Search PubMed⌕ Search

Biomedical subjects

J Kisslo

Publications and source records attributed to J Kisslo.

At least 19 recordsLinked to original sources
PubMed2001

Real-time, volumetric echocardiography: usefulness of volumetric scanning for the assessment of cardiac volume and function.

BACKGROUND: A novel imaging system has been introduced which uses a dedicated two-dimensional echo probe for rapid beam forming to scan a pyramidal volume in real time. Real-time volumetric echocardiography has the potential to determine accurate cardiovascular anatomy, volume and function in the beating heart without reconstructions. The results of animal and human studies using volumetric echocardiography are evaluated for the potential for clinical applications. IMAGING METHODOLOGY: A new type of ultrasound imaging, high-speed volumetric scanning based on phased array principles permits real-time three-dimensional, volumetric echocardiography (real-time 3-DE). The system requires no off-line reconstruction techniques, thus enabling dynamic three-dimensional visualization and quantification of the heart in real time using a transthoracic approach. Real-time 3-DE uses a 2-D matrix phased array transducer. Image formation employs 16:1 parallel processing to scan a pyramidal volume composed of multiple steering directions in the azimuth dimension and in the elevation dimension. The finished transducer is mounted in a hand-held case with a circular aperture of 16 mm diameter. The array consists of approximately 1,600 elements, operating at 2.5 MHz. Real-time 3-DE permits simultaneous, multiple plane display of two sector arcs (B-scans) and C-scan (parallel to the transducer face or inclined) on a single monitor, conveying the three-dimensional nature of the ultrasound data. This system also allows these planes to be angled for extra diagnostic flexibility. The motion of all the structures during the cardiac cycle can be evaluated in dynamic mode. METHODS: Real-time 3-DE was assessed for accuracy of volume measurement by measuring the volume of balloons of different size and shape, and the hearts of 15 closed chest dogs with myocardial contrast enhancement, and compared to the volumes measured by left ventricular angiography in the dogs. Real-time 3-DE was used to evaluate the endocardial border determination of the entire left ventricle by injecting contrast agent in 12 patients. The endocardial border determination of each segment was scored, and the endocardial border score index calculated. Both real-time 3-D images and cine magnetic resonance imaging (MRI) were performed in 16 patients to assess the accuracy of volume measurement of the left ventricle in humans. The endocardial border of the left ventricle was manually traced, and the volumes calculated by Simpson's rule. RESULTS: The volumes measured by real-time 3-DE correlated well with the true volumes for different sizes of balloon and for asymmetric balloons. The end-diastolic volume and end-systolic volume linear correlation of real-time 3-DE versus angiography measurements using manual tracing in vivo also gave a good correlation (r = 0.97, p < 0.001; r = 0.92, p < 0.01). Fifty-eight of 192 segments were rated as good at baseline and 143 rated as good after Levovist injection. Endocardial border determination was improved by Levovist injection in 100 of 137 segments (74.6%). The endocardial border score index was significantly higher after Levovist administration than at baseline (p < 0.003). The end-diastolic volume and end-systolic volume of the left ventricle measured by real-time 3-DE in humans correlated well with those measured by MRI (end-diastolic volume: r = 0.97, p < 0.001; end-systolic volume: r = 0.96, p < 0.001). CONCLUSIONS: Transthoracic real-time, volumetric echocardiography opens a new and exciting field of echocardiography. The results of these studies demonstrate that this system can accurately measure the ventricular volume and function without use of geometric assumptions. This volumetric mode or V-mode scanning is a new imaging modality that provides a practical methodology to investigate important clinical and research questions.

Animals↗
PubMed2000

Fenfluramine and phentermine and cardiovascular findings: effect of treatment duration on prevalence of valve abnormalities.

