers (p < 0.05). SBP drop > or = 20 mm Hg occurred in 54 patients (17%). Independent predictors of SBP drop were higher resting wall motion score index (p < 0.001), higher resting SBP (p < 0.0001), and older age (p < 0.05). In patients with myocardial infarction, left ventricular function and baseline systolic blood pressure are powerful predictors of SBP response to dobutamine stress testing.

Pulmonary venous flow in normal dogs recorded by transthoracic echocardiography: techniques, anatomic validations and flow characteristics

To observe pulmonary venous flow in dogs, the echocardiographic imaging planes and the techniques for examination, and the validations of anatomic location were investigated. Then, the velocity pattern of pulmonary venous flow was recorded in normal conscious dogs. Six imaging planes were available for observing the right or left caudal lobe pulmonary venous flow with two-dimensional or pulsed Doppler echocardiography. Of these, the left lateral apical 4-chamber view can be applied as standard view, because the pulmonary venous flow and transmitral flow could be recorded in this view simultaneously with small sampling angle. The velocity pattern of pulmonary venous flow demonstrated two forward waves in 19 of 20 dogs examined, with one peak occurring during ventricular systole and another during ventricular diastole. A reversed flow during atrial contraction was also seen in 11 dogs. In the two forward waves, the mean peak velocity and velocity-time integral of ventricular diastolic forward flow were significantly higher than those of systolic forward flow (46.49 +/- 6.79 vs. 31.13 +/- 4.92 cm/s, p < 0.0001 and 8.18 +/- 1.84 vs. 5.14 +/- 0.82 cm, p < 0.0001, respectively). The deceleration time of diastolic forward flow shortened with the increase of heart rate (r = -0.87, p < 0.0001). Pulmonary venous flow in dogs can be observed under transthoracic two-dimensional or pulsed Doppler echocardiography.

Exercise-induced changes in the QT interval duration and dispersion in patients with sudden cardiac death after myocardial infarction

BACKGROUND

Prolongation of the QT interval and increased QT dispersion have been proposed to be associated with arrhythmic risk after myocardial infarction. However, controversy remains regarding the prognostic value of ventricular repolarization abnormalities in the risk stratification of patients surviving acute myocardial infarction. HYPOTHESIS AND OBJECTIVE: The QT interval is sensitive to myocardial ischaemia, and exercise-induced ischaemia may change the QT interval regionally, resulting in increased QT dispersion. This study examined whether there are abnormalities of ventricular repolarization during exercise and whether assessment of the exercise-induced changes in QT interval duration and dispersion would be able to differentiate patients at high risk from those at low risk of sudden cardiac death after myocardial infarction.

METHODS

Twenty-six post-myocardial infarction patients (mean age 54.5+/-8.9 years, 22 men) were retrospectively studied. Thirteen patients who died suddenly (SCD patients) during a follow-up of 39+/-6 months were compared to 13 patients who remained event-free, i.e. no ventricular tachyarrhythmias, no reinfarction, no by-pass (MI survivors). The two groups were pair-matched for age, gender, site of infarction, left ventricular ejection fraction and use of beta blocker. A further 13 patients with chest pain, normal coronary arteriograms and negative exercise test results were studied as controls. They were age and gender matched with the post-infarction patients. A 12-lead exercise ECG was recorded from each patient before, during and after exercise. QT and RR interval were measured on the exercise ECGs at each stage and QT dispersion was defined as the difference between the maximum and minimum QT intervals across the 12-lead ECG.

RESULTS

There were no significant differences in RR, QT and QTc (Bazett's and Fridericia's correction) intervals, or QT dispersion between any groups before exercise. A significant difference in QT and QT dispersion was found at peak exercise between post-infarction patients and controls (P=0.03 and P=0.0001, respectively), but no difference was observed between SCD patients and MI survivors. The maximum QTc at peak exercise was longer in SCD patients compared with MI survivors (P=0.02) and a maximum QTc>440 ms (Bazett's correction) was common in SCD patients but not in MI survivors or controls (62%, 15%, 15%, P=0.01). The differences in QT, QTc or QT dispersion observed at peak exercise were no longer significant after exercise.

CONCLUSIONS

Exercise-induced prolongation of the QTc interval differentiates patients at high risk of sudden cardiac death from those at low risk, whereas exercise-induced changes in QT dispersion failed to identify patients at high risk of sudden cardiac death after myocardial infarction.

Right and left ventricular wall motion velocities as diagnostic indicators of constrictive pericarditis

The purpose of this study was to examine the usefulness of pulsed tissue Doppler imaging for diagnosing constrictive pericarditis. Motion velocities of the ventricular septum (VS) and left ventricular (LV) posterior wall along the short axis, and those of the anterior right ventricular (RV) wall, VS, and LV posterior wall along the long axis were recorded using pulsed tissue Doppler imaging in 12 patients with constrictive pericarditis, who were diagnosed by cardiac catheterization, and also in 20 normal subjects. Peak early diastolic and atrial systolic velocities (Ew and Aw, respectively) were calculated, and the time between the aortic component of the second heart sound and the peak of the early diastolic velocity (IIA-Ew) was determined. The peak Ew and II A-Ew along the short and long axes were significantly higher and shorter, respectively, in the patient group than in the normal group. In the patient group, the motion velocity of the VS along the short axis showed a "backward" motion with a sharp and marked peak velocity immediately before Ew, or a biphasic early diastolic wave; a clear "downward" motion immediately after Ew was observed in the motion velocities of the anterior RV wall, VS, and LV posterior wall along the long axis. These distinctive backward and downward motions were not observed in any of the ventricular walls of the normal subjects. In conclusion, the early diastolic RV and LV wall motion velocity patterns along the short and long axes as measured by pulsed tissue Doppler imaging provide important information for the diagnosis of constrictive pericarditis.

Amplitudes, durations, and timings of apically directed left ventricular myocardial velocities: I. Their normal pattern and coupling to ventricular filling and ejection

BACKGROUND

The left ventricular (LV) major axis shortening is an important determinant of its global function. But unlike the LV minor axis dynamics, the long-axis dynamics have not been well characterized. We investigated the amplitudes, durations, and timings of LV long-axis myocardial velocities and related them to LV filling and ejection in normal healthy volunteers.

METHODS AND RESULTS

Myocardial velocities from the basal, mid, and distal portions of the four LV walls were recorded from the apical window with spectral Doppler tissue imaging in 20 normal individuals. The timings, amplitudes, and durations were measured and compared both longitudinally and circumferentially. These were also related to mitral inflow and LV ejection. Analysis of the recordings indicated that there were three principal myocardial velocities: apically directed systolic velocity and atrially directed early and late diastolic velocities. The LV posterior wall had the highest shortening velocity and the amount of shortening. The lateral wall had the greatest amplitude of early diastolic lengthening velocity, amount of lengthening, and early to late lengthening velocity and integral ratios, probably indicating most favorable early diastolic properties. There was a striking synchrony in the myocardial velocities circumferentially. The myocardial velocities dropped progressively as the sampling site was moved distally and the LV apex was practically stationary. Although the onsets of the velocity profiles were simultaneous in the meridional orientation, their durations were shorter distally. All myocardial velocities preceded the corresponding blood flow velocities. They also ended before the corresponding blood flow velocities, this being more pronounced in the distal myocardial segments, indicating the presence of inertial factors responsible for the terminal portions of mitral and aortic flows.

