© 2014, Wiley Periodicals, Inc. DOI: 10.1111/echo.12519

Echocardiography

Hypertrophic Cardiomyopathy with Intermittent Free Mitral Regurgitation–A Surgical Dilemma Patrick H. Gibson, B.M.B.Ch., M.D.,* Sayra A. Khandekar, M.D.,* Dylan Taylor, M.D., F.R.C.P.C., F.A.C.C.,* and Harald Becher, M.D.† *Mazankowski Alberta Heart Institute, Edmonton, Alberta, Canada; and †Department of Cardiology, University of Alberta, Edmonton, Alberta, Canada

We describe the case of a 52-year-old woman presenting with non-ST elevation myocardial infarction, atrial fibrillation, and a new diagnosis of hypertrophic cardiomyopathy. Transesophageal echocardiography following hemodynamic deterioration revealed completely restricted mitral leaflet motion with free mitral regurgitation, and severe left ventricular outflow tract (LVOT) obstruction. Surgical intervention was considered; however, repeat imaging following a period of clinical stability revealed resolution of the findings suggesting a transient ischemic etiology. The case is supported by clinical and echocardiographic images with movie clips, and a discussion of the likely pathology in the context of the underlying condition. (Echocardiography 2014;31:E107–E110) Key words: hypertrophic cardiomyopathy, mitral regurgitation, ischemic mitral valve incompetence

A 52-year-old woman was admitted to the emergency department complaining of chest pain and dyspnea on a background of previous double lung transplant and Tacrolimus immunosuppression over 10 years. Her ECG demonstrated sinus rhythm with large voltages suggestive of left ventricular (LV) hypertrophy, and anterior ST segment depression (Fig. 1). Cardiac troponin I was elevated at 9.3 lg/L and she commenced treatment for non-ST elevation myocardial infarction. A transthoracic echocardiogram demonstrated marked asymmetric septal hypertrophy consistent with hypertrophic cardiomyopathy (HCM) in the absence of diagnosed hypertension. The mitral chordae and leaflet tips appeared thickened with mild mitral regurgitation (Fig. 2, movie clip S1). Coronary angiography (Siemens AG, Erlangen, Germany) revealed severe bridging of the mid-left anterior descending (LAD) artery (Fig. 3) which was not stented. The patient’s condition subsequently deteriorated with recurrent atrial arrhythmia associated with chest pain and widespread significant ST depression. This initially responded to Dr Becher is supported by an endowment from the Heart & Stroke Foundation of Alberta, NW Territories and Nunavut. Address for correspondence and reprint requests: Harald Becher, M.D., Professor of Medicine, Heart and Stroke Foundation Chair for Cardiovascular Research, ABACUS 0A8.32, Mazankowski Alberta Heart Institute, 8440 112 Street Edmonton, Alberta T6G 2B7, Canada. Fax 780-407-3489; E-mail: [email protected]

b-blockade and intravenous nitrate infusion. After several episodes complicated by hypotension and pulmonary edema, she required ventilation and circulatory support with inotropes, an intraaortic balloon pump and extra-corporeal membrane oxygenation (ECMO). A full two-dimensional (2D) and 3D transesophageal echocardiogram (Philips Healthcare, Bothell, WA, USA) was performed demonstrating anterior wall akinesis but preserved LV ejection fraction (movie clip S2). There was complete restriction of the entire subvalvar mitral apparatus resulting in a “wide open” mitral valve with free regurgitation (Fig. 4, movie clip S3). Color Doppler was unimpressive due to nonturbulent reflux (movie clip S4), and spectral Doppler displayed symmetrical mitral inflow and regurgitant profiles (Fig. 5) consistent with pressure equalization in the left atrium and ventricle. There was laminar systolic flow reversal in the pulmonary veins. In addition, systolic anterior motion (SAM) of the anterior mitral leaflet resulted in near occlusion of the left ventricular outflow tract (LVOT) in systole (Fig. 6, movie clips S5 and S6) —adequate Doppler signal to assess the outflow gradient was not obtained from transgastric views. No change in mitral valve function or LVOT obstruction was seen following alteration of ECMO flow settings. Urgent mitral valve replacement with coronary bypass surgery was initially considered. However, the patient’s condition subsequently E107

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Figure 1. Left ventricular hypertrophy by voltage criteria with marked global ST segment depression.

