- Email: [email protected]
Refinement of echocardiographic criteria for left ventricular noncompaction
International Journal of Cardiology 165 (2013) 463–467
Contents lists available at SciVerse ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Refinement of echocardiographic criteria for left ventricular noncompaction Claudia Stöllberger a,⁎, Birgit Gerecke b, Josef Finsterer a, c, Rolf Engberding b a b c
Krankenanstalt Rudolfstiftung, Juchgasse 25, A-1030 Wien, Austria Academic Hospital Wolfsburg, Sauerbruchstraße 7, D-38440 Wolfsburg, Germany Danube University Krems, Doktor-Karl-Dorrek-Straße 30, A-3500 Krems, Austria
a r t i c l e
i n f o
Article history: Received 31 July 2011 Accepted 26 August 2011 Available online 22 September 2011 Keywords: Echocardiography Noncompaction Cardiomyopathy
a b s t r a c t Background: Left ventricular hypertrabeculation/noncompaction (LVNC) is a cardiac abnormality whose echocardiographic criteria are still controversial. Cooperation between echocardiographic laboratories may contribute to uniformly accepted criteria, as illustrated by the following pilot study. Methods and results: Echocardiograms proposed for inclusion into a registry were reviewed. Three experts with 17–26 years experience with LVNC agreed on a common definition of LVNC: 1. N3 prominent trabeculous formations along the left ventricular endocardial border visible in end-diastole, distinct from papillary muscles, false tendons or aberrant bands; 2. trabeculations move synchronously with the compacted myocardium, 3. trabeculations form the noncompacted part of a two-layered myocardial structure, best visible at end-systole; and 4. perfusion of the intertrabecular spaces from the ventricular cavity is present at end-diastole on color-Doppler echocardiography or contrast echocardiography. During 3 sessions 115 cases (37% females, mean 57 years) were reviewed. Eleven patients(18% females, mean 60 years) were excluded because of b4 trabeculations(n=5), lack of a two-layered myocardial structure(n=1) and poor image quality(n=5). The observers agreed on inclusion or exclusion in all cases. Consensus was achieved that measurements of the thickness of the myocardial layers, and calculation of the noncompacted:compacted ratio is not feasible due to a lack of uniformly accepted standards for measurements. Conclusions: When diagnosing LVNC, end-systolic as well as end-diastolic images have to be considered. The presence of more than three trabeculations as well as a two-layered myocardium are required. Since these criteria are not anatomically controlled, a comparison of echocardiographic images with pathoanatomic findings for assessing sensitivity and specificity is urgently needed. © 2011 Elsevier Ireland Ltd. All rights reserved.
1. Introduction Left ventricular hypertrabeculation/noncompaction (LVNC), also termed “spongy myocardium” or “persisting sinusoids”, is a cardiac abnormality of unknown etiology, which was recently classified as “primary genetic cardiomyopathy” by the American Heart Association [1]. Since the echocardiographic findings in LVNC were published in 1984 for the first time [2], the echocardiographic criteria for LVNC are still controversial resulting in over- and underdiagnosis which may have a serious impact on a patient's life and profession [3,4], Cooperation between experts from different echocardiographic laboratories may contribute to uniformly accepted criteria, as illustrated by the following experiences of a pilot study. 2. Materials and methods Echocardiograms from patients proposed for inclusion into a German-Austrian left ventricular noncompaction registry, initiated by the “Arbeitsgemeinschaft Leitende
Kardiologische Krankenhausärzte” (ALKK), were jointly reviewed. The founders of this registry (RE, GB and CS) invited starting in 2007 cardiologists from Germany and Austria to send them clinical records, electrocardiograms, echocardiographic and cardiac magnetic resonance recordings of patients with LVNC [5]. Three experts with 17–26 years experience with LVNC (RE, CS, BG) convened and jointly reviewed cine-loops of echocardiograms which were carried out in different hospitals or offices in Germany and Austria [6,7]. Before reviewing the cine-loops, the experts discussed and agreed on a common definition of LVNC: LVNC was diagnosed echocardiographically when 1. N 3 prominent trabeculous formations along the left ventricular endocardial border were visible in end-diastole, distinct from papillary muscles, false tendons or aberrant bands, 2. these trabeculations moved synchronously with the compacted myocardium, 3. these trabeculations were the noncompacted part of a two-layered myocardial structure, best visible at end-systole, and 4. perfusion of the intertrabecular spaces from the ventricular cavity was present at end-diastole on color-Doppler echocardiography or contrast echocardiography (Fig. 1). All the 4 criteria had to be fulfilled for establishing the diagnosis of LVNC. Reasons for exclusion were documented.