CONCLUSIONS

Recording of apically directed myocardial velocities gives valuable insights into the regional myocardial function. These velocities show significant regional variations in healthy normal individuals. It is speculated that analysis of regional myocardial velocities may have a role in the diagnosis of early myocardial disease.

Phono-Doppler Timing Relationships in Patients with a Fourth Heart Sound

Controversies exist about the timing relationship between the fourth heart sound and the ventricular inflow Doppler events. Besides, there has been no data about the timing relationship between the fourth heart sound and the ventricular outflow Doppler events. This study was designed to measure these phono-Doppler timing relationships and to evaluate the influence of different Doppler modes on the timing relationship of the onset of the A wave. Twenty patients (61 +/- 9 years, 18 males and 2 females) with an audible and recordable fourth heart sound were included. No matter on the pulsed Doppler wave trace or on the continuous-wave trace, both the interval from the onset of the mitral A wave to the first vibration of the fourth heart sound and the interval from the peak velocity of the mitral A wave to the first vibration of the fourth heart sound differed significantly from zero (P < 0.001 for all). Nevertheless, the interval from the onset of the transmitted transmitral A wave to the first vibration of the fourth heart sound (0.4 +/- 1.7 ms) was not significantly different from zero (P = 0.314). The pulsed wave data and the continuous wave data were significantly correlated. Differences in the Doppler modes do not seem to lead to obvious changes in the Doppler-phono timing relationships.

Accurate noninvasive estimation of left ventricular end-diastolic pressure: comparison with catheterization

We evaluated the accuracy of a new Doppler-based method using the mitral regurgitant velocity at the time of aortic valve opening for the noninvasive estimation of left ventricular end-diastolic pressure. Sixty unselected patients were studied immediately before routine catheterization. Invasive left ventricular end-diastolic pressure was obtained using a fluid-filled pig-tail catheter. Noninvasive estimation of left ventricular pressure at aortic valve opening was taken as systemic diastolic pressure using an automated cuff. Noninvasive left ventricular end-diastolic pressure was calculated as diastolic blood pressure--4 x (mitral regurgitant velocity at aortic opening)2. Those making noninvasive determinations were blinded to catheterization results. An adequate mitral regurgitant Doppler recording was obtained in 24 patients (40%). In patients with a left ventricular end-diastolic pressure greater than 15 mm Hg the yield was 65%. Left ventricular end-diastolic pressures ranged from 4 mm Hg to 30 mm Hg. Bland and Altman analysis revealed no systematic bias and close agreement was found, with individual discrepancies not exceeding 5 mm Hg.

Amplitudes, durations, and timings of apically directed left ventricular myocardial velocities: II. Systolic and diastolic asynchrony in patients with left ventricular hypertrophy

BACKGROUND

Regional myocardial dysfunction may be the earliest manifestation of myocardial disease and can occur in the absence of abnormalities of global left ventricular (LV) function. The LV long-axis function, which is mainly due to subendocardial muscle fibers, may become abnormal in the presence of normal short-axis function. This study investigates the temporal and spatial characteristics of the LV long-axis function in patients with secondary LV hypertrophy in the presence of normal systolic function.

METHODS AND RESULTS

LV long-axis myocardial velocities were recorded in 18 patients with LV hypertrophy and preserved regional and global systolic function with Doppler tissue imaging. Apically directed myocardial velocities were recorded from the basal, mid, and apical segments of the four LV walls, and their amplitudes, timings, and durations were measured. The abnormalities uncovered by the analysis of regional myocardial velocities included (1) asynchrony in the onset of myocardial contraction circumferentially, (2) presence of postejection LV shortening, (3) asynchrony in the onset of early myocardial lengthening circumferentially, (4) reduced early myocardial lengthening velocity, (5) reduced early to late myocardial lengthening velocity and extents circumferentially, and (6) lack of variation in the basal myocardial velocities circumferentially in contrast to normal individuals.

CONCLUSIONS

Patients with secondary LV hypertrophy with preserved regional and global systolic performance have distinct abnormalities in the timings and amplitudes of apically directed myocardial velocities. These abnormalities may explain some of the changes in LV global diastolic behavior and may also serve as markers of early regional myocardial dysfunction.

Transventricular pressure-velocity wave propagation in diastole: adherence to the Moens-Korteweg equation

In the latter half of the diastolic phase of the cardiac cycle, the left atrium contracts and generates a pressure-velocity wave which enters the left ventricle. The wave moves through the inflow tract of the ventricle, reflects off the apex and heads towards the aortic valve. The time taken for the pressure-velocity wave to propagate through the ventricle, referred to as the A-Ar interval, may be measured using pulsed Doppler echocardiography and occurs in the range 20-80 ms. It has been shown previously that there is a significant negative linear correlation between the A-Ar interval and the passive elastic modulus of the ventricular wall (r = -0.782, p < 0.001). This relationship may be explained by modelling the left ventricle as a folded-over elastic tube through which the pressure-velocity wave is propagated according to the principles of the Moens-Korteweg equation.

Doppler-derived left ventricular rate of pressure rise and inotropic requirements during mitral valve surgery

BACKGROUND

The estimation of left ventricular (LV) contractility is difficult in the presence of significant mitral regurgitation (MR). Prediction of LV performance after MR repair is even more problematic. The intraoperative Doppler-derived LV rate of pressure rise (LV delta P/delta t) analyzed before cardiopulmonary bypass (CPB) was presumed to be a useful predictive parameter for LV performance. Therefore, its relation to perioperative inotropic requirements (PIR) necessary for separation from CPB after surgical MR repair was investigated.

METHODS

Twenty-eight patients scheduled for surgical MR repair fulfilled the selection criteria. Pre-CPB LV delta P/delta t, pre-CPB echocardiographic LV fractional area change (LV FAC), and pre-CPB thermodilution-derived cardiac index (CI) were recorded. After MR repair, separation from CPB was performed with regard to standardized guidelines. PIR during the first 60 minutes following separation were recorded.

RESULTS

Pre-CPB LV delta P/delta t could be assessed in 22 patients. Pre-CPB LV delta P/delta t was 882 +/- 450 mmHg/sec, pre-CPB LV FAC was 49% +/- 9%, and pre-CPB CI was 2.0 +/- 0.2 L/kg/min. Pre-CPB LV delta P/delta t was significantly correlated with pre-CPB LV FAC (r = 0.56), and with pre-CPB CI (r = 0.72). Inotropic support was necessary in 16 patients (73%), and was best predicted by the pre-CPB LV delta P/delta t, by means of logistic regression (p = 0.026).

CONCLUSIONS

Doppler-derived LV delta P/delta t was assessable in most patients with severe chronic MR, and was the best intraoperative predictive parameter of post-CPB inotropic requirements after surgical MR repair.

Diastolic indexes during dobutamine stress echocardiography in patients early after myocardial infarction

The aim of this study was to determine whether Doppler parameters assessed during dobutamine stress echocardiography in the early phase after myocardial infarction could discriminate patients with residual ischemia from those without. Thirty-six patients after a recent myocardial infarction with and without residual ischemia underwent dobutamine stress echocardiography, adenosine sestamibi scintigraphy, and coronary angiography within 2 weeks after the acute event. The only diastolic Doppler parameter discriminating the two groups was the isovolumic relaxation time (IVRT) measured at the peak of the dobutamine infusion. It became shorter in both groups but significantly more in patients without than in those with residual ischemia despite a larger increase in heart rate in the latter group. IVRT at rest was 78 +/- 18 msec and decreased with high-dose dobutamine to 54 +/- 11 msec in the control group and to 69 +/- 16 msec in the ischemic group (p < 0.01). In addition, the rate-corrected IVRT (IVRTc) was calculated: IVRTc = IVRT/sqrtRR. The value of IVRTc = 80 at peak dobutamine infusion is able to discriminate patients with residual ischemia from those without with a sensitivity of 80% and a specificity of 70%.

