International Journal of Cardiology 180 (2015) 60–62

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International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard

Letter to the Editor

Dynamic left ventricular outflow tract obstruction causing myocardial ischemia Julie He a, Brian Malm a,b,⁎ a b

Yale University, Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, United States Department of Cardiology, VA Connecticut Healthcare System, West Haven, CT, United States

a r t i c l e

i n f o

Article history: Received 10 November 2014 Accepted 22 November 2014 Available online 26 November 2014 Keywords: Echocardiography Left ventricular outflow tract Systolic anterior motion Mitral valve Ischemia

A 71 year old male with hypertension, hyperlipidemia, and diabetes presented to an outside hospital with exertional chest pain. He underwent an exercise myocardial perfusion study during which he developed chest pain and ischemic ECG changes (Fig. 1A–B). His myocardial perfusion imaging was normal. A transthoracic echocardiogram was obtained and interpreted as showing significant aortic stenosis. He was subsequently transferred to our medical center for further management. In the interim, he developed atrial fibrillation with rapid ventricular response. A repeat transthoracic echocardiogram (Fig. 2 A–B) revealed severe left ventricular outflow tract (LVOT) obstruction with a peak resting gradient of 64 mm Hg, mild concentric left ventricular hypertrophy with proximal septal thickening and preserved ejection fraction. A mobile echodensity was noted in the LVOT suggestive of systolic anterior motion of the mitral valve versus a sub-aortic membrane. The aortic valve was tri-leaflet and opened normally. The patient underwent a transesophageal echocardiogram (Fig. 2 C–D) which revealed a myxomatous anterior mitral valve leaflet with mild mitral regurgitation and systolic anterior motion leading to LVOT obstruction. There was no subaortic membrane. He was in sinus rhythm during this exam with a peak LVOT gradient of 27 mm Hg. Coronary angiography was normal (Fig. 3A–B). He subsequently underwent a treadmill stress echocardiogram which was terminated for chest pain and ischemic ⁎ Corresponding author at: Department of Cardiology, VA Connecticut Healthcare System, 950, Campbell Avenue, West Haven, CT 06516, United States. E-mail address: [email protected] (B. Malm).

http://dx.doi.org/10.1016/j.ijcard.2014.11.136 0167-5273/Published by Elsevier Ireland Ltd.

ECG changes. Continuous-wave Doppler imaging measured an LVOT gradient of 17 mm Hg at rest which increased to 84 mm Hg immediately following exercise (Fig. 3C–D). The patient was managed with beta-blockers and referred for mitral valve surgery. We present a case of a patient with exertional angina and inducible ischemia in the setting of dynamic left ventricular outflow tract obstruction, systolic anterior motion of the mitral valve (SAM), and normal coronary arteries. This presentation is common in patients with hypertrophic cardiomyopathy but has also been reported in other settings, including elderly patients [1] and patients with endstage renal disease [2]. Abnormalities of the mitral valve can account for a significant proportion of LVOT obstruction cases [3]. Dynamic LVOT obstruction during pharmacologic stress with dobutamine has been previously described [4]. Although dobutamine may provoke SAM [5], only a minority of these patients will go on to develop SAM with physiologic exercise stress testing [6]. Predisposing factors to developing LVOT obstruction include female gender and hypertension [4]. In a study of 300 patients referred for exercise echocardiography, Zywica et al. found dynamic LVOT obstruction in 5% of patients with 44% also demonstrating signs of ischemia [7]. In this study, independent predictors of exercise-induced LVOT obstruction were systolic anterior motion of the mitral valve, hyperdynamic LV function, small ventricular size, increased septal wall thickness, high peak systolic blood pressure, and interestingly, younger age. The strongest predictor was systolic anterior motion of the mitral valve, as was seen in our case. In a study of patients with dynamic LVOT obstruction during exercise and normal wall thickness, all patients had structural abnormalities of the mitral valve including elongated, redundant leaflets and anterior position of the papillary muscles [8]. Our patient had concentric left ventricular hypertrophy, proximal septal thickening, and SAM, all of which predisposed him to developing dynamic LVOT obstruction. In summary, in patients with demonstrable myocardial ischemia in the absence of obstructive coronary disease, exercise induced dynamic LVOT obstruction should be considered. Mitral valve abnormalities are common in this setting and are best evaluated with transesophageal echocardiography. Conflict of interest The authors report no relationships that could be construed as a conflict of interest.

J. He, B. Malm / International Journal of Cardiology 180 (2015) 60–62

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Fig. 1. 12-Lead ECG at rest (A) and during exercise (B) demonstrating ST depressions in leads II, III, aVF, V5, and V6 consistent with ischemia.

Fig. 2. Transthoracic echocardiogram showing an echodensity in the left ventricular outflow tract (A, arrow) and a continuous wave Doppler peak velocity of 4 m/s (B). Transesophageal echocardiogram showing systolic anterior motion of the mitral valve (C, arrow) and color Doppler evidence of turbulent flow in the left ventricular outflow tract (D).

Acknowledgments No funding source was used for this manuscript.

References [1] M. Henein, C. O'Sullivan, G. Sutton, D. Gibson, A. Coats, Stress-induced left ventricular outflow tract obstruction: a potential cause of dyspnea in the elderly, J. Am. Coll. Cardiol. 30 (1997) 1301–1307.

[2] R. Sharma, D. Pellerin, D. Gaze, M. Rajnikant, H. Gregson, C. Streather, P. Collinson, S. Brecker, Dynamic left ventricular outflow obstruction: a potential cause of angina in end stage renal disease, Int. J. Cardiol. 112 (2006) 295–301. [3] B. Maron, Hypertrophic cardiomyopathy: a systematic review, J. Am. Med. Assoc. 287 (2002) 1308–1320. [4] M.J. Sorrentino, et al., Left ventricular outflow tract obstruction as a cause for hypotension and symptoms during dobutamine stress echocardiography, Clin. Cardiol. 19 (1996) 225–230. [5] P.A. Pellikka, et al., Dynamic intraventricular obstruction during dobutamine stress echocardiography. A new observation, Circulation 86 (1992) 1429–1432. [6] P. Meimoun, et al., Significance of systolic anterior motion of the mitral valve during dobutamine stress echocardiography, J. Am. Soc. Echocardiogr. 18 (2005) 49–56.

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Fig. 3. Coronary angiography demonstrating normal left (A) and right (B) coronary arteries. Continuous-wave Doppler measuring an LVOT gradient of 17 mm Hg at rest (C) and 84 mm Hg following exercise (D).

[7] K. Zywica, R. Jenni, P. Pellikka, A. Faeh-Gunz, B. Seifert, Jost C. Attenhofer, Dynamic left ventricular outflow tract obstruction evoked by exercise echocardiography: prevalence and predictive factors in a prospective study, Eur. J. Echocardiogr. 9 (2008) 665–671.

[8] E. Alhaj, B. Kim, D. Cantales, S. Uretsky, F. Chaudhry, M. Sherrid, Symptomatic exercise-induced left ventricular outflow tract obstruction without left ventricular hypertrophy, J. Am. Soc. Echocardiogr. 26 (2013) 556–565.

Dynamic left ventricular outflow tract obstruction causing myocardial ischemia.

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