3. Results ⁎ Corresponding author at: Steingasse 31/18, A-1030 Wien, Österreich, Austria. Tel./fax: + 43 1 945 42 91. E-mail address: [email protected] (C. Stöllberger). 0167-5273/$ – see front matter © 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2011.08.845
Overall, 115 cases, all Caucasians (37% females, aged 18–87, mean 57 years) were reviewed during 3 sessions taking place from 2008–
464
C. Stöllberger et al. / International Journal of Cardiology 165 (2013) 463–467
Fig. 1. Apical trabeculations with perfusion of the intertrabecular spaces from the ventricular cavity visualized by color-Doppler echocardiography.
Fig. 2. Apical 4-chamber view of a patient who was excluded because there was only a two-layered myocardium but no trabeculations.
Fig. 3. Apical 4-chamber view of a patient who was excluded because of poor image quality. In the left ventricular apical region the image quality is not sufficient to delineate a two-layered structure or to count the number of abnormal trabeculations.
C. Stöllberger et al. / International Journal of Cardiology 165 (2013) 463–467
2010. The list of the participating centers is mentioned in the acknowledgments. By reviewing the cine-loops 11 patients (18% females, age 47–77, mean 60 years) were excluded because of b4 trabeculations (n = 5) (Fig. 2), lack of a two-layered myocardial structure (n = 1) and poor image quality (n = 5) (Fig. 3). In two cases, one observer initially diagnosed LVNC initially but eventually was convinced by the other two observers that LVNC should not be diagnosed. These two cases are depicted in Figs. 2 and 3. In the remaining cases, there was no disagreement about inclusion or exclusion among the three observers. Consensus was achieved that the number of trabeculations and the perfusion of the intertrabecular recesses could be best visualized at end-diastole, and the two-layered myocardium at end-
465
systole (Fig. 4 A and B). Helpful views were the parasternal short-axis view at the apical level for counting the number of trabeculations, and an atypical apical two-chamber view with visualization of the coronary sinus to assess the two-layered myocardium and to differentiate midventricular LVNC from papillary muscles (Fig. 5). Consensus was further achieved that measurements of the thickness of the myocardial layers, and subsequent calculation of the noncompacted:compacted ratio is not feasible due to a lack of uniformly accepted standards for measurements. Thus, the mere demonstration of a two-layered myocardium with a noncompacted layer due to prominent trabeculations seemed sufficient for diagnosing LVNC and no ratio was calculated.
Fig. 4. Endsystolic apical 4-chamber view of the two-layered structure in the left ventricular apex (A). The patient died 6 months later and post-mortem examination confirmed LVNC (B).
466
C. Stöllberger et al. / International Journal of Cardiology 165 (2013) 463–467
Fig. 5. Atypical apical two-chamber view with visualization of the coronary sinus (cs) to assess the two-layered myocardium and to differentiate midventricular LVNC (lvnc) from papillary muscles (pm).