Aneurysm of the mitral-aortic intervalvular fibrosa as a rare cause of angina pectoris: angiographic demonstration

Aneurysms of the mitral-aortic interventricular fibrosa (MAIF) are exceptionally rare complications, commonly following aortic valve endocarditis. This report describes the angiographic findings of such an aneurysm, in a patient who developed an uncommon symptomatology of unstable angina pectoris, caused by the aneurysm's expansion against the coronary arteries. Surgical treatment is also discussed.

Echocardiography for hemodynamic assessment of patients with advanced heart failure and potential heart transplant recipients

OBJECTIVES

This study sought to assess the accuracy of Doppler echocardiographic techniques for the determination of right heart catheterization hemodynamic variables in patients with advanced heart failure and in potential heart transplant recipients.

BACKGROUND

Doppler echocardiographic techniques permit the noninvasive acquisition of hemodynamic variables traditionally used for the assessment of patients with advanced heart failure and potential heart transplant candidates. However, the accuracy of these techniques has not been sufficiently well documented for clinical application in individual patients.

METHODS

Echocardiographic data required for estimation of mean right atrial, pulmonary artery and mean left atrial pressures and cardiac output were obtained. Right heart catheterization was performed immediately after Doppler echocardiographic data were acquired, before any intervention that might have altered the subject's hemodynamic status.

RESULTS

A complete Doppler echocardiographic hemodynamic data set was acquired in 21 (84%) of 25 subjects. For all variables, invasive and noninvasive hemodynamic values were highly correlated (p < 0.001), with minimal bias and narrow 95% confidence limits. An algorithm constructed from the noninvasive hemodynamic variable values identified all patients with adverse pulmonary vascular hemodynamic variables (i.e., transpulmonary gradient > or = 12 mm Hg, pulmonary vascular resistance > or = 3 Wood units or pulmonary vascular resistance index > or = 6 Wood units x m2). This algorithm identified 12 (71%) of 19 patients for whom right heart catheterization was unnecessary.

CONCLUSIONS

Doppler echocardiographic estimates of hemodynamic variables in patients with advanced heart failure are accurate and reproducible. This noninvasive methodology may assist with monitoring and optimization of medical therapy in patients with advanced heart failure and may obviate the need for routine right heart catheterization in potential heart transplant candidates.

Comparison of dobutamine and treadmill exercise echocardiography in inducing ischemia in patients with coronary artery disease

OBJECTIVES

We sought to compare the magnitude of ischemia precipitated by both treadmill exercise and dobutamine stress echocardiography.

BACKGROUND

Although it is alleged that dobutamine stress produces ischemia similar in degree and extent to that produced during treadmill exercise, a direct comparison with treadmill exercise, the most common form of exercise, has not been performed.

METHODS

Eighty-five consecutive patients with known coronary artery disease underwent both stress tests on the same day, in random order.

RESULTS

Sixty-two patients (73%) had positive results on exercise echocardiography compared with 53 (62%) who had positive results on dobutamine stress (p = NS). Of the 53 patients with positive dobutamine test results, wall motion abnormalities appeared after the addition of atropine in 35 patients (66%). During dobutamine infusion, 22 patients (26%) had a hypotensive response that was reversed in 16 by prompt administration of atropine. At peak dobutamine-atropine stress, heart rate was higher than that at peak exercise (p < 0.001), whereas systolic blood pressure and rate-pressure product were higher at peak exercise than at peak dobutamine-atropine stress (p = 0.0001). In the 53 patients with positive results on both tests, peak wall motion score index was greater with treadmill exercise than with dobutamine-atropine infusion ([mean +/- SD] 1.73 +/- 0.45 vs. 1.57 +/- 0.44, p < 0.001).

CONCLUSIONS

Echocardiography immediately after treadmill exercise induces a greater ischemic burden than dobutamine-atropine infusion. In the clinical setting, exercise echocardiography should therefore be chosen over dobutamine echocardiography for diagnosing ischemia, when possible. When dobutamine echocardiography is used as an alternative modality, maximal heart rate should always be achieved by the addition of atropine.

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

OBJECTIVES

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Mitral regurgitation: a new clinical perspective

Mitral regurgitation is a common valvular heart disease, particularly in the elderly population. The timing of surgical repair is controversial, but recent literature suggests a new clinical perspective on the management of this disease. Despite receiving medical treatment and having few initial symptoms, patients with mitral regurgitation due to flail leaflets have an excess mortality rate (6.3% per year) and high morbidity. Ten years after mitral regurgitation has been diagnosed, 90% of the patients have either died or undergone an operation. After surgical correction of mitral regurgitation, left ventricular dysfunction is a frequent complication and is the cause of excess heart failure and mortality. This complication is due to preoperative left ventricular dysfunction but is incompletely predictable with use of current methods. Conversely, considerable progress in surgery has resulted in an extremely low operative mortality rate (about 1% in patients younger than 75 years of age) and high feasibility of valve repair, even in patients with anterior leaflet prolapse. These facts have led to the new perspective that early surgical correction (before occurrence of overt symptoms or left ventricular dysfunction) should be considered when patients are diagnosed with severe mitral regurgitation.

Doppler Evaluation of Left Ventricular Diastolic Inflow and Outflow Waveforms in Normal Subjects

The measurements of the left ventricular inflow parameters do not necessarily reflect the measurements of the respective outflow ones. The A wave transit time from the mitral valve to the left ventricular outflow tract has been demonstrated to have a fair correlation with measures of the left ventricular late diastolic stiffness. We performed this study to obtain the normal patterns of the diastolic left ventricular outflow as well as inflow waveforms and to evaluate the roles of aging and other physiological parameters in their evolution. The study population consisted of 60 healthy subjects (aged 22-66 years). They were divided into three groups: group 1 (aged 20-34 years), group 2 (aged 35-49 years), and group 3 (aged 50-70 years). Pulse-wave Doppler echocardiography was performed to get the patterns of diastolic left ventricular inflow and outflow waveforms. With aging, the peak velocity and velocity-time integral of the transmitted transmitral E wave decreased, and those of the transmitted transmitral A wave increased with a progressive decrease in their ratio of transmitted transmitral E to A wave. The diastolic left ventricular inflows followed a similar aging course. There was no obvious aging trend in the A wave transit time from the mitral valve to the left ventricular outflow tract. Multiple linear regression analyses selected age as the most important determinant in the differences in most left ventricular inflow and outflow indices among normal subjects. Besides, heart rate had modest influences on some Doppler indices. This study confirms the age related changes in the left ventricular inflow waveforms and further establishes the concept that the diastolic left ventricular outflow waveforms are also significantly influenced by age and heart rate. Hence, both factors should be taken into account in interpreting the diastolic left ventricular outflow as well as inflow indices.

