Clinical impact of second harmonic imaging and left heart contrast in echocardiographic stress testing.

Second harmonic imaging and left heart contrast agents are recent echocardiographic advancements that enhance the assessment of wall motion. Because little information exists concerning their clinical impact on echocardiographic stress testing in daily practice, this was determined for 9-month periods before (1997) and after (1998) their introduction. Harmonic imaging was used in all patients after its introduction. A second generation intravenous left heart contrast agent (Optison) was used at the discretion of the sonographer and physician team. Both exercise and dobutamine stress tests were included. At the time of study interpretation, diagnostic confidence was assigned as high, medium, or low. For all patients who underwent coronary angiography < or = 6 months after stress testing, the diagnostic accuracy was determined (true positive plus true negative/total studies). There were 574 studies before and 746 studies after implementation. Optison was used in 28% of the harmonic imaging studies. Study cancellations due to uninterpretable images fell from 6.4% to 1.2% (p <0.001) despite a more obese population completing testing (body mass index: 29 +/- 7 to 31 +/- 8 kg/m2, p = 0.02), whereas high diagnostic confidence increased from 55% to 64% (p <0.001). For the 7% of patients who underwent cardiac catheterization, the diagnostic accuracy remained unchanged (74 vs 73%) although a prior negative stress test was less common (40% to 20% p = 0.04). Thus, these new technologies had a favorable clinical impact.

Factors leading to progression of valvular aortic stenosis.

The rate of progression of aortic stenosis (AS) in adults is variable. To determine whether clinical or echocardiographic variables are associated with more rapid hemodynamic progression, we identified 91 AS patients (initial valve area < or = 2.0 cm2) with 2 technically adequate studies separated by > or = 6 months. From the first study, left ventricular dimensions and AS severity were measured by standard Doppler-echocardiographic methods. Each aortic valve was graded for severity of calcification and degree of restricted leaflet motion; the sum of these grades provided a severity index reflecting leaflet pathology. Clinical and electrocardiographic variables were abstracted from medical records. Mean age was 68 years (range 29 to 89) and 61 were women. Initial AS severity ranged from an aortic valve area of 0.6 to 2.0 cm2 (median 1.3 cm2). During a mean follow-up of 1.8 years the aortic valve area decreased 0.04 cm2/year. The patient group with more rapid progression (decrease in aortic valve area > or = 0.1 cm2/year) had a larger proportion of men (p <0.01) and patients with an elevated serum creatinine (p = 0.04), a higher left ventricular mass index (p = 0.01), and a higher severity index (p <0.001). Multivariable regression analysis identified the severity index (direct relation) and the initial aortic valve area (inverse relation) as the only independent variables associated with more rapid progression. In conclusion, the rate of AS progression, although highly variable, is more rapid when leaflet calcification is more marked.

Embolic risk based on aortic atherosclerotic morphologic features and aortic spontaneous echocardiographic contrast.

BACKGROUND: Different aortic atherosclerotic plaque morphologic features may have varying embolic potentials. Spontaneous echocardiographic contrast (SEC) in the aorta, as in the left atrium, has been associated with an increased risk of embolic events and often occurs with complex aortic atherosclerosis. Thus an evaluation of their isolated and combined association with embolic events was undertaken. METHODS: We retrospectively studied all patients who underwent biplane or multiplane transesophageal echocardiography meeting the following inclusion and exclusion criteria: age >/=55 years and no other cardiac pathologic condition known to be associated with embolic events other than aortic atherosclerosis or aortic SEC. The 105 patients meeting the criteria were divided into those with aortic atherosclerosis and/or aortic SEC (the study group) and those without these aortic pathologic conditions (the comparison group). Complex aortic atherosclerosis was defined as mobile, ulcerated, or protuberant (> 4 mm). SEC was defined as a pulsatile, swirling echo pattern within the aortic lumen. Embolic events included strokes, transient ischemic attacks, or peripheral emboli. RESULTS: The 61 study patients and 44 comparison patients did not significantly differ with respect to the reason for referral, age, or sex. Embolic events occurred in 35 patients. Those with ulcerated or mobile plaques had a greater prevalence of embolic events (odds ratio 4.50; 95% confidence interval, 1.30-15.5; P <.05). The highest embolic event rate was seen in patients with any complex atherosclerosis and concomitant SEC (odds ratio 9.00; 95% confidence interval, 2.06-39.3; P <.01). Patients with SEC alone or protuberant plaques alone did not have a higher event rate (odds ratio 1.71 and 0.60; 95% confidence interval, 0.57-5.17 and 0.15-2. 47, respectively). CONCLUSIONS: Embolic events were associated with the presence of ulcerated or mobile aortic plaques. In addition, the combination of aortic SEC and any complex atherosclerosis had the highest embolic association.

