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Pittman LA, Whittaker P, Milne ML, Chung CS. Collagenase treatment reduces the anisotropy of ultrasonic backscatter in rat myocardium by reducing collagen crosslinks. Physiol Rep 2023; 11:e15849. [PMID: 37960992 PMCID: PMC10643982 DOI: 10.14814/phy2.15849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 10/19/2023] [Accepted: 10/19/2023] [Indexed: 11/15/2023] Open
Abstract
Dysregulation of collagen deposition, degradation, and crosslinking in the heart occur in response to increased physiological stress. Collagen content has been associated with ultrasonic backscatter (brightness), and we have shown that the anisotropy of backscatter can be used to measure myofiber alignment, that is, variation in the brightness of a left ventricular short-axis ultrasound. This study investigated collagen's role in anisotropy of ultrasonic backscatter; female Sprague-Dawley rat hearts were treated with a collagenase-containing solution, for either 10 or 30 min, or control solution for 30 min. Serial ultrasound images were acquired at 2.5-min intervals throughout collagenase treatment. Ultrasonic backscatter was assessed from anterior and posterior walls, where collagen fibrils are predominately aligned perpendicular to the angle of insonification, and the lateral and septal walls, where collagen is predominately aligned parallel to the angle of insonification. Collagenase digestion reduced backscatter anisotropy within the myocardium. Collagen remains present in the myocardium throughout collagenase treatment, but crosslinking is altered within 10 min. These data suggest that crosslinking of collagen modulates the anisotropy of ultrasonic backscatter. An Anisotropy Index, derived from differences in backscatter from parallel and perpendicularly aligned fibers, may provide a noninvasive index to monitor the progression and state of myocardial fibrosis.
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Affiliation(s)
| | | | - Michelle L. Milne
- Department of PhysicsSt Mary's College of MarylandSt Mary's CityMarylandUSA
| | - Charles S. Chung
- Department of PhysiologyWayne State UniversityDetroitMichiganUSA
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Xiaoqing W, Zhengyu Y, Dajung Q, Qiang W, Xiaoping B, Jianqiu Z. Very early stage detection of acute myocardial infarction by harmonic ultrasonic integrated backscatter. ULTRASOUND IN MEDICINE & BIOLOGY 2008; 34:567-572. [PMID: 18222030 DOI: 10.1016/j.ultrasmedbio.2007.09.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2007] [Revised: 08/13/2007] [Accepted: 09/27/2007] [Indexed: 05/25/2023]
Abstract
To study the very early diagnosis of acute myocardial infarction (AMI) by harmonic imaging ultrasonic integrated backscatter (IBS). Thirty normal persons, 68 cases with AMI, of whom 28 cases were at the very early stage of acute myocardial infarction (in 2 h), and 40 cases with acute myocardial infarction (in 2 to 12 h) were examined by IBS and the cyclic variation of integrated backscatter (CVIB) with HP-5500 ultrasonic system in different segment (the segment of myocardial infarction and no myocardial infarction). In the segment of AMI of the very early stage (in 2 h) the IBS (dB) is much higher than that of the segment of no AMI (18.7 versus 8.3), p < 0.001, the CVIB (dB) are lower (6.1 versus 7.6), p < 0.001. But at that time there are no obvious changes in ECG. In the other 40 cases with AMI in 2 to 12 h, IBS in the segment of AMI is obviously higher than the normal person and no infarction segment in the same heart (21.3:8.3, 20.2:8.5) p < 0.05, but CVIB (dB) is obviously lower than the normal person and no infarction segment in the same heart (5.8:7.6, 5.9:9.4) p < 0.05 the changes of the ultrasonic is coincidence with ECG. IBS (dB) are very obvious just as in ECG. The result demonstrates that ultrasonic tissue characterization with harmonic imaging integrated backscatter can be used for diagnosis in the very early stage of AMI, and can judge the segment range of AMI and function of the whole heart.
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Affiliation(s)
- Wu Xiaoqing
- The Cardiovascular Department of the No 1 Hospital of Wuxi of the Affiliated Hospital of Nanjing Medical University, Wuxi, Jiangsu, PR China.
