Effect of mitral regurgitation on pulmonary venous velocities derived from transesophageal echocardiography color-guided pulsed Doppler imaging.

The effect of mitral regurgitation on pulmonary venous flow velocity was studied in 66 patients undergoing transesophageal echocardiography. Nine patients were studied intraoperatively before and after surgery, so that 75 pulmonary venous flow tracings were analyzed. Fifty-four patients had no significant (0 to 1+) mitral regurgitation and 21 had significant (2 to 3+) mitral regurgitation. Comparison of both groups revealed significant differences in the pulmonary venous flow pattern. In patients with no significant mitral regurgitation, the peak systolic velocity was higher (55 +/- 16 vs. -4 +/- 16 cm/s; p less than 0.0001) and the peak diastolic velocity was lower (43 +/- 13 vs. 59 +/- 17 cm/s; p less than 0.01) when compared with values in patients with significant mitral regurgitation. Consequently, the peak systolic/diastolic velocity ratio was significantly higher in the patients without significant mitral regurgitation (1.4 +/- 0.5 vs. 0.4 +/- 1.3; p less than 0.0001). The same trend was noted with respect to the systolic and diastolic velocity integrals. As the degree of mitral regurgitation increased, the peak diastolic velocity and diastolic velocity integral increased, whereas the peak systolic velocity and systolic velocity integral decreased. In patients with severe mitral regurgitation, the systolic flow became reversed (retrograde). The sensitivity of reversed systolic flow for severe mitral regurgitation was 90% (9 of 10), the specificity was 100% (65 of 65), the positive predictive value was 100% (9 of 9), the negative predictive value was 98% (65 of 66) and the predictive accuracy was 99% (74 of 75).(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of pulmonary venous flow by transesophageal echocardiography in subjects with a normal heart: comparison with transthoracic echocardiography.

Nineteen normal subjects and five patients with atrial fibrillation underwent transesophageal and transthoracic echocardiographic studies to evaluate the normal pulmonary venous flow pattern, compare right and left pulmonary venous flow and assess the effect of sample volume location on pulmonary venous flow velocities. Best quality tracings were obtained by transesophageal echocardiography. Anterograde flow during systole and diastole was observed in all patients by both techniques. Reversed flow during atrial contraction was observed with transesophageal echocardiography in 18 of the 19 subjects in normal sinus rhythm, but in only 7 subjects with transthoracic echocardiography. Two forward peaks during ventricular systole were clearly identified in 14 subjects (73%) with transesophageal echocardiography, but in none with the transthoracic technique. The early systolic wave immediately followed the reversed flow during atrial contraction and was strongly related to the timing of atrial contraction (r = 0.78; p less than 0.001), but not to the timing of ventricular contraction, and appeared to be secondary to atrial relaxation. Conversely, the late systolic wave was temporally related to ventricular ejection (r = 0.66; p less than 0.001), peaking 100 ms before the end of the aortic valve closure and was unrelated to atrial contraction time. Quantitatively, significantly higher peak systolic flow velocities were obtained in the left upper pulmonary vein compared with the right upper pulmonary vein (60 +/- 17 vs. 52 +/- 15 cm/s; p less than 0.05) and by transesophageal echocardiography compared with transthoracic studies (60 +/- 17 vs. 50 +/- 14 cm/s; p less than 0.05). Increasing depth of interrogation beyond 1 cm from the vein orifice resulted in a significant decrease in the number of interpretable tracings.(ABSTRACT TRUNCATED AT 250 WORDS)

Color Doppler echocardiographic evaluation of patients with a flail mitral leaflet.

