© 2014, Wiley Periodicals, Inc. DOI: 10.1111/echo.12543
Echocardiography
CHALLENGING CASES
Hypertrophic Cardiomyopathy with Right Ventricular Outflow Tract and Left Ventricular Intracavitary Obstruction Rabiya Malik, M.D., Martin S. Maron, M.D., Hassan Rastegar, M.D., and Natesa G. Pandian, M.D. Cardiovascular Center, Tufts Medical Center, Tufts University School of Medicine, Boston, Massachusetts
Obstruction of the right ventricular outflow tract (RVOT) is a rare finding in hypertrophic cardiomyopathy (HCM) patients unlike left ventricular outflow tract (LVOT) obstruction. Although there are guidelines that aid in clinical decision making in patients with LVOT obstruction, there are none addressing RVOT obstruction. As RVOT obstruction may pose serious clinical implications similar to LVOT obstruction, appropriate medical and surgical management is very important. A unique phenotype of HCM with RVOT obstruction in conjunction with left ventricle (LV) intracavitary obstruction is discussed. (Echocardiography 2014;31:682–685) Key words: hypertrophic cardiomyopathy, right ventricular outflow tract obstruction, left ventricular intracavitary obstruction, biventricular obstruction Hypertrophic cardiomyopathy (HCM) patients mostly present with dynamic obstruction to left ventricular outflow tract (LVOT) due to asymmetrical septal hypertrophy, systolic anterior motion (SAM) of the mitral valve, and SAM-septal contact.1–3 Although abnormalities of right ventricular (RV) wall thickness and mass have been reported in HCM patients,4–8 the presence of right ventricular outflow tract (RVOT) obstruction remains an infrequent finding. This report will present a rare and unique phenotype of HCM with RVOT obstruction accompanied by left ventricle (LV) intracavitary obstruction. Case Presentation: A 37-year-old female was referred to our HCM Clinic for evaluation regarding her management strategies for HCM. Her original history started a decade ago when she developed exertional dyspnea and chest pain. At that time, she was found to have obstructive HCM and underwent leftsided surgical myectomy, which was followed by a long symptom-free period. However, more recently, she started developing debilitating symptoms of exertional dyspnea, fatigue, and palpitations again. Beta blockade and calcium channel blockade therapy did not alleviate her symptoms. An implantable cardioverter defibrillator (ICD) was placed following an episode of synAddress for correspondence and reprint requests: Natesa G. Pandian, M.D., Tufts Medical Center, 800 Washington Street, Box#32, Boston, MA 02111. Fax: 617-636-8070; E-mail: [email protected]
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cope. However, she subsequently had several episodes of presyncope as well as loss of consciousness without any evidence of arrhythmias detected on her ICD. The ICD was placed mainly for primary prevention of sudden cardiac death. Her father and paternal uncle died young at ages 29 years and 16 years, respectively, of unknown cause, presumably HCM. Transthoracic echocardiography (iE33, Philips, Bothell, WA, USA) showed a hyperdynamic heart with an ejection fraction of 65%. LV was asymmetrically hypertrophied with a maximum wall thickness of 19 mm in the septum. The mitral valve was normal in size and function. No SAM of the mitral valve was present and therefore, there was no LVOT obstruction at rest or following Valsalva maneuver. However, an LV intra-cavitary gradient of 40 mmHg was detected, due to opposition of the septum and the LV free wall (Fig. 1 and movie clip S1). Right ventricle was moderately hypertrophied with a resting RVOT gradient of 50 mmHg (Figs. 2 and 3 and movie clip S2) and an elevated RV systolic pressure of 60 mmHg. Postexercise echocardiographic imaging revealed an increase in LV intracavitary gradient to 65 mmHg with no evidence of a subaortic gradient, and an increase in RVOT gradient to 80 mmHg. Both LV intracavitary and RVOT obstruction have been reported to present with life-threatening symptoms, either in isolation or in combination with LVOT obstruction.4,5 Hence, the duo of LV intracavitary and RVOT obstruction was considered to be a deadly combination which
Hypertrophic Cardiomyopathy with Biventricular Obstruction
Figure 1. Two-dimensional and Doppler echocardiographic images showing left ventricular intracavitary obstruction. A. Parasternal long-axis view showing asymmetrical septal hypertrophy; B. Apical four-chamber view showing opposition of the septum and the left ventricular free wall; C. Apical four-chamber view with color Doppler profile across the left ventricular cavity; D. Continous-wave Doppler recording in the left ventricular cavity showing increased velocity profile consistent with left ventricular intracavitary obstruction. LA = left atrium; LV = left ventricle.
