CASE REPORT
European Journal of Cardio-Thoracic Surgery 48 (2015) 334–335 doi:10.1093/ejcts/ezu351 Advance Access publication 1 October 2014
Cite this article as: Shimahara Y, Kobayashi J, Fujita T, Sato S. Transapical myectomy and surgical cryoablation for refractory ventricular tachycardia due to hypertrophic cardiomyopathy with apical aneurysm. Eur J Cardiothorac Surg 2015;48:334–5.
Transapical myectomy and surgical cryoablation for refractory ventricular tachycardia due to hypertrophic cardiomyopathy with apical aneurysm Yusuke Shimahara*, Junjiro Kobayashi, Tomoyuki Fujita and Shunsuke Sato Department of Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Osaka, Japan * Corresponding author. Department of Cardiovascular Surgery, National Cerebral and Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan. Tel: +81-6-68335012; fax: +81-6-68727486; e-mail: [email protected] (Y. Shimahara). Received 13 March 2014; received in revised form 15 July 2014; accepted 5 August 2014
Abstract Ventricular tachycardia (VT) associated with midventricular hypertrophic cardiomyopathy and apical aneurysm is rare, but is frequently refractory to medical therapy. We report a case of a 44-year old man with incessant VT despite undergoing catheter ablation in the neck of a left ventricular apical aneurysm. Resection of a hypertrophied midventricular muscle through an apical incision and surgical cryoablation of the aneurysm border from the epicardial and endocardial surface were performed successfully. The patient was well without ventricular arrhythmic events at 2 years postoperatively. Keywords: Ventricular tachycardia • Hypertrophic cardiomyopathy • Surgical treatment • Cryoablation
INTRODUCTION Monomorphic ventricular tachycardia (VT) is considered a rare complication of hypertrophic cardiomyopathy (HCM) and more likely to occur in midventricular HCM with apical aneurysm [1]. When antiarrhythmic agents fail to control VT, catheter ablation may be helpful. However, catheter ablation is not always successful and cannot treat intracavitary obstruction. Although an implantable cardioverter-defibrillator (ICD) is the main treatment for VT, recurrent ICD shocks aggravate the prognosis and the quality of life [2]. Here, we describe successful transapical myectomy and surgical cryoablation for refractory VT due to HCM.
CASE REPORT A 44-year old man with HCM developed chest pain with subsequent loss of consciousness. A diagnosis of repetitive monomorphic VT accompanied by HCM with apical aneurysm was established. As intravenous antiarrhythmic treatment was not effective, epicardial and endocardial catheter ablation was performed at the septum in the apical aneurysm border where voltage mapping indicated the focus of VT (Fig. 1A). However, catheter ablation failed to terminate the VT, and the patient was referred to our hospital. Electrocardiogram-gated computed tomography angiography (CTA) revealed a midventricular hypertrophied myocardium with a wall thickness of 30 mm and apical cavity ballooning (Fig. 1B and C). We decided to perform emergency surgery to eliminate VT and midventricular obstruction.
The operation was performed by median sternotomy and cardiopulmonary bypass with bicaval cannulation. The direct intracavitary pressure measurement showed a pressure gradient of 50 mmHg across the midventricular obstructive portion. After cardioplegic arrest, a 6-cm incision was made along the left anterior descending artery at the apex of the left ventricle (LV). The LV muscle from the apex to the mid-portion was resected gradually and carefully through the apical incision (Fig. 2A). Then, the apical aneurysm border in the septum was ablated from the epicardial and endocardial surface simultaneously using a cryoablation system (CCS-200, Cooper Surgical, Shelton, CT, USA) (Fig. 2B). The probe was cooled to −60°C and applied for 3 min. The incision was closed using double polypropylene running sutures. The direct pressure measurement revealed no pressure gradient across the mid-portion of the LV. The total mass of the resected LV muscle was 35.0 g (Fig. 2C). The postoperative course was uncomplicated. Postoperative CTA revealed the significantly augmented LV cavity (Fig. 1D and E). The patient remained free from VT recurrence at two years postoperatively.
DISCUSSION In patients with HCM, catheter ablation is sometimes inadequate because a VT circuit is often located deep within the hypertrophic myocardium [1]. In addition, haemodynamic pressure overload of the LV apex due to mid-cavitary obstruction is regarded as a potential cause of VT onset. In such cases, surgical myectomy
© The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
Y. Shimahara et al. / European Journal of Cardio-Thoracic Surgery
335
Figure 1: (A) A 3D bipolar voltage map of the combined LV endocardium and epicardium. The image above shows that the earliest activation sites in the septum of aneurysm border were ablated from the surface of both the endocardium and the epicardium. The image below demonstrates the epicardial low voltage zone in the LV apex. (B and C) Preoperative electrocardiogram-gated CTAs during the diastolic (B) and systolic (C) phases show the hypertrophied muscle obstructing the mid-cavity of the LV and apical ballooning. (D and E) Postoperative electrocardiogram-gated CTAs during the diastolic (D) and systolic (E) phases show the left ventricular cavity enlarged by surgery. There is no pressure gradient across the LV mid-portion and outflow tract. CTA: computed tomography angiography; LV: left ventricle; RV: right ventricle.
