Perioperative Ventricular Arrhythmias in Patients Undergoing Partial Left Ventriculectomy

BACKGROUND: Although incidence of ventricular arrhythmias after partial left ventriculectomy (PLV) has been reported, there are no studies comparing incidence before and after PLV. Although operative scars may give rise to arrhythmias, improved energetic efficiency after PLV may decrease their incidence. METHODS: Pre- and postoperative ventricular arrhythmias were monitored by Holter ECG and analyzed in 17 patients undergoing PLV in Curitiba, Brazil. RESULTS: Although total 24-hour heart beat (THB) increased significantly (p = 0.018), ventricular premature contractions (VPCs) decreased markedly (p = 0.036), excluding one patient dying in low cardiac output (LOS) who had terminal arrhythmias increased multifold. In the remaining 16 patients, VPC pairs were also reduced significantly on the average (p = 0.038). In contrast, ventricular tachycardia (VT; more than three consecutive VPCs) disappeared in five patients, decreased in two patients, and newly occurred in four patients, with five patients showing no change; one of them developed a prolonged VT, successfully reversed by external cardioversion. CONCLUSIONS: Despite notable significant increase in THB immediately after PLV, PVC and PVC pairs were significantly decreased in contrast to VT, which disappeared in some patients and newly occurred in other patients, remaining constant on the average. Sustained VT occurring in a patient with all other arrhythmias suppressed may suggest a unique electrophysiological substrate, may justify prophylactic use of amiodarone or an implantable cardioverter-defibrillator, and may underscore the importance of further and extended studies.     

A Rat Model of Dilated Cardiomyopathy to Investigate Partial Left Ventriculectomy

Background: This study is the first to assess a small animal model of dilated cardiomyopathy (DCM) for evaluation of partial left ventriculectomy. Method: Eighteen Dahl salt-sensitive (DS) rats were divided into three groups. Six rats were fed an 8% high-salt diet from the age of 7 weeks (Group 1), and similarly six rats from 8 weeks (Group 2) and six from 9 weeks (Group 3). Blood pressure (BP) was measured by the tail-cuff method and left ventricular (LV) dimensions by echocardiography. Results: In Groups 1 and 2, systolic BP rose and reached 200 mmHg by the 10th to 11th week, when all rats died within a week without signs of heart failure. However, in Group 3, systolic BP gradually rose to 196 ± 15 mmHg (mean ± SD) at the age of 14 weeks, when LV end-diastolic diameter (EDD) was 6.2 ± 0.4 mm (control 5.1 ± 0.7 mm) and LV fractional shortening (FS) was 77 ± 3% (control 68 ± 3%). At the age of 25 to 30 weeks, all rats in Group 3 showed signs of congestive heart failure, systolic BP remained high, EDD markedly increased (8.7 ± 0.6 mm), and LVFS decreased (38.9 ± 8.1%). From this stage, rats survived for 13.7 ± 5.9 days. We employed the Group 3 model for our pilot PLV study. Eight rats had PLV with a beating heart by plicating the LV area between the papillary muscle bases. Two rats died perioperatively but the rest survived (60% survival 3 weeks after PLV). Postoperatively, the rats' LVEDD decreased and FS improved significantly. Conclusions: Using DS rats, we developed a DCM model for investigating PLV. The model may contribute to scientific investigation of PLV.     

Impact of Apex-Sparing Partial Left Ventriculectomy on Left Ventricular Geometry, Function, and Long-Term Survival of Patients with End-Stage Dilated Cardiomyopathy

Abstract   Background and Aim : Currently, partial left ventriculectomy (PLV) has not been widely accepted as a treatment option for dilated cardiomyopathy (DCM) because its results thus far have been inconsistent. In an animal study, apex-sparing PLV (AS-PLV) was shown to produce greater improvement in left ventricle (LV) function than conventional PLV in which the apex was removed. The aim of this study is to investigate the effectiveness of AS-PLV in a clinical setting. Patients and Methods: From September 1999 to December 2007, 13 patients with DCM underwent AS-PLV. Left ventriculotomy was made in the thinnest portion of the lateral wall without injuring the apex, the papillary muscles, and the circumflex coronary artery, which supplies the neighboring myocardium. Results: All patients were discharged from the hospital, except for one patient who developed refractory ventricular fibrillation on postoperative day 35. After AS-PLV, the LV diastolic dimension decreased from 71 ± 10 mm to 55 ± 9 mm; LV ejection fraction (EF) from 28%± 8% to 39%± 11%; and New York Heart Association (NYHA) class from 3 ± 1.7 to 1.5 ± 0.6; the differences were significant (p < 0.01). LV function and geometry remained unchanged 2 years after AS-PLV with LVDD of 60 ± 7 mm, LVEF of 34%± 8%, and NYHA class of 1.7 ± 0.6, respectively (N.S vs. at discharge). Conclusions: Regardless of the etiology of LV dilatation, AS-PLV restored the ellipsoidal shape of the LV and improved LV function. AS-PLV is a feasible option for treating diseased LVs with lateral wall lesions.     