4. Discussion The results of the cooperation of experts from different echocardiographic laboratories in the present pilot study are: When diagnosing LVNC, end-systolic as well as end-diastolic frames have to be considered. An increased number of trabeculations as well as a two-layered myocardium should be present. Uniformly accepted standards for measurements of the thickness of the myocardial layers and calculation of a noncompacted:compacted ratio are still lacking. In the literature there is disagreement how LVNC should be echocardiographically defined. Is LVNC present if there are more than three trabeculations, which is based on a pathoanatomical study defining abnormal trabeculations if exceeding a number of three, or is it sufficient to recognize a two-layered structure without counting any abnormally formed myocardial structures? [8,9]. Application of the pathoanatomical cut-off for echocardiography does not seem to be appropriate, since there is no proof that the structures visualized on echocardiography indeed correspond to trabeculations seen pathoanatomically [10]. There is also no proof that the anatomical cut-off is correct, applies to all ethnic groups, to both genders, and to children and adults, since there are no studies available which confirmed Boyd's findings in all these subgroups [9]. Diagnosing LVNC on the mere demonstration of a two-layered myocardial structure may lead to overdiagnosis of LVNC, because from echocardiographic and cardiac magnetic resonance imaging studies we know that a two-layered myocardium is visible in healthy volunteers, athletes, patients with hypertrophic cardiomyopathy, with hypertensive heart disease and with aortic stenosis [11,12]. In order to avoid overdiagnosis of LVNC a quantification of the noncompacted:compacted ratio and diagnostic cut-off values were proposed. In 1990 Chin et al., for the first time, included in their diagnostic criteria for LVNC the ratio X (distance between epicardial surface and trough of the intertrabecular recesses) to Y (distance between epicardial surface and peak of the trabeculations), which indicated LVNC if b0.5 and if it progressively decreased from the papillary muscles toward the apex [13]. In 1999 Ichida et al. requested that the noncompacted:compacted myocardium ratio needs to exceed a cut-off of 2.3 to be diagnostic [14]. Since then, proposals with various different ratio values were published [15–17]. To render the diagnosis of LVNC even more confusing, there is no agreement, if the ratio should be measured at end-diastole as proposed by Ichida et al., or at end-systole, as proposed by Oechslin et al. [14,15]. Furthermore, no data about interobserver and intraobserver variabilities in measuring
the ratio are available in the literature. All ratio figures are arbitrarily chosen and not supported by any pathoanatomic studies. In our study the delineation between the two myocardial layers was better visible in end-systole than in end-diastole. However, we did not perform calculation of the noncompacted:compacted ratio for the diagnosis of LVNC, since at present, there is no agreement at which location and in which imaging plane the ratio should be measured and no pathoanatomic base for standardization of such measurements is available. Thus, we propose to diagnose LVNC considering only the increased number of trabeculations at end-diastole as well as the two-layered structure at end-systole. Future work is needed to develop uniformly accepted measurement standards. Limitations of the study are that it was not pathoanatomically controlled, thus the sensitivity and specificity of the diagnostic criteria cannot be compared with a golden standard, that the proposed diagnostic criteria were not prospectively tested, and that no inter- and intraobserver variabilities of the criteria were assessed. A further limitation is that the results are based on the analysis of a Caucasian population only. There are indications that in Africans the morphology of the left ventricle might be different with more “normal” trabeculations [4]. Cardiac magnetic resonance imaging is increasingly performed to diagnose LVNC. The present study focused on the echocardiographic examination and we did not investigate if the proposed echocardiographic criteria also apply