Age dependency of left atrial and left ventricular acoustic quantification waveforms for the evaluation of diastolic performance in left ventricular hypertrophy

We evaluated diastolic performance in 50 normal subjects and 50 patients with concentric left ventricular (LV) hypertrophy. Age-dependent normal values were determined for LV and left atrial (LA) acoustic quantification parameters. Pulsed wave Doppler echocardiography was also performed on all subjects. Patients with LV hypertrophy had higher peak velocities of atrial contraction and atrial contributions to filling. The acoustic quantification waveforms revealed lower rapid filling percentage of total filling and lower peak rapid filling rates. The LA acoustic quantification analysis confirmed the dependence on active atrial emptying in the patients with LV hypertrophy. There were significant correlations with age for most of the LV and LA acoustic quantification parameters. Acoustic quantification provided confirmatory results in subjects with an abnormal relaxation or restrictive Doppler pattern. In subjects with a normal Doppler pattern, the acoustic quantification was of added diagnostic value, identifying abnormalities in 77% to 80% of the patients.

Differences among geriatricians, general internists, and cardiologists in the care of patients with heart failure: a cautionary tale of quality assessment

OBJECTIVES

To describe differences in the characteristics, processes of care, and resource utilization of patients with heart failure cared for by geriatricians, general internists, cardiologists, and combinations of physicians.

DESIGN

A retrospective cohort study.

SETTING

An urban academic medical center.

PARTICIPANTS

A total of 439 outpatients with a billing diagnosis of heart failure or cardiomyopathy who were treated by geriatricians, general internists, cardiologists, and combinations of physicians.

MEASUREMENTS

Demographic and clinical characteristics, medication use, diagnostic testing, hospitalizations, and inpatient and outpatient costs were measured.

RESULTS

Compared with patients of cardiologists, patients cared for by geriatricians were older, more likely to have hypertension, diastolic dysfunction, and high comorbidity, and less likely to undergo echocardiography, cardiac catheterization, and electrocardiography. Use of angiotensin-converting enzyme inhibitors was similar among patients with reduced systolic function. Patients cared for by geriatricians had the same costs, rates of hospitalization, and likelihood of being symptomatic as patients of cardiologists.

CONCLUSIONS

The processes of care for patients with heart failure seen solely by geriatricians differ from those for patients seen by other physicians, but the case-mix also varies. Assessment of left ventricular function by geriatricians probably needs to be increased. However, although they were older and had more comorbidity, patients of geriatricians had total costs and symptomatology similar to those of patients of cardiologists. Future work is needed to identify those patients most likely to benefit from treatment by geriatricians and to determine how care can be optimally coordinated among different types of physicians and health providers.

Use of harmonic imaging without echocardiographic contrast to improve two-dimensional image quality

The aim of this study was to determine whether harmonic imaging (HI) improves endocardial visualization during 2-dimensional echocardiography without echocardiographic contrast. HI differs from fundamental imaging (FI) by transmitting ultrasound at one frequency and receiving at twice the transmitted frequency. This technique has been used in conjunction with contrast echocardiography to enhance myocardial contrast visualization. HI and FI were sequentially performed in 20 patients. Images were digitally stored and subsequently reviewed by 2 observers for the quality of endocardial visualization. In addition, acoustic quantification was performed in both FI and HI modes and endocardial tracking qualitatively judged. HI was compared with FI during dobutamine stress echocardiography in 17 patients who were imaged at baseline and peak stress. Overall, the harmonic images had less clutter and better myocardial blood contrast. Individual segments were better visualized with HI in 30% to 73% of cases. The acoustic quantification endocardial tracking was rated better with HI in 67% of short-axis views and in 58% of apical 4-chamber views. During dobutamine stress testing the overall number of interpretable segments improved from 64% for FI to 84% with HI. Many segments traditionally difficult to image were improved with HI. HI without the use of contrast agents improved endocardial visualization during routine 2-dimensional echocardiography. This improved endocardial visualization led to better endocardial tracking with acoustic quantification and to more segments being clinically interpretable during dobutamine stress testing.