Partial Left Ventriculectomy for Patients with Ischemic Cardiomyopathy

BACKGROUND: Partial left ventriculectomy (PLV) has been performed in patients with dilated cardiomyopathy (DCM), but improved myocardial energetics may make PLV useful also for ischemic cardiomyopathy (ICM) unamenable to conventional treatment. METHODS: Of 262 patients undergoing PLV, 94 patients with ICM as the underlying pathology were analyzed and compared with 168 patients with DCM. RESULTS: ICM patients were older (57.3 years vs 50.9 years, p = 0.0001) and heavier (69.7 kg vs 65.9 kg, p = 0.039) than those with DCM, but ventricular end-diastolic and end-systolic dimensions were similar with comparably depressed fractional shortening (16% vs 15%, p = 0.294) and equally severe functional limitation [New York Heart Association (NYHA) Class 3.7 vs 3.6, p = 0.734]. A majority of patients in both groups underwent lateral PLV (76% vs 74%, p = 0.883) with myocardium excised between papillary muscles and simultaneous mitral valvuloplasty (41% vs 74%, p < 0.0001). Because ICM patients required coronary artery bypass grafting (CABG) more frequently (79% vs 0.6%, p < 0.0001), operation was more extensive in terms of bypass time (74 minutes vs 47 minutes, p < 0.0001), percentage requiring cardiac arrest (43% vs 19%, p < 0.0001), and arrest duration (34 minutes vs 28 minutes, p = 0.280), but all had similar resection and postoperative ventricular dimensions. Nonetheless, ICM patients required shorter intensive care unit (ICU) time (4.4 days vs 5.9 days, p = 0.048) and similar postoperative hospital stays, resulting in similar hospital survival rates (69% vs 71%, p = 0.778) and functional capacity in long-term follow-up. CONCLUSIONS: Results suggest that PLV can be performed in patients with ICM with comparable risks and benefits as in DCM. Relative efficacy of CABG and mitral repair as compared to volume reduction remains to be studied.     

Partial Left Ventriculectomy to Improve Left Ventricular Function in End-Stage Heart Disease

A bstract We present a case of a 34-year-old male with dilated cardiomyopathy in whom we performed a new surgical procedure; i.e., ventricular volume reduction to improve function. This initial human experience was preceded by a series of ten sheep in which we demonstrated that by enlarging the left ventricle (LV), the ejection fraction was reduced, and by restoring normal diameter, the LV function returned to normal.     

Improved Left Ventricular Contraction and Energetics in a Patient with Chagas' Disease Undergoing Partial Left Ventriculectomy

A 43-year-old patient with heart failure, precluded from heart transplantation or dynamic cardiomyoplasty because of Chagas' disease cardiomyopathy, mitral regurgitation, and ventricular mural thrombi, underwent mitral valvuloplasty and partial left ventriculectomy (PLV) between the papillary muscles. Intraoperative pressure-volume relationship analyses suggested improvement in left ventricular contraction, energetics, isovolumic relaxation, and mitral valve competency. These improvements allowed prompt, short-term recovery despite unchanged myocardial pathology, which suggests that a surgical approach can alter anatomic-geometric factors and achieve clinical improvement in a dilated failing ventricle.     

Enterovirus RNA Replication in Cases of Dilated Cardiomyopathy: Light Microscopic In Situ Hybridization and Virological Analyses of Myocardial Specimens Obtained at Partial Left Ventriculectomy

OBJECTIVE: Recently, attention has been focused on enteroviral infection of the heart in the genesis of dilated cardiomyopathy (DCM). To determine the location of enteroviral RNA in the myocardium, we performed light microscopic in situ hybridization (ISH) and virological analyses of myocardial specimens obtained at partial left ventriculectomy (PLV). METHODS: Posterolateral walls of the left ventricle from 26 DCM patients were examined. Myocardial specimens were tested for the presence of enteroviral genomes by polymerase chain reaction (PCR). We selected two age-matched groups (10 patients each) in which enteroviruses were either present (EV-plus group) or not (EV-minus group). For both groups, we examined in situ localization of enteroviral RNA in the myocardium by ISH. RESULTS: In PCR studies, both sense and antisense enteroviral RNA were detected in the myocardium of seven patients in the EV-plus group. The presence of this RNA indicates active viral replication in the myocardium. Five of seven patients who exhibited both sense and antisense enteroviral RNA died early after surgery. On ISH, three patients had evidence of active replication of enteroviral genomes. Viral genomes were present in myocardial lesions, especially in endocardial sites. Viral signals were found in degenerating myocardial cells, interstitial inflammatory cells, and endothelial cells of small vessels. These positive signals were not detected in the myocardium of the EV-negative group. CONCLUSIONS: We detected both sense and antisense enteroviral RNA in various myocardial lesions. This suggests that active enteroviral replication plays a role in the development of myocardial lesions in DCM patients. Active viral replication appears to be a prognostic factor for DCM after PLV. Further study of active viral replication in myocardial lesions will provide information useful for evaluating different therapeutic strategies for DCM.     