for cardiac magnetic resonance imaging. When diagnosing LVNC, end-systolic as well as end-diastolic images have to be considered. The presence of both criteria, more than three trabeculations as well as a two-layered myocardium are required for diagnosing LVNC. Atypical views should be added if conventional views fail to be diagnostic. To assess sensitivity and specificity, there is an urgent need to compare echocardiographic images with pathoanatomic findings. To assess the reproducibility of the proposed criteria, there is a need for inter- and intraobserver-variability studies. Acknowledgments Participating centers 1. Academic Hospital Wolfsburg, Germany — R. Engberding, B. Gerecke 2. Rudolfstiftung, Academic Hospital, Vienna, Austria — C. Stöllberger 3. Academic Hospital Robert-Bosch Stuttgart, Germany — U. Sechtem, P. Ong 4. University Hospital Münster, Germany — G.Breithardt, S.Zellerhoff
C. Stöllberger et al. / International Journal of Cardiology 165 (2013) 463–467
5. University Hospital Greifswald, Germany — S. Felix, A. Hummel 6. Academic Hospital Idar-Oberstein, Germany — H.H. Klein, W. Toepel 7. Academic Hospital Braunschweig, Germany — F. Gradaus 8. University Hospital Charite Berlin, Germany — A.C. Borges 9. Cardiovascular Center Bethanien Frankfurt, Germany — A. Schmermund 10. Marienhospital Helmstedt , Germany — S.H. Nguyen 11. Diakoniehospital, Acad. Hosp., Rotenburg Wümme, Germany — H.Andresen 12. Academic Hospital Ludwigsburg, Germany — C.Wolpert, D. Nothnagel 13. Academic Hospital Ingolstadt, Germany — C. Pfafferott, A. Schöpflin 14. Ambulatory Cardiocenter Dr. Fritsch,Cologne, Germany — J. Fritsch 15. St. Vinzenz-Hospital, Academic Hospital, Cologne, Germany — W. Fehske 16. Sana Kliniken, Academic Hospital, Lübeck, Germany — B. Schneider 17. Ambulatory Cardiocenter Dr. Krug, Frankfurt, Germany — T. Krug 18. Mathias-Spital, Acad. Hospital, Rheine, Germany — S.Middendorf 19. German Heart Center Berlin, Berlin, Germany — E. Fleck, J.H. Li 20. Alfried Krupp Hospital, Academic Hospital, Essen, Germany — T.Budde 21. Academic Hospital Celle, Germany — A.Libner 22. Herz und Gefäßzentrum, Bad Bevensen, Germany — B. Remppis, M.Bugna 23. Ambulatory Cardiocenter Vogelpohl, Rotenburg, Germany — J.Vogelpohl 24. Academic Hospital Hildesheim, Germany — J.Tebbenjohanns, K.Rühmkorf 25. St-Johannes Hospital, Dortmund, Germany — H.Heuer, C.Starke 26. Klinikum Frankfurt Höchst, Frankfurt, Germany — S. Sen, C.Kadel The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology. References [1] Maron BJ, Towbin JA, Thiene G, et al. Contemporary definitions and classification of the cardiomyopathies. An American Heart Association Scientific Statement from the Council on Clinical Cardiology, Heart Failure and Transplantation Committee; Quality of Care and Outcomes Research and Functional Genomics and Translational Biology Interdisciplinary Working Groups; and Council on Epidemiology and Prevention. Circulation 2006;113:1807–16.
467
[2] Engberding R, Bender F. Identification of a rare congenital anomaly of the myocardium by two-dimensional echocardiography: Persistence of isolated myocardial sinusoids. Am J Cardiol 1984;53:1733–4. [3] Finsterer J, Stöllberger C, Tymms T, Fazio G, Siejka S. Shall a pilot with left ventricular hypertrabeculation/noncompaction fly passengers? Int J Cardiol 2010;145:72–3. [4] Stöllberger C, Finsterer J. A diagnostic dilemma in non-compaction, resulting in near expulsion from the football world cup. Eur J Echocardiogr 2011;12:E8. [5] Engberding R, Yelbuz TM, Breithardt G. Isolated noncompaction of the left ventricular myocardium — a review of the literature two decades after the initial case description. Clin Res Cardiol 2007;96:481–8. [6] Stöllberger C, Blazek G, Wegner C, Winkler-Dworak M, Finsterer J. Neuromuscular and cardiac comorbidity determines survival in 140 patients with left ventricular hypertrabeculation/noncompaction. Int J Cardiol 2010;150:71–4. [7] Engberding R, Stöllberger C, Ong P, Yelbuz TM, Gerecke BJ, Breithardt G. Isolated non-compaction cardiomyopathy. Dtsch Arztebl Int 2010;107:206–13. [8] Burke A, Mont E, Kutys R, Virmani R. Left ventricular noncompaction: a pathological study of 14 cases. Hum Pathol 2005;36:403–11. [9] Boyd MT, Seward JB, Tajik AJ, Edwards WD. Frequency and location of