Etiology and diagnosis of bilateral leg edema in primary care.

PURPOSE: To identify the causes of bilateral leg edema in a primary care setting, and to determine the ability of primary care providers to arrive at the correct diagnosis using the information available at the initial clinical encounter. PATIENTS AND METHODS: Fifty-eight ambulatory adult patients with bilateral leg edema were enrolled at an inner city family practice during a 3-year period. Historical information, physical examination findings, and clinical impressions of primary care providers were compared with the results of laboratory evaluations consisting of echocardiograms, venous duplex ultrasound leg scans, serum albumin levels, and when appropriate, 24-hour urinalyses. RESULTS: Forty-five patients (78%) completed the study. The initial clinical impression was venous insufficiency in 32 (71%) patients and congestive heart failure in 8 (18%) patients. In actuality, 15 (33%) patients had a cardiac condition as a cause of their leg edema, and 19 (42%) had pulmonary hypertension. All of the patients with heart disease, and almost all of those with pulmonary hypertension, were age 45 years or older. Only 10 (22%) of the subjects had venous insufficiency. Renal conditions, medication use, and hypoalbuminemia were less common. CONCLUSIONS: Utilizing clinical information only, many patients with cardiopulmonary pathology were incorrectly diagnosed as having more benign conditions, most commonly venous insufficiency. Echocardiographic evaluation, including an estimation of pulmonary artery pressure, may be advisable in many patients with bilateral leg edema, especially if they are at least 45 years old.

Aortic sinotubular junction calcium as a marker of severe aortic atherosclerosis.

Because the significance of calcification of the sinotubular junction is poorly understood, we retrospectively investigated its association with aortic atherosclerosis in 101 patients who underwent transesophageal echocardiography. Such calcification was found to be a marker of more severe aortic atherosclerosis and, specifically, aortic arch disease.

Beta 1-adrenoreceptors regulate resting metabolic rate.

This was a randomized, cross-over experiment designed to determine which beta-adrenergic receptors, beta 1, beta 2, or both, regulate metabolic rate in humans. All subjects (3 women, 4 men) were administered a 7-d therapeutic dose of a selective beta 1-antagonist (atenolol 50 mg BID), a combined beta 1, beta 2-antagonist (propranolol 80 mg BID), and a placebo control (BID). Indirect calorimetry was determined before and after 1 h of submaximal exercise. Exercise was performed at 50% of the trial specific VO2peak because maximal exercise was significantly decreased in the presence of the nonselective beta 1, beta 2-antagonist (VO2peak placebo: 44.90 +/- 4.40 mL.kg-1.min-1 vs beta 1, beta 2-antagonism: 39.20 +/- 3.00 mL.kg-1.min-1; P < 0.05). Both the beta 1 and the combined beta 1, beta 2-adrenoreceptor antagonists reduced resting oxygen consumption to a similar extent (0.247 +/- 0.007 L.min-1 placebo, vs 0.218 +/- 0.007 L.min-1 beta 1-antagonism, vs 0.226 +/- 0.007 L.min-1 beta 1, beta 2-antagonism; P < 0.05). However, the 30-min and 60-min excess post-exercise oxygen consumption (mean EPOC) remained unchanged. It is concluded that the beta 1-receptors are regulating the effects of the sympathetic nervous system on resting but not exercise recovery metabolic rate. These metabolic side effects may suggest that changes need to be made in the nutritional requirements of patients using beta-adrenergic antagonists.

A geometric method of measuring the left ventricular ejection fraction on gated Tc-99m sestamibi myocardial imaging.

