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How to define noncompaction?
International Journal of Cardiology 128 (2008) 277 – 278 www.elsevier.com/locate/ijcard
Letter to the Editor
How to define noncompaction? Josef Finsterer a,⁎, Claudia Stöllberger b a
b
Krankenanstalt Rudolfstiftung, Postfach 20, 1180 Vienna, Austria 2nd Medical Department, Krankenanstalt Rudolfstiftung, Vienna, Austria Received 19 July 2007; accepted 10 August 2007 Available online 20 February 2008
Keywords: Noncompaction; Left ventricular hypertrabeculation; Hypertrophic cardiomyopathy; Heart failure; Neuromuscular disorder; Myopathy
We thank Dr. Shimamoto for his thorough and profound comments [1] on our previous proposal to unite Oechslin's and Stöllberger's echocardiographic criteria for diagnosing left ventricular (LV) hypertrabeculation/noncompaction (LVHT) and to classify LVHT as definite, probable or possible, depending on how many of the definitions are fulfilled [2]. We want to defend our previous proposals with the arguments listed below and want to add some comments to the points raised by Dr. Shimamoto. We don't agree that neonates often die from LVHT. LVHT is frequently associated with other cardiac abnormalities, including heart failure or severe rhythm abnormalities. It is much more likely that a fatal outcome in a patient with LVHT is caused by these additional cardiac abnormalities than by the structural abnormality of the myocardium itself. We also don't agree that the risk of thromboembolism is increased in adults with LVHT. This opinion derives from class III evidence and was not confirmed by a controlled study on 64 age-, sex- and LV-function-matched controls [3]. The treatment of heart failure by surgical removal of akinetic or dyskinetic segments appears a courageous therapeutic proposal [4]. However, there is only little experience with this technique and some doubt that such a therapy may be applicable to a large number of LVHT patients and that all LVHT patients will profit from such an approach. We never expressed the opinion that compacted and noncompacted layers are difficult to differentiate in normally sized and well contracting left ventricles. We only criticized ⁎ Corresponding author. Tel.: +43 1 71165 92085; fax: +43 1 4781711. E-mail address: [email protected] (J. Finsterer). 0167-5273/$ - see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2007.08.088
that noncompaction is difficult to recognize in systole where the noncompacted myocardium is turned into a state of compaction by the physiologic contraction of the myocardium during systole [5]. The impact of the diagnosis LVHT with regard to cardiac therapy is at present unknown. Cardiac symptoms in LVHT patients usually derive from cardiac abnormalities other than LVHT, why cardiac therapy should focus on these abnormalities. Since patients with isolated LVHT do not require a cardiac therapy and since cardiac abnormalities in patients with LVHT should be treated as usual, the detection of LVHT has only a therapeutic impact if additional cardiac abnormalities are present. We don't agree that myocardial segments with LVHT are generally hypokinetic. It is true that LVHT is described more often in hypokinetic than in normokinetic segments. However, LVHT is not necessarily associated with hypokinesia. This is substantiated by LVHT occurring in normally sized ventricles and in relatives of LVHT patients without any other cardiac problem [6]. Reasons for hypokinesia of LVHT segments are that LVHT is better visible in dilated as compared to normally sized ventricles, that LVHT may be the cause or consequence of systolic dysfunction, and that patients with LV dysfunction will exhibit more likely cardiac problems and are thus more frequently referred for echocardiography. We also disagree with Shimamoto's opinion that the “majority of adult LVHT patients shows dilation during diastole and reduced systolic function at initial presentation”. In accordance with other studies we found that heart failure, systolic dysfunction, and presence of neuromuscular disorders
278
J. Finsterer, C. Stöllberger / International Journal of Cardiology 128 (2008) 277–278