BACKGROUND: The combination of fenfluramine and phentermine was a widely used obesity treatment before the withdrawal of fenfluramine for an association with heart valve regurgitation. The prevalence and clinical significance of regurgitation among patients treated with these medications has yet to be fully established. METHODS AND RESULTS: To evaluate the potential association between the duration of treatment and the prevalence of heart valve abnormalities, we examined 1163 patients who had taken fenfluramine-phentermine and 672 control patients who had not taken the drug combination within 5 years. Mild or greater aortic regurgitation was present in 8.8% of treated patients and 3.6% of control patients (P<0.001). Moderate or greater mitral regurgitation was present in 2.6% of treated patients and 1.5% of control patients (P=0.18). The adjusted odds ratio compared with controls of aortic regurgitation of mild or greater severity increased according to duration of treatment: 90 to 180 days, 1.5 (P=0.23); 181 to 360 days, 2.4 (P=0.002); 361 to 720 days, 4.6 (P<0.001); >720 days, 6.2 (P<0.001). CONCLUSIONS: This is the largest study to demonstrate a relation between the length of treatment with fenfluramine-phentermine and the prevalence of valvular abnormalities. These findings suggest that valvular abnormalities in patients who took fenfluramine-phentermine primarily involve those who had taken these medications for >6 months and predominantly results in mild aortic regurgitation. The valve regurgitation identified by this study was not accompanied by significant differences in cardiovascular symptoms nor physical findings other than a higher prevalence of heart murmurs.

Aortic Valve Insufficiency↗
PubMed2000

Clinical information determines the impact of transesophageal echocardiography on the diagnosis of infective endocarditis by the duke criteria.

BACKGROUND: Although transesophageal echocardiography (TEE) is more sensitive than transthoracic echocardiography (TTE) in detecting echocardiographic evidence of infective endocarditis (IE), the impact of TEE on the clinical diagnosis of IE has not been clearly delineated. METHODS AND RESULTS: We studied 112 patients with 114 suspected episodes of IE over a 6-year period who underwent both TTE and TEE during their diagnostic evaluation. Using the results of these studies along with clinical and microbiologic data, we attempted to determine the incremental value of TEE to the Duke Endocarditis Diagnostic Criteria. Patients were initially classified into a diagnostic category of the Duke criteria with TTE data, and then the diagnostic classification was reconsidered with TEE data. A diagnostic category reassignment occurred in 25 of 114 episodes of IE evaluated when TEE results were incorporated into the evaluation with the Duke criteria (22 patients were reclassified from possible IE to definite IE whereas 3 patients were reclassified from rejected to possible IE). Diagnostic reclassification occurred in 9 (11%) of the 80 episodes of suspected IE with native cardiac valves and 13 (34%) of 34 episodes with prosthetic cardiac valves. Most patients reclassified from possible IE to definite IE with TEE data (19 of 22) had an intermediate clinical likelihood of IE, whereas 92% of patients had negative TTE results. Pathologic examination of valvular tissue in 22 of the 114 episodes of suspected IE revealed that the positive predictive value of the Duke criteria with TEE data for diagnosis of IE was 85% in patients with native valves and 89% in patients with prosthetic valves. CONCLUSIONS: When clinical evidence of IE is present, TEE improves the sensitivity of the Duke criteria to diagnose definite IE. TEE data appears to be especially useful for the diagnostic evaluation of patients with suspected IE who have prosthetic valves.

Diagnosis, Differential↗
PubMed2000

Real-time 3-dimensional echocardiography evaluation of congenital heart disease.

We evaluated the ability of real-time 3-dimensional (RT3D) echocardiography to diagnose congenital heart defects and its potential for presenting structural abnormalities in novel views. Seventy-five patients with suspected congenital heart defects were examined with the use of RT3D echocardiography. Images were reviewed off-line as multiple slices of the raw data or as volume-rendered images by a blinded observer. Diagnoses made from blinded review of the RT3D images were compared with the clinical report of the 2D echocardiogram obtained at the same visit. Real-time 3D echocardiography identified all structural abnormalities except for small atrial septal defects in 2 patients and coronary artery anatomy in D-transposition of the great arteries. Less than 5 minutes were needed to acquire RT3D images in all cases, and sedation was never required. Unique region-oriented views obtained from the 3D data set can be acquired quickly and have the potential to enhance understanding of complex cardiac anatomy.

Adolescent↗
PubMed2000

Real-time volumetric echocardiography: the technology and the possibilities.