Figure 2. Transthoracic parasternal long-axis view; asymmetric septal hypertrophy with normal mitral leaflet closure. Figure 4. Three-dimensional mid-esophageal frame in midsystole. The tricuspid valve is closed with the mitral valve remaining wide open. The aortic valve has closed early due to left ventricular outflow tract (LVOT) obstruction.

Figure 3. Coronary angiogram; myocardial bridging with severe obstruction of the mid-left anterior descending (LAD) artery.

stabilized with resolution of the ECG changes, and a repeat transesophageal echocardiogram (TEE) (Philips Healthcare) 2 days later demonE108

Figure 5. Continuous-wave Doppler through the mitral valve. Symmetrical inflow and regurgitant profiles suggest pressure equalization between the left atrium and ventricle.

HCM with Reversible Free MR

Figure 6. Mid-esophageal long-axis view with color Doppler demonstrating severe left ventricular outflow tract obstruction and a broad jet of mitral regurgitation.

strated complete resolution of the previously described findings, with return of normal mitral leaflet motion and only mild regurgitation (movie clips S7 and S8). Supportive therapy was therefore continued and removal of the peripheral ECMO cannulae performed after 5 days. Further clinical deterioration led to a repeat TEE, which showed recurrence of free mitral regurgitation and severe LVOT obstruction. Surgical intervention was again contemplated but deferred due to positive fungal cultures, and the patient died shortly after from intractable ventricular arrhyth-

mia. Subsequent autopsy confirmed extensive anteroseptal myocardial infarction. Echocardiographically, the appearances of the mitral valve are reminiscent of tricuspid immobility seen in carcinoid heart disease. While the pathophysiology is distinct, this case is unusual as it demonstrates complete reversibility. We hypothesize that the combination of hypertrophy, ischemia, and atrial arrhythmia resulted in repeated myocardial stunning and a vicious cycle of hemodynamic compromise. In spite of a significant anterior wall-motion abnormality, LV ejection fraction was preserved due to an increased myocardial thickness with hypercontractile function in other segments (movie clip S2), and reduced afterload in the context of severe MR. Significantly elevated LV filling pressure may have impaired coronary perfusion beyond the infarct territory, precipitated by the onset of atrial dysrhythmias and worsening mitral regurgitation. Coincident LVOT obstruction and early closure of the aortic valve further reduced cardiac output. The resulting global subendocardial ischemia was manifest in retraction of the papillary muscles and severe apical leaflet tethering (Fig. 7, movie clip S9). Reduced longitudinal motion due to myocardial ischemia is a recognized cause of mitral regurgitation—so called “ischemic” MR. This usually occurs in the context of an inferolateral wall-motion abnormality causing restriction of

Figure 7. Mid-esophageal long-axis views demonstrating reversible papillary muscle dysfunction. A, B. Early diastolic and systolic frames show marked tethering of both mitral leaflets with a large coaptation gap in systole. C, D. Corresponding images obtained 2 days later demonstrate normal papillary muscle function.