but not the extension of LVHT determine the prognosis of LVHT patients [7]. Criticism on measuring compacted and noncompacted layer only in the short axis view refers to the inability to differentiate between papillary muscle and trabeculations in the short axis view and does not take into account that LVHT is located distally to the papillary muscles in the vast majority of the cases. Actually, 3D-echocardiography has not been proven to detect LVHT more accurately than conventional 2D-echocardiography. We agree that a correct diagnosis is a prerequisite for an effective therapy. However, a limitation of all imaging techniques is the occurrence of artifacts from summation and motion. Often it is difficult to know if something seen on the screen represents a morphological structure or just an artifact. Though cardiac structures can be visualized much better nowadays than 23 years earlier when LVHT was described for the first time [8], artifacts are still diagnosed as LVHT. Prone to artifacts are the variability of the normal left ventricle due to trabeculations, variation in size, insertion site, or morphology of the papillary muscles, false tendons, or aberrant bands. Additionally, cardiac structures continuously move when investigated. Results of imaging techniques should be correlated with patho-anatomic specimens as the golden standard. This is of particular relevance to prevent from over-diagnosing LVHT. We also agree that visualization of LVHT in the apex is often challenging. Poor visualization of the apex may impair counting of the trabeculations and may lead to an underestimation of the prevalence of LVHT if Stöllberger's criteria are applied. However, prevalence rates were not much different if either Oechslin's or Stöllberger's criteria were applied for diagnosing LVHT, why the number of trabeculations appears to be an accurate criterion for diagnosing LVHT [9]. Regarding the applicability of Oechslin's criteria it would be useful to show in images how measurements of the x/y ratio were actually performed and to know the results of the inter- and intra-observer variability. Of particular interest is how the ratio x/y was measured in the long-axis views. We agree that diagnosing LVHT is dependent on the image resolution of the echocardiographic machine. The higher the image resolution the more likely LVHT is detected and the more precise will the number of trabeculations be determined.
We proposed the categories definite, probable, or possible LVHT following the experience that LVHT is not only a congenital abnormality but may also occur during lifetime [10]. Since LVHT may undergo a dynamic development it may increase in number and extension with age. Patients with possible or probable LVHT thus require close surveillance not to miss the conversion to definite LVHT. Additionally, no consensus about the echocardiographic criteria for diagnosing LVHT has been reached yet. Despite the rarity of the abnormality, LVHT should be diagnosed according to the same criteria ubiquitously. Our proposal to differentiate between definite, probable and possible LVHT has to be regarded as an attempt in this direction. If the discussion about the morphologic abnormality is mixed up with speculations about its etiology and reasons for LV dysfunction more confusion than clarification may occur. References [1] Shimamoto T. There should not be any bprobableQ or bpossibleQ left ventricular noncompaction. Int J Cardiol 2008;128:275–6. [2] Finsterer J, Stöllberger C. Definite, probable, and possible left ventricular hypertrabeculation/noncompaction. Int J Cardiol 2008;123: 175–6. [3] Stöllberger C, Finsterer J. Left ventricular hypertrabeculation/noncompaction and stroke or embolism. Cardiology 2005;103:68–72. [4] Shimamoto T, Marui A, Yamanaka K, et al. Left ventricular restoration surgery for isolated left ventricular noncompaction: report of the first successful case. J Thorac Cardiovasc Surg 2007;134:246–7. [5] Stöllberger C, Finsterer J. Cardiologic and neurologic findings in left ventricular hypertrabeculation/non-compaction related to wall thickness, size and systolic function. Eur J Heart Failure 2005;7:95–7. [6] Pignatelli RH, McMahon CJ, Dreyer WJ, et al. Clinical characterization of left ventricular noncompaction in children. A relatively common form of cardiomyopathy. Circulation 2003;108:2672–8. [7] Stöllberger C, Winkler-Dworak M, Blazek G, Finsterer J. Prognosis of left ventricular hypertrabeculation/noncompaction is dependent on cardiac and neuromuscular comorbidity. Int J Cardiol 2007;121:187–93. [8] 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. [9] 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. [10] Finsterer J, Stöllberger C, Gaismayer K, Janssen B. Acquired noncompaction in Duchenne muscular dystrophy. Int J Cardiol 2006;106:420–1.