Assessment of small-diameter aortic mechanical prostheses: physiological relevance of the Doppler gradient, utility of flow augmentation, and limitations of orifice area estimation

BACKGROUND

Noninvasive assessment of functionally stenotic small-diameter aortic mechanical prostheses is complicated by theoretical constraints relating to the hemodynamic relevance of Doppler-derived transprosthetic gradients. To establish the utility of Doppler echocardiography for evaluation of these valves, 20-mm Medtronic Hall and 19-mm St Jude prostheses were studied in vitro and in vivo.

METHODS AND RESULTS

Relations between the orifice transprosthetic gradient (equivalent to Doppler), the downstream gradient in the zone of recovered pressure (equivalent to catheter), and fluid mechanical energy losses were examined in vitro. Pressure-flow relations across the 2 prostheses were evaluated by Doppler echocardiography in vivo. For both types of prosthesis in vitro, the orifice was higher than the downstream gradient (P<0.001), and fluid mechanical energy losses were as strongly correlated with orifice as with downstream pressure gradients (r2=0.99 for both). Orifice and downstream gradients were higher and fluid mechanical energy losses were larger for the St Jude than the Medtronic Hall valve (all P<0.001). Whereas estimated effective orifice areas for the 2 valves in vivo were not significantly different, model-independent dynamic analysis of pressure-flow relations revealed higher gradients for the St Jude than the Medtronic Hall valve at a given flow rate (P<0.05).

CONCLUSIONS

Even in the presence of significant pressure recovery, the Doppler-derived gradient across small-diameter aortic mechanical prostheses does have hemodynamic relevance insofar as it reflects myocardial energy expenditure. Small differences in function between stenotic aortic mechanical prostheses, undetectable by conventional orifice area estimations, can be identified by dynamic Doppler echocardiographic analysis of pressure-flow relations.

Acoustic quantification indexes of left ventricular size and function: effects of signal averaging

BACKGROUND

The aim of this study was to evaluate the clinical utility of using signal-averaged acoustic quantification (SAAQ) waveforms for improved assessment of left ventricular (LV) size and function.

METHODS AND RESULTS

Four separate protocols were performed in 47 subjects. SAAQ waveforms were used to assess alterations in LV function induced by dobutamine (15 microg/kg per minute) and esmolol (200 microg/kg per minute) in eight normal subjects. Subsequently, we analyzed SAAQ waveforms obtained in 12 patients with LV dysfunction secondary to dilated cardiomyopathy and 12 age-matched normal subjects. Finally, we developed computer software for monitoring of LV function on the basis of continuous acquisition and repeated analysis of SAAQ waveforms. We compared the interbeat variability in indexes of LV function obtained from raw AQ and SAAQ during 10 minutes of steady-state monitoring in eight patients undergoing transesophageal echocardiography. The feasibility of long-term monitoring in the intensive care setting was then studied in seven patients undergoing abdominal surgery. Our analysis tracked variations in LV function induced by dobutamine and esmolol. Significant differences in all measured indexes were found between normal subjects and patients with dilated cadiomyopathy. Signal averaging during steady-state monitoring significantly reduced the interbeat variability of all indexes (21% to 42%). In the operating room, the SAAQ monitoring system tracked hemodynamic changes in close agreement with invasive measurements.

CONCLUSIONS

SAAQ allows fast and easy quantification of LV function and can track hemodynamic trends in the operating room setting.

Cor triatriatum in a 70-year-old woman: role of transesophageal echocardiography and dynamic three-dimensional echocardiography in diagnostic assessment

In this report we describe a 70-year-old woman with unrecognized nonobstructive cor triatriatum (CT). She had concomitant mitral regurgitation and coronary artery disease. Diagnosis of CT and its hemodynamic assessment were accomplished by transesophageal echocardiography. Dynamic three-dimensional echocardiography demonstrated multiple fenestrations in the left atrial membrane. Intraoperative findings confirmed the diagnostic accuracy of three-dimensional echocardiography. To our knowledge, this is the first case of CT that has anatomic correlation with three-dimensional echocardiography.

Quantification of traumatic hemomediastinum using transesophageal echocardiography: impact on patient management

STUDY OBJECTIVES

To determine whether the quantitative evaluation of hemomediastinum using transesophageal echocardiography (TEE) is predictive of the presence of a traumatic disruption of the thoracic aorta (TDA) or its branches in patients who have sustained severe blunt chest trauma.

DESIGN

Retrospective study.