Geometric measurements of the left ventricular diameters as used in biplane angiocardiography and echocardiography were applied to gated SPECT Tc-99m sestamibi myocardial scintigrams in order to calculate the left ventricular ejection fraction. These measurements take no longer than 5 minutes and require no additional computer software. In a review of 79 examinations, the left ventricular ejection fraction calculated using these measurements correlated well with the echocardiographically estimated ejection fraction (r = 0.78, P < 0.0001). The technique is highly reproducible with an intraobserver correlation of r = 0.94 and interobserver correlation of r = 0.93.

Spontaneous echocardiographic contrast in the thoracic aorta: factors associated with its occurrence and its association with embolic events.

Spontaneous echocardiographic contrast is associated with embolic events when it occurs in the left atrium. Because little is known about spontaneous echocardiographic contrast in the aorta, we investigated this association retrospectively in 343 patients without aortic dissection or aneurysm who had undergone transesophageal echocardiography. Two independent readers concurred on the presence of spontaneous echocardiographic contrast in the aorta in 93% of the study patients, with the remainder agreed on by consensus. Spontaneous echocardiographic contrast was found in 65 patients (19%) and was associated with older age (p < 0.0001), male sex (p < 0.0001), slightly larger aortas (p < 0.0001), and complex aortic atherosclerosis (p = 0.0001). Thirty-four (28.6%) of 119 patients with clinical embolic events had spontaneous echocardiographic contrast in the aorta in contrast to 31 (13.8%) of 224 patients referred for other reasons (p = 0.0001). This finding remained significant when spontaneous echocardiographic contrast in the aorta was the only abnormality allowed (n = 207, p = 0.0065) or when other echocardiographic variables known to be related to embolic events were included in a multivariate analysis. Thus, spontaneous echocardiographic contrast in the aorta can often be detected by transesophageal echocardiography and is associated with a higher prevalence of embolic events.

The relationship of autonomic function to age-related changes in left ventricular filling in normal subjects.

Heart rate and age are independent variables associated with the pattern of normal left ventricular filling. Since heart rate variability also varies with age, the relationship between these and left ventricular filling in normal subjects was assessed. In 31 subjects (age range 21 to 71 years), power spectral analysis of heart rate variability was determined from 24 h Holter tapes, and left ventricular filling was assessed by Doppler echocardiography. Relationships between heart rate variability and left ventricular filling were assessed by univariate and multivariate regression analyses. Total, low frequency and high frequency power each significantly correlated with the peak filling velocity with atrial systole (A) (r = -0.70, P < 0.0001; r = -0.69, P < 0.0001; r = -0.54, P < 0.01, respectively), but did not correlate with measures of early diastolic left ventricular filling. Although age and A were related (r = 0.46, P < 0.010), age was no longer a significant variable when measures of heart rate variability were included in the multivariate regression model for A. Thus, the variability in measures of early diastolic filling in normal subjects appears to be independent of measures of heart rate variability, whereas, A is significantly associated with these measures.

Prognostic value of dobutamine stress echocardiography in patients referred because of suspected coronary artery disease.

To determine whether dobutamine stress echocardiography (DSE) provides prognostic information beyond that available from routine clinical data, we reviewed the outcome of 210 consecutive patients referred for DSE to evaluate chest pain, perioperative risk, and myocardial viability. Dobutamine was infused in increments of 10 micrograms/kg/min in 5-minute stages to a maximum of 40 micrograms/kg/min. The dobutamine stress echocardiogram was considered abnormal only if dobutamine induced a new wall motion abnormality as determined by review of the digitized echocardiographic images in a quad screen format and on videotape. Thirty percent of tests were abnormal. An abnormal test was more common (p < or = 0.02) in men and patients with angina pectoris, in patients taking nitrate therapy, or those with prior myocardial infarction or abnormal left ventricular wall motion at rest. Twenty-two deaths, 17 of which were cardiac, occurred over a median follow-up of 240 days (range 30 to 760). Sixteen cardiac deaths occurred in the 63 patients with versus 1 cardiac death among the 147 without a new wall motion abnormality (p < or = 0.0001). Other variables associated with cardiac death (p < or = 0.05) were age > 65 years, nitrate therapy, ventricular ectopy during DSE, suspected angina pectoris, and hospitalization at the time of DSE. When cardiac death, myocardial infarction, and revascularization procedures were all considered as adverse outcomes, a new wall motion abnormality continued to be the most powerful predictor of an adverse cardiac event.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of Tc-99m sestamibi infusion for detection of hibernating myocardium. A preliminary report.