Letter to the Editor
How to define noncompaction? Josef Finsterer a,⁎, Claudia Stöllberger b a
b
Krankenanstalt Rudolfstiftung, Postfach 20, 1180 Vienna, Austria 2nd Medical Department, Krankenanstalt Rudolfstiftung, Vienna, Austria Received 19 July 2007; accepted 10 August 2007 Available online 20 February 2008
Keywords: Noncompaction; Left ventricular hypertrabeculation; Hypertrophic cardiomyopathy; Heart failure; Neuromuscular disorder; Myopathy
We thank Dr. Shimamoto for his thorough and profound comments [1] on our previous proposal to unite Oechslin's and Stöllberger's echocardiographic criteria for diagnosing left ventricular (LV) hypertrabeculation/noncompaction (LVHT) and to classify LVHT as definite, probable or possible, depending on how many of the definitions are fulfilled [2]. We want to defend our previous proposals with the arguments listed below and want to add some comments to the points raised by Dr. Shimamoto. We don't agree that neonates often die from LVHT. LVHT is frequently associated with other cardiac abnormalities, including heart failure or severe rhythm abnormalities. It is much more likely that a fatal outcome in a patient with LVHT is caused by these additional cardiac abnormalities than by the structural abnormality of the myocardium itself. We also don't agree that the risk of thromboembolism is increased in adults with LVHT. This opinion derives from class III evidence and was not confirmed by a controlled study on 64 age-, sex- and LV-function-matched controls [3]. The treatment of heart failure by surgical removal of akinetic or dyskinetic segments appears a courageous therapeutic proposal [4]. However, there is only little experience with this technique and some doubt that such a therapy may be applicable to a large number of LVHT patients and that all LVHT patients will profit from such an approach. We never expressed the opinion that compacted and noncompacted layers are difficult to differentiate in normally sized and well contracting left ventricles. We only criticized ⁎ Corresponding author. Tel.: +43 1 71165 92085; fax: +43 1 4781711. E-mail address: [email protected] (J. Finsterer). 0167-5273/$ - see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ijcard.2007.08.088
that noncompaction is difficult to recognize in systole where the noncompacted myocardium is turned into a state of compaction by the physiologic contraction of the myocardium during systole [5]. The impact of the diagnosis LVHT with regard to cardiac therapy is at present unknown. Cardiac symptoms in LVHT patients usually derive from cardiac abnormalities other than LVHT, why cardiac therapy should focus on these abnormalities. Since patients with isolated LVHT do not require a cardiac therapy and since cardiac abnormalities in patients with LVHT should be treated as usual, the detection of LVHT has only a therapeutic impact if additional cardiac abnormalities are present. We don't agree that myocardial segments with LVHT are generally hypokinetic. It is true that LVHT is described more often in hypokinetic than in normokinetic segments. However, LVHT is not necessarily associated with hypokinesia. This is substantiated by LVHT occurring in normally sized ventricles and in relatives of LVHT patients without any other cardiac problem [6]. Reasons for hypokinesia of LVHT segments are that LVHT is better visible in dilated as compared to normally sized ventricles, that LVHT may be the cause or consequence of systolic dysfunction, and that patients with LV dysfunction will exhibit more likely cardiac problems and are thus more frequently referred for echocardiography. We also disagree with Shimamoto's opinion that the “majority of adult LVHT patients shows dilation during diastole and reduced systolic function at initial presentation”. In accordance with other studies we found that heart failure, systolic dysfunction, and presence of neuromuscular disorders
278
J. Finsterer, C. Stöllberger / International Journal of Cardiology 128 (2008) 277–278