Figure 2. Two-dimensional and Doppler echocardiographic images showing right ventricular outflow tract (RVOT) obstruction. A. Parasternal short-axis view of the RVOT showing obstruction (white arrow); B. Transgastric view depicting narrowing of the RVOT; C. Mid-esophageal right ventricular inflow–outflow view with color Doppler profile across the right outflow tract obstruction; D. Continous-wave Doppler recording across the RVOT showing increased velocity profile consistent with RVOT obstruction. RA = right atrium; RV = right ventricle; PA = pulmonary artery.
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Malik, et al.
Figure 3. Three-dimensional echocardiographic images showing left ventricular intracavitary and RVOT obstruction. A. Apical four-chamber view showing left ventricular intracavitary obstruction due to opposition of the septum and the left ventricular free wall; B. Mid-esophageal right ventricular inflow–outflow view depicting RVOT obstruction (arrow); C. En face view of RVOT obstruction during diastole (red arrow); D. En face view of RVOT obstruction during systole (arrow). LA = left atrium; LV = left ventricle; RV = right ventricle; RVOT = right ventricular outflow tract; PA = pulmonary artery.
required immediate surgical correction. Following the plan, the patient underwent an extended left-sided septal myectomy through an aortotomy and resection of the hypertrophied RV musculature through a right ventriculotomy. After resection of the hypertrophied RV musculature, the RVOT was reinforced by an acellular xenograft patch to create space and prevent the obstruction from recurring. Postoperatively, both RVOT and LV intracavitary gradients were relieved. The patient was symptom-free and no medications were required postoperatively. Discussion: Obstruction of LVOT is a common finding in HCM patients.1–3 However, RVOT obstruction remains a rare finding despite appreciation of morphological abnormalities of RV wall thickness and mass in HCM patients.6–9 Although there are guidelines to aid in the clinical management of 684
HCM patients with LVOT obstruction, there are none addressing RVOT obstruction owing to the infrequent nature of the pathology. Subpulmonic gradients have been observed in conjunction with LV outflow obstruction in the past.8 However, obstruction of RVOT in combination with LV intracavitary obstruction is a unique phenotypical manifestation of HCM. Right ventricular outflow tract obstruction has appeared to be mainly due to hypertrophy of the RV musculature, most frequently the crista supraventricularis.6,8 Hence, as opposed to LVOT obstruction which is predominantly a dynamic obstruction due to SAM of the mitral valve, RVOT obstruction is mainly a static and fixed muscular impediment to outflow.8 Obstruction of RVOT due to protrusion of the hypertrophied septum into the RV cavity or SAM of the tricuspid valve has not been reported so far. The same mutations in the cardiac sarcomere that cause phenotypical
Hypertrophic Cardiomyopathy with Biventricular Obstruction
expression of LV hypertrophy are considered to be responsible for RV hypertrophy also.6,10 In conclusion, despite the rare nature of RVOT obstruction, morphological abnormalities of RV are common in HCM.6 Therefore, HCM is a genetic cardiomyopathic process involving both the left and the right sides of the heart, and to accurately define and manage this heterogeneous disease it is important to consider the presence of RV morphological abnormalities as well. References 1. Maron BJ: Hypertrophic cardiomyopathy: A systemic review. JAMA 2002;287:1308–1320. 2. Spirito P, Maron BJ: Patterns of systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy: Assessment by two-dimensional echocardiography. Am J Cardiol 1984;54:1039–1046. 3. Maron MS, Olivotto I, Betocchi S, et al: Effect of left ventricular outflow tract obstruction on clinical outcome in hypertrophic cardiomyopathy. N Engl J Med 2003;348:295–303. 4. Butz T, Horstkotte D, Langer C, et al: Significant obstruction of the right and left ventricular outflow tract in a patient with biventricular hypertrophic cardiomyopathy. Eur J Echocardiogr 2008;9:344–345. 5. Kunkala MR, Schaff HV, Nishimura RA, et al: Transapical approach to myectomy for midventricular obstruction in hypertrophic cardiomyopathy. Ann Thorac Surg 2013;96:564–570.