The heart is a dynamic organ with complexities in its shape. As such, it places special demands on three-dimensional techniques for reconstruction. Real-time volumetric echocardiography, which is based on phased array and parallel processing principles to enhance line density within a scan volume, provides rapid image acquisition. We introduce the principle, potential clinical importance, current limitations, and future of volumetric imaging methods.

Echocardiography, Three-Dimensional↗
PubMed1999

Familial hypertrophic cardiomyopathy and atrial fibrillation caused by Arg663His beta-cardiac myosin heavy chain mutation.

More than 40 different beta-cardiac myosin heavy chain (beta-MHC) missense mutations have been identified that cause familial hypertrophic cardiomyopathy (FHC). Some of these are recognized to have important clinical manifestations, such as an increased incidence of sudden death. We report that the beta-MHC missense mutation Arg663His causes predominant cardiac morphology and atrial fibrillation. Longitudinal clinical evaluations were performed in a kindred with FHC. The nucleotide sequence of the beta-MHC gene was analyzed to define the causal mutation. A missense mutation in the beta-MHC gene, Arg663His, was identified in 24 individuals. Clinical studies demonstrated modest left ventricular hypertrophy in affected individuals, predominantly localized in the proximal segment of the interventricular septum, which increased (average = 40 +/- 8%) during 7 years of follow-up. Results showed that 47% of Arg663His adults (age > 16 years) with ventricular hypertrophy developed atrial fibrillation, significantly more (p <0.001) than observed in ungenotyped FHC populations. Survival of affected individuals remained near normal. The beta-MHC missense mutation Arg663His causes a characteristic pattern of ventricular hypertrophy. Arg663His individuals have a markedly higher prevalence of atrial fibrillation, compared with a population with ungenotyped hypertrophic cardiomyopathy. The demonstration of phenotype as a direct consequence of genotype further extends the utility of molecular data in clinical medicine. Early identification of Arg663His individuals has the potential to minimize the serious sequelae of this arrhythmia in this FHC group.

Adolescent↗
PubMed1999

Real-time, three-dimensional echocardiography: feasibility of dynamic right ventricular volume measurement with saline contrast.

BACKGROUND: The asymmetry and complex shape of the right ventricle have made it difficult to determine right ventricular (RV) volume with 2-dimensional echocardiography. Three-dimensional cardiac imaging improves visualization of cardiac anatomy but is also complex and time consuming. A newly developed volumetric scanning system holds promise of obviating past limitations. METHODS: Real-time, transthoracic 3-dimensional echocardiographic images of the right ventricle were obtained with a high-speed volumetric ultrasound system that uses a 16:1 parallel processing schema from a 2.5 MHz matrix phased-array scanner to interrogate an entire pyramidal volume in real time. The instrumentation was used to measure RV volume in 8 excised canine hearts; dynamic real-time 3-dimensional images were also obtained from 14 normal subjects. RESULTS: Three-dimensional images were obtained in vitro and in vivo during intravenous hand-agitated saline injection to determine RV volumes. The RV volumes by real-time 3-dimensional echocardiography are well correlated with those of drained in vitro (y = 1.26x - 9.92, r = 0.97, P <.0001, standard error of the estimate = 3.26 mL). For human subjects, the end-diastolic and end-systolic RV volumes were calculated by tracing serial cross-sectional, inclined C scans; functional data were validated by comparing the scans with conventional 2-dimensional echocardiographic indexes of left ventricular stroke volume. CONCLUSIONS: These data indicate that RV volume measurements of excised heart by real-time 3-dimensional echocardiography are accurate and that beat-to-beat RV quantitative measurement applying this imaging method is possible. The new application of real-time 3-dimensional echocardiography presents the opportunity to develop new descriptors of cardiac performance.

Animals↗
PubMed1999

Assessment of regional wall motion abnormalities with real-time 3-dimensional echocardiography.