but not the extension of LVHT determine the prognosis of LVHT patients [7]. Criticism on measuring compacted and noncompacted layer only in the short axis view refers to the inability to differentiate between papillary muscle and trabeculations in the short axis view and does not take into account that LVHT is located distally to the papillary muscles in the vast majority of the cases. Actually, 3D-echocardiography has not been proven to detect LVHT more accurately than conventional 2D-echocardiography. We agree that a correct diagnosis is a prerequisite for an effective therapy. However, a limitation of all imaging techniques is the occurrence of artifacts from summation and motion. Often it is difficult to know if something seen on the screen represents a morphological structure or just an artifact. Though cardiac structures can be visualized much better nowadays than 23 years earlier when LVHT was described for the first time [8], artifacts are still diagnosed as LVHT. Prone to artifacts are the variability of the normal left ventricle due to trabeculations, variation in size, insertion site, or morphology of the papillary muscles, false tendons, or aberrant bands. Additionally, cardiac structures continuously move when investigated. Results of imaging techniques should be correlated with patho-anatomic specimens as the golden standard. This is of particular relevance to prevent from over-diagnosing LVHT. We also agree that visualization of LVHT in the apex is often challenging. Poor visualization of the apex may impair counting of the trabeculations and may lead to an underestimation of the prevalence of LVHT if Stöllberger's criteria are applied. However, prevalence rates were not much different if either Oechslin's or Stöllberger's criteria were applied for diagnosing LVHT, why the number of trabeculations appears to be an accurate criterion for diagnosing LVHT [9]. Regarding the applicability of Oechslin's criteria it would be useful to show in images how measurements of the x/y ratio were actually performed and to know the results of the inter- and intra-observer variability. Of particular interest is how the ratio x/y was measured in the long-axis views. We agree that diagnosing LVHT is dependent on the image resolution of the echocardiographic machine. The higher the image resolution the more likely LVHT is detected and the more precise will the number of trabeculations be determined.
We proposed the categories definite, probable, or possible LVHT following the experience that LVHT is not only a congenital abnormality but may also occur during lifetime [10]. Since LVHT may undergo a dynamic development it may increase in number and extension with age. Patients with possible or probable LVHT thus require close surveillance not to miss the conversion to definite LVHT. Additionally, no consensus about the echocardiographic criteria for diagnosing LVHT has been reached yet. Despite the rarity of the abnormality, LVHT should be diagnosed according to the same criteria ubiquitously. Our proposal to differentiate between definite, probable and possible LVHT has to be regarded as an attempt in this direction. If the discussion about the morphologic abnormality is mixed up with speculations about its etiology and reasons for LV dysfunction more confusion than clarification may occur. References [1] Shimamoto T. There should not be any bprobableQ or bpossibleQ left ventricular noncompaction. Int J Cardiol 2008;128:275–6. [2] Finsterer J, Stöllberger C. Definite, probable, and possible left ventricular hypertrabeculation/noncompaction. Int J Cardiol 2008;123: 175–6. [3] Stöllberger C, Finsterer J. Left ventricular hypertrabeculation/noncompaction and stroke or embolism. Cardiology 2005;103:68–72. [4] Shimamoto T, Marui A, Yamanaka K, et al. Left ventricular restoration surgery for isolated left ventricular noncompaction: report of the first successful case. J Thorac Cardiovasc Surg 2007;134:246–7. [5] Stöllberger C, Finsterer J. Cardiologic and neurologic findings in left ventricular hypertrabeculation/non-compaction related to wall thickness, size and systolic function. Eur J Heart Failure 2005;7:95–7. [6] Pignatelli RH, McMahon CJ, Dreyer WJ, et al. Clinical characterization of left ventricular noncompaction in children. A relatively common form of cardiomyopathy. Circulation 2003;108:2672–8. [7] Stöllberger C, Winkler-Dworak M, Blazek G, Finsterer J. Prognosis of left ventricular hypertrabeculation/noncompaction is dependent on cardiac and neuromuscular comorbidity. Int J Cardiol 2007;121:187–93. [8] 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. [9] 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. [10] Finsterer J, Stöllberger C, Gaismayer K, Janssen B. Acquired noncompaction in Duchenne muscular dystrophy. Int J Cardiol 2006;106:420–1.