6. Maron MS, Hauser TH, Dubrow E, et al: Right ventricular involvement in hypertrophic cardiomyopathy. Am J Cardiol 2007;100:1293–1298. 7. Recupero A, Di Bella G, Patane S, et al: Right ventricular outflow tract obstruction in hypertrophic cardiomyopathy. Int J Cardiol 2010;144:e56–e57. 8. Maron BJ, McIntosh CL, Klues HG, et al: Morphologic basis for obstruction to right ventricular outflow in hypertrophic cardiomyopathy. Am J Cardiol 1993;71:1089– 1094. 9. Krecki R, Lipiec P, Piotrowska-Kownacka D, et al: Predominant, severe right ventricular outflow tract obstruction in hypertrophic cardiomyopathy. Circulation 2007;116: e551–e553. 10. Marian AJ, Roberts R: Recent advances in the molecular genetics of hypertrophic cardiomyopathy. Circulation 1995;92:1336–1347.
Supporting Information Additional Supporting Information may be found in the online version of this article: Movie clip S1. Apical four-chamber view showing turbulent color Doppler velocity profile across the left ventricular intracavitary obstruction. Movie clip S2. Mid-esophageal right ventricular inflow–outflow view showing turbulent color Doppler velocity profile across the right ventricular outflow tract obstruction.
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Echocardiography
CHALLENGING CASES
Hypertrophic Cardiomyopathy with Right Ventricular Outflow Tract and Left Ventricular Intracavitary Obstruction Rabiya Malik, M.D., Martin S. Maron, M.D., Hassan Rastegar, M.D., and Natesa G. Pandian, M.D. Cardiovascular Center, Tufts Medical Center, Tufts University School of Medicine, Boston, Massachusetts
Obstruction of the right ventricular outflow tract (RVOT) is a rare finding in hypertrophic cardiomyopathy (HCM) patients unlike left ventricular outflow tract (LVOT) obstruction. Although there are guidelines that aid in clinical decision making in patients with LVOT obstruction, there are none addressing RVOT obstruction. As RVOT obstruction may pose serious clinical implications similar to LVOT obstruction, appropriate medical and surgical management is very important. A unique phenotype of HCM with RVOT obstruction in conjunction with left ventricle (LV) intracavitary obstruction is discussed. (Echocardiography 2014;31:682–685) Key words: hypertrophic cardiomyopathy, right ventricular outflow tract obstruction, left ventricular intracavitary obstruction, biventricular obstruction Hypertrophic cardiomyopathy (HCM) patients mostly present with dynamic obstruction to left ventricular outflow tract (LVOT) due to asymmetrical septal hypertrophy, systolic anterior motion (SAM) of the mitral valve, and SAM-septal contact.1–3 Although abnormalities of right ventricular (RV) wall thickness and mass have been reported in HCM patients,4–8 the presence of right ventricular outflow tract (RVOT) obstruction remains an infrequent finding. This report will present a rare and unique phenotype of HCM with RVOT obstruction accompanied by left ventricle (LV) intracavitary obstruction. Case Presentation: A 37-year-old female was referred to our HCM Clinic for evaluation regarding her management strategies for HCM. Her original history started a decade ago when she developed exertional dyspnea and chest pain. At that time, she was found to have obstructive HCM and underwent leftsided surgical myectomy, which was followed by a long symptom-free period. However, more recently, she started developing debilitating symptoms of exertional dyspnea, fatigue, and palpitations again. Beta blockade and calcium channel blockade therapy did not alleviate her symptoms. An implantable cardioverter defibrillator (ICD) was placed following an episode of synAddress for correspondence and reprint requests: Natesa G. Pandian, M.D., Tufts Medical Center, 800 Washington Street, Box#32, Boston, MA 02111. Fax: 617-636-8070; E-mail: [email protected]