Methodology, feasibility, safety and diagnostic accuracy of dobutamine stress echocardiography

Large numbers of patients referred for evaluation of chest pain are unable to perform adequate, diagnostic exercise testing. In these patients, dobutamine stress echocardiography (DSE) represents an alternative, exercise-independent stress modality. Apart from the approximately 5% of patients with an inadequate acoustic window, 10% of patients referred for this test have nondiagnostic (submaximal negative) test results. Serious side effects during or shortly after DSE are uncommon, with ventricular fibrillation or myocardial infarction occurring in approximately 1 of 2,000 studies. No deaths have been reported. On the basis of a total number of 2,246 patients, reported in 28 studies, the sensitivity, specificity and accuracy of the test for the detection of coronary artery disease (CAD) were 80%, 84% and 81%, respectively. Mean sensitivities for one-, two- and three-vessel disease were 74%, 86% and 92%, respectively. The sensitivity for detection of disease in the left circumflex coronary artery (55%) was lower, both compared with that for left anterior descending (72%) and right coronary artery disease (76%). The sensitivity of predicting multivessel disease by multiregion echocardiographic abnormalities varied widely, from 8% to 71%. In direct comparisons, DSE was superior to exercise electrocardiography and dipyridamole echocardiography and comparable to exercise echocardiography and radionuclide imaging. DSE is a useful, feasible and safe exercise-independent stress modality for assessing the presence, localization and extent of CAD.

Effect of coronary angioplasty on QT dispersion

Increased QT dispersion (QTmax-QTmin [QTd]) reflects inhomogeneous ventricular repolarization that may provide a substrate for serious arrhythmias and is associated with adverse clinical outcomes in patients with heart disease. Effective treatment of acute myocardial infarction or ventricular arrhythmias may reduce QTd, but the effect of coronary revascularization on QTd in patients without these conditions is unknown. In this study, QTd was measured before and 4 and 24 hours after successful angioplasty in 94 patients without ongoing symptomatic myocardial ischemia or malignant arrhythmias. QTd decreased from 434 +/- 17 msec before angioplasty to 354 +/- 15 msec 4 hours (p < 0.05) and 33 +/- 14 msec 24 hours after angioplasty (p < 0.05). QTd was improved in 64% of patients, worse in 28%, and unchanged in 8%. Thus angioplasty significantly improves QTd. This may reflect increased myocardial perfusion and may be inherently beneficial by reducing the propensity for arrhythmias.

Value of QT dispersion in the interpretation of exercise stress test in women

BACKGROUND

Exercise testing in women is associated with a high incidence of false-positive ECG changes and should be combined with an imaging study. The QT dispersion (QTD), recorded as the difference between maximum and minimum QT intervals on a 12-lead ECG, is sensitive to myocardial ischemia and may improve the accuracy of exercise testing in women.

METHODS AND RESULTS

Exercise ECGs were analyzed in 64 women who had undergone exercise ECG and coronary angiography for clinical indications: 20 patients with normal exercise stress test and nonsignificant (< or = 50% diameter narrowing of a major epicardial coronary artery) coronary artery disease (CAD) on angiography (true-negative; TN group), 20 patients with positive exercise stress tests (> or = 1 mm ST-segment depression or reversible perfusion defects) and significant CAD (true-positive; TP group), and 24 patients with positive exercise stress tests but no significant CAD (false-positive; FP group). The exercise QTD was 45+/-15 ms in TN, 80+/-23 ms in TP (P<.0001 versus TP), and 41+/-14 ms in FP (P=NS versus TN and <.0001 versus TP) groups. A stress QTD of > 60 ms had a sensitivity of 70% and specificity of 95% for the diagnosis of significant CAD compared with 55% (P<.05) and 63% (P<.01), respectively, for > or = 1 mm ST-segment depression during stress. When QTD of > 60 ms was added to ST-segment depression as a condition for positive test, the specificity increased to 100%.

CONCLUSIONS

Exercise QTD is an easily measurable ECG variable that significantly increases the accuracy of exercise testing in women.

Targeting of dobutamine to ischemic myocardium without systemic effects by selective suction and pressure-regulated retroinfusion

OBJECTIVE

To study the effects of low-dose dobutamine and/or glyceryl trinitrate in addition to selective suction and pressure-regulated retroinfusion with arterial blood on regional myocardial function of the ischemic myocardium and systemic hemodynamics.

METHODS

Using a pig model of repeated brief (90 s) occlusions of the left anterior descending artery, selective suction and pressure-regulated retroinfusion was carried out either with arterial blood alone (SSRalone) or with arterial blood and simultaneous application of low-dose dobutamine (0.1 microgram/kg/min (SSRDOB), glyceryl trinitrate (0.03 mg/kg/min) (SSRNIT) or the combination of both drugs (SSRDOB + NIT). Regional myocardial function of the ischemic and non-ischemic myocardium was determined by sonomicrometry (segment shortening).

RESULTS

Segment shortening in the ischemic area after 90 s of ischemia was preserved at 57.5 +/- 9.2% with SSRalone but at 78.0 +/- 22.3% of baseline with SSRDOB (P < 0.05). The addition of glyceryl trinitrate did not improve regional myocardial function further. No effects of locally applied dobutamine were observed with regard to non-ischemic myocardium or heart rate. Cardiac output and mean arterial blood pressures tended to be further stabilized with SSRDOB.

CONCLUSIONS

Local application of low-dose dobutamine together with arterial blood by selective suction and pressure-regulated retroinfusion during brief myocardial ischemia resulted in improved regional myocardial function without undesired effects on non-ischemic myocardium or systemic hemodynamics.

AAIR versus DDDR pacing in patients with impaired sinus node chronotropy: an echocardiographic and cardiopulmonary study

The aim of this study was to compare AAIR and DDDR pacing at rest and during exercise. We studied 15 patients (10 men, age 65 +/- 6 years) who had been paced for at least 3 months with activity sensor rate modulated dual chamber pacemakers. All had sick sinus syndrome (SSS) with impaired sinus node chronotropy. The patients underwent a resting echocardiographic evaluation of systolic and diastolic LV function at 60 beats/min during AAIR and DDDR pacing with an AV delay, which ensured complete ventricular activation capture. Cardiac output (CO) was also measured during pacing at 100 beats/min in both pacing modes. Subsequently, the oxygen consumption (VO2AT) and VO2AT pulse at the anaerobic threshold were measured during exercise in AAIR mode and in DDDR mode with an AV delay of 120 ms. The indices of diastolic function showed no significant differences between the two pacing modes, except for patients with a stimulus-R interval > 220 ms, for whom the time velocity integral of LV filling and LV inflow time were significantly lower under AAI than under DDD pacing. At 60 beats/min, CO was higher under AAI than under DDD mode only when the stimulus-R interval was below 220 ms. For stimulus-R intervals longer than 220 ms, and also during pacing at 100 beats/min, the CO was higher in DDD mode. The stimulus-R interval decreased in all patients during exercise. The time to anaerobic threshold, VO2AT, and VO2AT pulse showed no significant differences between the two pacing modes. Our results indicate that, at rest, although AAIR pacing does not improve diastolic function in patients with SSS, it maintains a higher CO than does DDDR pacing in cases where the stimulus-R interval is not excessively prolonged. On exertion, the two pacing modes appear to be equally effective, at least in cases where the stimulus-R interval decreases in AAIR mode.

Dynamic Left Ventricular Outflow Tract Obstruction During Myocardial Ischemia in Mitral Valve Prolapse Syndrome

Systolic anterior motion of the mitral valve (MV) with dynamic left ventricular (LV) outflow tract obstruction is a well known phenomenon in hypertrophic cardiomyopathy, or other forms of hyperdynamic LV function associated with hypovolemic states, or LV hypertrophy. We report three patients with MV prolapse in the absence of the above predisposing factors, who developed an LV outflow dynamic gradient during acute transient myocardial ischemia. An interaction between structural abnormalities of the mitral apparatus and ischemia-dependent LV shape deformity most likely accounted for the outflow gradient.