SETTING

ICU of a tertiary referral teaching hospital.

PATIENTS

Forty-one patients sustaining severe blunt chest trauma (32 men, nine women; mean age, 43+/-16 years; mean Injury Severity Score, 39+/-22) who underwent a TEE study were divided into two groups, patients with (group TDA+, n=15) or without (group TDA-, n=26) major vascular injury diagnosed using an alternative method such as aortography, surgery, or necropsy. The control group included 41 age- and sex-matched patients with an unremarkable TEE study performed to rule out an intracardiac source of emboli.

INTERVENTIONS

The presence of hemomediastinum was quantitatively assessed by measuring the distances between the esophageal scope and anteromedial aortic wall (distance 1), and between the posterolateral aortic wall and left visceral pleura (distance 2) at the level of the aortic isthmus. An observer who was unaware of both medical history and final diagnosis measured the distances.

MEASUREMENTS AND RESULTS

In group TDA+, TEE demonstrated aortic injuries in 13 patients, revealed an isolated hemomediastinum in one patient (ruptured intercostal arteries), and was unremarkable in the remaining patient, who sustained a disrupted right subclavian artery. No associated major vessel injuries were diagnosed in the group TDA- (normal aortograms). When compared to the control group, mean distances were greater in patients with chest trauma (distance 1=5.5+/-4.4 mm vs 2.7+/-0.8 mm, p=0.001; distance 2=3.8+/-5.0 mm vs 1.2+/-0.3 mm, p=0.02). The corresponding distances were even greater in group TDA+ when compared with group TDA- (distance 1=8.6+/-5.9 mm vs 3.7+/-1.5 mm, and distance 2=7.1+/-7.0 mm vs 2.0+/-1.7; for both differences, p<0.01). A threshold value of 5.5 mm for distance 1 or 6.6 mm for distance 2 had a sensitivity of 80%, a specificity of 92%, a positive and negative predictive value of 86% and 89%, respectively, for the diagnosis of underlying major vascular injury.

CONCLUSIONS

TEE allows quantitative assessment of traumatic hemomediastinum. The presence of a large hemomediastinum requires further evaluation by aortography, even if the thoracic aorta appears normal during the TEE examination, in order to rule out an underlying major vascular injury which may be outside the field of view of the echocardiographer.

Dilated cardiomyopathy in transgenic mice expressing a dominant-negative CREB transcription factor in the heart

Idiopathic-dilated cardiomyopathy (IDC) is a common primary myocardial disease of unknown etiology characterized by progressive biventricular failure, cardiac dilatation, and premature mortality. Here we show that transgenic mice expressing a dominant-negative form of the CREB transcription factor (CREBA133) under the control of the cardiac myocyte-specific alpha-MHC promoter develop dilated cardiomyopathy that closely resembles many of the anatomical, physiological, and clinical features of human IDC. Between 2 and 20 wk of age, these mice develop four chamber cardiac dilatation, decreased systolic and diastolic left ventricular function, and attenuated contractile responses to the beta-adrenergic agonist, isoproterenol. Histologically, the CREBA133 hearts demonstrated both atrophic and hypertrophied fibers as well as significant interstitial fibrosis. These anatomical and hemodynamic changes were associated with hepatic congestion and peripheral edema, intracardiac thrombi, and premature mortality. Taken together, these results implicate CREB as an important regulator of cardiac myocyte function and provide a genetic model of dilated cardiomyopathy which should facilitate studies of both the pathogenesis and therapy of this clinically important disorder.

Use of color kinesis for evaluation of left ventricular filling in patients with dilated cardiomyopathy and mitral regurgitation

OBJECTIVES

We tested the feasibility of using analysis of color kinesis images to objectively assess global and regional left ventricular (LV) diastolic function in patients with dilated cardiomyopathy (DCM). In addition, the ability of this technique to track drug-induced changes on LV diastolic properties was studied.

BACKGROUND

Diastolic dysfunction contributes to symptomatology in patients with DCM. The assessment of LV diastolic function using conventional Doppler echocardiography is indirect and is confounded by multiple variables. Moreover, the noninvasive evaluation of regional diastolic properties is difficult. In contrast, color kinesis directly tracks and color-encodes regional diastolic endocardial motion.