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Yong J, Jing B, Kezheng C, Can Y. 2-D CVIB imaging in animal experiments. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2004:1419-22. [PMID: 17271960 DOI: 10.1109/iembs.2004.1403440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
To demonstrate the feasibility and validity of 2-D CVIB (Cyclic variation of Integrated Backscatter) imaging method, animal experiments were conducted. Among 10 anesthetized open-chest dogs, acute myocardial ischemia was induced by occluding left anterior descending coronary artery. While scanning normal hearts and ischemic hearts with the ultrasonic B scanner, digital radiofrequency data were acquired by a real-time acquisition system in synchronism. The offline analysis to the radio-frequency signal with the 2-D CVIB imaging method was performed to verify the consistency between the imaging results and the design of the experiments. The experimental results showed that the 2-D CVIB imaging method was successful in detecting the ischemic myocardium and might provide a new noninvasive way for the cardiologists to both quantitatively and visually evaluate the contractile performance of the myocardium.
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Affiliation(s)
- Jiang Yong
- Dept. of Biomed. Eng., Tsinghua Univ., Beijing, China
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Bai J, Jiang Y, Li X, Pan D, Hu G, He P. Novel ultrasonic fusion imaging method based on cyclic variation in myocardial backscatter. Med Biol Eng Comput 2002; 40:163-7. [PMID: 12043796 DOI: 10.1007/bf02348120] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Quantitative ultrasonic tissue characterisation of the myocardium based on integrated backscatter (IB) has the potential of becoming an effective method for detecting and evaluating myocardial ischaemia. To facilitate IB-based clinical applications, a new imaging method has been developed that combines the anatomical information of a B-mode image with the contractile performance of a selected myocardial region. To produce such a fusion image, a region of interest (ROI) in a B-mode cardiac image was first selected by the user. Algorithms for detection of the endocardium and epicardium were developed, and the resulting mean distance between the computer-detected curve and the manually traced curve was 0.83mm for the endocardium and 0.58mm for the epicardium. The cyclic variation of IB (CVIB) of each myocardial tissue element within the ROI was then calculated over one cardiac cycle. Finally, a grey-scale B-mode image at the end of diastole was displayed as a still image, and the pixels representing the myocardial tissue in the ROI colour-coded according to the corresponding CVIB over the past heart cycle. Both the B-mode image and the colour-coded region were refreshed (up-dated) at the next end-of-diastole. Preliminary results from normal (CVIB= 10-12dB) and ischaemic (CVIB = 5-7 dB) canine hearts are presented that demonstrate the utility of this new imaging method.
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Affiliation(s)
- J Bai
- Institute of Biomedical Engineering, Department of Electrical Engineering, Tsinghua University, Beijing, China.
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5
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Janerot-Sjöberg B, von Schmalensee N, Schreckenberger A, Richter A, Brandt E, Kirkhorn J, Wilkenshoff U. Influence of respiration on myocardial signal intensity. ULTRASOUND IN MEDICINE & BIOLOGY 2001; 27:473-479. [PMID: 11368860 DOI: 10.1016/s0301-5629(00)00327-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Echocardiographic quantification of myocardial perfusion after IV contrast is possible, based on the intensity of the received intermittent second harmonic signal. To investigate the influence of respiration on the intensity of myocardial signals, we examined nine patients with normal coronary angiograms. At baseline, end-expiratory and end-inspiratory images were obtained in broadband radiofrequency (RF) and intermittent second harmonic modes, the latter repeated during IV contrast at rest and at peak stress. In mid-septum at baseline, end-inspiratory integrated backscatter intensity was 4 dB higher (p < 0.05, both in second harmonic and fundamental domains) than end-expiratory intensity. In second harmonic imaging, contrast increased signal intensity by 4 dB (p < 0.05) in six examined segments, but the increase in the midseptal region (2 dB) was not significant. Contrast-enhanced intensity at end-inspiration was higher (3 dB, p < 0.01) than baseline intensity at end-expiration. We conclude that the increase in myocardial signal intensity during inspiration may resemble the contrast effect in intermittent second harmonic mode. The respiratory variation persists after contrast and may mask or exaggerate the effect of myocardial contrast.