Safety and feasibility of dobutamine-atropine stress testing in hypertensive patients

Dobutamine stress testing is increasingly used for the diagnosis and functional evaluation of coronary artery disease. The aim of this study was to assess the hemodynamic profile, safety, and feasibility of dobutamine stress testing in hypertensive patients. Dobutamine (up to 40 micrograms/kg per minute)-atropine (up to 1 mg) stress echocardiography was performed for the detection of myocardial ischemia in 1164 patients with limited exercise capacity (age, 60 +/- 12 years; 761 men); 446 patients were known to have hypertension. The test was considered feasible when 85% of the maximal heart rate and/or an ischemic end point (new or worsened wall motion abnormalities, ST segment depression, or angina) was achieved. No myocardial infarction or death occurred during the test. Dobutamine induced a significant increase of heart rate in patients with and without hypertension (59 +/- 25 and 63 +/- 23 beats per minute, respectively). Peak rate pressure product was similar in patients with and without hypertension (18,566 +/- 4584 and 18,230 +/- 4508). Hypotension (systolic pressure drop > 40 mm Hg) during the test was more frequent in hypertensive patients (7% versus 4% in normotensive, P < .05). Independent predictors of hypotension were baseline systolic pressure greater than 140 mm Hg (odds ratio, 6.9; 95% confidence interval, 3.4 to 14), older age (odds ratio, 1.04; 95% confidence interval, 1.01 to 1.07), and medication with calcium channel blockers (odds ratio, 1.8; 95% confidence interval, 1.1 to 3.5). The prevalence of ventricular tachycardia was similar (4.1%) in both groups. Episodes of 10 beats or more (0.06% of patients) were terminated promptly by intravenous metoprolol administration. Dobutamine stress testing was considered feasible in 91% of patients with and 92% of patients without hypertension. Dobutamine-atropine stress echocardiography is a safe and feasible method for the assessment of hypertensive patients referred for evaluation of myocardial ischemia. Despite the higher prevalence of dobutamine-induced hypotension in these patients, the feasibility of the test is comparable to that in individuals without hypertension.

Doppler echocardiography in cardiac transplant patients: allograft rejection and its relationship to diastolic function

Right ventricular endomyocardial biopsy has been the traditional gold standard for determining cardiac transplant rejection. Although endomyocardial biopsy has proved useful in guiding rejection therapy, this procedure is not without risk. The objective of the present study was to determine whether a noninvasive method for assessing cardiac diastolic function would be of value in predicting biopsy scores. Doppler echocardiographic indices of left ventricular function were compared with biopsy scores in 43 studies from 23 patients (age 50 +/- 8 years). The average time from transplant to echocardiographic study was 1.5 years. Standard clinical indices of diastolic function failed to predict biopsy results. The A-Ar interval, evaluated in 36 studies, was found to significantly decrease (p < 0.003) with increasing biopsy scores. Preliminary results suggest that this echocardiographic parameter may prove useful in predicting biopsy results.

Clinical and echocardiographic correlates of mitral E-wave transmission inside the left ventricle: potential insights into left ventricular diastolic function

The mitral inflow wave is initially directed to the left ventricular apex and then turns around facing the left ventricular outflow tract. The E and A waves are transmitted to the left ventricular outflow tract where they are registered as Er and Ar waves, respectively. We hypothesized that the E-wave transit time to the left ventricular outflow tract recorded as the E-Er interval may depend on left ventricular early diastolic performance such as relaxation. This hypothesis was tested in clinical settings known to have abnormal left ventricular relaxation. Mitral E and left ventricular outflow tract Er waves were recorded with pulsed wave Doppler technique in 63 subjects: 25 healthy subjects, 18 patients with secondary left ventricular hypertrophy, and 20 patients with hypertrophic cardiomyopathy. The E-Er interval was measured from the onset of E wave to the onset of Er wave timed to the R wave of the electrocardiogram. The E-Er interval ranged from 45 to 300 msec: 96 +/- 28 msec in the controls, 127 +/- 46 msec in patients with left ventricular hypertrophy (p = 0.0091 versus controls), and 179 +/- 57 msec in patients with hypertrophic cardiomyopathy (p < 0.0001 versus controls). It correlated with left ventricular free wall thickness (r = 0.42, p = 0.0006), thickness of the ventricular septum (r = 0.43, p = 0.0004), left ventricular end-diastolic diameter (r = -0.38, p = 0.0022), left ventricular end-systolic diameter (r = -0.55, p < 0.0001), left ventricular isovolumic relaxation time (r = 0.39, p = 0.0063), RR interval (r = 0.28, p = 0.045), mitral E/A velocity ratio (r = -0.33, p = 0.010), and E-wave deceleration time (r = 0.38, p < 0.0044) but not with age. Multivariate analysis with all the previously mentioned variables and the group the patient belonged to as the dichotomous variable showed that the grouping variable was the sole independent determinant of the E-Er interval (multiple r = 0.74). The E-Er interval is an easily measurable Doppler parameter which is increased in left ventricular hypertrophy and hypertrophic cardiomyopathy. It is related to left ventricular wall thickness, left ventricular isovolumic relaxation time, mitral E/A velocity ratio, and E-wave deceleration time and may provide useful insight into left ventricular early diastolic performance-possibly the relaxation process.

Evolution of dobutamine echocardiography protocols and indications: safety and side effects in 3,011 studies over 5 years

OBJECTIVES

This study sought to document the safety of dobutamine stress echocardiography as it has evolved at a single center and to define predictors of adverse events.

BACKGROUND

The indications and protocol for dobutamine stress testing have evolved over 5 years of clinical use, but the influence of these changes on the safety and side effects of the test is undefined.

METHODS

Over 5 years, 3,011 consecutive dobutamine stress studies were performed in 2,871 patients, using an incremental protocol from 5 to 40 micrograms/kg body weight per min in 3-min stages, followed by atropine or an additional stage with 50 micrograms/kg per min, if required. Clinical data were gathered prospectively, and hemodynamic and echocardiographic findings were recorded at each stage, including recovery. Dobutamine echocardiography was defined as positive for ischemia in the presence of new or worsening wall motion abnormalities; in the absence of ischemia, failure to attain 85% of age-predicted maximal heart rate was identified as a nondiagnostic result.

RESULTS

Studies were performed for risk assessment (70%) and symptom evaluation (30%); over the study period, there was an increment in the use of dobutamine echocardiography for preoperative evaluation. Most tests (n = 2,194 [73%]) were terminated due to attainment of peak dose with achievement of target heart rate (> 85% maximal age-predicted heart rate); 455 patients (15%) failed to achieve > 85% maximal predicted heart rate despite maximal doses of dobutamine and atropine. The protocol was stopped prematurely in 230 patients (7.6%) because of side effects, including ventricular (n = 27 [0.9%]) and supraventricular rhythm disorders (n = 22 [0.7%]), severe hypertension (n = 24 [0.8%]) and hypotension or left ventricular outflow tract obstruction (n = 112 [3.8%]). Noncardiac symptoms, such as headache, nausea or anxiety, caused early test termination in 45 patients (1.6%). The remaining tests were stopped because of severe chest pain (n = 106 [3.5%]) or severe ischemia by echocardiography (n = 26 [0.9%]). Serious complications occurred in nine patients, including sustained ventricular tachycardia in five, myocardial infarction in one and other conditions in three requiring hospital admission (sustained supraventricular tachycardia, hypotension, suspected myocardial infarction), but neither ventricular fibrillation nor death occurred. Independent predictors of serious complications could not be defined. Over 5 years, higher dose protocols and more frequent use of atropine have raised the number of diagnostic protocols from 59% to 80%, without increasing the incidence of major side effects.