combined with cryoablation can be effective. Transapical myectomy is an efficient procedure for enlarging the LV cavity, increasing stroke volumes and eliminating intracavitary obstruction while preserving the mitral apparatus [3, 4]. Surgical cryoablation under cardiac arrest can ablate deep lesion, and preoperative electroanatomical mapping enables accurate lesion set [5]. In the present case, transapical myectomy and cryoablation were effective for refractory VT due to midventricular HCM with apical aneurysm. Although the patient, who has been taking amiodarone and a beta-blocker, has not had any cardiac events without ICD implantation, close observation needs to be continued.
Conflict of interest: none declared.
REFERENCES [1] Dukkipati SR, d’Avila A, Soejima K, Bala R, Inada K, Singh S et al. Long-term outcomes of combined epicardial and endocardial ablation of monomorphic ventricular tachycardia related to hypertrophic cardiomyopathy. Circ Arrhythm Electrophysiol 2011;4:185–94. [2] Wissner E, Stevenson WG, Kuck KH. Catheter ablation of ventricular tachycardia in ischaemic and non-ischaemic cardiomyopathy: where are we today? A clinical review. Eur Heart J 2012;33:1440–50. [3] Shah DK, Schaff HV, Abel MD, Gersh BJ. Ventricular tachycardia in hypertrophic cardiomyopathy with apical aneurysm. Ann Thorac Surg 2011;91:1263–5. [4] Kunkala MR, Schaff HV, Nishimura RA, Abel MD, Sorajja P, Dearani JA et al. Transapical approach to myectomy for midventricular obstruction in hypertrophic cardiomyopathy. Ann Thorac Surg 2013;96:564–70. [5] Anter E, Hutchinson MD, Deo R, Haqqani HM, Callans DJ, Gerstenfeld EP et al. Surgical ablation of refractory ventricular tachycardia in patients with nonischemic cardiomyopathy. Circ Arrhythm Electrophysiol 2011;4:494–500.
CASE REPORT
Figure 2: Intraoperative photographs show the apical ventriculotomy lateral to the left anterior descending artery (arrowheads) (A) and surgical cryoablation of the apical aneurysm border (B). The excised specimen consisted of small muscle fragments because the muscle was resected carefully and gradually/slowly (C).
European Journal of Cardio-Thoracic Surgery 48 (2015) 334–335 doi:10.1093/ejcts/ezu351 Advance Access publication 1 October 2014
Cite this article as: Shimahara Y, Kobayashi J, Fujita T, Sato S. Transapical myectomy and surgical cryoablation for refractory ventricular tachycardia due to hypertrophic cardiomyopathy with apical aneurysm. Eur J Cardiothorac Surg 2015;48:334–5.
Transapical myectomy and surgical cryoablation for refractory ventricular tachycardia due to hypertrophic cardiomyopathy with apical aneurysm Yusuke Shimahara*, Junjiro Kobayashi, Tomoyuki Fujita and Shunsuke Sato Department of Cardiovascular Surgery, National Cerebral and Cardiovascular Center, Osaka, Japan * Corresponding author. Department of Cardiovascular Surgery, National Cerebral and Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan. Tel: +81-6-68335012; fax: +81-6-68727486; e-mail: [email protected] (Y. Shimahara). Received 13 March 2014; received in revised form 15 July 2014; accepted 5 August 2014
Abstract Ventricular tachycardia (VT) associated with midventricular hypertrophic cardiomyopathy and apical aneurysm is rare, but is frequently refractory to medical therapy. We report a case of a 44-year old man with incessant VT despite undergoing catheter ablation in the neck of a left ventricular apical aneurysm. Resection of a hypertrophied midventricular muscle through an apical incision and surgical cryoablation of the aneurysm border from the epicardial and endocardial surface were performed successfully. The patient was well without ventricular arrhythmic events at 2 years postoperatively. Keywords: Ventricular tachycardia • Hypertrophic cardiomyopathy • Surgical treatment • Cryoablation
INTRODUCTION Monomorphic ventricular tachycardia (VT) is considered a rare complication of hypertrophic cardiomyopathy (HCM) and more likely to occur in midventricular HCM with apical aneurysm [1]. When antiarrhythmic agents fail to control VT, catheter ablation may be helpful. However, catheter ablation is not always successful and cannot treat intracavitary obstruction. Although an implantable cardioverter-defibrillator (ICD) is the main treatment for VT, recurrent ICD shocks aggravate the prognosis and the quality of life [2]. Here, we describe successful transapical myectomy and surgical cryoablation for refractory VT due to HCM.