Chordal rupture with a subsequent flail mitral valve leaflet is now the most common cause of pure mitral regurgitation. To describe the Doppler color flow findings in flail mitral leaflet and the determinants of these findings, Doppler color flow mapping and conventional Doppler echocardiography were performed in 31 consecutive patients presenting with a flail mitral leaflet. In the 23 patients with a posterior flail leaflet, a distinctive highly eccentric and turbulent jet directed toward the posterior wall of the aorta was noted. In the eight patients with an anterior flail leaflet, a jet directed toward the posterolateral left atrial wall was noted. Maximal regurgitant jet area was significantly larger in patients with a flail anterior leaflet (13.1 +/- 3.0 cm2) than in those with a flail posterior leaflet (5.8 +/- 3.0 cm2, p = 0.0001). Maximal jet area to left atrial ratio was also significantly higher in those with a flail anterior leaflet (0.56 +/- 0.16) than in those with a flail posterior leaflet (0.27 +/- 0.17, p = 0.0006). When systolic left atrial velocities encoded as red were incorporated into the maximal jet area measurement, 7 of the 8 patients with an anterior flail leaflet had a jet area greater than 8 cm2, consistent with severe mitral regurgitation, compared with 13 of the 23 patients with a flail posterior leaflet. There was no correlation between jet area or jet area to left atrial ratio and any hemodynamic variable. Patients with acute mitral regurgitation exhibited a trend toward smaller jet areas, but this did not reach statistical significance. Regurgitant fraction calculated from pulsed Doppler recording of mitral and aortic flow was consistent with moderately severe or severe mitral regurgitation in all cases and averaged 70%. Thus, patients with a flail mitral valve leaflet have distinctive Doppler color flow findings. A highly eccentric and turbulent jet directed posteriorly to the aorta may contribute to a systematic underestimation of severe mitral regurgitation by conventional Doppler color flow criteria. The use of pulsed Doppler ultrasound to calculate regurgitant fraction in patients with a flail mitral valve leaflet may be helpful in reliably assessing the degree of mitral regurgitation.

Superiority of transesophageal echocardiography in detecting cardiac source of embolism in patients with cerebral ischemia of uncertain etiology.

The diagnostic yield of transesophageal and transthoracic echocardiography for identifying a cardiac source of embolism was compared in 79 patients presenting with unexplained stroke or transient ischemic attack. There were 35 men and 44 women with a mean age of 59 years (range 17 to 84); 52% had clinical cardiac disease. Both transthoracic and transesophageal echocardiograms were performed using Doppler color flow and contrast imaging. Transesophageal echocardiography identified a potential cardiac source of embolism in 57% of the overall study group compared with only 15% by transthoracic echocardiography (p less than 0.0005). Compared with transthoracic echocardiography, transesophageal echocardiography more frequently identified atrial septal aneurysm associated with a patent foramen ovale (9 versus 1 of 79 patients, p less than 0.005), left atrial thrombus or tumor (6 versus 0 of 79 patients, p less than 0.05) and left atrial spontaneous contrast (13 versus 0 of 79 patients, p less than 0.0005). All cases of left atrial thrombus or spontaneous contrast were identified in patients with clinically identified cardiac disease. In the 38 patients with no cardiac disease, transesophageal echocardiography identified isolated atrial septal aneurysm and atrial septal aneurysm with a patent foramen ovale more frequently than transthoracic echocardiography (8 versus 2 of 38 patients, p less than 0.05). The two techniques had a similar rate of identifying apical thrombus and mitral valve prolapse. Overall, transesophageal echocardiography identified abnormalities in 39% of patients with no cardiac disease versus 19% for transthoracic echocardiography (p less than 0.005). Thus, transesophageal echocardiography identifies potential cardiac sources of embolism in the majority of patients presenting with unexplained stroke.(ABSTRACT TRUNCATED AT 250 WORDS)

Mobile aortic atheroma and systemic emboli: efficacy of anticoagulation and influence of plaque morphology on recurrent stroke.

OBJECTIVES: We sought to determine the influence of plaque morphology and warfarin anticoagulation on the risk of recurrent emboli in patients with mobile aortic atheroma. BACKGROUND: An epidemiologic link between aortic atheroma and systemic emboli has been described both in pathologic and transesophageal studies. Likewise, a few studies have found an increased incidence of recurrent emboli in these patients. The therapeutic implications of these findings has not been studied. METHODS: Thirty-one patients presenting with a systemic embolic event and found to have mobile aortic atheroma were studied. The height, width and area of both immobile and mobile portions of atheroma were quantitated. The dimensions of the mobile component was used to define three groups: small, intermediate and large mobile atheroma. The patients were followed up by means of telephone interview and clinical records, with emphasis on anticoagulant use and recurrent embolic or vascular events. RESULTS: Patients not receiving warfarin had a higher incidence of vascular events (45% vs. 5%, p = 0.006). Stroke occurred in 27% of these patients and in none of those treated with warfarin. The annual incidence of stroke in patients not taking warfarin was 0.32. Myocardial infarction occurred in 18% of patients also in this group. Taken together, the risk of myocardial infarction or stroke was significantly increased in this group (p = 0.001). Forty-seven percent of patients with small, mobile atheroma did not receive warfarin. Recurrent stroke occurred in 38% of these patients, representing an annual incidence of 0.61. There were no strokes in patients with small, mobile atheroma treated with warfarin (p = 0.04). Likewise, none of the patients with intermediate or large mobile atheroma had a stroke during follow-up. Only three of these patients had not been taking warfarin. CONCLUSIONS: Patients presenting with systemic emboli and found to have mobile aortic atheroma on transesophageal echocardiography have a high incidence of recurrent vascular events. Warfarin is efficacious in preventing stroke in this population. The dimension of the mobile component of atheroma should not be used to determine the need for anticoagulation.