METHODS

We studied 24 patients with DCM and mitral regurgitation (MR) and 24 age-matched normal subjects. Transmitral and pulmonary vein flow velocities were measured using pulsed Doppler echocardiography. Diastolic color kinesis images were used to calculate indexes of magnitude and timing of global and regional diastolic function. Diastolic asynchrony was evaluated in different subgroups of patients with DCM. The effects of drug infusions (nitroprusside and dobutamine) were also studied.

RESULTS

Color kinesis indexes of global diastolic function showed significant differences between patients with DCM and normal subjects. Compared with Doppler indexes, color kinesis was less confounded by MR and was capable of differentiating between drug-induced lusitropic and vasodilator effects. Diastolic asynchrony was increased in patients with DCM and severe MR.

CONCLUSIONS

Quantitative analysis of global and regional LV diastolic function in patients with DCM using color kinesis is feasible.

Quantitative evaluation of global and regional left ventricular diastolic function with color kinesis

BACKGROUND

Diastolic wall motion asynchrony is a major determinant of impaired left ventricular (LV) filling in patients with concentric hypertrophy and coronary artery disease. We evaluated the ability of Color Kinesis, a new echocardiographic technique that color-encodes endocardial motion, to quantitatively assess global and regional LV filling properties.

METHODS AND RESULTS

Color Kinesis images and mitral and pulmonary vein flow Doppler data were acquired in 29 patients with LV hypertrophy and 29 age-matched control subjects. In addition, Color Kinesis data were correlated to coronary angiographic findings in 15 patients with suspected coronary artery disease. Segmental analysis of Color Kinesis images was used to obtain time histograms of regional diastolic fractional area change, wherein early and late peaks (peaks 1 and 2) reflected rapid LV filling and atrial contraction, respectively. Regional mean LV filling time and filling curves were used to objectively identify diastolic endocardial motion asynchrony in patients with LV hypertrophy and coronary artery disease. None of the mitral and pulmonary vein Doppler indices differentiated patients with normalized mitral Doppler profile (n=13) from control subjects, whereas reduced peak1/peak2 ratio and prolonged mean filling time indicated augmented contribution of atrial contraction toward LV filling (P<.05). In 22 of 25 patients with LV hypertrophy and preserved systolic function and in all patients with coronary artery disease, delayed diastolic endocardial motion was observed in at least one segment.

CONCLUSIONS

Analysis of Color Kinesis images provides objective assessment of global and regional LV filling properties and allows identification of both diastolic dysfunction in patients with normalized Doppler indices and wall motion asynchrony.

The relationship between cardiothoracic ratio and left ventricular ejection fraction in congestive heart failure. Digitalis Investigation Group

BACKGROUND

Left ventricular ejection fraction (EF) is a valuable prognostic index in patients with congestive heart failure (CHF). Although EF can be readily measured, many clinicians use roentgenographic heart size as a clue to differentiate systolic from diastolic dysfunction, even in the absence of solid supportive data.

OBJECTIVE

To test the hypothesis that the cardiothoracic ratio (CTR) measured from the chest roentgenogram can be used to estimate left ventricular EF in individuals with CHF.

METHODS

To answer this question, the database of the Digitalis Investigation Group trial was used. The CTR, determined using the Danzer method, and quantitative EF, measured locally using angiographic, radionuclide, or 2-dimensional echocardiographic techniques, were compared in 7476 patients with clinical CHF (New York Heart Association functional classes I-IV) due to acquired left-sided cardiac disease of ischemic, hypertensive, idiopathic, and alcohol-related causes.

RESULTS

Mean (+/-SD) CTR for the cohort was 0.53+/-.07. Mean (+/-SD) EF was 31.7%+/-12.2%. A weak, negative correlation between CTR and EF was observed (r=-0.176). Similar findings were obtained when the results were stratified by cause of CHF, presence of clinically defined right ventricular dysfunction, and method of EF measurement. Categorical analysis failed to yield a CTR cutoff point that facilitated useful segregation of individuals with an EF greater than 35% or 35% and below; greater than 40% or 40% and below; and greater than 45% or 45% and below in any patient group.

CONCLUSIONS

Although a weak, negative correlation exists between CTR and EF, this relationship does not allow for accurate determination of systolic function in individual patients with CHF. Considering the morbidity and mortality associated with CHF, and the clinical implications of systolic function in this syndrome, direct measurement of EF is recommended.

