Effects of Septal Myectomy on Left Ventricular Diastolic Function and Left Atrial Volume in Patients With Hypertrophic Cardiomyopathy Albree Tower-Rader, MD, Nicholas Furiasse, MD, Jyothy J. Puthumana, MD, Jane Kruse, RN, Zhi Li, MS, Adin-Cristian Andrei, PhD, Vera Rigolin, MD, Robert O. Bonow, MD, MS, Patrick M. McCarthy, MD, and Lubna Choudhury, MD, MRCP* Ventricular septal myectomy in patients with obstructive hypertrophic cardiomyopathy (HC) has been shown to reduce left ventricular (LV) outflow tract (LVOT) gradient and improve symptoms, although little data exist regarding changes in left atrial (LA) volume and LV diastolic function after myectomy. We investigated changes in LA size and LV diastolic function in patients with HC after septal myectomy from 2004 to 2011. We studied 25 patients (age 49.2 – 13.1 years, 48% women) followed for a mean of 527 days after surgery who had serial echocardiography at baseline and at most recent follow-up, at least 6 months after myectomy. In addition to myectomy, 3 patients (12%) underwent Maze surgery and 13 (52%) underwent mitral valve surgery, of whom 5 had a mitral valve replacement or mitral annuloplasty. Patients with mitral valve replacement or mitral annuloplasty were excluded from LV diastolic function analysis. LA volume index decreased (from 47.2 – 17.6 to 35.9 – 17.0 ml/m2, p [ 0.001) and LV diastolic function improved with an increase in lateral e0 velocity (from 7.3 – 2.9 to 9.8 – 3.1 cm/sec, p [ 0.01) and a decrease in E/e0 (from 14.8 – 6.3 to 11.7 – 5.5, p [ 0.051). Ventricular septal thickness and LVOT gradient decreased, and symptoms of dyspnea and heart failure improved, with reduction in the New York Heart Association functional class III/IV symptoms from 21 (84%) to 1 (4%). In conclusion, relief of LVOT obstruction in HC by septal myectomy results in improved LV diastolic function and reduction in LA volume with improved symptoms. Ó 2014 Elsevier Inc. All rights reserved. (Am J Cardiol 2014;114:1568e1572) Hypertrophic cardiomyopathy (HC) is a common genetic cardiovascular disease that causes symptomatic left ventricular (LV) outflow tract (LVOT) obstruction in a proportion of patients resulting in symptoms of heart failure. Atrial fibrillation (AF) with or without thromboembolic complications or sudden cardiac death occurs in about 13% of patients.1 Septal myectomy is an established therapy for patients with obstructive HC with symptoms refractory to maximal medical therapy and results in improved LVOT obstruction, decreased mitral regurgitation, and symptomatic improvement.2e4 Left atrial (LA) dilation has been shown to be associated with an increased incidence of AF and stroke, and in patients with HC, it has also been shown to be a marker for decreased exercise tolerance and increased incidence of morbidity and mortality related to heart failure and stroke.5e11 Although reduction in LVOT gradient and improvement in symptoms are well documented, little data exist regarding changes in LA volume and LV diastolic parameters after septal myectomy in HC. We sought to further explore whether LV diastolic function and LA size improve after septal myectomy with or without mitral valve repair and whether there is a decreased incidence of AF after this procedure.

Division of Cardiology, Department of Medicine, Bluhm Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois. Manuscript received June 12, 2014; revised manuscript received and accepted August 5, 2014. See page 1571 for disclosure information. *Corresponding author: Tel: (312) 695-0059; fax: (312) 695-0063. E-mail address: [email protected] (L. Choudhury). 0002-9149/14/$ - see front matter Ó 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.amjcard.2014.08.029