prominent left ventricular trabeculations at autopsy in 474 normal human hearts: Implications for evaluation of mural thrombi by two-dimensional echocardiography. J Am Coll Cardiol 1987;9:323–6. [10] Stöllberger C, Finsterer J, Sodeck GH, Grassberger M, Zimpfer D. Stroke from noncompaction overlooked by echocardiography. Int J Cardiol 2011;148:357–8. [11] Frischknecht BS, Attenhofer Jost CH, Oechslin EN, et al. Validation of noncompaction criteria in dilated cardiomyopathy, and valvular and hypertensive heart disease. J Am Soc Echocardiogr 2005;18:865–72. [12] Petersen SE, Selvanayagam JB, Wiesmann F, et al. Left ventricular noncompaction. Insights from cardiovascular magnetic resonance imaging. J Am Coll Cardiol 2005;46:101–5. [13] Chin TK, Perloff JK, Williams RG, Jue K, Mohrmann R. Isolated noncompaction of left ventricular myocardiu. A study of eight cases. Circulation 1990;82:507–13. [14] Ichida F, Hamamichi Y, Miyawaki T, et al. Clinical features of isolated noncompaction of the ventricular myocardium. Long-term clinical course, hemodynamic properties, and genetic background. J Am Coll Cardiol 1999;34:233–40. [15] Oechslin EN, Attenhofer Jost CH, Rojas JR, Kaufmann PA, Jenni R. Long term follow-up of 34 adults with isolated left ventricular noncompaction: A distinct cardiomyopathy with poor prognosis. J Am Coll Cardiol 2000;36:493–500. [16] Belanger AR, Miller MA, Donthireddi UR, Najovits AJ, Goldman ME. New classification scheme of left ventricular noncompaction and correlation with ventricular performance. Am J Cardiol 2008;102:92–6. [17] Stanton C, Bruce C, Connolly H, et al. Isolated left ventricular noncompaction syndrome. Am J Cardiol 2009;104:1135–8.
Contents lists available at SciVerse ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Refinement of echocardiographic criteria for left ventricular noncompaction Claudia Stöllberger a,⁎, Birgit Gerecke b, Josef Finsterer a, c, Rolf Engberding b a b c
Krankenanstalt Rudolfstiftung, Juchgasse 25, A-1030 Wien, Austria Academic Hospital Wolfsburg, Sauerbruchstraße 7, D-38440 Wolfsburg, Germany Danube University Krems, Doktor-Karl-Dorrek-Straße 30, A-3500 Krems, Austria
a r t i c l e
i n f o
Article history: Received 31 July 2011 Accepted 26 August 2011 Available online 22 September 2011 Keywords: Echocardiography Noncompaction Cardiomyopathy
a b s t r a c t Background: Left ventricular hypertrabeculation/noncompaction (LVNC) is a cardiac abnormality whose echocardiographic criteria are still controversial. Cooperation between echocardiographic laboratories may contribute to uniformly accepted criteria, as illustrated by the following pilot study. Methods and results: Echocardiograms proposed for inclusion into a registry were reviewed. Three experts with 17–26 years experience with LVNC agreed on a common definition of LVNC: 1. N3 prominent trabeculous formations along the left ventricular endocardial border visible in end-diastole, distinct from papillary muscles, false tendons or aberrant bands; 2. trabeculations move synchronously with the compacted myocardium, 3. trabeculations form the noncompacted part of a two-layered myocardial structure, best visible at end-systole; and 4. perfusion of the intertrabecular spaces from the ventricular cavity is present at end-diastole on color-Doppler echocardiography or contrast echocardiography. During 3 sessions 115 cases (37% females, mean 57 years) were reviewed. Eleven patients(18% females, mean 60 years) were excluded because of b4 trabeculations(n=5), lack of a two-layered myocardial structure(n=1) and poor image quality(n=5). The observers agreed on inclusion or exclusion in all cases. Consensus was achieved that measurements of the thickness of the myocardial layers, and calculation of the noncompacted:compacted ratio is not feasible due to a lack of uniformly accepted standards for measurements. Conclusions: When diagnosing LVNC, end-systolic as well as end-diastolic images have to be considered. The presence of more than three trabeculations as well as a two-layered myocardium are required. Since these criteria are not anatomically controlled, a comparison of echocardiographic images with pathoanatomic findings for assessing sensitivity and specificity is urgently needed. © 2011 Elsevier Ireland Ltd. All rights reserved.