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Affiliation(s)
- B Janerot-Sjöberg
- Department of Clinical Physiology, Linköping Heart Center, University of Health Sciences, Linköping, Sweden.
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Bom N, van der Steen AF, Nosir YF, Kasprzak JD. Studies of cardiac function and myocardial tissue characterization. Proc Inst Mech Eng H 2000; 214:141-9. [PMID: 10825772 DOI: 10.1243/0954411001535318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The heart can be studied using ultrasound techniques. The shape of the heart, its chambers, wall thicknesses, wall tissue characteristics as well as motion of walls and valve leaflets are all diagnostic information. In addition, the blood velocity and its timing within the cardiac cycle is an important diagnostic tool. In the present paper focus will be limited to the analysis of the left ventricular function as observed with two-dimensional and three-dimensional echocardiography and the characteristics of backscattered ultrasound information from the left ventricular chamber wall. Function of the heart is often studied by observation of local wall motion or comparison of chamber volume in maximum and minimum shapes during the cardiac cycle (ejection fraction). Integrated backscatter from the wall is described in examples of cardiac transplantation and hypertrophy. Study of cyclic variation of frequency-dependent attenuation and integrated backscatter indicates that these are independent parameters.
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Affiliation(s)
- N Bom
- Thoraxcentre, Erasmus University Rotterdam, The Netherlands
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Bijnens B, D'hooge J, Schrooten M, Pislaru S, Pislaru C, De Man B, Nuyts J, Suetens P, Van de Werf F, Sutherland GR, Herregods MC. Are changes in myocardial integrated backscatter restricted to the ischemic zone in acute induced ischemia? An in vivo animal study. J Am Soc Echocardiogr 2000; 13:306-15. [PMID: 10756249 DOI: 10.1067/mje.2000.103595] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Integrated backscatter (IB) from a myocardial region, calculated from radiofrequency echocardiographic data, has been proposed as a useful parameter for investigating changes in myocardial tissue induced by ischemia. In 10 closed-chest dogs, 5 minutes of myocardial ischemia was induced by either a proximal occlusion of the circumflex coronary artery (CX) (5 dogs), resulting in extensive ischemia in the posterior wall, or by occluding the distal CX vessel (5 dogs) to produce a small localized ischemic zone in the posterior wall. High-resolution digital radiofrequency data from the whole left ventricular myocardium, in the imaging plane during one complete heart cycle, were acquired with a whole-image real-time acquisition approach. Regions in the septum and posterior wall (both ischemic tissue and, in the case of distal occlusions, tissue surrounding the ischemic zone) were chosen for analysis, and IB and cyclic variation (CV) of IB were calculated. Post occlusion, an increase in mean IB values was found in the ischemic segment. However, an increase in CV was also observed in the peri-ischemic zone for the distal CX occlusion and in the septum after proximal CX occlusion. These findings show that changes in CV are not restricted to the ischemic zone but may also occur in distal myocardium. This may be explained by changes in the regional contractile state and loading conditions of the "normal" myocardium, which are altered in response to the distal ischemia.
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Affiliation(s)
- B Bijnens
- Department of Cardiology and the Department of Nuclear Medicine, Medical Image Computing, Gasthuisberg University Hospital, Herestraat 49, B-3000 Leuven, Belgium.