Noninvasive assessment of pacemaker hemodynamics by Doppler echocardiography: importance of left atrial size.

The relative decrease in cardiac output with ventricular pacing versus "physiologic" modes was measured noninvasively using Doppler echocardiography in 26 patients. Standard echocardiographic measurements of left ventricular size (diastolic diameter), left ventricular function (shortening fraction) and left atrial size were examined to determine which of these variables might best identify patients more likely to benefit from maintenance of atrioventricular (AV) synchrony. Decreases in relative cardiac output, expressed as reduction in the Doppler-derived flow velocity integral, with loss of AV synchrony ranged from 0 to 43% (mean decrease 21%). There was no correlation between left ventricular size or function and effect of pacing mode on relative cardiac output. There was, however, correlation between left atrial size and sensitivity to pacing mode. Patients with normal left atrial size were significantly more sensitive to loss of AV synchrony. In this subgroup, the decrease in flow velocity integral with ventricular pacing was 32 +/- 11% compared with only 11 +/- 13% in patients with left atrial enlargement. Thus, Doppler echocardiography is useful in assessing optimal pacing mode in the individual patient. Echocardiographically measured left atrial size may identify patients in whom physiologic pacing may be major benefit.

Systolic and diastolic flow abnormalities in elderly patients with hypertensive hypertrophic cardiomyopathy.

Seventeen patients with clinical and echocardiographic features of hypertensive hypertrophic cardiomyopathy of the elderly were studied to more completely characterize left ventricular systolic and diastolic function in this group. Measurements of left ventricular structure and systolic and diastolic function were made in the study patients and compared with those of age-matched control subjects. The study group had significantly greater left ventricular mass, wall thickness, shortening fraction and relative wall thickness than did the control subjects. Left ventricular end-diastolic dimension was smaller and left atrial size was not different in study patients compared with control subjects. Left ventricular filling was characterized by an increased peak atrial velocity and reduced ratio of peak early to peak atrial velocity in the study group. Left ventricular outflow velocities were elevated in 14 of the 17 study patients with peak velocities ranging from 1.2 to 5.0 m/s corresponding to a peak intraventricular gradient of 16 to 100 mm Hg. The velocity waveforms in these patients were late-peaking, similar to those described in hypertrophic obstructive cardiomyopathy. The elevated velocities were localized to the left ventricular outflow tract. These findings imply a pathophysiologic state in these elderly patients with long-standing hypertension, very similar to that in hypertrophic obstructive cardiomyopathy, and provide further support for the use of pharmacologic agents with negative inotropic properties or positive lusitropic properties in this group.

Diastolic function in patients undergoing coronary angioplasty: influence of degree of revascularization.

To assess the early effects of successful coronary angioplasty on Doppler-derived left ventricular filling patterns and the significance of the extent of revascularization on these variables, 31 patients undergoing coronary angioplasty were examined within 24 h before and after the revascularization procedure. After angioplasty, the peak early to late velocity ratio increased from 0.89 +/- 0.2 to 1.05 +/- 0.3 (p less than 0.0001) and the one-third filling fraction increased from 42 +/- 10% to 48 +/- 10% (p less than 0.0001). The percent atrial contribution to filling decreased from 45 +/- 7% to 41 +/- 8% (p less than 0.01), and the pressure half-time and the isovolumetric relaxation time shortened from 55 +/- 15 to 43 +/- 13 ms (p less than 0.001) and from 100 +/- 14 to 82 +/- 17 ms (p less than 0.0001), respectively. When comparing patients with complete (n = 23) and incomplete (n = 8) revascularization, the same changes in the Doppler variables were observed. However, the mean rate of acceleration of early filling increased significantly after angioplasty only in those patients with complete revascularization. These data indicate that the left ventricular diastolic filling pattern is modified significantly as early as 24 h after successful coronary angioplasty. Improvement in impaired relaxation appears to be the most likely explanation for these changes, although increased myocardial stiffness in patients with incomplete revascularization is an alternative hypothesis.