Doppler echocardiographic reference values for healthy rhesus monkeys under ketamine hydrochloride sedation

Cardiac ultrasound is a noninvasive technique that is commonly used to serially evaluate cardiac structure and function. Recent advances in Doppler-Echocardiography enable the ultrasonographer to perform a sophisticated noninvasive assessment of cardiovascular physiology. The Rhesus monkey is a frequently used non-human primate animal model of human cardiovascular disease because this species closely models human anatomy and physiology. However, while this species is frequently used in cardiovascular research, standardized echocardiographic values generated from large numbers of normal Rhesus are not available. In the present study, we performed cardiac ultrasound imaging on 28 healthy Rhesus monkeys to obtain normal reference values of cardiovascular structure and function in this species. Nomograms were generated from these data by plotting parameters of cardiovascular geometry and function with body weight. These normal reference data were compared to previously reported values obtained from prior studies that used noninvasive, invasive, and morphometric techniques.

Evaluation of ventricular and arterial hemodynamics in anesthetized closed-chest mice

Transgenic and knock-out mice with cardiovascular phenotypes have created the need for methods to measure murine arterial and ventricular mechanics. The aims of this study were (1) to develop a method for the assessment of wall stress (sigma es)-rate corrected velocity of fiber shortening (Vcfc) relation and (2) to assess the feasibility of quantifying global arterial function in normal mice. This method can thus serve as a reference for future studies in genetically altered mice by establishing normal values for comparison. Ten anesthetized closed-chest mice were studied with targeted M-mode echocardiography of the left ventricle recorded simultaneously with high-fidelity aortic pressures. Data were acquired at baseline and during infusions of methoxamine and isoproterenol. Tracings were digitized to obtain end-systolic wall stress (sigma es) and rate-corrected velocity of fiber shortening (Vcfc) relationships and plots of systolic meridional wall stress. Instantaneous aortic pressures and continuous wave aortic Doppler velocities were digitized to study arterial hemodynamics. The Vcfc-sigma es relationship was inverse and linear in all mice studied with a median value of r2 = 0.94. Isoproterenol resulted in an upward shift from the baseline contractility line obtained with methoxamine (mean shift = 2.0 +/- 0.3 circ/sec). Relative to baseline the integral of wall stress decreased with isoproterenol and increased with methoxamine. Methoxamine increased mean arterial pressure and total vascular resistance and decreased heart rate, cardiac output, and arterial compliance. Isoproterenol decreased total vascular resistance and increased cardiac output. Stress-shortening relationships, systolic wall stress, and evaluation of vascular function can be obtained in a closed-chest mouse model.

Objective echocardiographic evaluation of the cardiovascular system: state of the art

For over a quarter of a century, echocardiography has made an unparalleled contribution to clinical cardiology as a major tool for real-time imaging of cardiac dynamics. Echocardiography is widely used to assess cardiac function and provides noninvasive information, which is invaluable for the diagnosis of various disease states. However, despite its numerous advantages echocardiography has remained mostly qualitative and subjective. The continued progress in our understanding of the interaction between ultrasound and tissue has brought about several new developments, which allow quantitative analysis of ultrasound data. Among these new developments are endocardial boundary detection (frequently referred to as acoustic quantification) and color kinesis, which provide a more objective, robust, and convenient evaluation of cardiac and vascular dynamics that embraces multiple clinical applications. This review describes these two techniques, focusing on their current status and the evolving clinical applications.

Comparative effects of losartan and enalapril on exercise capacity and clinical status in patients with heart failure. The Losartan Pilot Exercise Study Investigators

OBJECTIVES

This study was designed to determine 1) whether 12-week oral administration of losartan, an angiotensin II receptor antagonist, in patients with heart failure is well tolerated; and 2) whether functional capacity and clinical status of patients with heart failure in whom treatment with an angiotensin-converting enzyme (ACE) inhibitor is replaced with losartan for 12 weeks will remain similar to that noted in patients in whom treatment with an ACE inhibitor is continued.

BACKGROUND

Losartan is a specific, nonpeptide angiotensin II receptor antagonist. Although specific receptor blockade with losartan has certain theoretic advantages over nonspecific ACE inhibition, definitive demonstration of comparable effects in patients with congestive heart failure is lacking.

