Interact CardioVasc Thorac Surg 2008;7:931-932. doi:10.1510/icvts.2008.179192
© 2008 European Association of Cardio-Thoracic Surgery
Case report - Transplantation |
Significance of morphological and electrophysiological left ventricular restoration in idiopathic dilated cardiomyopathy
Takeshi Shimamotoa,*,
Akira Maruia,
Tsutomu Takagib and
Masashi Komedaa,c
a Department of Cardiovascular Surgery, Kyoto University Graduate School of Medicine, 54 Shogoin-Kawahara Sakyo, Kyoto 606-8507, Japan
b Takagi Cardiology Clinic, Kyoto, Japan
c Toyohashi Heart Center, Toyohashi, Japan
Received 4 March 2008;
received in revised form 19 May 2008;
accepted 20 May 2008
*Corresponding author. Tel.: +81-75-751-3784; fax: +81-75-751-4960.
E-mail address: shimamo{at}kuhp.kyoto-u.ac.jp (T. Shimamoto).
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Abstract
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Treatment of non-ischemic dilated cardiomyopathy (NIDCM) remains a challenge. Morphological left ventricular (LV) restoration such as septal anterior ventricular exclusion (SAVE) can be effective in treating NIDCM; however, residual electrophysiological disorders such as atrioventricular and intraventricular conduction disturbances become apparent in the form of atrial fibrillation (AF) and LV dyssynchrony, which deteriorate postoperative LV function. Thus, the combination of morphological and electrophysiological LV restoration may further improve LV function. Here, we report the case of a patient with end-stage NIDCM complicated with AF and LV dyssynchrony, who was successfully treated with the combined use of SAVE, undersized mitral annuloplasty, left atrial (LA) Maze procedure with cryoablation, and postoperative biventricular pacing. This combination treatment was beneficial in restoring the sinus rhythm and LA and LV functions with improved and synergic wall motion by excluding the dyskinetic/akinetic area, downsizing the LV, resolving mitral regurgitation, and optimizing conduction and rhythm abnormalities. Notably, biventricular pacing was shown to be effective in resolving residual dyssynchrony between the septum and lateral wall after SAVE, wherein a firm, non-compliant Dacron patch was sutured to the septum.
Key Words: Cardiomyopathy; Arrhythmia surgery; Left ventricular restoration; Biventricular pacing; Atrial fibrillation
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1. Clinical summary
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A 59-year-old male (162 cm in height, 71 kg in weight, body surface area of 1.76 m2) was referred to our hospital for worsening dyspnea induced by congestive heart failure (CHF) with New York Heart Association class III. Twelve years ago, the patient had undergone aortic valve replacement with a 25-mm Carbomedics bileaflet mechanical prosthesis (CarboMedics Inc., Austin, TX) for aortic regurgitation. The postoperative course was uneventful, and the left ventricular ejection fraction (LVEF) was 53% at the time of discharge. Echocardiogram obtained at admission to our hospital revealed a diffusely hypokinetic LV with akinetic anteroseptal apical wall. The LV diastolic dimension (LVDd) was 76 mm and the LVEF was 21%. The peak and mean pressure gradient across the aortic prosthesis were 16 and 10 mmHg, respectively. In addition, the patient had moderate functional mitral regurgitation (MR) with tethering of the leaflets due to the dilated LV and mitral annulus. Electrocardiogram showed atrial fibrillation (AF) with a wide QRS complex of 190 ms. LV dyssynchrony was present with the delay of peak systolic velocities between septum and lateral wall (septal-to-lateral delay) of 108 ms. The coronary angiogram was intact. Computed tomography scan showed dilatation of the aortic root and proximal aorta, with a maximum diameter of 69 mm.
Surgical ventricular restoration (SVR) by the septal anterior ventricular exclusion (SAVE) technique, replacement of the aortic root and ascending aorta with the Dacron graft; patched coronary reconstruction attached to the forementioned Dacron graft; undersized mitral annuloplasty (UMAP) with a 25-mm flexible annuloplasty ring, and left atrial (LA) Maze procedure with cryoablation [1] were performed through median sternotomy (Video 1). As preparation for biventricular pacing (BiVP), permanent epicardial pacing leads were placed on the right atrium, LV mid-lateral wall, and right ventricular free wall. The aortic cross-clamp time was 177 min, and the cardiopulmonary bypass time was 317 min. With the use of catecholamines and intraaortic balloon pumping (IABP), the patient was weaned off the cardiopulmonary bypass under the sinus rhythm.