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Liu YB, Wu CC, Lin LC, Ho YL, Kao HL, Lee YT. Alterations in ultrasonic backscatter during intra-aortic balloon counterpulsation support in patients with acute myocardial infarction. ULTRASOUND IN MEDICINE & BIOLOGY 1999; 25:1185-1193. [PMID: 10576261 DOI: 10.1016/s0301-5629(99)00072-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Alterations of ultrasonic backscatter parameters have been evident in humans with myocardial infarction or ischemia. The backscatter variability could be restored in ischemic or stunned myocardium after reperfusion. The aims of this study were to determinate changes in regional myocardial ultrasonic backscatter during intra-aortic balloon counterpulsation (IABP) support in patients with acute myocardial infarction (AMI), and to evaluate whether backscatter imaging could be a functional guide of IABP support. A total of 9 patients with AMI were investigated during IABP support with a two-dimensional (2-D) ultrasonic backscatter imaging approach for parasternal short-axis view. Coronary angiography was performed in 6 of the 9 patients. A total of 21 vessel territories were studied in different modes of IABP support: 1:1, 1:2 and standby. Restoration of cyclic variation of backscatter after IABP support was demonstrated in 10 vessel territories. Failure of restoration of cyclic variation of backscatter after IABP support was noted in 6 vessel territories with severe coronary lesions (total or nearly total occlusion) or scar tissue. No changes of the ultrasonic backscatter were found in nonischemic vessel territories with patent coronary arteries or TIMI III coronary flow. In addition, the wall motion score did not change significantly with different IABP support. These results suggest that IABP could restore the cyclic variation of backscatter in ischemic myocardium. Myocardial anisotropy may play an influential role in the alterations of ultrasonic backscatter. We propose that ultrasonic backscatter could be a noninvasively functional guide of IABP use in patients with AMI.
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Affiliation(s)
- Y B Liu
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, ROC
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Zuber M, Gerber K, Erne P. Myocardial tissue characterization in heart failure by real-time integrated backscatter. EUROPEAN JOURNAL OF ULTRASOUND : OFFICIAL JOURNAL OF THE EUROPEAN FEDERATION OF SOCIETIES FOR ULTRASOUND IN MEDICINE AND BIOLOGY 1999; 9:135-43. [PMID: 10413749 DOI: 10.1016/s0929-8266(99)00019-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Differentiation between normal and abnormal physical state of the myocardium, not possible with conventional echocardiography, so far could be done with integrated backscatter (IBS) as a research tool only. METHODS This study investigates myocardial texture analysis with new commercially available real time IBS in 12 normal individuals and in 18 patients with severe left ventricular dysfunction due to coronary artery disease (CAD) in 8 and dilated cardiomyopathy (DCM) in 10 patients. Analysis of IBS amplitude and cyclic variation (dB) in the parasternal long and short axis view of the septum and the posterior wall were measured and corrected with IBS curve of the blood to get absolute values. RESULTS Compared to normal individuals patients with left ventricular dysfunction had a reduced myocardial cyclic variation (P<0.0001), which correlated to regional systolic wall thickening (r=0.64, P=0.001) and global shortening fraction (r=0.62, P<0.01). Although systolic wall thickening in the posterior wall was lower in CAD patients (% thickening, 11.9+/-10 vs. 21.9+/-8, P=0.004), absolute cyclic variation was reduced in both, CAD and DCM patients in the same order of magnitude. However, the higher maximal IBS amplitude in the posterior wall observed in CAD when compared to DCM patients (13.2+/-4.4 vs. 9.2+/-2.4 dB; P=0.002) indicate fibrosis or scar. The dissociation between cyclic variation and systolic wall thickening could implicate hybernating myocardium. CONCLUSION Real-time IBS has progressed from research to routine as a tool to obtain additional and valuable information to conventional echocardiography in daily practice.
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Affiliation(s)
- M Zuber
- Division of Cardiology, Kantonsspital, CH-6000, Luzern 16, Switzerland
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Lin LC, Wu CC, Ho YL, Chen MF, Liau CS, Lee YT. Ultrasonic tissue characterization in predicting residual ischemia and myocardial viability for patients with acute myocardial infarction. ULTRASOUND IN MEDICINE & BIOLOGY 1998; 24:1107-1120. [PMID: 9833578 DOI: 10.1016/s0301-5629(98)00104-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The identification of viable myocardium and residual ischemia in patients with acute myocardial infarction has important prognostic implications. The ultrasonic tissue characterization with integrated backscatter and dobutamine-atropine stress echocardiography were performed 8.3+/-3 days after AMI in 30 patients. After coronary angioplasty for the residual stenosis of infarct-related artery, both modalities were repeated. The parameter obtained from ultrasonic tissue characterization, phase-weighted variation, could differentiate the myocardium with residual coronary stenosis or nonviable myocardium from the viable myocardium without residual coronary stenosis (p < 0.001). Using the cutoff value of 5.8 dB, the sensitivity, specificity and accuracy for detecting viable myocardium without residual coronary stenosis were 75%, 100% and 90.2%, respectively. The phase-weighted variation of the viable infarction zone restored after the coronary stenosis was relieved. In contrast, the nonviable myocardium had a small phase-weighted variation that was irrelevant to the patency of the infarct-related artery. The ultrasonic tissue characterization may be used in identifying patients with acute myocardial infarction whose infarction zones are viable without residual ischemia.