Quantitation of mitral regurgitation by transesophageal echocardiography with Doppler color flow mapping: correlation with cardiac catheterization.

Eighty consecutive patients who underwent both left ventriculography and single-plane transesophageal echocardiography with Doppler color flow mapping were studied to compare the two techniques in the assessment of mitral regurgitation. Only the mosaic aspect of the regurgitant jet was included in the measurements. Values for inter- and intraobserver variability for the maximal regurgitant area measurements were 10 +/- 9% and 9 +/- 8%, respectively. The best correlation between angiography and Doppler color flow imaging was obtained with the maximal regurgitant area (r = 0.90). A maximal regurgitant area less than 3 cm2 predicted mild mitral regurgitation with a sensitivity of 96%, specificity of 100% and a predictive accuracy of 98%, whereas a maximal regurgitant area greater than 6 cm2 predicted severe mitral regurgitation with a sensitivity of 91%, a specificity of 100% and a predictive accuracy of 98%. A strong, although inferior, correlation was found for the maximal regurgitant area/left atrial area ratio (r = 0.81). A ratio less than 20% predicted mild mitral regurgitation with 94% accuracy, whereas a ratio greater than 35% predicted severe mitral regurgitation with 85% accuracy. Thus, single-plane transesophageal echocardiography with Doppler color flow mapping is an exquisitely sensitive technique for the diagnosis of mitral regurgitation. Minimal degrees of mitral regurgitation can be detected in approximately 62% of patients in whom no mitral regurgitation is detected by angiography. The mosaic maximal regurgitant area is a simple and easily obtainable Doppler echocardiographic index that provides an accurate estimation of mitral regurgitation severity.

Echocardiographic evaluation of cardiac structure and function in elderly subjects with isolated systolic hypertension.

One hundred four participants in the Systolic Hypertension in the Elderly Program (SHEP) trial (mean age 71 +/- 6 years) were examined by Doppler echocardiography to gain information on the cardiac structural and functional alterations in isolated systolic hypertension. Participants had a systolic blood pressure greater than 160 mm Hg with diastolic blood pressure less than 90 mm Hg and were compared with 55 age-matched normotensive control subjects. Left ventricular mass index was significantly higher in the participants than in the normotensive subjects (103 +/- 28 versus 87 +/- 23 g/m2, p = 0.0014) and 26% of the participants met echocardiographic criteria for left ventricular hypertrophy compared with 10% of normotensive subjects. Left atrial index was also greater in participants than in normotensive subjects (2.26 +/- 0.32 versus 2.11 +/- 0.24 cm/m2, p = 0.005) and 51% of participants had left atrial enlargement. Doppler measures of diastolic filling were significantly different between the two groups, with peak atrial velocity higher (76 +/- 17 versus 69 +/- 17 cm/s, p = 0.02) and ratio of peak early to atrial velocity lower (0.76 +/- 0.23 versus 0.86 +/- 0.22, p = 0.0124) in participants. There was no correlation between left ventricular mass index and Doppler measures of diastolic function, but relative wall thickness correlated significantly with peak atrial velocity (r = 0.22, p = 0.016) and peak early to peak atrial velocity ratio (r = 0.24, p = 0.007). There was no difference in M-mode ejection phase indexes of systolic performance (shortening fraction and peak velocity of circumferential fiber shortening) between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial septal aneurysm and stroke: a transesophageal echocardiographic study.

The prevalence and morphologic characteristics of atrial septal aneurysms identified by transesophageal echocardiography in 410 consecutive patients are described. Two groups of patients were compared: Group I consisted of 133 patients referred for evaluation of the potential source of an embolus and Group II consisted of 277 patients referred for other reasons. An atrial septal aneurysm was diagnosed by transesophageal echocardiography in 32 (8%) of the 410 patients. Surface echocardiography identified only 12 of these aneurysms. Atrial septal aneurysm was significantly more common in patients with stroke (20 [15%] of 133 vs. 12 [4%] of 277) (p less than 0.05); right to left shunting at the atrial level was demonstrated in 70% of patients in Group I and 75% of patients in Group II by saline contrast echocardiography. Four patients in Group I had an atrial septal defect with additional left to right flow. There was no difference between the two groups in aneurysm base width, total excursion or left atrial or right atrial excursion. However, Group I patients had a thinner atrial septal aneurysm than did Group II patients. It is concluded that an atrial septal aneurysm occurs commonly in patients with unexplained stroke, is more frequently detected by transesophageal echocardiography than by surface echocardiography and is usually associated with right to left atrial shunting. Treatment (anticoagulant therapy vs. surgery) of atrial septal aneurysm identified in stroke patients can be determined only by long-term follow-up studies.