Accurate characterization of regional wall motion abnormalities requires a thorough evaluation of the entire left ventricle (LV). Although 2-dimensional echocardiography is frequently used for this purpose, the inability of tomographic techniques to record the complete endocardial surface is a limitation. Three-dimensional echocardiography, with real-time volumetric imaging, has the potential to overcome this limitation by capturing the entire volume of the LV and displaying it in a cineloop mode. The purpose of this study was to assess the feasibility of using real-time 3-dimensional (RT3D) echocardiography to detect regional wall motion abnormalities in patients with abnormal LV function and to develop a scheme for the systematic evaluation of wall motion by using the 3-dimensional data set. Twenty-six patients with high-quality 2-dimensional echo images and at least 1 regional wall motion abnormality were examined with RT3D echocardiography. For 2-dimensional echocardiography, wall motion was analyzed with a 16-segment model and graded on a 4-point scale from normal (1) to dyskinetic (4), from which a wall motion score index was calculated. Individual segments were then grouped into regions (anterior, inferoposterior, lateral, and apical) and the number of regional wall motion abnormalities was determined. The RT3D echocardiogram was recorded as a volumetric, pyramid-shaped data set that contained the entire LV. Digital images, consisting of a single cardiac cycle cineloop, were analyzed off-line with a computerized display of the apical projection. Two intersecting orthogonal apical projections were simultaneously displayed in cineloop mode, each independently tilted to optimize orientation and endocardial definition. The 2 planes were then slowly rotated about the major axis to visualize the entire LV endocardium. Wall motion was then graded in 6 equally spaced views, separated by 30 degrees, yielding 36 segments per patient. A higher percentage of segments were visualized with 2-dimensional versus RT3D echocardiography (97% vs 83%, respectively, P <.001). With the use of the 2-dimensional echocardiographic results as the standard, RT3D echocardiography detected 55 (96%) of 57 regional wall motion abnormalities. Analysis of the RT3D echocardiograms resulted in 3 false-negative and 5 false-positive findings. The total number of regional wall motion abnormalities was correctly classified by RT3D echocardiography in 19 (73%) of 26 patients. RT3D echocardiography detected 11 of 13 anterior, 19 of 20 inferoposterior, 9 of 9 lateral, and 15 of 15 apical wall motion abnormalities. An excellent correlation was found between the 2 techniques for assessment of the regional wall motion score index (r = 0.89, P <.001). This initial clinical study demonstrates the feasibility and potential advantages of RT3D echocardiography for the assessment of regional LV function. Compared with 2-dimensional echocardiography, this new method permits recording of the entire LV in a single beat, allowing the extent and location of the regional wall motion abnormalities to be determined.

Cardiomyopathy, Dilated↗
PubMed1998

Real-time three-dimensional echocardiography for determining right ventricular stroke volume in an animal model of chronic right ventricular volume overload.

BACKGROUND: The lack of a suitable noninvasive method for assessing right ventricular (RV) volume and function has been a major deficiency of two-dimensional (2D) echocardiography. The aim of our animal study was to test a new real-time three-dimensional (3D) echo imaging system for evaluating RV stroke volumes. METHODS AND RESULTS: Three to 6 months before hemodynamic and 3D ultrasonic study, the pulmonary valve was excised from 6 sheep (31 to 59 kg) to induce RV volume overload. At the subsequent session, a total of 14 different steady-state hemodynamic conditions were studied. Electromagnetic (EM) flow probes were used for obtaining aortic and pulmonic flows. A unique phased-array volumetric 3D imaging system developed at the Duke University Center for Emerging Cardiovascular Technology was used for ultrasonic imaging. Real-time volumetric images of the RV were digitally stored, and RV stroke volumes were determined by use of parallel slices of the 3D RV data set and subtraction of end-systolic cavity volumes from end-diastolic cavity volumes. Multiple regression analyses showed a good correlation and agreement between the EM-obtained RV stroke volumes (range, 16 to 42 mL/beat) and those obtained by the new real-time 3D method (r=0.80; mean difference, -2.7+/-6.4 mL/beat). CONCLUSIONS: The real-time 3D system provided good estimation of strictly quantified reference RV stroke volumes, suggesting an important application of this new 3D method.