Partial Left Ventriculectomy: History, Current Status, and Future Role

Whereas discouraging clinical results and lack of scientific evidence decreased the initial interest in partial left ventriculectomy (PLV), factors contributing to success and failure have now been identified by clinical observations, theoretical analyses, and data from an international registry, which are herein reviewed to outline the current status and future role of this procedure as a treatment of heart failure.     

Left Ventricular Assist for Pediatric Patients With Dilated Cardiomyopathy Using the Medos Vad Cannula and a Centrifugal Pump

Ventricular assist devices for small pediatric patients are expensive and commercially unavailable in Taiwan. We used the Medos ventricular assist device cannula (Medos, Aachen, Germany) and a centrifugal pump to support pediatric patients with dilated cardiomyopathy and decompensated heart failure. From January 2007 to December 2008, three pediatric patients with dilated cardiomyopathy were supported using a centrifugal pump as the left ventricular assist device. The Medos arterial cannula was sutured to the ascending aorta, and the Apex cannula was fixed into the left ventricular apex. When the patient was weaned off of cardiopulmonary bypass, the left ventricular assist device pump was started. The pump flow was gradually titrated according to the filling status of the left ventricle. All the left ventricular assist devices were successfully implanted and functioned well. Two patients on extracorporeal membrane oxygenation had severe lung edema before left ventricular assist device implantation. Both patients required extracorporeal membrane oxygenation for the postoperative period until the pulmonary edema was resolved. Among the three patients, two successfully bridged to heart transplantation after support for 6 and 11 days, respectively. The first patient (10 kg) expired due to systemic emboli 30 days after left ventricular assist device support. In summary, these results suggest that the Medos ventricular assist device cannula and a centrifugal pump is an option for temporary left ventricular assist device support in patients with intractable heart failure and as a bridge to heart transplantation.     

Experimental Study of a New Operative Procedure for Nonischemic Dilated Cardiomyopathy: Overlapping Cardiac Volume Reduction Operation

Purpose: To assess a newly devised procedure for cardiac volume reduction without resecting any cardiac muscle and evaluate its effectiveness in an experimental settings. Methods: Ten beagle dogs underwent a rapid pacing leading to heart failure for 3 weeks and then underwent left ventricular reduction by a procedure called the overlapping cardiac volume reduction operation (OLCVR), which consisted of a longitudinal incision in the left ventricular (LV) free wall, sutures from the left margin to the septal wall, and the right margin to the LV free wall. A slope of the linear preload recruitable stroke work relationship (M _w), with an X-intercept (V _o) were calculated as precise indicators of the LV systolic function. The constant of isovolumic pressure decay (Tau) and the peak filling rate (PFR) were also calculated as indicators of the LV diastolic function. Results: The LV end-diastolic dimensions significantly decreased by OLCVR (43 ± 2 to 25 ± 1 mm). Fractional shortening significantly improved by OLCVR (11% ± 2% to 30% ± 4%). M _w (erg · cm⁻³ · 10³) also significantly improved (21 ± 2 to 33 ± 3 (P < 0.001)), whereas V _o, Tau, and PFR did not show any significant changes. Conclusion: The OLCVR significantly increased the early LV systolic function without any detrimental effects on the diastolic function. This procedure may therefore be a useful therapeutic option for end-stage cardiomyopathy. Received: April 8, 2002 / Accepted: September 3, 2002 Reprint requests to: Y. Matsui, Department of Cardiovascular Surgery, NTT East Corporation Sapporo Hospital, South 1 West 15, Sapporo 060-0061, Japan     

Ischemic Cardiomyopathy Due to Localized Takayasu Arteritis Treated by Heart Transplantation Following Left Ventricular Assisted Device Implantation: A Case Report

A 19-year-old Asian woman presented to the emergency department with ventricular fibrillation. Emergent coronary angiography revealed a 99% ostial stenosis of the left main coronary trunk, and percutaneous coronary intervention was performed. Takayasu arteritis was suspected, but fluorodeoxyglucose positron emission tomography scanning showed no active inflammation. Cardiac function was affected by ischemic cardiomyopathy, and an extracorporeal left ventricular assisted device was implanted under INTERMACS profile 1 status. Histopathology of the ascending aortic wall at the outflow anastomosis site showed no significant sign of Takayasu arteritis. The absence of systemic inflammation led to the replacement of the extracorporeal left ventricular assisted device with a Jervik 2000 as a bridge to transplant. An orthotropic heart transplant took place after a 39-month wait. Histopathology of the explanted heart revealed intimal and adventitial thickening with destruction of the elastic lamina localized at the sinus of Valsalva. Our final pathologic diagnosis was localized Takayasu arteritis. To counter the increased risk of stenosis or pseudoaneurysm formation at the vascular anastomosis site, anti-inflammatory therapy was essential in Takayasu arteritis. The post-heart transplant immunosuppression regime was considered stronger than that for Takayasu arteritis, and we therefore administered prednisolone, mycophenolate mofetil, and tacrolimus as standard protocol. There have been no signs of either relapse or rejection of transplantation for over 1 year. Further closed observation is required to clarify the long-term outcome of this rare condition with regard to heart transplantation.