CONCLUSIONS

Despite the use of more aggressive protocols and alterations of the indications for testing to include sicker patients, major side effects are a rare complication of dobutamine echocardiography.

Doppler Study of Transmitted Transmitral A Wave in Patients with a Fourth Heart Sound

To investigate the characters of the transmitted transmitral A wave associated with a fourth heart sound, left ventricular inflow, and outflow Doppler echocardiography and phonocardiography were recorded in 13 patients with a fourth heart sound and 9 age-matched control subjects. The Doppler echocardiographic data were compared between both groups and the peak velocity and acceleration rate of the transmitted transmitral A wave were correlated with other parameters. The peak velocity and acceleration rate of the transmitted transmitral A wave were significantly greater, but the A wave transit time from the mitral valve to the left ventricular outflow tract (A-Ar interval) was significantly shorter in patients with a fourth heart sound. There was a significant correlation between the A-Ar interval and the peak velocity (r = -0.54, P = 0.01) or acceleration rate (r = -0.63, P = 0.002) of the transmitted transmitral A wave. The A-Ar interval was shown to be the independent determinant of both the peak velocity and acceleration rate of the transmitted transmitral A wave by stepwise multiple linear regression. In conclusion, the presence of a fourth heart sound was associated with a higher peak velocity and acceleration rate of the transmitted transmitral A wave, to which increased ventricular stiffness may make some contributions.

Comparison Between the Mean dP/dt During Isovolumetric Contraction and Other Echocardiographic Indexes of Ventricular Systolic Function

Echocardiographic assessments of ventricular function derived from estimates of the mean dP/dt during isovolumetric contraction (mean dP/dt(ic)) were compared with those obtained from measurements of the shortening fraction and the stress-velocity index (SVI). Mean dP/dt(ic) correlated well with the shortening fraction, r = 0.74, P < 0.0001. Furthermore, 10 out of 11 patients with mean dP/dt(ic) below 800 had a shortening fraction < 0.28, whereas all patients with a mean dP/dt(ic) > 1000 mmHg/sec had a shortening fraction > 0.28. A good correlation also existed between mean dP/dt(ic) and the SVI, r = 0.73, P < 0.0001. Nine out of 11 patients with a mean dP/dt(ic) < 800 mmHg/sec had an SVI > 2 standard deviations below normal, whereas all patients with mean dP/dt(ic) > 1000 mmHg/sec had normal or increased SVI. The correlation between mean dP/dt(ic) and the SVI was strengthened when mean dP/dt(ic) was adjusted for heart rate and preload. Hence, assessments of ventricular function derived from measurements of mean dP/dt(ic) appear to agree well with those provided by the shortening fraction and SVI. Because the determination of mean dP/dt(ic) is not hampered by unusual anatomy or wall motion (conditions which compromise the validity of the shortening fraction and SVI), mean dP/dt(ic) may be a good index of ventricular function in cases where measurements of the shortening fraction and SVI would be unreliable.

Correlation of end-diastolic pressure and myocardial elasticity with the transit time of the left atrial pressure wave (A-Ar interval)

Contraction of the left atrium in diastole generates a pressure wave that moves along the postero-lateral wall of the left ventricle (LV), rebounds off the LV apex, and is then directed toward the outflow tract. The movement of this atrial pressure wave may be detected with pulsed Doppler echocardiography by placing a sample volume in the LV outflow tract. The resulting spectral profile shows the initial. A velocity wave and also the Ar velocity wave, which is caused by the atrial pressure wave rebounding off the LV apex. The transit time from the inflow tract to the outflow tract of the atrial pressure wave (A-Ar interval) may be determined from the time axis of the spectral profile by measuring the peak-to-peak separation of the A and Ar, velocity waves. It occurs in the range 25 to 80 milliseconds. The primary determinant of the A-Ar interval is the elasticity of the LV myocardium. We correlated ventricular elasticity with the A-Ar interval in 47 patients and found a significant negative linear correlation (r = -0.782, p < 0.001). Because the pressure in a viscoelastic conduit such as the LV is determined by the elasticity of the ventricular wall, we correlated end-diastolic pressure with the A-Ar interval and again showed a significant negative linear correlation (r = -0.701, p < 0.001). The A-Ar interval is an easily measured noninvasive index of the diastolic function of the LV that reflects its intrinsic elasticity and end-diastolic pressure. It is therefore a quantitative measurement of LV wall stiffness and end-diastolic pressure.

Prognostic significance of systolic blood pressure changes during dobutamine-atropine stress technetium-99m sestamibi perfusion scintigraphy in patients with chest pain and known or suspected coronary artery disease

To investigate the prognostic value of dobutamine stress-induced changes in systolic blood pressure (BP) 418 patients (mean age 60 years, 238 men) with chest pain and known or suspected coronary artery disease, who underwent a dobutamine-atropine stress technetium-99m sestamibi myocardial perfusion scintigraphic study, were followed up for 25 +/- 15 months. Blood pressure was measured by automatic sphygmomanometry every 3 minutes. A marked decrease and increase in systolic BP from rest to peak were defined as changes of > or = 20 mm Hg, and > or = 30 mm Hg, respectively. Worst outcome events were cardiac death (n = 30), nonfatal myocardial infarction (n = 17), and hospitalization for congestive heart failure (n = 8). A decrease in systolic BP (prevalence 16%) was associated with older age and higher baseline systolic BP. Fixed and reversible sestamibi perfusion defects and follow-up results were similar to patients without a systolic BP decrease. In contrast, an increase in systolic BP (prevalence 24%) was associated with younger age, lower baseline systolic BP, and with absence of a history of prior congestive heart failure or treatment with angiotensin-converting enzyme inhibitors. Furthermore, these patients had fewer fixed perfusion defects and tended to have fewer annual event rates (3.5% vs 7.5%, p < 0.10). In a multivariate model, an increase in systolic BP was not an independent predictor for subsequent events. In conclusion, a dobutamine-induced decrease in systolic BP is not associated with fixed or reversible sestamibi defects or adverse prognosis. An increase in systolic BP, however, is associated with less fixed sestamibi defects and a tendency toward less annual event rates.