Animals↗
PubMed1997

Influences of ultrasonic machine settings, transducer frequency and placement of region of interest on the measurement of integrated backscatter and cyclic variation.

Integrated backscatter and its cyclic variation are potentially important parameters to discriminate normal from diseased myocardium. Cyclic variation of integrated backscatter is expected to be independent of machine settings. Backscatter images of swine hearts were taken using a two-dimensional backscatter system while acoustic power was varied at different time gain control (TGC) settings. Cyclic variation was measured in vivo with various acoustic power and TGC settings using different transducer frequencies. Three different regions were analyzed. For any given TGC setting, the relationship between acoustic power and integrated backscatter in vitro was linear only over a narrow range. In vivo, cyclic variation was present at all regions studied in both long- and short-axis views. However, lower acoustic power (< 15 dB) and TGC (< 20 dB), or excessive settings of acoustic power (> 35 dB) and TGC (> 50 dB), produced minimal cyclic variation. Appropriate acoustic power (20-35 dB) and TGC (30-50 dB) produced larger and more consistent cyclic, variation at the posterior region of the left ventricle. These data indicate that each region has specific, appropriate machine settings to maximize the magnitude of cyclic variation.

Acoustics↗
PubMed1996

Evaluation of the effect of transthoracic cardioversion from ventricular tachycardia to sinus rhythm on left atrial mechanical function.

We measured left atrial function during sinus rhythm before and after ventricular tachycardia was induced in an electrophysiology laboratory, using peak transmitral A-wave velocity from pulsed-Doppler transthoracic echocardiography as a marker of left atrial mechanical function. The results of this prospective study do not support the hypothesis that a transthoracic shock of mild to moderate energy diminishes atrial mechanical function.

Adolescent↗
PubMed1996

Negative predictive value of the Duke criteria for infective endocarditis.

With use of new Duke criteria, 405 episodes of suspected endocarditis were previously classified as "definite," "possible," or "rejected" endocarditis. To determine the negative predictive value of the Duke clinical criteria for the classification of suspected endocarditis, chart review and follow-up were performed for the 52 episodes in which the diagnosis of endocarditis was rejected. Three of 52 episodes were reclassified to possible endocarditis; 49 episodes in 48 patients met the criteria for rejected endocarditis. Of these 49 episodes, 31 (63%) had a firm alternate diagnosis other than endocarditis, 17 (35%) had resolution of the clinical syndrome leading to the suspicion of endocarditis with < or = 4 days of antibiotics, and 1 patient had no evidence of endocarditis at surgery. Echocardiograms recorded in 3 patients with rejected endocarditis had evidence of oscillating valvular masses, and blood cultures were positive in 13 episodes; none of these patients had evidence of endocarditis at follow-up. Follow-up or outcome information was available in all 49 episodes. Excluding the 5 in-hospital deaths, mean duration (+/- SD) of follow-up was 39.9 +/- 28.8 months (range 0.5 to 108.0); in living patients, mean time to final follow-up was 56.2 +/- 25.2 months (range 25.0 to 108.0). One patient had possible infective endocarditis at autopsy. No patient in our series whose diagnosis of endocarditis had been rejected had proven endocarditis. Therefore, the negative predictive value of the Duke clinical criteria for endocarditis is at least 92%.

Adult↗
PubMed1995

Transesophageal echocardiographic assessment of reversal of systolic pulmonary venous flow in mitral stenosis.

Transesophageal echocardiography and diagnostic cardiac catheterization were performed in 36 patients with symptomatic mitral stenosis to assess the incidence and significance of systolic flow reversal in the pulmonary veins. Mitral regurgitation was graded by contrast ventriculography, and left atrial pressure was directly measured after transseptal puncture. Pulmonary venous flow was recorded with transesophageal Doppler imaging from the left upper pulmonary vein. Early systolic flow reversal was identified in 11 patients (31%) and began an average of 58 +/- 13 ms after QRS onset. This pattern correlated strongly with the presence of atrial fibrillation or flutter. Late systolic flow reversal was identified in 8 patients (22%), beginning an average of 245 +/- 46 ms after the QRS complex. These patients had higher left atrial V-wave pressure (36 +/- 10 vs 29 +/- 8 mm Hg; p < 0.05) and V-wave peak-X-descent trough (18 +/- 7 vs 11 +/- 5 mm Hg; p < 0.01) than patients without systolic flow reversal. Neither pattern of pulmonary venous flow reversal was related to the severity of angiographic mitral regurgitation. Systolic reversal of pulmonary venous flow is not specific for angiographically severe mitral regurgitation in patients with mitral stenosis. Similar limitations to pulmonary venous flow analysis likely apply to other patient groups with elevated left atrial pressure and poor left atrial compliance.