Methods All patients were identified from the Bluhm Cardiovascular Institute’s Clinical Trials Unit Cardiovascular Research Database approved by the Institutional Review Board at Northwestern University (IRB #STU00012288). Preoperative, operative, and postoperative data were obtained from the database and medical record review, and data were de-identified before analysis. Patients who did not opt to participate in the research database are not included in this study. Patients aged 18 years who underwent septal myectomy for refractory symptoms on maximally tolerated medical therapy, with or without concomitant mitral valve or Maze surgery, at our institution from June 1, 2004, to December 31, 2011, were eligible for inclusion in the study. Analysis of preoperative and postoperative echocardiograms was performed. The postoperative echocardiogram selected for analysis was the most recent echocardiogram after the first 6 months after surgery. Patients were excluded if preoperative and postoperative echocardiograms were not available for review. Obstructive HC was defined by the presence of symptoms with a peak LVOT gradient of 30 mm Hg at rest or 50 mm Hg with provocation or at rest.12 Patients were noted to have AF if it was documented by electrocardiogram, ambulatory monitoring, or telemetry, only if it occurred after 30 days from surgery. Using the recommendations from the American Society of Echocardiography, 2-dimensional and Doppler echocardiographic measurements were performed.13 In the apical 4-chamber view, pulse-wave Doppler was used at the tips of www.ajconline.org

Cardiomyopathy/Diastolic Function and LAVI After Septal Myectomy


Table 2 Preoperative and follow-up comparison of echocardiographic characteristics Pre-Operative (n ¼ 25)

Follow-Up (n ¼ 25)

47.2  17.6 35.9  17.0 LA volume index (ml/m2) LV end systolic dimension (cm) 2.8  0.7 3.2  0.7 LV end diastolic dimension (cm) 4.2  0.5 4.5  0.6 Interventricular septal thickness 2.1  0.5 1.5  0.3 (cm) Posterior wall thickness (cm) 1.2  0.2 1.2  0.2 LV mass index 146.1  50.8 118.5  33.2 LV ejection fraction (%) 64.2  7.5 63.2  11.2 E velocity (cm/sec)* 96.8  27.0 98.9  30.4 A velocity (cm/sec)* 70.9  21.4 84.2  27.8 E/A ratio* 1.4  0.5 1.2  0.4 Deceleration time (msec)* 256.0  64.7 226.4  71.0 Lateral e0 velocity (cm/sec)* 7.3  2.9 9.8  3.1 Lateral E/e0 ratio* 14.8  6.3 11.7  5.5 5.4  1.1 20.7  10.9 Septal e0 velocity (cm/sec)* Septal E/e0 ratio* 18.4  7.2 5.6  1.7 LV outflow tract gradient 52.2  51.3 18.2  25.0 (mm Hg)

Table 1 Demographic and clinical characteristics Pre-Operative (n ¼ 25) 49  13 12 (48%) 13 (52%) 10 (40%) 3 (12%) 2 (8%) 3 (12%) 0 527

Age at surgery (years) Women Mitral valve surgery Alfieri repair Annuloplasty Replacement Maze surgery Coronary bypass Time to post-operative echo from surgery (days) Pre-Operative and Follow-Up Comparison

Pre-Operative Follow-Up p-Value (n ¼ 25) (n ¼ 25) Systolic blood pressure (mm Hg) Diastolic blood pressure (mm Hg) Heart rate (beats/minute) LVOT gradient >30 mm Hg at rest Atrial fibrillation Dyspnea NYHA functional class III/IV Moderate/severe mitral regurgitation

114  23 70  14 72  11 14 (56%) 4 (16%) 23 (92%) 21 (84%) 10 (40%)

120  18 72  10 73  13 4 (16%) 3 (12%) 3 (12%) 1 (4%) 3 (12%)

0.001 0.007 0.012

Effects of septal myectomy on left ventricular diastolic function and left atrial volume in patients with hypertrophic cardiomyopathy.

Ventricular septal myectomy in patients with obstructive hypertrophic cardiomyopathy (HC) has been shown to reduce left ventricular (LV) outflow tract...
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