Evaluation of left ventricular systolic and diastolic dysfunction during transient myocardial ischemia produced by angioplasty.

Acute myocardial ischemia is known to cause impairment of both left ventricular systolic and diastolic function. To further investigate these changes as well as their relation to common clinical variables (electrocardiographic [ECG] changes and chest pain), 32 patients were evaluated with Doppler echocardiography during coronary angioplasty. Doppler indexes of left ventricular diastolic function included the ratios of peak early to late and peak early to mean diastolic velocities as well as the ratios of early to late and first third to total velocity integral (one-third filling fraction). All diastolic indexes showed significant impairment by 15 seconds after coronary occlusion (ratio peak early to late filling velocity: 1.11 versus 0.96, p less than 0.01; ratio peak early to mean filling velocity: 1.9 versus 1.7, p less than 0.01; ratio early to late velocity integral: 1.58 versus 1.25, p less than 0.01; one-third filling fraction: 41.2 versus 37.7, p less than 0.01). Left ventricular systolic function was evaluated during coronary occlusion both qualitatively, as assessed by the appearance of a new wall motion abnormality on two-dimensional echocardiography (mean 28.8 seconds), and quantitatively by measurement of systolic percent area change on the two-dimensional short-axis view as well as the Doppler echocardiographic stroke integral index. Systolic indexes did not show significant change until 30 seconds after balloon inflation (percent area change: 42.8 versus 29.2, p less than 0.01; stroke integral index: 11.04 versus 9.36, p less than 0.01). ECGs were performed at 15 second intervals.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemodynamic benefit of atrioventricular synchrony: prediction from baseline Doppler-echocardiographic variables.

The purpose of this study was to determine if baseline Doppler-echocardiographic variables of systolic or diastolic function could predict the hemodynamic benefit of atrioventricular (AV) synchronous pacing. Twenty-four patients with a dual chamber pacemaker were studied. Baseline M-mode and two-dimensional echocardiograms were obtained and Doppler-echocardiographic measurements of mitral inflow and left ventricular outflow were made in VVI mode (single rate demand) and in VDD (atrial synchronous, ventricular inhibited) and DVI (AV sequentially paced) modes at AV intervals ranging from 50 to 300 ms. Forward stroke volume and cardiac output were determined in each mode at each AV interval from the left ventricular outflow tract flow velocities, and the percent increase in cardiac output over VVI mode was determined. M-mode measurements, including left ventricular end-diastolic dimension, shortening fraction and left atrial size and Doppler measurement of diastolic filling, including peak early velocity and percent atrial contribution, did not correlate with the percent increase in cardiac output during physiologic pacing. The stroke volume in VVI mode correlated significantly with the percent increase in cardiac output during physiologic pacing (r = -0.61, p less than 0.005 for VDD mode and r = -0.55, p less than 0.05 for DVI mode). Five of the 15 patients with VVI stroke volume less than 50 ml but none of the 9 patients with stroke volume greater than 50 ml had ventriculoatrial (VA) conduction.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular diastolic function: comparison of pulsed Doppler echocardiographic and hemodynamic indexes in subjects with and without coronary artery disease.