Acute hemodynamic effects of atrioventricular pacing at differing sites in the right ventricle individually and simultaneously

We hypothesized that pacing, which provided a rapid uniform contraction of the ventricles with a narrower QRS, would produce a better stroke volume and cardiac output (CO). We sought to study whether pacing simultaneously at two sites in the right ventricle (right ventricular apex and outflow tract) would provide a narrower QRS and improved CO in 11 patients undergoing elective electrophysiology studies. Patients were studied by transthoracic echocardiography measurement of CO using the Doppler flow velocity method in normal sinus rhythm, AOO pacing (rate 80), DOO pacing in the right ventricular apex (AV delay 100 ms), DOO pacing in the right ventricular outflow tract, and DOO pacing at both right ventricular sites simultaneously in random order. The COs were 5.42 +/- 1.83, 5.61 +/- 1.97, 5.67 +/- 1.6, 5.84 +/- 1.68, and 5.86 +/- 1.52 L/min, respectively (no significant difference by repeated measures analysis of variance [ANOVA]). The QRS durations were 0.09 +/- 0.02, 0.09 +/- 0.02, 0.13 +/- 0.027, 0.13 +/- 0.03, and 0.11 +/- 0.03 secs respectively. Repeated measures ANOVA showed that the QRS duration significantly increased with right ventricular apex or right ventricular outflow tract pacing compared to sinus rhythm and AOO pacing (P < 0.001) but then diminished with pacing at both sites (P < 0.01). QRS duration was not correlated with CO, however the change in QRS duration correlated significantly with the change in CO when pacing was performed at the two right ventricular sites simultaneously. In conclusion, during DOO pacing, there was a trend for pacing in the right ventricular outflow tract or both sites to improve the CO compared to the right ventricular apex. With simultaneous pacing at both ventricular sites, the QRS narrowed. Further studies will be required to see if this approach has value in patients with poor left ventricular function or congestive heart failure.

Comparison of arbutamine and exercise echocardiography in diagnosing myocardial ischemia

Arbutamine is a new catecholamine designed for use as a pharmacologic stress agent. This study compared the sensitivity of arbutamine with symptom-limited exercise to induce echocardiographic signs of ischemia. Arbutamine was administered by a computerized closed-loop delivery system that controls the infusion rate of arbutamine toward a predefined rate of heart rate increase and maximum heart rate limit. Beta blockers were stopped > or = 48 hours before both tests. Stress was stopped for intolerable symptoms, or clinical, electrocardiographic or echocardiographic signs of ischemia (new or worsening wall motion abnormality), target heart rate (> or = 85% age predicted maximum heart rate), or plateau of heart rate response. Thirty-seven patients were entered into the study (35 arbutamine and exercise, 1 arbutamine only, 1 exercise only), of which 30 had angiographic evidence of coronary artery disease (> or = 50% lumen diameter narrowing). Rate-pressure product increased significantly in response to both stress modalities (p < 0.001) and was significantly greater with exercise (11,308 +/- 2,443) than with arbutamine (9,486 +/- 2,479, p < 0.001). The time to maximum heart rate was longer during arbutamine stress echocardiography than during exercise testing (17.3 +/- 9.4 versus 9.3 +/- 4.2 minutes, respectively, p < 0.001). There were more patients with interpretable echo data for arbutamine (82%) than for exercise (67%). Sensitivity for recognition of myocardial ischemia was 94% (95% confidence interval 70% to 100%) and 88% (95% confidence interval 62% to 98%), respectively. The most frequent adverse events during arbutamine (n = 36) were dyspnea (5.6%) and tremor (5.6%). Two arbutamine stress tests were discontinued due to arrhythmias: 1 patient had premature atrial and ventricular beats, and the other had premature atrial contractions and atrial fibrillation. Arrhythmias were well tolerated and resolved without sequelae. In conclusion, the sensitivity of arbutamine to induce echocardiographic signs of ischemia was similar to that of exercise despite a lower rate-pressure product. Arbutamine was well tolerated and provides a reliable alternative to exercise echocardiography.

[Usefulness of the Doppler index delta P/delta t in the evaluation of left ventricular systolic dysfunction]

INTRODUCTION AND OBJECTIVES

It has been shown that the delta P/delta t index, derived from the continuous Doppler mitral regurgitation signal correlates strongly with dP/dt. This study evaluates the feasibility, reproducibility and correlation of the index with ejection fraction and other conventional echocardiographic parameters.

MATERIAL AND METHODS

One hundred and ten patients with mitral regurgitation demonstrated by colour Doppler were studied. delta P/delta t were calculated by the ratio between the interval of pression between two points of the Doppler signal (-1 and -3 m/s; 32 mmHg, applying the modified Bernouilli equation) and the interval of time (s) which separates both. Ejection fraction was measured in 70 patients by non-echocardiographic methods (isotopic ventriculography, n = 52, and angiography, n = 18).

RESULTS

The index was feasible in 91 cases, the variability of intra and interobserver was 5% and 7% respectively. The correlation between delta P/delta t and ejection fraction was significant although weak (r = 0.59; p < 0.001; n = 70). It was better in the group of dilated idiopathic myocardiopathy (r = 0.72; p < 0.001; n = 18) than in the group of myocardial infarction (r = 0.54; p < 0.01; n = 25). No significant correlation was founded in the cases with mitral rheumatic valvulopathy. Regarding to the echocardiographic parameters, the best correlation was obtained with end systolic diameter (r = -0.64; p < 0.001; n = 49). Finally, a value of delta P/delta t < 1,000 mmHg/s predicted the existence of left ventricular systolic dysfunction with high accuracy (84%), sensitivity (80%) and specificity (92%).

CONCLUSIONS

High feasibility when mitral regurgitation exists, adequate reproducibility and heightened precision in diagnosing left ventricular systolic dysfunction, are characteristics which make delta P/delta t useful in the echocardiographic routine practice.

Assessment of mitral A-wave transit time to cardiac outflow tract and isovolumic relaxation time of left ventricle in the appropriate and small-for-gestational-age human fetus

Mitral A-wave transit time (Ta; ms) from the mitral valve to the left ventricular outflow tract and left ventricular isovolumic relaxation time (IRT) were studied by pulsed Doppler ultrasound in 17 appropriate-for-gestational-age fetuses (AGA, 30-39 wk) and 12 small-for-gestational-age fetuses (SGA, 30-36 wk). Ta was measured from the peak of the A-wave to the peak of the reflected A-wave (Ar) from the left ventricular wall. IRT was determined from the interval between the aortic valve closure artefact and the onset of transmitral flow. The mean Ta in the SGA fetus (42 +/- 7 [1 SD] ms) was significantly shorter (p < 0.03) than in the AGA fetus (47 +/- 11 [1 SD] ms), whereas this was not so for IRT (51 +/- 8 [1 SD] ms vs. 60 +/- 15 [1 SD] ms). In the SGA fetus, a positive correlation (r = +0.82, p < 0.01) was established between Ta (ms) and gestational age. No such correlation existed for the AGA fetus. It is speculated that, in the SGA fetus, the shorter Ta may reflect an increase in left ventricular stiffness.

Diastolic heart failure. What primary care physicians need to know

Congestive heart failure (CHF) with normal left ventricular systolic function and abnormal diastolic performance is a common clinical entity. Typically, signs and symptoms are indistinguishable from those of heart failure related to systolic dysfunction. Coronary artery disease, systemic hypertension, and aging are all associated with diastolic CHF. Diagnosis depends on a clinical suspicion of heart failure, followed by assessment of left ventricular systolic performance, which is normal in this condition. Ventricular diastolic performance can be assessed by noninvasive procedures, the most reliable and easily performed of which is echocardiography. General guidelines include searching for precipitants such as ischemia, tachycardia, and loss of atrial-ventricular synchrony. Treatment includes judicious use of nitrates and diuretics to relieve pulmonary congestion. There is no specific therapy to improve left ventricular diastolic function directly. However, calcium channel blockers and beta blockers are beneficial, and there is growing evidence that angiotensin-converting enzyme inhibitors may prove valuable.

Left ventricular function after valve repair for chronic mitral regurgitation: predictive value of preoperative assessment of contractile reserve by exercise echocardiography

OBJECTIVES

We evaluated the value of preoperative assessment of left ventricular contractile reserve in predicting ventricular function after valve repair for minimally symptomatic mitral regurgitation.