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cope. However, she subsequently had several episodes of presyncope as well as loss of consciousness without any evidence of arrhythmias detected on her ICD. The ICD was placed mainly for primary prevention of sudden cardiac death. Her father and paternal uncle died young at ages 29 years and 16 years, respectively, of unknown cause, presumably HCM. Transthoracic echocardiography (iE33, Philips, Bothell, WA, USA) showed a hyperdynamic heart with an ejection fraction of 65%. LV was asymmetrically hypertrophied with a maximum wall thickness of 19 mm in the septum. The mitral valve was normal in size and function. No SAM of the mitral valve was present and therefore, there was no LVOT obstruction at rest or following Valsalva maneuver. However, an LV intra-cavitary gradient of 40 mmHg was detected, due to opposition of the septum and the LV free wall (Fig. 1 and movie clip S1). Right ventricle was moderately hypertrophied with a resting RVOT gradient of 50 mmHg (Figs. 2 and 3 and movie clip S2) and an elevated RV systolic pressure of 60 mmHg. Postexercise echocardiographic imaging revealed an increase in LV intracavitary gradient to 65 mmHg with no evidence of a subaortic gradient, and an increase in RVOT gradient to 80 mmHg. Both LV intracavitary and RVOT obstruction have been reported to present with life-threatening symptoms, either in isolation or in combination with LVOT obstruction.4,5 Hence, the duo of LV intracavitary and RVOT obstruction was considered to be a deadly combination which
Hypertrophic Cardiomyopathy with Biventricular Obstruction
Figure 1. Two-dimensional and Doppler echocardiographic images showing left ventricular intracavitary obstruction. A. Parasternal long-axis view showing asymmetrical septal hypertrophy; B. Apical four-chamber view showing opposition of the septum and the left ventricular free wall; C. Apical four-chamber view with color Doppler profile across the left ventricular cavity; D. Continous-wave Doppler recording in the left ventricular cavity showing increased velocity profile consistent with left ventricular intracavitary obstruction. LA = left atrium; LV = left ventricle.
Figure 2. Two-dimensional and Doppler echocardiographic images showing right ventricular outflow tract (RVOT) obstruction. A. Parasternal short-axis view of the RVOT showing obstruction (white arrow); B. Transgastric view depicting narrowing of the RVOT; C. Mid-esophageal right ventricular inflow–outflow view with color Doppler profile across the right outflow tract obstruction; D. Continous-wave Doppler recording across the RVOT showing increased velocity profile consistent with RVOT obstruction. RA = right atrium; RV = right ventricle; PA = pulmonary artery.
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Figure 3. Three-dimensional echocardiographic images showing left ventricular intracavitary and RVOT obstruction. A. Apical four-chamber view showing left ventricular intracavitary obstruction due to opposition of the septum and the left ventricular free wall; B. Mid-esophageal right ventricular inflow–outflow view depicting RVOT obstruction (arrow); C. En face view of RVOT obstruction during diastole (red arrow); D. En face view of RVOT obstruction during systole (arrow). LA = left atrium; LV = left ventricle; RV = right ventricle; RVOT = right ventricular outflow tract; PA = pulmonary artery.