CASE REPORT A 44-year old man with HCM developed chest pain with subsequent loss of consciousness. A diagnosis of repetitive monomorphic VT accompanied by HCM with apical aneurysm was established. As intravenous antiarrhythmic treatment was not effective, epicardial and endocardial catheter ablation was performed at the septum in the apical aneurysm border where voltage mapping indicated the focus of VT (Fig. 1A). However, catheter ablation failed to terminate the VT, and the patient was referred to our hospital. Electrocardiogram-gated computed tomography angiography (CTA) revealed a midventricular hypertrophied myocardium with a wall thickness of 30 mm and apical cavity ballooning (Fig. 1B and C). We decided to perform emergency surgery to eliminate VT and midventricular obstruction.
The operation was performed by median sternotomy and cardiopulmonary bypass with bicaval cannulation. The direct intracavitary pressure measurement showed a pressure gradient of 50 mmHg across the midventricular obstructive portion. After cardioplegic arrest, a 6-cm incision was made along the left anterior descending artery at the apex of the left ventricle (LV). The LV muscle from the apex to the mid-portion was resected gradually and carefully through the apical incision (Fig. 2A). Then, the apical aneurysm border in the septum was ablated from the epicardial and endocardial surface simultaneously using a cryoablation system (CCS-200, Cooper Surgical, Shelton, CT, USA) (Fig. 2B). The probe was cooled to −60°C and applied for 3 min. The incision was closed using double polypropylene running sutures. The direct pressure measurement revealed no pressure gradient across the mid-portion of the LV. The total mass of the resected LV muscle was 35.0 g (Fig. 2C). The postoperative course was uncomplicated. Postoperative CTA revealed the significantly augmented LV cavity (Fig. 1D and E). The patient remained free from VT recurrence at two years postoperatively.
DISCUSSION In patients with HCM, catheter ablation is sometimes inadequate because a VT circuit is often located deep within the hypertrophic myocardium [1]. In addition, haemodynamic pressure overload of the LV apex due to mid-cavitary obstruction is regarded as a potential cause of VT onset. In such cases, surgical myectomy
© The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
Y. Shimahara et al. / European Journal of Cardio-Thoracic Surgery
335
Figure 1: (A) A 3D bipolar voltage map of the combined LV endocardium and epicardium. The image above shows that the earliest activation sites in the septum of aneurysm border were ablated from the surface of both the endocardium and the epicardium. The image below demonstrates the epicardial low voltage zone in the LV apex. (B and C) Preoperative electrocardiogram-gated CTAs during the diastolic (B) and systolic (C) phases show the hypertrophied muscle obstructing the mid-cavity of the LV and apical ballooning. (D and E) Postoperative electrocardiogram-gated CTAs during the diastolic (D) and systolic (E) phases show the left ventricular cavity enlarged by surgery. There is no pressure gradient across the LV mid-portion and outflow tract. CTA: computed tomography angiography; LV: left ventricle; RV: right ventricle.
combined with cryoablation can be effective. Transapical myectomy is an efficient procedure for enlarging the LV cavity, increasing stroke volumes and eliminating intracavitary obstruction while preserving the mitral apparatus [3, 4]. Surgical cryoablation under cardiac arrest can ablate deep lesion, and preoperative electroanatomical mapping enables accurate lesion set [5]. In the present case, transapical myectomy and cryoablation were effective for refractory VT due to midventricular HCM with apical aneurysm. Although the patient, who has been taking amiodarone and a beta-blocker, has not had any cardiac events without ICD implantation, close observation needs to be continued.
Conflict of interest: none declared.
REFERENCES [1] Dukkipati SR, d’Avila A, Soejima K, Bala R, Inada K, Singh S et al. Long-term outcomes of combined epicardial and endocardial ablation of monomorphic ventricular tachycardia related to hypertrophic cardiomyopathy. Circ Arrhythm Electrophysiol 2011;4:185–94. [2] Wissner E, Stevenson WG, Kuck KH. Catheter ablation of ventricular tachycardia in ischaemic and non-ischaemic cardiomyopathy: where are we today? A clinical review. Eur Heart J 2012;33:1440–50. [3] Shah DK, Schaff HV, Abel MD, Gersh BJ. Ventricular tachycardia in hypertrophic cardiomyopathy with apical aneurysm. Ann Thorac Surg 2011;91:1263–5. [4] Kunkala MR, Schaff HV, Nishimura RA, Abel MD, Sorajja P, Dearani JA et al. Transapical approach to myectomy for midventricular obstruction in hypertrophic cardiomyopathy. Ann Thorac Surg 2013;96:564–70. [5] Anter E, Hutchinson MD, Deo R, Haqqani HM, Callans DJ, Gerstenfeld EP et al. Surgical ablation of refractory ventricular tachycardia in patients with nonischemic cardiomyopathy. Circ Arrhythm Electrophysiol 2011;4:494–500.
CASE REPORT
Figure 2: Intraoperative photographs show the apical ventriculotomy lateral to the left anterior descending artery (arrowheads) (A) and surgical cryoablation of the apical aneurysm border (B). The excised specimen consisted of small muscle fragments because the muscle was resected carefully and gradually/slowly (C).