To evaluate whether a prolonged infusion of Tc-99m sestamibi allows for visualization of viable myocardium in areas of hypoperfused myocardium, 25 patients were prospectively studied. Each patient was imaged four times in two consecutive days in the following manner: day 1:1) immediately after injection of Tl-201 at rest, 2) 1 hour after a bolus injection of Tc-99m sestamibi at rest; and day 2: 1) imaging in the Tl-201 window for 24 hour redistribution, 2) imaging after a 1-hour infusion of Tc-99m sestamibi. The two Tc-99m sestamibi and two Tl-201 studies were evaluated for presence of redistribution. This was present both on the Tl-201 and Tc-99m sestamibi studies (concordant) in 13 cases, and absent on both the Tl-201 and Tc-99m sestamibi studies (concordant) in 9 cases. In two cases redistribution was seen on the Tl-201 images only, and in one case it was seen on the Tc-99m sestamibi images only (discordant). Tc-99m sestamibi infusion may provide information about the presence of viable myocardium which is similar to that provided by Tl-201 24-hour imaging.

Limitations of transesophageal echocardiography in the risk assessment of patients before nonanticoagulated cardioversion from atrial fibrillation and flutter: an analysis of pooled trials.

Recent studies have proposed that the exclusion of an atrial thrombus by transesophageal echocardiography (TEE) would allow for the safe cardioversion from atrial fibrillation or flutter without the need of prophylactic anticoagulation. Because all of the TEE trials have been small and descriptive and have lacked randomized, conventionally treated control groups, the pooled risk of embolic events from TEE trials was compared with that of a control group pooled from the literature on cardioversion both with and without conventional anticoagulation. Studies were identified from a MEDLINE search, references in review articles, and recent cardiology abstracts and were included if there were > 10 patients and if atrial fibrillation or flutter was of > 48 hours' duration. Where > 1 study had been published by the same group only the largest study was used. Studies were not selected by cause of arrhythmia, by predisposing risk factors for atrial fibrillation and flutter, or by method of cardioversion. The only patients excluded from TEE reports were those with atrial thrombi diagnosed on the precardioversion TEE or those documented to have adequate standard precardioversion anticoagulation. Seven TEE and 18 control studies met the inclusion criteria. More patients in the control studies had rheumatic valvular disease. Embolic events were significantly more frequent in the TEE group than in the anticoagulated control group (1.34% vs 0.33%, respectively; p = 0.04), whereas there was no significant difference between the TEE group and the nonanticoagulated control group (2.00%; p = 0.26). Thus the use of TEE screening to exclude patients with atrial thrombi before cardioversion does not identify patients who can safely undergo this procedure without anticoagulation.

Transient myocardial ischemia in infants prenatally exposed to cocaine.

This prospective study examined whether neonates of pregnant women who used cocaine during pregnancy are at a risk for the development of transient myocardial ischemia and altered autonomic function, as in adults. We studied 21 of 35 infants with a history of prenatal exposure to cocaine. The ST segment changes and heart rate variability were evaluated from three-channel Holter monitors within 48 hours of birth. The data were compared with those on 20 control infants with similar birth weight, gestational age, and postnatal age. Six infants (29%) who were exposed to cocaine in utero had transient ST segment elevation, versus only one infant (5%) from the control group (odds ratio = 7.6; 95% confidence interval, 1.14, 50.64). Heart rates, results of total power and low-frequency power spectral analyses for heart rate variability, and arrhythmias were not significantly different in the two groups. However, a lower ratio of low-to high-frequency power reflected increased vagal activity in cocaine-exposed infants. We conclude that cocaine use in pregnant mothers is associated with transient ST segment abnormalities in their infants. These abnormalities are consistent with transient myocardial ischemia.

Relation of exercise Doppler left ventricular filling to thallium lung uptake.