BACKGROUND

The optimal timing for operation in minimally symptomatic patients with significant mitral regurgitation is controversial. Accurate preoperative assessment of left ventricular function is difficult, and the ability to predict postoperative function is limited. Previous studies in patients undergoing mitral valve replacement may not be applicable in the present era of valve repair.

METHODS

We performed exercise echocardiography in 139 patients with isolated mitral regurgitation and no coronary disease, 74 of whom subsequently underwent uncomplicated valve repair. We measured rest left ventricular end-systolic dimension, end-systolic wall stress and positive first derivative of left ventricular pressure (dP/dt). End-diastolic and end-systolic volumes and ejection fraction were measured preoperatively at rest, immediately after exercise and postoperatively.

RESULTS

Ejection fraction decreased postoperatively to 55 +/- 10% from a rest preoperative value of 64 +/- 9% (p < 0.001). Compared with patients with a postoperative ejection fraction > or = (n = 56), patients with postoperative ejection fraction < 50% (n = 18) had a significantly lower preoperative exercise ejection fraction (57 +/- 11% vs. 73 +/- 9%, p < 0.0005), a larger exercise end-systolic volume index (32 +/- 8 vs. 18 +/- 7 cm3/m2, p < 0.0005) and a lower change in ejection fraction with exercise (-4 +/- 8% vs. 9 +/- 10%, p < 0.005). Preoperative rest indexes, including dP/dt, end-systolic wall stress and end-systolic volume index were less predictive, whereas exercise capacity, rest ejection fraction and end-systolic dimension were not predictive of post-repair ejection fraction. An exercise end-systolic volume index > 25 cm3/m2 was the best predictor of postoperative dysfunction, with a sensitivity and specificity of 83%.

CONCLUSIONS

In minimally symptomatic patients with mitral regurgitation, latent ventricular dysfunction may be indicated by a limited contractile reserve, manifest at exercise as an inadequate increase in ejection fraction and a larger end-systolic volume. These variables may also be used to predict left ventricular function after repair.

Mitral annular descent velocity by tissue Doppler echocardiography as an index of global left ventricular function

Mitral annular descent has been described as an index of left ventricular (LV) systolic function, which is independent of endocardial definition. Echocardiographic tissue Doppler imaging is a new technique that calculates and displays color-coded cardiac tissue velocities on-line. To evaluate mitral annular descent velocity as a rapid index of global LV function, we performed tissue Doppler imaging studies in 55 patients, aged 56 +/-15 years, within 3 hours of radionuclide ventriculographic ejection fraction. Tissue Doppler M-mode studies were obtained from each of 6 mitral annular sites, as follows: inferoseptal and lateral from apical 4-chamber views, anterior and inferior from apical 2-chamber views, and anteroseptal and posterior from apical long-axis views. Only 1 patient with severe mitral annular calcification was excluded. The group mean 6-site average peak mitral annular descent velocity was 5.5 +/- 1.9 cm/s (range 2.4 to 10.5), and the group mean ejection fraction was 49 +/- 18% (range 17 to 80%). The 6-site average peak annular descent velocity correlated linearly with LV ejection fraction (r = 0.86, SEE = 1.02 cm/s): LV ejection fraction = 8.2 (average peak mitral annular descent velocity) + 3%. The 6-site peak mitral annular descent velocity average >5.4 cm/s was 88% sensitive and 97% specific for ejection fraction >50%. The peak mitral annular descent velocity from the apical 4-chamber view (average from inferoseptal and lateral sites) correlated most closely with the LV ejection fraction (r = 0.85) as an individual view. Peak mitral annular descent velocity by tissue Doppler imaging has the potential to estimate rapidly the global LV function.

Assessment of mitral annular dynamics during diastole by Doppler tissue imaging: comparison with mitral Doppler inflow in subjects without heart disease and in patients with left ventricular hypertrophy

The purpose of this study was to determine the normal pattern and magnitude of mitral annular velocities in diastole by Doppler tissue imaging (DTI) and to assess whether this is altered in patients with left ventricular hypertrophy. Mitral annulus velocities were measured by DTI. Peak and time-velocity integral were measured from the DTI tracings and the timing of the velocities in relation to electrocardiogram. DTI was compared with M-mode echo of the annulus and mitral inflow Doppler velocities. Integrated annular velocities by DTI correlated with the annular displacement. Early diastolic velocities decreased with age and in patients with left ventricular hypertrophy. In the hypertrophy group, early diastolic velocities were significantly lower than normal even after correcting for age. Patients with left ventricular hypertrophy also showed a delay in peak early diastolic mitral annular velocity (5.5 +/- 21 msec after the E wave). In conclusion, mitral annular velocity in diastole is readily recorded by DTI. The magnitude and the pattern of these velocities are significantly altered by age and by left ventricular hypertrophy. This method provides a new insight into diastolic filling events and may prove useful in detecting abnormal diastolic function.

Newer Doppler measures of left ventricular diastolic function

Left ventricular (LV) diastolic dysfunction is an important cause of heart failure, and recent advances in the application of Doppler techniques allow a semiquantitative assessment of LV diastolic performance. This review discusses the use of Doppler echocardiography in the comprehensive assessment of LV diastolic function and performance in terms of the normal mitral and pulmonary venous flow profiles, their physiologic basis, and alterations in diseased states. There is also a discussion on the newer aspects of mitral flows such as relative durations of mitral A and pulmonary vein AR waves, E- and A- wave propagation inside the LV with their hemodynamic correlates, and derivation of ventricular dP/dt and Tau from the mitral regurgitation velocity profile. Analysis of these flow profiles and the other Doppler measures alluded to above allow one to make a fairly precise hemodynamic assessment of a patient in terms of left atrial pressure, LV relaxation and stiffness and the profile of LV diastolic pressure in terms of pre- 'a' wave and 'a' wave pressures and ventricular end-diastolic pressure.

Assessment of endocarditis and associated complications with transesophageal echocardiography

TEE offers many benefits in the evaluation of patients with IE. It provides increased sensitivity as compared to TTE in the detection of this disease, and is better able to identify and delineate many of the associated complications and hemodynamic aberrancies. TEE also has helped expand our knowledge of the pathophysiology and natural history of IE. Continued advances in the technology of TEE instrumentation undoubtedly will lead to further improvements in our ability to assess and to treat patients stricken with this serious infection. Nevertheless, IE continues to exact a significant toll on its victims, and our efforts to diagnose, to treat, and to prevent it must not weaken.

Doppler diastolic filling indexes in relation to disease states

This study compares mean Doppler-derived diastolic filling indexes in a variety of disease states in a large, population-based sample. Pulse-wave Doppler was used to examine 880 eligible participants of the Framingham Heart Study. Peak velocity of early flow and late flow, ratio of early to late peak velocities, atrial filling fraction, and early filling wave acceleration and deceleration times were obtained. Multiple linear regression analyses were performed comparing mean values for individuals with hypertension, diabetes, coronary disease, cardiovascular disease, and pulmonary disease. Hypertension was associated with a greater peak velocity late flow (0.027 m/sec; 95% confidence interval, 0.006, 0.047; p = 0.011), and diabetes was associated with a larger mean deceleration time (0.12 sec, confidence interval, 0.002, 0.021; p = 0.016). In multivariate analyses, hypertension continued to show a strong association with altered Doppler diastolic filling patterns, p value 0.009, whereas in diabetes, the multivariate p value was 0.28.