Copyright © 2016 International Anesthesia Research Society. Unauthorized reproduction of this article is prohibited. Copyright © 2016 International Anesthesia Research Society. Unauthorized reproduction of this article is prohibited. 1094 www.anesthesia-analgesia.org November 2016 • Volume 123 • Number 5 W ritten informed consent was obtained from the patient for publication of this report. A 59-year-old man with hypertrophic cardiomyopathy (HCM) was referred to our institution for myectomy. His symp- toms included nonradiating midsternal pain and shortness of breath occurring after mild to moderate physical activ- ity. A preoperative transthoracic echocardiogram revealed systolic anterior motion (SAM) of the anterior mitral leafet, which increased markedly with exercise resulting in a peak systolic left ventricular outfow tract (LVOT) gradient of 129 mm Hg. A peak systolic left ventricular midcavity gradient of 73 mm Hg was also noted. The basal septum was mod- erately hypertrophic with a thickness of 1.5 cm. Cardiac magnetic resonance (CMR) imaging was also performed to evaluate papillary muscle (PM) morphology. Apart from a mild hypertrophy of the anterolateral PM, CMR was unre- markable. Since medical management did not improve symptoms, surgical myectomy was advised. Intraoperative transesophageal echocardiography (TEE) confrmed SAM, systolic fow acceleration in LVOT, and mitral regurgitation of 2+ severity (Figure 1). A hypertro- phic anterolateral PM (Figure 2) with abnormal movement toward the interventricular septum during systole was also observed (Supplemental Digital Content 1, Video 1, http:// links.lww.com/AA/B498). Further evaluation using 3D TEE revealed a muscle bridge originating from the antero- lateral PM and attaching itself to the interventricular sep- tum (Supplemental Digital Content 2, Video 2, http://links. lww.com/AA/B499). This abnormal subvalvular anatomy resulted in abnormal displacement of anterolateral PM toward the septum during systole, causing LVOT obstruc- tion. The details of the abnormal PM anatomy were commu- nicated with the surgical team, aided by 3D images. Routine echocardiographic measurement of the septum was also obtained to determine the extent of myectomy. The anatomy seen on 3D echocardiography was confrmed surgically. In addition to standard septal myectomy, the verti- cally oriented bridging segment of the anterolateral PM was excised. After separation from cardiopulmonary bypass, TEE confrmed absence of SAM (Supplemental Digital Content 3, Video 3, http://links.lww.com/AA/B500), and showed triv- ial mitral regurgitation and absent LVOT gradients (Figure 3), on provocation with isoproterenol at 20 μg/min). Rest of the surgery and postoperative stay was unremarkable. DISCUSSION HCM, with a prevalence of 1 in 500 adult individuals, is the most commonly inherited cardiovascular disease. Presence of LVOT obstruction is the most important predictor of adverse outcome among these patients. 1 The classically described mechanism is LVOT narrowing and SAM due to asymmetric hypertrophy of the basal interventricular sep- tum. However, advent of newer imaging modalities, such as 3D echocardiography and CMR, has improved our under- standing about the role of mitral subvalvular apparatus in the pathophysiology of LVOT obstruction. Various pheno- typic variations and abnormalities of the mitral subvalvular apparatus are reported in HCM, some being associated with dynamic LVOT obstruction, even in the absence of signif- cant septal hypertrophy. For instance, an anteroapically dis- placed PM would drag the mitral valve leafet toward the LVOT, resulting in SAM and LVOT obstruction. Location of PM on the apical one-third of the left ventricle, as measured by CMR, increased the risk of LVOT obstruction. Similarly, a double bifd PM and direct insertion of PM into anterior mitral leafet has been associated with LVOT obstruction. 2,3 HCM-related PM abnormalities described in literature are enumerated in the Table. PM characterization is lacking in contemporary 2D or 3D echocardiography. Some investigators recommend trans- gastric midpapillary short-axis and 2-chamber views, and midesophageal commissural view to interrogate PM mor- phology. 4 Literature is silent on standard 3D TEE evaluation of PM morphology, but the concept may be extrapolated from CMR imaging. Multiplanar reconstruction of 3D data set allows the operator to reliably align the 2D planes along the desired structures. For instance, aligning the 2 longitu- dinal axes in the 3D volume to traverse the left ventricular apex can ensure that the reconstructed 2D midesophageal views are not foreshortened, but has the left ventricular apex truly represented. This could assist in quantifying api- cal displacement of PM. Furthermore, the functionality of adaptive cropping, provided by certain vendors, enhances understanding of spatial anatomical relationship between structures in question. In our case, this allowed us to inter- rogate the anatomy of the PM in relation to interventricu- lar septum. In comparison with 2D imaging, 3D neither improves image quality nor resolution, but provides a bet- ter insight into morphological relationship between struc- tures. In addition, 3D data sets with adequate frame rates can give important dynamic temporal information adding value to the intraoperative diagnostic imaging. Real-time orthogonal imaging, which most 3D probes are capable Copyright © 2016 International Anesthesia Research Society DOI: 10.1213/ANE.0000000000001553 From the *Department of Cardiothoracic Anesthesiology; and †Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic, Cleveland, Ohio. Accepted for publication June 27, 2016. Funding: None. The authors declare no conficts of interest. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s website (www.anesthesia-analgesia.org). Reprints will not be available from the authors. Address correspondence to Abraham Sonny, MD, Department of Cardio- thoracic Anesthesiology, Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH 44195. Address e-mail to absonny@gmail.com. Abnormalities of Mitral Subvalvular Apparatus in Hypertrophic Cardiomyopathy: Role of Intraoperative 3D Transesophageal Echocardiography Abraham Sonny, MD,* Shiva Sale, MD,* and Nicholas G. Smedira, MD† ECHO ROUNDS E