required immediate surgical correction. Following the plan, the patient underwent an extended left-sided septal myectomy through an aortotomy and resection of the hypertrophied RV musculature through a right ventriculotomy. After resection of the hypertrophied RV musculature, the RVOT was reinforced by an acellular xenograft patch to create space and prevent the obstruction from recurring. Postoperatively, both RVOT and LV intracavitary gradients were relieved. The patient was symptom-free and no medications were required postoperatively. Discussion: Obstruction of LVOT is a common finding in HCM patients.1–3 However, RVOT obstruction remains a rare finding despite appreciation of morphological abnormalities of RV wall thickness and mass in HCM patients.6–9 Although there are guidelines to aid in the clinical management of 684
HCM patients with LVOT obstruction, there are none addressing RVOT obstruction owing to the infrequent nature of the pathology. Subpulmonic gradients have been observed in conjunction with LV outflow obstruction in the past.8 However, obstruction of RVOT in combination with LV intracavitary obstruction is a unique phenotypical manifestation of HCM. Right ventricular outflow tract obstruction has appeared to be mainly due to hypertrophy of the RV musculature, most frequently the crista supraventricularis.6,8 Hence, as opposed to LVOT obstruction which is predominantly a dynamic obstruction due to SAM of the mitral valve, RVOT obstruction is mainly a static and fixed muscular impediment to outflow.8 Obstruction of RVOT due to protrusion of the hypertrophied septum into the RV cavity or SAM of the tricuspid valve has not been reported so far. The same mutations in the cardiac sarcomere that cause phenotypical
Hypertrophic Cardiomyopathy with Biventricular Obstruction
expression of LV hypertrophy are considered to be responsible for RV hypertrophy also.6,10 In conclusion, despite the rare nature of RVOT obstruction, morphological abnormalities of RV are common in HCM.6 Therefore, HCM is a genetic cardiomyopathic process involving both the left and the right sides of the heart, and to accurately define and manage this heterogeneous disease it is important to consider the presence of RV morphological abnormalities as well. References 1. Maron BJ: Hypertrophic cardiomyopathy: A systemic review. JAMA 2002;287:1308–1320. 2. Spirito P, Maron BJ: Patterns of systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy: Assessment by two-dimensional echocardiography. Am J Cardiol 1984;54:1039–1046. 3. Maron MS, Olivotto I, Betocchi S, et al: Effect of left ventricular outflow tract obstruction on clinical outcome in hypertrophic cardiomyopathy. N Engl J Med 2003;348:295–303. 4. Butz T, Horstkotte D, Langer C, et al: Significant obstruction of the right and left ventricular outflow tract in a patient with biventricular hypertrophic cardiomyopathy. Eur J Echocardiogr 2008;9:344–345. 5. Kunkala MR, Schaff HV, Nishimura RA, et al: Transapical approach to myectomy for midventricular obstruction in hypertrophic cardiomyopathy. Ann Thorac Surg 2013;96:564–570.
6. Maron MS, Hauser TH, Dubrow E, et al: Right ventricular involvement in hypertrophic cardiomyopathy. Am J Cardiol 2007;100:1293–1298. 7. Recupero A, Di Bella G, Patane S, et al: Right ventricular outflow tract obstruction in hypertrophic cardiomyopathy. Int J Cardiol 2010;144:e56–e57. 8. Maron BJ, McIntosh CL, Klues HG, et al: Morphologic basis for obstruction to right ventricular outflow in hypertrophic cardiomyopathy. Am J Cardiol 1993;71:1089– 1094. 9. Krecki R, Lipiec P, Piotrowska-Kownacka D, et al: Predominant, severe right ventricular outflow tract obstruction in hypertrophic cardiomyopathy. Circulation 2007;116: e551–e553. 10. Marian AJ, Roberts R: Recent advances in the molecular genetics of hypertrophic cardiomyopathy. Circulation 1995;92:1336–1347.
Supporting Information Additional Supporting Information may be found in the online version of this article: Movie clip S1. Apical four-chamber view showing turbulent color Doppler velocity profile across the left ventricular intracavitary obstruction. Movie clip S2. Mid-esophageal right ventricular inflow–outflow view showing turbulent color Doppler velocity profile across the right ventricular outflow tract obstruction.
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