1. Introduction Left ventricular hypertrabeculation/noncompaction (LVNC), also termed “spongy myocardium” or “persisting sinusoids”, is a cardiac abnormality of unknown etiology, which was recently classified as “primary genetic cardiomyopathy” by the American Heart Association [1]. Since the echocardiographic findings in LVNC were published in 1984 for the first time [2], the echocardiographic criteria for LVNC are still controversial resulting in over- and underdiagnosis which may have a serious impact on a patient's life and profession [3,4], Cooperation between experts from different echocardiographic laboratories may contribute to uniformly accepted criteria, as illustrated by the following experiences of a pilot study. 2. Materials and methods Echocardiograms from patients proposed for inclusion into a German-Austrian left ventricular noncompaction registry, initiated by the “Arbeitsgemeinschaft Leitende
Kardiologische Krankenhausärzte” (ALKK), were jointly reviewed. The founders of this registry (RE, GB and CS) invited starting in 2007 cardiologists from Germany and Austria to send them clinical records, electrocardiograms, echocardiographic and cardiac magnetic resonance recordings of patients with LVNC [5]. Three experts with 17–26 years experience with LVNC (RE, CS, BG) convened and jointly reviewed cine-loops of echocardiograms which were carried out in different hospitals or offices in Germany and Austria [6,7]. Before reviewing the cine-loops, the experts discussed and agreed on a common definition of LVNC: LVNC was diagnosed echocardiographically when 1. N 3 prominent trabeculous formations along the left ventricular endocardial border were visible in end-diastole, distinct from papillary muscles, false tendons or aberrant bands, 2. these trabeculations moved synchronously with the compacted myocardium, 3. these trabeculations were the noncompacted part of a two-layered myocardial structure, best visible at end-systole, and 4. perfusion of the intertrabecular spaces from the ventricular cavity was present at end-diastole on color-Doppler echocardiography or contrast echocardiography (Fig. 1). All the 4 criteria had to be fulfilled for establishing the diagnosis of LVNC. Reasons for exclusion were documented.
3. Results ⁎ Corresponding author at: Steingasse 31/18, A-1030 Wien, Österreich, Austria. Tel./fax: + 43 1 945 42 91. E-mail address: [email protected] (C. Stöllberger). 0167-5273/$ – see front matter © 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2011.08.845
Overall, 115 cases, all Caucasians (37% females, aged 18–87, mean 57 years) were reviewed during 3 sessions taking place from 2008–
464
C. Stöllberger et al. / International Journal of Cardiology 165 (2013) 463–467
Fig. 1. Apical trabeculations with perfusion of the intertrabecular spaces from the ventricular cavity visualized by color-Doppler echocardiography.
Fig. 2. Apical 4-chamber view of a patient who was excluded because there was only a two-layered myocardium but no trabeculations.
Fig. 3. Apical 4-chamber view of a patient who was excluded because of poor image quality. In the left ventricular apical region the image quality is not sufficient to delineate a two-layered structure or to count the number of abnormal trabeculations.
C. Stöllberger et al. / International Journal of Cardiology 165 (2013) 463–467
2010. The list of the participating centers is mentioned in the acknowledgments. By reviewing the cine-loops 11 patients (18% females, age 47–77, mean 60 years) were excluded because of b4 trabeculations (n = 5) (Fig. 2), lack of a two-layered myocardial structure (n = 1) and poor image quality (n = 5) (Fig. 3). In two cases, one observer initially diagnosed LVNC initially but eventually was convinced by the other two observers that LVNC should not be diagnosed. These two cases are depicted in Figs. 2 and 3. In the remaining cases, there was no disagreement about inclusion or exclusion among the three observers. Consensus was achieved that the number of trabeculations and the perfusion of the intertrabecular recesses could be best visualized at end-diastole, and the two-layered myocardium at end-
465
systole (Fig. 4 A and B). Helpful views were the parasternal short-axis view at the apical level for counting the number of trabeculations, and an atypical apical two-chamber view with visualization of the coronary sinus to assess the two-layered myocardium and to differentiate midventricular LVNC from papillary muscles (Fig. 5). Consensus was further achieved that measurements of the thickness of the myocardial layers, and subsequent calculation of the noncompacted:compacted ratio is not feasible due to a lack of uniformly accepted standards for measurements. Thus, the mere demonstration of a two-layered myocardium with a noncompacted layer due to prominent trabeculations seemed sufficient for diagnosing LVNC and no ratio was calculated.