METHODS

A double-blind, multicenter, randomized, parallel, enalapril-controlled study was conducted in 116 patients with congestive heart failure (New York Heart Association functional classes II to IV) and left ventricular ejection fraction < or = 45% previously treated with stable doses of ACE inhibitors and diuretic agents, with or without concurrent digitalis and other vasodilators. After a baseline exercise period, open-label ACE inhibitors were discontinued, and patients were randomly assigned to 12 weeks of therapy with losartan, 25 mg/day (n = 38); losartan, 50 mg/day (n = 40); or enalapril, 20 mg/day (n = 38). Drug efficacy was evaluated by changes in maximal treadmill exercise time (using a modified Naughton protocol), 6-min walk test, left ventricular ejection fraction and dyspnea-fatigue index. Safety was measured by the incidence of clinical and laboratory adverse experiences.

RESULTS

The treadmill exercise time and the 6-min walk test did not change significantly after replacement of ACE inhibitor therapy with losartan. Similarly, a significant change was not observed in either the dyspnea-fatigue index or left ventricular ejection fraction at the end of double-blind period relative to baseline.

CONCLUSIONS

Losartan was generally well tolerated and comparable to enalapril in terms of exercise tolerance in this short-term (12-week) study of patients with heart failure. The clinical effects of long-term angiotensin II receptor blockade compared with ACE inhibition remain to be studied.

Utilization and dosing of angiotensin-converting enzyme inhibitors for heart failure. Effect of physician specialty and patient characteristics

To determine if physician specialty is associated with underutilization and underdosing of angiotensin-converting enzyme inhibitors among patients with heart failure, we reviewed the charts of 214 outpatients with decreased systolic function at an urban academic medical center. Regardless of whether patients were cared for by cardiologists, generalist physicians, or a combination of the two specialities, approximately 75% of the patients were taking an angiotensin-converting enzyme inhibitor. However, only approximately 60% of these patients were taking dosages proved to be efficacious in trials. Emphasis on adequate dosing is needed among all specialty groups.

Transnasal transesophageal echocardiography

Transesophageal echocardiography has been used as a diagnostic tool in the critical care unit. However, long-term serial evaluation of ventricular function with transesophageal echocardiography is difficult because of the current probe sizes and intolerance to prolonged oral intubation. We performed 139 intubations (64 oral and 75 transnasal) with a new prototype probe in 128 patients referred for transesophageal echocardiography. Transnasal intubation with the prototype probe was possible in 63/75 attempts. Oral intubation was successful in all 64 attempts. Patients tolerated transnasal intubation well when mildly sedated or awake. Two-dimensional echocardiographic views obtained with the nasal probe were similar to those obtained with a standard monoplane probe. Image quality was rated as good or acceptable in nearly all cases. Transgastric short-axis imaging of the left ventricle combined with acoustic quantification provided stable left ventricular area waveforms. Using custom developed software we showed the feasibility of monitoring left ventricular performance with minimal probe adjustment while graphically displaying and updating left ventricular area and fractional area change. Thus, transesophageal echocardiography with a prototype miniaturized monoplane probe passed transnasally is feasible, safe, and well tolerated by patients. This probe provides excellent two-dimensional echocardiographic images and may allow long-term echocardiographic monitoring of ventricular performance.

Differences in generalist and specialist physicians' knowledge and use of angiotensin-converting enzyme inhibitors for congestive heart failure

OBJECTIVE

To quantify the extent and determinants of underutilization of angiotensin-converting enzyme (ACE) inhibitors for patients with congestive heart failure, especially with respect to physician specialty and clinical indication.

DESIGN

Survey of a national systematic sample of physicians.

PARTICIPANTS

Five hundred family practitioners, 500 general internists, and 500 cardiologists.