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the posterior leaflet and an eccentric posteriorly directed jet. Central “ischemic” MR may also arise from annular dilation with a larger insult involving the anterior territory. Regurgitation by these mechanisms may be reversible or chronic, depending on the outcome of revascularization, or adverse ventricular remodeling following extensive infarction.1 Likewise SAM of the mitral valve is one of the echocardiographic hallmarks of hypertrophic obstructive cardiomyopathy. Previously attributed to a pressure drop caused by flow acceleration in the LVOT (Venturi effect), the pathophysiology is now recognized to be more complex and likely involves a variety of structural and functional abnormalities of the papillary muscles, chordae, and mitral leaflets.2 SAM has been described as a transient or reversible finding in other conditions particularly with dynamic LV contraction, including acute myocardial infarction3 or basal hyperkinesis with takotsubo cardiomyopathy.4 However, the mechanism in this case is unusual with severe papillary muscle traction causing complete noncoaptation of the mitral valve. The resulting regurgitant flow pushes the thickened anterior chordae and leaflet toward the basal septum (movie clip S5), analogous to the previously described phenomenon of “atypical SAM.”5 The role of Tacrolimus in the etiology of HCM in this case is uncertain. There are reports of an association in the pediatric population,6,7 and a more recent case describes partial regression of hypertrophy in an adult after discontinuing Tacrolimus.8 However, an increased prevalence of HCM on echocardiography has not been demonstrated in a large adult transplant cohort taking this medication.9 Despite the relatively frequent coexistence of HCM and myocardial ischemia, the transient nature, pathophysiology, and severity of mitral regurgitation and LVOT obstruction described here are not commonly seen. Despite apparent reversibility of regurgitation, the outcome was poor and recurrence of this scenario might lead the authors to recommend early surgery. However, to our knowledge, there are no series reporting outcomes in similar cases to guide decisions or timing of intervention. References 1. Unger P, Magne J, Dedobbeleer C, et al: Ischemic mitral regurgitation: Not only a bystander. Curr Cardiol Rep 2012;14:180–189. 2. Hagege AA, Bruneval P, Levine RA, et al: The mitral valve in hypertrophic cardiomyopathy: Old versus new concepts. J Cardiovasc Transl Res 2011;4:757–766. 3. Haley JH, Sinak LJ, Tajik AJ, et al: Dynamic left ventricular outflow tract obstruction in acute coronary syndromes: An

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important cause of new systolic murmur and cardiogenic shock. Mayo Clin Proc 1999;74:901–906. Rao RV, Wright D, Dokainish H: Acute mitral regurgitation in suspected acute coronary syndrome: What is the cause? Echocardiography 2013;30:E118–E120. Klues HG, Roberts WC, Maron BJ: Morphological determinants of echocardiographic patterns of mitral valve systolic anterior motion in obstructive hypertrophic cardiomyopathy. Circulation 1993;87:1570–1579. Pappas PA, Weppler D, Pinna AD, et al: Sirolimus in pediatric gastrointestinal transplantation: The use of sirolimus for pediatric transplant patients with tacrolimus-related cardiomyopathy. Pediatr Transplant 2000;4:45–49. Turska-Kmiec A, Jankowska I, Pawlowska J, et al: Reversal of tacrolimus-related hypertrophic cardiomyopathy after conversion to rapamycin in a pediatric liver transplant recipient. Pediatr Transplant 2007;11:319–323. Liu T, Gao Y, Gao YL, et al: Tacrolimus-related hypertrophic cardiomyopathy in an adult cardiac transplant patient. Chin Med J (Engl) 2012;125:1352–1354. Coley KC, Verrico MM, McNamara DM, et al: Lack of tacrolimus-induced cardiomyopathy. Ann Pharmacother 2001;35:985–989.

Supporting Information Additional Supporting Information may be found in the online version of this article: Movie clip S1. Marked septal hypertrophy and mild mitral regurgitation seen from the parasternal long-axis view (Codec MPEG-1). Movie clip S2. Transgastric imaging demonstrates preserved ejection fraction despite anterior wall akinesis (Codec MPEG-1). Movie clip S3. A Three-dimensional reconstruction looking from the atrial aspect shows the mitral valve to be widely patent throughout the cardiac cycle (Codec MPEG-1). Movie clip S4. Mid-esophageal four-chamber view. Color Doppler is relatively unimpressive despite free mitral regurgitation (Codec MPEG-1). Movie clip S5. Systolic anterior motion of the anterior mitral leaflet results in near occlusion of the left ventricular outflow tract. Note the short duration of aortic valve opening (Codec MPEG-1). Movie clip S6. Further color Doppler assessment of mitral regurgitation and left ventricular outflow tract obstruction (Codec MPEG-1). Movie clip S7. Repeat transesophageal imaging demonstrates a return of normal mitral leaflet motion with mild regurgitation (Codec MPEG-1). Movie clip S8. Resolution of mitral valve function seen on three-dimensional imaging, reconstructed from the atrial aspect (Codec MPEG-1). Movie clip S9. Mid-esophageal view demonstrating marked apical tethering of both mitral leaflets, seen throughout the cardiac cycle (Codec MPEG-1).

Hypertrophic cardiomyopathy with intermittent free mitral regurgitation-a surgical dilemma.

We describe the case of a 52-year-old woman presenting with non-ST elevation myocardial infarction, atrial fibrillation, and a new diagnosis of hypert...
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