Ann Thorac Surg 2007;83:1873-1874
© 2007 The Society of Thoracic Surgeons
Case Reports
Cardiac Resynchronization Therapy for Mitral Systolic Anterior Motion in a Child
Gerben Truin, MDa,*,
Ad Backx, MDb,
Herbert van Wetten, MDc,
Chris Neeleman, MD, PhDa
a Pediatric Cardiac Intensive Care, Radboud University Medical Centre Nijmegen, Nijmegen, the Netherlands
b Pediatric Cardiology, Radboud University Medical Centre Nijmegen, Nijmegen, the Netherlands
c Pediatric Thoracic Surgery, Radboud University Medical Centre Nijmegen, Nijmegen, the Netherlands
Accepted for publication November 13, 2006.
* Address correspondence to Dr Truin, Department of Intensive Care and Anesthesiology, Radboud University Medical Centre Nijmegen, Internal Post Number 833, Post Box 9101, Nijmegan, 6500HB the Netherlands (Email: g.truin{at}cukz.umcn.nl).
 |
Abstract
|
|---|
We describe the successful use of cardiac resynchronization therapy for treatment of mitral valve systolic anterior motion with left ventricle outflow tract obstruction after re-excision of a subaortic membrane and septal myectomy in a 12-year-old child. In the recovery phase, a total atrioventricular block persisted. Therefore a permanent atrioventricular pacing system was implanted.
|
Introduction
|
|---|
In recent years, cardiac resynchronization therapy has emerged as a useful therapy in adults with ventricular dysfunction [1, 2]. However, experience with cardiac resynchronization therapy in children is still very limited. Preliminary data show cardiac resynchronization therapy to be effective in pediatric cardiac failure both in the acute postoperative setting as well as in the ambulatory setting [3, 4]. Electrical resynchronization is able to restore ventricular synchrony leading to significant improvement in ventricular performance [5, 6]. The phenomenon of mitral valve systolic anterior motion and its role in left ventricular outflow tract obstruction has been well described in patients with hypertrophic cardiomyopathy [7].
We present the case of a 12-year-old girl with intraoperative systolic anterior motion of the mitral valve, which was successfully treated with cardiac resynchronization therapy.
A 12-year-old girl with congenital subvalvular aortic stenosis underwent resection of a fibrous subaortic membrane at the age of 1 year. She has a bicuspid aortic valve, which is frequently seen in patients with subaortic stenosis. A re-stenosis developed during the following years. Because of progressive left ventricular outflow tract obstruction with a noninvasive measured gradient of 50 mm of mercury and the development of left ventricular hypertrophy, surgery was again required at the age of 12 years.
Re-excision of the subaortic membrane and an extensive septal myectomy was indicated. During the procedure a small ventricular septum defect was made. The defect was closed through the aortic valve with a single "U" suture with pericardial patches for reinforcement. No additional ventricular incision was made in this procedure. Although care was taken to avoid injury to the conduction system, the patient developed a complete atrioventricular block.
As conduction tissue is not visible during the operation, unfortunately we can not pinpoint exactly if the block was created during the septomy or during the closure of the ventricular septum defect. Because of significant bradycardia, standard DDD epicardial pacing was started using a lead on the right ventricle anterior wall and a lead on the right atrium. Intraoperative transesophageal echocardiography showed no residual anatomic left ventricular outflow tract obstruction.
After weaning from cardiopulmonary bypass, transesophageal echocardiography showed a hypokinetic intraventricular septum and systolic anterior motion of the mitral valve (Fig 1), both with and without standard DDD epicardial right atrial and right ventricular pacing. Echocardiography and clinical assessment of the patient showed no signs of a hyperdynamic state of the heart. There was an invasive measured gradient of 120 mm of mercury between the left ventricle and the ascending aorta causing an acute pressure overload of the left ventricle with imminent circulatory failure.
View larger version (74K):
[in this window]
[in a new window]
|
Fig 1. Transesophageal echocardiogram of the systolic anterior motion of the mitral valve (arrow). (AO = aorta; IVS = interventricular septum; LA = left atrium; LV = left ventricle; LVOT = left ventricular outflow tract; RV = right ventricle.)
|
|
We decided to reposition the ventricular epicardial pacing lead on the lateral wall of the left ventricle toward the apex. The position of the left ventricular lead was believed to be in the vicinity of the papillary muscles to synchronize the chordal apparatus (ie, early systolic activation of the papillary muscles), thus preventing the systolic anterior motion of the mitral valve. The leads were attached to a temporary pacemaker (ie, Biotronik EDP 30/S [Biotronik GmbH, Berlin, Germany]) and electrical cardiac resynchronization using right atrial and left univentricular pacing was started. With this pacing strategy the systolic anterior motion of the mitral valve was immediately abolished. A minimal gradient of 10 to 15 mm of mercury between the left ventricle and the ascending aorta and normal mitral valve function without systolic anterior motion was shown by transesophageal echocardiography.