The exercise-induced changes in left ventricular filling in patients with coronary artery disease are poorly understood. Therefore these changes were studied in relation to a noninvasive indicator of exercise pulmonary venous congestion, the lung-to-heart (L:H) ratio on symptom-limited thallium stress testing. Fifty-six patients undergoing diagnostic treadmill testing were studied; 50 of them had technically adequate Doppler recordings and became the subjects of this study. Doppler left ventricular filling was assessed with patients in the supine position both before and after exercise. Measurements included early (E) and late (A) filling velocities, their ratio, the diastolic time-velocity integral, and the diastolic filling time. The L:H ratio was considered abnormal if it was greater than the upper 95% confidence limit for a separate group of normal subjects. Twelve subjects had a documented prior myocardial infarction, 16 had stress-induced ischemia, and 20 had abnormal L:H ratios. A greater E and a longer diastolic filling time in the group with an abnormal L:H ratio were the only postexercise measurements that differed; however, E was the only filling parameter that both differed between groups after exercise (abnormal L:H group 87 +/- 25 cm/sec; normal 68 +/- 20 cm/sec; p < 0.01) and whose change from rest to after exercise was significantly different (p < 0.05). Since Doppler velocities are directly related to instantaneous gradients, the higher E in patients with evidence of exercise pulmonary congestion suggests a higher exercise early diastolic left atrial pressure.

Predicting left heart failure after a myocardial infarction: a preliminary study of the value of echocardiographic measures of left ventricular filling and wall motion.

Heart failure occurs from both systolic and diastolic dysfunction. To determine whether simple Doppler echocardiographic measures of left ventricular filling could improve upon the ability of systolic function to predict heart failure after infarction, patients with acute myocardial infarction were studied within the first 36 hours by Doppler and two-dimensional echocardiography. Forty-eight patients who did not have heart failure before the Doppler echocardiographic study and who did not have myocardial revascularization, moderate or severe mitral regurgitation, or other complications during recovery were monitored for 6 months or to the onset of heart failure (n = 10). The univariate predictors of heart failure were age (p less than 0.05), anterior infarction (p less than 0.05), early diastolic peak filling velocity (p = 0.05), filling velocity with atrial systole (p less than 0.05), the ratio of these velocities (p less than 0.001), the percentage of filling with atrial systole (p less than 0.001), and the wall motion score index (p less than 0.001). However, the only independent predictors of heart failure by use of multivariant stepwise logistic regression analysis were the wall motion score index (p less than 0.05) and either the ratio of early and late peak filling velocities (p less than 0.001) or the percentage of filling with atrial systole (p less than 0.001). The combined use of a measure of systolic function and measures of the relative contribution of atrial systole to ventricular filling were useful predictors in identifying patients likely to develop subsequent heart failure after myocardial infarction.

Left ventricular filling shortly after an uncomplicated myocardial infarction as a predictor of subsequent exercise capacity.

Resting measurements of left ventricular systolic function do not reliably predict exercise capacity in patients with cardiac disease. Therefore left ventricular filling shortly after a myocardial infarction was prospectively studied to determine whether it could predict subsequent exercise time. Consecutive patients with an acute infarction underwent Doppler and two-dimensional echocardiography within 36 hours of infarction. The study group was composed of the 26 men who did not have reperfusion, who had an uncomplicated myocardial infarction, and who had undergone symptom-limited stress testing during recovery (modified Bruce protocol, 44 +/- 23 days after myocardial infarction). Systolic function was measured by ejection fraction and a wall motion score. Ventricular filling was assessed by the peak transmitral Doppler velocity in early diastole (E), with atrial systole (A), their ratio (A/E), and the percentage of filling from atrial systole. The only parameter of systolic or diastolic function that correlated with exercise time was E (r = 0.65, p less than 0.001). This relationship was particularly strong for the 16 subjects taking beta blockers at the time of stress testing (r = 0.88, p less than 0.001). Stepwise multivariate regression analysis showed that only E and beta blocker therapy at the time of stress testing contributed to the model predicting recovery exercise time (R2 = 0.55). In summary, E, measured soon after an uncomplicated myocardial infarction, is one factor that predicts exercise capacity during recovery.

Endomyocardial invasion by esophageal carcinoma. Demonstration by echocardiography.

Two cases of esophageal carcinoma with echocardiographically demonstrable direct extension are presented. Recognition of esophageal carcinoma metastatic to the heart is clinically difficult but can be facilitated by two-dimensional echocardiography. Earlier recognition of cardiac metastases by echocardiography may allow more effective therapy.