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Affiliation(s)
- L C Lin
- Department of Internal Medicine (Cardiology Section), National Taiwan University Hospital, Taipei
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van der Steen AF, Rijsterborgh H, Lancee CT, Mastik F, Krams R, Verdouw PD, Roelandt JR, Bom N. Influence of data processing on cyclic variation of integrated backscatter and wall thickness in stunned porcine myocardium. ULTRASOUND IN MEDICINE & BIOLOGY 1997; 23:405-414. [PMID: 9160908 DOI: 10.1016/s0301-5629(96)00227-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This study was performed to investigate the relationship between the cyclic variation of integrated backscatter and myocardial wall thickening in stunned myocardium. Different definitions of cyclic variation were evaluated to be able to compare with other studies. Ultrasound data were acquired from 10 open-chested Yorkshire pigs (25-33 kg) at baseline, during regional ischemia and during 30 min of stunning, using a broadband ultrasound transducer (3-7 MHz) sutured directly upon the left ventricular myocardial wall. Cyclic variation of integrated backscatter and myocardial wall thickening were calculated using three definitions obtained from the literature. Independent of the definition, cyclic variation of wall thickness and integrated backscatter were blunted during acute ischemia and returned transiently to or above baseline during the first minute of reperfusion, followed by a gradual decrease to a level under baseline during stunning. An early return of the cyclic variation of the integrated backscatter was not observed in pigs, independent of the data processing used. The relationship between integrated backscatter and wall thickness was maintained.
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Affiliation(s)
- A F van der Steen
- Department of Cardiology, Thoraxcenter, Erasmus University Rotterdam, The Netherlands
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Vitale DF, Bonow RO, Calabrò R, De Cristofaro M, Pacileo G, Caso P, Gerundo G, Bordini C, Losi MA, Rengo C, Rengo F. Myocardial ultrasonic tissue characterization in pediatric and adult patients with hypertrophic cardiomyopathy. Circulation 1996; 94:2826-30. [PMID: 8941108 DOI: 10.1161/01.cir.94.11.2826] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Hypertrophic cardiomyopathy (HCM) has different clinical and prognostic aspects in young than in adult patients. This study was undertaken to determine whether these reported differences are reflected by changes in ultrasonic backscatter parameters and whether oral treatment with verapamil modifies backscatter variables in children with HCM. METHODS AND RESULTS Sixty-eight subjects underwent backscatter analysis to assess the ultrasonic myocardial reflectivity and the amplitude of the cardiac cycle-dependent variation of the backscatter power curve. Subjects were divided into four groups: 10 HCM and 23 normal subjects < 10 years old and 17 HCM and 18 normal adults. Myocardial reflectivity and amplitude of the cyclic variation were assessed in the septum and in the posterior wall of all subjects. The children with HCM were restudied after long-term oral administration of verapamil. Both children and adult patients, compared with the normal control groups, showed a significant reduction in the amplitude of the cyclic variation both in the septum and in the posterior wall. In contrast, myocardial reflectivity, although significantly increased in adult HCM patients, was unchanged in the young HCM group. Verapamil administration did not significantly alter the results in the children with HCM. CONCLUSIONS These data demonstrate that in young HCM patients, the ultrasonic myocardial reflectivity is normal, in contrast to the significant increase observed in adult patients affected by the same disease. This observation is in accord with the different clinical manifestations reported in young HCM patients and indicates an age-dependent difference in the echogenic structure of the hypertrophied myocardium in HCM.
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Affiliation(s)
- D F Vitale
- Facoltà di Medicina Federico II, Cattedra di Geriatria, Naples, Italy
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