Fig. 4. Endsystolic apical 4-chamber view of the two-layered structure in the left ventricular apex (A). The patient died 6 months later and post-mortem examination confirmed LVNC (B).
466
C. Stöllberger et al. / International Journal of Cardiology 165 (2013) 463–467
Fig. 5. Atypical apical two-chamber view with visualization of the coronary sinus (cs) to assess the two-layered myocardium and to differentiate midventricular LVNC (lvnc) from papillary muscles (pm).
4. Discussion The results of the cooperation of experts from different echocardiographic laboratories in the present pilot study are: When diagnosing LVNC, end-systolic as well as end-diastolic frames have to be considered. An increased number of trabeculations as well as a two-layered myocardium should be present. Uniformly accepted standards for measurements of the thickness of the myocardial layers and calculation of a noncompacted:compacted ratio are still lacking. In the literature there is disagreement how LVNC should be echocardiographically defined. Is LVNC present if there are more than three trabeculations, which is based on a pathoanatomical study defining abnormal trabeculations if exceeding a number of three, or is it sufficient to recognize a two-layered structure without counting any abnormally formed myocardial structures? [8,9]. Application of the pathoanatomical cut-off for echocardiography does not seem to be appropriate, since there is no proof that the structures visualized on echocardiography indeed correspond to trabeculations seen pathoanatomically [10]. There is also no proof that the anatomical cut-off is correct, applies to all ethnic groups, to both genders, and to children and adults, since there are no studies available which confirmed Boyd's findings in all these subgroups [9]. Diagnosing LVNC on the mere demonstration of a two-layered myocardial structure may lead to overdiagnosis of LVNC, because from echocardiographic and cardiac magnetic resonance imaging studies we know that a two-layered myocardium is visible in healthy volunteers, athletes, patients with hypertrophic cardiomyopathy, with hypertensive heart disease and with aortic stenosis [11,12]. In order to avoid overdiagnosis of LVNC a quantification of the noncompacted:compacted ratio and diagnostic cut-off values were proposed. In 1990 Chin et al., for the first time, included in their diagnostic criteria for LVNC the ratio X (distance between epicardial surface and trough of the intertrabecular recesses) to Y (distance between epicardial surface and peak of the trabeculations), which indicated LVNC if b0.5 and if it progressively decreased from the papillary muscles toward the apex [13]. In 1999 Ichida et al. requested that the noncompacted:compacted myocardium ratio needs to exceed a cut-off of 2.3 to be diagnostic [14]. Since then, proposals with various different ratio values were published [15–17]. To render the diagnosis of LVNC even more confusing, there is no agreement, if the ratio should be measured at end-diastole as proposed by Ichida et al., or at end-systole, as proposed by Oechslin et al. [14,15]. Furthermore, no data about interobserver and intraobserver variabilities in measuring
the ratio are available in the literature. All ratio figures are arbitrarily chosen and not supported by any pathoanatomic studies. In our study the delineation between the two myocardial layers was better visible in end-systole than in end-diastole. However, we did not perform calculation of the noncompacted:compacted ratio for the diagnosis of LVNC, since at present, there is no agreement at which location and in which imaging plane the ratio should be measured and no pathoanatomic base for standardization of such measurements is available. Thus, we propose to diagnose LVNC considering only the increased number of trabeculations at end-diastole as well as the two-layered structure at end-systole. Future work is needed to develop