Adult↗
PubMed1995

Hypotension during dobutamine stress echocardiography: is it related to dynamic intraventricular obstruction?

Although it has been shown that a hypotensive response during dobutamine stress echocardiography is not a marker of coronary artery disease, the mechanism of this response remains unclear. We hypothesize that hypotension during dobutamine stress echocardiography is not related to the development of dynamic intraventricular obstruction. The development of left ventricular outflow obstruction was defined as a late-peaking Doppler velocity profile that exceeded baseline outflow velocity by at least 1 m/sec in 104 consecutive patients undergoing dobutamine stress echocardiography. Left ventricular outflow obstruction was seen in 13% of 15 patients with a hypotensive response (group 1) and in 13% of 89 patients without a hypotensive response (group 2). The mean baseline systolic blood pressure was 157 +/- 21 mm Hg in group 1 compared to 139 +/- 25 mm Hg in group 2 (p = 0.008). An ischemic response to dobutamine infusion as manifested by the development of new or worsening wall motion abnormalities was seen in 40% of group 1 patients and 34% of group 2 patients (p = 0.77). These data demonstrate that a hypotensive response is not related to the development of dynamic intraventricular obstruction during dobutamine stress echocardiography. Rather, there is a significant association between a higher baseline systolic blood pressure and a hypotensive response during dobutamine infusion.

Adult↗
PubMed1995

Effect of dobutamine stress echocardiography on mitral regurgitation.

OBJECTIVES: This study was performed to examine the effect of dobutamine stress echocardiography on mitral regurgitation and to test the hypothesis that mitral regurgitation will increase in patients with an ischemic response. BACKGROUND: New or worsening mitral regurgitation during stress testing has been proposed as a marker of ischemia. However, it is unclear whether ischemia induced by dobutamine is associated with mitral regurgitation because the hemodynamic effects of dobutamine may vary with regard to mitral regurgitation, depending on left ventricular function and maximal dose attained. METHODS: Dobutamine stress echocardiography was performed in 102 consecutive patients with suspected or known coronary artery disease. Color flow Doppler was used to determine the presence and change in mitral regurgitation at baseline and peak dobutamine infusion (up to 40 micrograms/kg body weight per min). The mitral regurgitation color flow Doppler area was semiquantitatively graded as mild (< 4 cm2), moderate (4 to 8 cm2) or severe (> 8 cm2). Patients were assigned to ischemic and nonischemic groups according to the dobutamine stress echocardiographic results. RESULTS: The two groups achieved the same maximal dose and demonstrated similar blood pressure and heart rate responses to dobutamine infusion. Only two patients developed new mitral regurgitation during dobutamine infusion, and both had a normal dobutamine echocardiographic result. More patients without ischemia had no mitral regurgitation compared with patients with ischemia. There was an insufficient number of patients with coronary angiographic data to determine the effects of mitral regurgitation on the sensitivity and specificity of dobutamine stress echocardiography. Of 23 patients with a rest ejection fraction < 50%, 61% had an improvement in mitral regurgitation grade compared with 25% of patients with a rest ejection fraction > or = 50% (p < 0.02). CONCLUSIONS: These data indicate that although dobutamine infusion often improves mitral regurgitation in patients with left ventricular dysfunction during stress echocardiography, it does not induce or worsen mitral regurgitation in those who demonstrate an ischemic response. Future studies are necessary, with large numbers of patients, to determine the effects of mitral regurgitation on the sensitivity and specificity of dobutamine stress echocardiography.

Adult↗