In the postoperative period, the pacemaker was repeatedly switched off to check the possible recurrence of sinus rhythm and cardiac function. After 72 hours, cardiac resynchronization therapy could be discontinued because of an adequate escape rhythm without systolic anterior motion of the mitral valve.
In the subsequent postoperative recovery phase a total atrioventricular block persisted. Therefore a permanent transvenous atrioventricular pacing system with a single ventricular lead in the right ventricular outflow tract was implanted. With this lead position, no recurrence of systolic anterior motion of the mitral valve was observed.
|
Comment
|
|---|
There is little experience with cardiac resynchronization therapy in pediatric patients, and little is known about the optimal pacing sites for this therapy in children. In generally, multisite testing with different right ventricle-left ventricle pacing intervals is considered to be an effective way to optimize cardiac function in chronic heart failure [1, 2]. In our patient, severe systolic anterior motion of the mitral valve with an extreme left ventricle outflow tract pressure gradient of more than 120 mm of mercury occurred intraoperatively both with and without standard DDD pacing using right atrium and right ventricular free wall epicardial leads. Intraoperative mitral systolic anterior motion is generally caused by changes in ventricular geometry and function. Blood flow in the left ventricular outflow tract is believed to lift the mitral valve toward the septum by the Venturi effect [7]. In our patient, showing postoperative changes in ventricular geometry, repositioning of the ventricular lead to the left ventricular lateral wall toward the apex improved ventricular function and immediately eliminated mitral systolic anterior motion. We hypothesized that synchronization of the chordal apparatus by placing the epicardial lead in the vicinity of the papillary muscles played an important role in the improvement of mitral function and treatment of mitral systolic anterior motion. Thus, in our opinion, placing the epicardial lead to the left ventricular free wall toward the apex was of critical importance in abolishing mitral systolic anterior motion and in relieving the acute pressure overload of the left ventricle. As this was the primary goal of resynchronization therapy in our patient, it could be accomplished by univentricular left ventricle pacing. If mitral systolic anterior motion had not been abolished by univentricular pacing at this particular site, multisite testing with different right ventricle-left ventricle pacing intervals would have been indicated to optimize cardiac synchrony and abolish the systolic anterior motion of the mitral valve.
Myocardial stunning as a result of ischemia-reperfusion injury and septal hypokinesia due to intraoperative injury may have played a role in left ventricle dyssynchrony and the development of mitral systolic anterior motion in our patient. Spontaneous improvement of ventricular function in the postoperative period resulted in an adequate escape rhythm without mitral systolic anterior motion making cardiac resynchronization pacing only temporarily necessary. We believe that this is the first report describing cardiac resynchronization for treating acute intraoperative mitral systolic anterior motion in congenital heart surgery. We showed that intraoperative mitral systolic anterior motion can be abolished with a simple technique bridging the period to recovery of ventricular function and geometry in our patient. Cardiac resynchronization is an effective tool in the treatment of acute intraoperative mitral systolic anterior motion.
|
References
|
|---|
- Bradley DJ, Bradley EA, Baughman KL, et al. Cardiac resynchronization and death from progressive heart failure: a meta-analysis of randomized controlled trials JAMA 2003;289:730-740.[Abstract/Free Full Text]
- McAlistar FA, Ezekowitz JA, Wiebe N, et al. Systematic review: cardiac resynchronization in patients with symptomatic heart failure Ann Intern Med 2004;141:381-390.[Abstract/Free Full Text]
- Khairy P, Fournier A, Thibault B, Dubuc M, Therien J, Vobecky SJ. Cardiac resynchronization therapy in congenital heart disease Int J Cardiol 2006;109:160-168.[Medline]
- Dubin AM, Janousek J, Rhee E, et al. Resynchronization therapy in paediatric and congenital heart disease patients: an international multicentre study J Am Coll Cardiol 2005;46:2277-2283.[Abstract/Free Full Text]
- Zimmerman FJ, Starr JP, Koenig PR, Smith P, Hijzai ZM, Bacha EA. Acute hemodynamic benefit of multisite ventricular pacing after congenital heart surgery Ann Thorac Surg 2003;75:1775-1780.[Abstract/Free Full Text]
- Janousek J, Vojtovic P, Hucin B, et al. Resynchronization pacing is a useful adjunct to the management of acute heart failure after surgery for congenital heart disease Am J Cardiol 2001;88:145-152.[Medline]
- Sasson Z, Rakowski H, Wigle ED. Hypertrophic cardiomyopathy Cardiol Clin 1988;6:233-288.[Medline]
This article has been cited by other articles:
|
|
|
|
 
M Luckie and R S Khattar
Systolic anterior motion of the mitral valve--beyond hypertrophic cardiomyopathy
Heart,
November 1, 2008;
94(11):
1383 - 1385.
[Full Text]
[PDF]
|
|
|
Top
Abstract
Introduction