MEASUREMENTS AND MAIN RESULTS

Physicians' choice of medications were determined for four hypothetical patients with left ventricular systolic dysfunction: (1) new-onset, symptomatic; (2) asymptomatic; (3) chronic heart failure, on digitalis and diuretic; and (4) asymptomatic, post-myocardial infarction. For each patient, randomized controlled trials have demonstrated that ACE inhibitors decrease mortality or the progression of symptoms. Among the 727 eligible physicians returning surveys (adjusted response rate 58%), approximately 90% used ACE inhibitors for patients with chronic heart failure who were already taking digitalis and a diuretic. However, family practitioners and general internists chose ACE inhibitors less frequently (p < or = .01) than cardiologists for the other indications. Respective rates of ACE inhibitor use for each simulated patient were new-onset, symptomatic (family practitioners 72%, general internists 76%, cardiologists 86%); asymptomatic (family practitioners 68%, general internists 78%, cardiologists 93%): and asymptomatic, postmyocardial infarction (family practitioners 58%, general internists 70%, cardiologists 94%). Compared with generalists, cardiologists were more likely [p < or = .05] to increase ACE inhibitors to a target dosage (45% vs 26%) and to tolerate systolic blood pressures of 90 mm Hg or less [43% vs 15%).

CONCLUSIONS

Compared with cardiologists, family practitioners and general internists probably underutilize ACE inhibitors, particularly among patients with decreased ejection fraction who are either asymptomatic or post-myocardial infarction. Educational efforts should focus on these indications and emphasise the dosages demonstrated to lower mortality and morbidity in the trials.

Serial assessment of the cardiovascular system in normal pregnancy. Role of arterial compliance and pulsatile arterial load

BACKGROUND

Temporal changes in systemic arterial compliance and wave propagation properties (pulsatile arterial load) and their role in ventricular-systemic arterial coupling during gestation have not been explored. Noninvasive methods combined with recently developed mathematical modeling techniques were used to characterize vascular and left ventricular (LV) mechanical adaptations during normal gestation.

METHODS AND RESULTS

Fourteen healthy women were studied at each trimester of pregnancy and again postpartum. Experimental measurements included instantaneous aortic pressure (subclavian pulse tracings) and flow (aortic Doppler velocities) and echocardiographic imaging of the LV. A small increase in LV muscle mass and end-diastolic chamber dimension occurred by late gestation, with no significant alterations in myocardial contractility. Cardiac output increased and the steady component of arterial load (total vascular resistance) decreased during pregnancy. Several changes in pulsatile arterial load were noted: Global arterial compliance increased (approximately 30%) during the first trimester and remained elevated thereafter. The magnitude of peripheral wave reflections at the aorta was reduced. The mathematical model-based analysis revealed that peripheral wave reflections at the aorta were delayed and that both conduit and peripheral vessels contributed to the increased arterial compliance. Finally, coordinated changes in the pulsatile arterial load and LV properties were responsible for maintaining the efficiency of LV-to-arterial system energy transfer.

CONCLUSIONS

The rapid time course of compliance changes and the involvement of both conduit and peripheral vessels are consistent with reduced vascular tone as being the main underlying mechanism. The pulsatile arterial load alterations during normal pregnancy are adaptive in that they help to accommodate the increased intravascular volume while maintaining the efficiency of ventricular-arterial coupling and diastolic perfusion pressure.

Segmental analysis of color kinesis images: new method for quantification of the magnitude and timing of endocardial motion during left ventricular systole and diastole

BACKGROUND

We describe a method for objective assessment of left ventricular (LV) endocardial wall motion based on Color Kinesis, a new echocardiographic technique that color-encodes pixel transitions between blood and myocardial tissue.

METHODS AND RESULTS

We developed a software that analyzes Color Kinesis images and provides quantitative indices of magnitude and timing of regional endocardial motion. Images obtained in 12 normal subjects were used to evaluate the variability in each index. Esmolol, dobutamine, and atropine were used to track variations in LV function in 14 subjects. Objective evaluation of wall motion was tested in 20 patients undergoing dobutamine stress testing. Regional fractional area change, displacement, and radial shortening were displayed as histograms and time curves. Global function was assessed by calculating magnitude and timing of peak ejection or filling rates and mean time of ejection or filling. Patterns of endocardial motion were consistent between normal subjects. Fractional area change and peak ejection rate decreased with esmolol and increased with dobutamine. Time to peak ejection and mean time of contraction were prolonged with esmolol and shortened with dobutamine. Using atropine, we proved that our findings with dobutamine were not secondary to its chronotropic effects. Dobutamine induced regional wall motion abnormalities in 10 patients in 38 segments diagnosed conventionally. Segmental analysis detected abnormalities in 36 of these 38 segments and in an additional 5 of 322 segments.