To evaluate the influence of left ventricular chamber stiffness and relaxation on Doppler echocardiographic indexes of diastolic function, 35 patients (mean age 60 +/- 12 years) were examined; 24 had coronary artery disease and 11 (Group I) had no cardiovascular disease. Micromanometer left ventricular pressure was recorded simultaneously with Doppler echocardiograms of mitral valve inflow and M-mode echocardiograms of left ventricular diameter. The chamber stiffness constant (k) was derived from the pressure-diameter relation. Relaxation was assessed by the isovolumic relaxation time constant (tau) derived from the exponential left ventricular pressure decay. The patients with coronary artery disease were classified into two groups on the basis of complete (Group II; n = 10) and incomplete (Group III; n = 14) relaxation. In Group I (no coronary disease), significant correlations were demonstrated between the chamber stiffness constant and the peak early filling velocity (r = 0.73; p less than 0.02), peak early to atrial filling velocity ratio (r = 0.82; p less than 0.005), atrial time-velocity integral (r = -0.73; p less than 0.02), early to atrial time-velocity integral ratio (r = 0.70; p less than 0.05), percent atrial contribution to filling (r = -0.64; p less than 0.05) and one-half filling fraction (r = 0.73; p less than 0.02). In Group II (coronary disease with complete relaxation), the chamber stiffness constant correlated with peak early filling velocity (r = 0.68; p less than 0.05), early filling time-velocity integral (r = 0.65; p less than 0.05) and early to atrial time-velocity integral ratio (r = 0.74; p less than 0.02). No correlations between k and Doppler indexes were found in Group III (coronary disease with incomplete relaxation). However, Group III demonstrated significant correlations between tau and the peak early filling velocity (r = -0.71; p less than 0.005), percent atrial contribution to filling (r = 0.56; p less than 0.05) and mean acceleration rate of early filling (r = -0.79; p less than 0.002). Thus, in subjects with normal relaxation, increasing chamber stiffness was associated with an enhanced peak early filling velocity and volume and decreased filling during atrial systole. This finding differs strikingly from the proposed influence of chamber stiffness on diastolic filling postulated by several researchers.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of pharmacologic coronary hyperemia on echocardiographic left ventricular function in patients with single vessel coronary artery disease.

To assess whether pharmacologic coronary vasodilation could provoke new left ventricular wall motion abnormalities in patients with single vessel coronary artery disease, systemic hemodynamics, coronary blood flow velocity and left ventricular wall motion were measured by two-dimensional echocardiography during administration of 10 mg of intracoronary papaverine in 14 patients before and again immediately after left coronary angioplasty (group 1). As a comparison with an intravenous method, left ventricular wall motion was analyzed after 0.56 mg/kg body weight of intravenous dipyridamole in a separate group of 13 patients with single vessel coronary disease (group 2). Heart rate-blood pressure product increased 3% to 6% in papaverine-treated patients and 14 +/- 11% (p = NS) in dipyridamole-treated patients. No angiographic collateral vessels were present in either group. Although intracoronary mean flow velocity measured in the 14 group 1 patients and in 5 normal control subjects during papaverine treatment increased from 125% to 400% of basal flow velocity, papaverine induced new left ventricular wall motion abnormalities in only 5 of the 14 patients before coronary angioplasty. In three of five patients, left ventricular wall motion abnormalities persisted after successful coronary angioplasty. Four of the 14 patients demonstrated augmentation of left ventricular wall motion with papaverine. After intravenous dipyridamole, only 3 of the 13 group 2 patients developed new left ventricular regional asynergy. These data suggest that selective (papaverine) and, most likely, global (dipyridamole) augmentation of coronary flow alone does not reliably identify potential ischemic left ventricular regions affected by critical single vessel coronary artery disease.

The hemodynamic benefit of differential atrioventricular delay intervals for sensed and paced atrial events during physiologic pacing.

The ability to program different atrioventricular (AV) delay intervals for paced and sensed atrial events is incorporated in the design of some newer dual chamber pacemakers. However, little is known regarding the hemodynamic benefit of differential AV delay intervals or the magnitude of difference between optimal AV delay intervals for paced and sensed P waves in individual patients. In this study, Doppler-derived cardiac output was used to examine the optimal timing of paced and sensed atrial events in 24 patients with a permanent dual chamber pacemaker. The hemodynamic effect of utilizing separate optimal delay intervals for sensed and paced events compared with utilizing the same fixed AV delay interval for both was determined. The optimal delay interval during DVI (AV sequential) pacing and VDD (atrial triggered, ventricular inhibited) pacing at similar heart rates was 176 +/- 44 and 144 +/- 48 ms (p less than 0.002), respectively. The mean difference between the optimal AV delay intervals for sensed (VDD) and paced (DVI) P waves was 32 ms and was up to 100 ms in some individuals. The difference between optimal AV delay intervals for sensed and paced atrial events was similar in patients with complete heart block and those with intact AV node conduction. At the respective optimal AV delay intervals for sensed and paced P waves, there was no significant difference in the cardiac output during VDD compared with DVI pacing. However, cardiac output significant declined during VDD pacing at the optimal AV delay interval for a paced event and during DVI pacing at the optimal interval for a sensed event.(ABSTRACT TRUNCATED AT 250 WORDS)

Opacification and border delineation improvement in patients with suboptimal endocardial border definition in routine echocardiography: results of the Phase III Albunex Multicenter Trial.