uniformly accepted measurement standards. Limitations of the study are that it was not pathoanatomically controlled, thus the sensitivity and specificity of the diagnostic criteria cannot be compared with a golden standard, that the proposed diagnostic criteria were not prospectively tested, and that no inter- and intraobserver variabilities of the criteria were assessed. A further limitation is that the results are based on the analysis of a Caucasian population only. There are indications that in Africans the morphology of the left ventricle might be different with more “normal” trabeculations [4]. Cardiac magnetic resonance imaging is increasingly performed to diagnose LVNC. The present study focused on the echocardiographic examination and we did not investigate if the proposed echocardiographic criteria also apply for cardiac magnetic resonance imaging. When diagnosing LVNC, end-systolic as well as end-diastolic images have to be considered. The presence of both criteria, more than three trabeculations as well as a two-layered myocardium are required for diagnosing LVNC. Atypical views should be added if conventional views fail to be diagnostic. To assess sensitivity and specificity, there is an urgent need to compare echocardiographic images with pathoanatomic findings. To assess the reproducibility of the proposed criteria, there is a need for inter- and intraobserver-variability studies. Acknowledgments Participating centers 1. Academic Hospital Wolfsburg, Germany — R. Engberding, B. Gerecke 2. Rudolfstiftung, Academic Hospital, Vienna, Austria — C. Stöllberger 3. Academic Hospital Robert-Bosch Stuttgart, Germany — U. Sechtem, P. Ong 4. University Hospital Münster, Germany — G.Breithardt, S.Zellerhoff
C. Stöllberger et al. / International Journal of Cardiology 165 (2013) 463–467
5. University Hospital Greifswald, Germany — S. Felix, A. Hummel 6. Academic Hospital Idar-Oberstein, Germany — H.H. Klein, W. Toepel 7. Academic Hospital Braunschweig, Germany — F. Gradaus 8. University Hospital Charite Berlin, Germany — A.C. Borges 9. Cardiovascular Center Bethanien Frankfurt, Germany — A. Schmermund 10. Marienhospital Helmstedt , Germany — S.H. Nguyen 11. Diakoniehospital, Acad. Hosp., Rotenburg Wümme, Germany — H.Andresen 12. Academic Hospital Ludwigsburg, Germany — C.Wolpert, D. Nothnagel 13. Academic Hospital Ingolstadt, Germany — C. Pfafferott, A. Schöpflin 14. Ambulatory Cardiocenter Dr. Fritsch,Cologne, Germany — J. Fritsch 15. St. Vinzenz-Hospital, Academic Hospital, Cologne, Germany — W. Fehske 16. Sana Kliniken, Academic Hospital, Lübeck, Germany — B. Schneider 17. Ambulatory Cardiocenter Dr. Krug, Frankfurt, Germany — T. Krug 18. Mathias-Spital, Acad. Hospital, Rheine, Germany — S.Middendorf 19. German Heart Center Berlin, Berlin, Germany — E. Fleck, J.H. Li 20. Alfried Krupp Hospital, Academic Hospital, Essen, Germany — T.Budde 21. Academic Hospital Celle, Germany — A.Libner 22. Herz und Gefäßzentrum, Bad Bevensen, Germany — B. Remppis, M.Bugna 23. Ambulatory Cardiocenter Vogelpohl, Rotenburg, Germany — J.Vogelpohl 24. Academic Hospital Hildesheim, Germany — J.Tebbenjohanns, K.Rühmkorf 25. St-Johannes Hospital, Dortmund, Germany — H.Heuer, C.Starke 26. Klinikum Frankfurt Höchst, Frankfurt, Germany — S. Sen, C.Kadel The authors of this manuscript have certified that they comply with the Principles of Ethical Publishing in the International Journal of Cardiology. References [1] Maron BJ, Towbin JA, Thiene G, et al. Contemporary definitions and classification of the cardiomyopathies. An American Heart Association Scientific Statement from the Council on Clinical Cardiology, Heart Failure and Transplantation Committee; Quality of Care and Outcomes Research and Functional Genomics and Translational Biology Interdisciplinary Working Groups; and Council on Epidemiology and Prevention. Circulation 2006;113:1807–16.
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