CONCLUSIONS

Analysis of Color Kinesis images allows fast, objective, and automated evaluation of regional wall motion sensitively enough to evaluate clinical dobutamine stress data. This method has significant potential in the diagnosis of myocardial ischemia.

Contractile reserve in patients with peripartum cardiomyopathy and recovered left ventricular function

OBJECTIVES

Peripartum cardiomyopathy is a rare complication of pregnancy. Thirty percent of patients with this disorder are reported to recover baseline ventricular function within 6 months of delivery, but the ability of these ventricles to respond to hemodynamic stress is unknown. The aim of this investigation was to quantitatively assess the contractile reserve of patients with a history of peripartum cardiomyopathy and recovered left ventricular function.

STUDY DESIGN

Baseline left ventricular contractility was assessed by use of the load and heart rate-independent relationship between end-systolic stress and rate-corrected velocity of fiber shortening. Data were acquired from "recovered" patients (10.5 +/- 11.6 months after delivery) and compared with data from matched nonpregnant controls with use of two-dimensionally targeted M-mode echocardiography and calibrated subclavian pulse tracings that were recorded over a wide range of afterloads (end-systolic stress) generated by methoxamine (1 mg/min) infusion. Contractile reserve was assessed by a dobutamine challenge (5 micrograms/kg/min) and quantified as the vertical deviation of the dobutamine end-systolic stress minus the corrected velocity of fiber shortening data point from the baseline contractility line.

RESULTS

Patients with peripartum cardiomyopathy and matched controls had normal baseline heart rates, blood pressures, ventricular dimensions, and left ventricular function. Contractile reserve, however, was reduced in patients with recovered peripartum cardiomyopathy (0.30 +/- 0.12 vs 0.17 +/- 0.04 circ/sec, p < 0.03).

CONCLUSIONS

Women with a history of peripartum cardiomyopathy who have regained normal resting left ventricular size and performance have decreased contractile reserve revealed by the use of a dobutamine challenge test. Ventricles of these women may respond suboptimally to hemodynamic stress in spite of evidence of recovery by routine echocardiographic evaluation.

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.

Feasibility of aortic diameter measurement by multiplane transesophageal echocardiography for preoperative selection and preparation of homograft aortic valves

BACKGROUND

Preoperative knowledge of the aortic annular diameter could enable the preoperative selection and preparation of an appropriately sized homograft aortic valve.

OBJECTIVE

The aims of this study were to prospectively determine whether the combined use of transthoracic and multiplane transesophageal echocardiography allows accurate preoperative aortic annular measurements for the selection and preparation of adequately sized homograft aortic valves and to retrospectively evaluate the influence of the echocardiographic approach (transthoracic vs transesophageal) and the reader's level of experience on the accuracy of these measurements.

METHODS

Aortic annular measurements were performed before the operation by an experienced reader who used a combination of transthoracic and multiplane transesophageal images of 25 patients (mean age 52 +/- 13 years) referred for homograft aortic valve replacement. Measurements were also performed retrospectively by three additional readers with different levels of training in echocardiography. These readers acquired aortic annular diameters from prerecorded tapes and obtained measurements from each echocardiographic modality independently. All values were compared with the surgical measurement obtained with a ring valve sizer.

RESULTS

With the combined echocardiographic approach, excellent agreement was found between preoperative echocardiographic and surgical measurements (mean difference +/- 2 standard deviations = 0.2 +/- 1.4 mm). All echocardiographic data were found to be within 2 mm of the surgical measurement. These measurements were used to select and prepare the aortic homograft valve before insertion. The accuracy of annular measurements appeared to increase in parallel to the level of experience. The aortic annular measurements obtained retrospectively by a second experienced reader were more accurate with the use of transesophageal than with transthoracic echocardiography (p < 0.01). In contrast, the echocardiographic modality had no influence on the accuracy of measurements of less experienced readers (p > 0.2).

CONCLUSIONS

Preoperative measurement of the aortic annular diameter by transthoracic and multiplane transesophageal echocardiography is accurate and clinically feasible. Preoperative knowledge of the aortic annular diameter may be used to select and prepare the aortic homograft, improving valve availability and reducing ischemic time.