OBJECTIVES: This study was designed to assess the safety and efficacy of intravenously administered sonicated human serum albumin for enhancing echocardiographic delineation of the left ventricular endocardium and improving assessment of wall motion in patients with incomplete depiction of noncontrast echocardiography. BACKGROUND: Echocardiographic regional wall motion analysis is impaired by incomplete endocardial definition in as many as 10% of patients. Sonicated human serum albumin is a stable contrast material that, unlike other agents, opacifies the left ventricle when administered intravenously. METHODS: One hundred seventy-five patients were enrolled at eight centers on the basis of incomplete echocardiographic endocardial depiction. Sonicated 5% human serum albumin, a stable preparation of air-filled microspheres (size range 1 to 10 microns), was administered intravenously in divided doses: 0.08 ml/kg body weight in all patients, followed by 0.14 and 0.08 ml/kg or a single dose of 0.22 ml/kg, depending on the result of the initial dose. Investigators and independent reviewers blinded to the protocol scored the echocardiograms for degree of left ventricular opacification and improvement of endocardial border depiction. RESULTS: Overall, 81% of patients had at least moderate left ventricular chamber opacification with at least one contrast dose, and endocardial definition was improved in 83%. In the subgroup with inadequate left ventricular opacification from the initial dose, a second, larger dose (0.22 ml/kg) improved endocardial depiction in 64%. No significant side effects occurred. CONCLUSIONS: In patients with incomplete echocardiographic endocardial definition, sonicated human serum albumin is a safe, effective contrast agent that, when administered intravenously, produces left ventricular chamber opacification, improves endocardial depiction and enhances regional wall motion analysis.

Analysis of coronary blood flow velocity dynamics in angiographically normal and stenosed arteries before and after endolumen enlargement by angioplasty.

OBJECTIVES: This study was designed to assess whether the spectral waveform of coronary velocity on Doppler study is characteristically altered in the presence of significant stenosis with normalization of the spectral waveform after relief of endolumen obstruction. BACKGROUND: Although coronary flow reserve determinations have provided physiologic information complementary to the angiographic percent diameter narrowing, flow velocity measurements have been limited to proximal arteries with inconsistent results after angioplasty. A 12-MHz Doppler guide wire permits flow velocity determination in the proximal and distal coronary artery with fast Fourier spectral analysis. METHODS: With the Doppler guide wire, proximal arterial flow velocity and flow reserve measurements in 17 angiographically normal arteries were compared with measurements in 29 significantly stenosed arteries. Proximal and distal flow velocity measurements were also obtained before and after angioplasty of the 29 abnormal arteries. Velocity spectrum was digitized to compute peak diastolic velocity, peak systolic velocity, mean velocity, diastolic/systolic velocity ratio and first third and first half flow fraction. RESULTS: Compared with proximal stenosed arteries, proximal normal arteries had significantly higher peak diastolic velocity (64 +/- 26 cm/s vs. 41 +/- 26 cm/s) and higher coronary vasodilator reserve (2.3 +/- 0.8 vs. 1.6 +/- 0.7). Normal arteries had higher flows in the first third and first half of the coronary cycle (46 +/- 3% vs. 39 +/- 7% and 65 +/- 2% vs. 56 +/- 10%, respectively). Before angioplasty, coronary velocity variables were significantly lower distal than proximal to the stenosis. After angioplasty, there was a greater mean increase in distal velocities (200% vs. 90% for the proximal arteries) that resulted in near equalization of proximal and distal mean velocity and a significant reduction in proximal/distal mean velocity ratio (2.4 +/- 1.7 vs. 1.2 +/- 0.4). CONCLUSIONS: Before angioplasty, abnormal coronary flow velocity dynamics are more marked distal than proximal to the stenosis. Greater increase in coronary flow velocities in the distal circulation after relief of endolumen obstruction results in a significant reduction in the proximal/distal flow velocity ratio. Thus, normalization of Doppler-derived flow velocity variables with marked reduction of the proximal/distal flow velocity ratios parallels angiographic success and may prove useful as an additional end point measurement in interventional cases with questionable angiographic findings.