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Video 1. Videoclip showing how the operation with multiple procedures was performed and transthoracic echocardiogram both at long axis and short axis view taken intraoperatively, postoperatively without BiVP, and postoperatively with BiVP.
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The postoperative course was uneventful. IABP was terminated on postoperative day (POD) 6. Echocardiogram obtained on POD 28 revealed that LVDd had reduced to 67 mm with LVEF of 19% and septa-to-lateral delay of 108 ms, suggesting that SVR successfully excluded the akinetic anteroseptal apical lesion and downsized the LV; however, the LV function and dyssynchrony between the lateral wall and basal septum did not show any remarkable improvement. On POD 35 when the postoperative inflammation was controlled, a permanent DDD pacemaker was implanted with connections to the epicardial leads placed intraoperatively; consequently, BiVP was initiated. The systolic blood pressure increased by approximately 15 mmHg. The QRS width and septal-to-lateral delay decreased from 190 to 118 ms and from 108 to 2 ms, respectively (Fig. 1). LVDd reduced to 63 mm, and LVEF increased to 24%. On POD 46, the patient was discharged from the hospital with NYHA class I. Two years after the operation, the patient is doing well with NYHA class I, sinus rhythm, LVDd of 65 mm, and LVEF of 25%.
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Fig. 1. Tissue synchronization imaging (TSI) analysis was performed in three apical views – preoperatively, postoperatively without BiVP, and postoperatively with BiVP. The TSI was performed to measure the time to peak myocardial systolic velocity during the ejection phase. These values were subsequently transformed into various color codes depending on the severity of the delay, in the sequence of red, orange, yellow, and green. (a) Schematic presentation of the LV basal septum and lateral wall on an echocardiogram; (b) preoperatively, the patient had moderate wall motion delay in the lateral wall (yellow) and severe wall motion delay in the basal septal wall (green); (c) postoperatively, the corresponding view showed residual wall motion delay between the lateral and septal walls (orange to green); and (d) with BiVP, the wall motion delay between the lateral and septal walls (yellow and orange) reduced significantly.
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2. Discussion
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In NIDCM patients, as the disease progresses and the atrial/ventricular wall tension increases, cardiac structures such as the myocardium, the mitral annulus and the conduction system are overstretched. This leads to serious complications such as AF, MR, LV dyssynchrony, and localized wall motion abnormalities; all these factors have been reported to be predictors of cardiac mortality or CHF worsening [2–4].
Because UMAP alone offers no survival benefit to NIDCM patients, and operative outcome worsens once LVDd exceeds 65 mm [4, 5], additional surgical procedures are necessary for LV reverse remodeling. In NIDCM patients with anteroseptal dyskinesis/akinesis similar to our patient, SVR by the SAVE method reshapes the dilated LV into a more normal elliptical form and offers favorable operative outcome and long-term survival. However, the morphological limitation of the SAVE method is that the basal septum is inevitably left unexcluded to a certain degree when the maintenance of appropriate LV volume is intended postoperatively [6].
Thus far, regarding LV dyssynchrony, there is no established consensus as to whether or not SVR by itself ameliorates or aggravates it [7]. In fact, the wall motion delay between the unexcluded septum and lateral wall did not show any improvement after SVR in our patient. BiVP has emerged as an effective therapy for patients with moderate to severe degree of CHF with LV dyssynchrony [2]; however, the presence of AF is reported to decrease or even nullify the positive effect of BiVP [2]. In our case, LA Maze procedure with cryoablation played a major role in terminating AF and rendering BiVP effective in resynchronizing the motions of lateral wall and the surgically unexcluded basal septum as well as improving the hemodynamic status. Notably, in our case, BiVP was shown to be effective for post SVR status in which a firm, non-compliant Dacron patch was sutured to the septum.
In conclusion, this case indicates that end-stage NIDCM could be treated by the combination of morphological and electrophysiological LV restoration. Long-term follow-up and accumulation of experiences are necessary to prove the efficacy of this treatment.
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References
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Abstract
1. Clinical summary