Quantitative evaluation of aortic insufficiency by continuous wave Doppler echocardiography.

To assess the usefulness of continuous wave Doppler echocardiography in the evaluation of aortic insufficiency, the aortic regurgitant flow velocity pattern obtained with continuous wave Doppler examination was compared with the results of aortography and conventional pulsed Doppler techniques in 25 individuals with aortic insufficiency. The diastolic deceleration slope as measured from the continuous wave tracing was significantly different among subgroups of patients with mild (1.6 +/- 0.5 m/s2), moderate (2.7 +/- 0.5 m/s2) and severe (4.7 +/- 1.5 m/s2) aortic insufficiency as determined from aortography. Deceleration slopes greater than 2 m/s2 separated individuals with moderate and severe insufficiency from those with mild insufficiency. Similar findings were seen when comparing the pressure half-time method of diastolic velocity decay with the more severe grades of aortic insufficiency exhibiting the shortest pressure half-times. There was also a high correlation (r = 0.85) between the deceleration slope measured by continuous wave Doppler recordings and the grade of insufficiency as assessed by pulsed Doppler echocardiography. End-diastolic velocities correlated poorly (r = 0.28) with catheter-measured end-diastolic pressure difference between the aorta and the left ventricle. These findings demonstrate that the aortic regurgitant flow pattern by continuous wave Doppler echocardiography may be useful in quantitating the degree of aortic insufficiency by assessing the rate with which aortic and left ventricular pressures equilibrate during diastole.

Immediate and short-term effects of aortic balloon valvuloplasty on left ventricular diastolic function and filling in humans.

The effect of aortic balloon valvuloplasty on left ventricular diastolic function and filling was investigated in 44 adult patients with severe aortic stenosis. Two-dimensional and Doppler echocardiography was performed in all patients before and 24 h after valvuloplasty. In 19 patients (short-term group) repeat studies were performed at 3 (n = 2) and 6 (n = 17) months. Left ventricular relaxation, chamber stiffness and filling were assessed in 16 patients (immediate post-valvuloplasty group) before and immediately after valvuloplasty by simultaneous micromanometer left ventricular pressure tracings and echocardiograms. Immediately after valvuloplasty, relaxation was slightly impaired in the immediate post-valvuloplasty group, as reflected by the isovolumic relaxation time constant (56 +/- 26 to 68 +/- 39 ms; p less than 0.01) and maximal negative dP/dt (2,063 +/- 640 to 1,767 +/- 495 mm Hg/s; p less than 0.001). The chamber stiffness constants and diastolic filling dynamics were unchanged immediately after valvuloplasty. Twenty-four hours after valvuloplasty, patients without mitral regurgitation (n = 24) showed increases in the peak early filling velocity (72 +/- 31 to 83 +/- 28 cm/s; p less than 0.05) and peak early to atrial filling velocity ratio (0.8 +/- 0.6 to 1.0 +/- 0.7; p less than 0.05). However, in patients with mitral regurgitation (n = 20), the diastolic filling dynamics were not significantly changed. In the short-term group at the 3 to 6 month follow-up period, patients without mitral regurgitation (n = 12) showed striking increases compared with pre-valvuloplasty values in the peak early filling velocity (66 +/- 21 to 93 +/- 31 cm/s; p less than 0.02), peak early to atrial filling velocity ratio (0.6 +/- 0.2 to 0.9 +/- 0.4; p less than 0.02) and early time-velocity integral (9 +/- 4 to 16 +/- 6 cm; p less than 0.002). In patients with mitral regurgitation (n = 7) decreases occurred in the peak early filling velocity (123 +/- 32 to 106 +/- 28 cm/s; p less than 0.05) and peak early to atrial filling velocity ratio (1.5 +/- 0.7 to 1.1 +/- 0.6; p less than 0.05). Functional class in hospital improved after valvuloplasty (3.1 +/- 1.0 to 2.6 +/- 0.9; p less than 0.001) and correlated modestly with the percent decrease in Doppler-derived peak gradient (rs = 0.41, p less than 0.02) and mean gradient (rs = 0.36, p less than 0.05), but did not correlate with changes in aortic valve area, left ventricular ejection fraction or diastolic filling variables.(ABSTRACT TRUNCATED AT 400 WORDS)