Ann Thorac Surg 2007;84:1236-1242
© 2007 The Society of Thoracic Surgeons
Original Articles: Cardiovascular
Sustained Benefits of the CorCap Cardiac Support Device on Left Ventricular Remodeling: Three Year Follow-up Results From the Acorn Clinical Trial
Randall C. Starling, MD, MPHa,*,*,
Mariell Jessup, MDb,
Jae K. Oh, MDd,
Hani N. Sabbah, PhD, ACCe,
Michael A. Acker, MDc,
Douglas L. Mann, MDf,
Spencer H. Kubo, MD, FACCg
a The Cleveland Clinic, Kaufman Center for Heart Failure, Cleveland, Ohio
b Department of Cardiology, University of Pennsylvania, Philadelphia, Pennsylvania
c Department of Cardiothoracic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania
d Department of Cardiology, Mayo Clinic, Rochester, Minnesota
e Department of Cardiology, Henry Ford Health System, Detroit, Michigan
f Department of Cardiology, Baylor College of Medicine, Houston, Texas
g Acorn Cardiovascular Inc, St. Paul, Minnesota
Accepted for publication March 20, 2007.
* Address reprint requests to Dr Starling, Section of Heart Failure and Cardiac Transplant Medicine, Cleveland Clinic, Department of Cardiovascular Medicine, Desk F-25, 9500 Euclid Avenue, Cleveland, OH 44195 (Email: starlir{at}ccf.org).
| All authors disclose that they have a financial relationship with Acorn Cardiovascular.
|
 |
Abstract
|
|---|
Background: The objective of this study was to assess the long-term effects of the CorCap Cardiac Support Device (CSD; Acorn Cardiovascular, Inc, St. Paul, MN) on left ventricular (LV) structure and function in patients with heart failure. Cardiac support devices, which reduce LV wall stress, have been shown to promote reverse remodeling in three different experimental models of heart failure. However, long-term effects in patients with heart failure have not been reported.
Methods: We enrolled 300 patients with heart failure in the Acorn Randomized Trial, as previously reported (Ann Thorac Surg 2007;84:1226–35). Echocardiograms were obtained every six months until the last patient was followed for one year, and then annually thereafter. Standard measurements of LV volumes, ejection fraction, and sphericity index were made by a Core laboratory at the Mayo Clinic who were blinded to treatment assignment.
Results: Patients treated with the CorCap Cardiac Support Device had significant reductions in LV end diastolic volume (average difference 18.8 mL; p = 0.005) and LV end systolic volume (average difference 15.6 mL; p = 0.013) compared with the control group. Sphericity index was significantly increased in the treatment group (average difference 0.045 units; p = 0.018). These changes were maintained over three years of follow-up. The improvements in LV size and shape were observed when the CorCap was implanted concomitantly with mitral value surgery or by itself.
Conclusions: These results demonstrate that the CorCap Cardiac Support Device has a long-term beneficial impact on LV size and shape in patients with heart failure.
Left ventricular (LV) remodeling is characterized by LV enlargement, a change from an ellipsoidal to a more spherical shape and a decreased ejection fraction [1]. These changes are important in the pathophysiology of heart failure because they are strong predictors of survival and because many therapies with known effectiveness in heart failure have beneficial effects on reversing or attenuating the remodeling process [2]. Cardiac support devices (CSD), which provide circumferential diastolic support to reduce LV wall stress, have been shown to promote reverse remodeling in three different experimental models of heart failure [3–6]. Early clinical experience has confirmed these findings using both echocardiography and electron beam tomography [7–9]. However, the long-term effects of the CSD in humans on the remodeling process have not been demonstrated.
Results of the Acorn Randomized Trial have been presented elsewhere [10]. Compared to control patients, CSD treatment patients had a statistically significant improvement in a clinical composite score based on survival, the need for additional major cardiac procedures, and a change in a Core lab assessment of New York Heart Association functional class. The purpose of this report is to summarize the extended (three years) effects of the cardiac support device on echocardiographic measures of LV remodeling.
|
Material and Methods
|
|---|
The overall design of the Acorn Trial has been presented elsewhere [11]. In brief, 300 patients with heart failure, who were receiving optimal medical therapy, were enrolled. Patients who had significant mitral regurgitation and a clinical indication for mitral valve repair-replacement (MVR) were enrolled in the MVR stratum (193 patients), and were randomized to either treatment (MVR surgery plus CSD) or control (MVR surgery alone). Patients without mitral regurgitation (
2+) were enrolled in the no-MVR stratum, and were randomized to either treatment (CSD implant plus optimal medical therapy) or control (optimal medical therapy alone).
Patient eligibility criteria, follow-up visit schedule, and surgical implant techniques have all been described previously [10, 11]. This study was approved by the Institutional Review Boards of the participating institutions. No individual patients were identified in this manuscript.
Echocardiographic Core Lab
All studies (transthoracic 2-D, Doppler, and color flow imaging) were sent to the Echocardiography Core Laboratory at the Mayo Clinic. Images and recordings were digitized by a research sonographer using the Digiview (Digisonics, Inc, Houston, TX) workstation and stored in an optical disk. Quantitative analyses for LV volume were performed by a research sonographer and approved by a Core Lab cardiologist. All measurements and analyses were performed without knowledge of any clinical or randomization data. An average of two to three cycles were used for sinus rhythm; in atrial fibrillation or in frequent ectopic rhythms, three to five cardiac cycles with an adequate RR interval were used.
Left Ventricular Dimensions
Left ventricular dimensions were measured from parasternal long-axis view primarily for short-axis dimension at a point immediately distal to the mitral leaflet. If this view was not available, the parasternal short-axis view at the midventricular level was used. In each patient, the same view was used to record LV dimension for every follow-up period. Long-axis dimension was measured from an apical four-chamber view. The LV sphericity was calculated as the ratio of the LV long-axis dimension and the maximum short-axis dimension.
LV Volume and LVEF Measurement
Left ventricular volume was measured by the biplane Simpson volumetric method. A combination of apical four- and two-chamber views was preferentially used. If an apical two-chamber view was not available, a combination of apical four- and long-axis views were used. The LV endocardial border was traced contiguously from one side of the mitral annulus to the other side excluding the papillary muscles and trabeculations. Left ventricular ejection fraction (LVEF) was calculated using the following formula:
|
Mitral Regurgitation
Evaluation of mitral regurgitation was performed primarily from semiquantitative assessment of color flow imaging, visualized from the parasternal long-axis and apical views. The largest mitral regurgitant jet area from color Doppler imaging was measured and severity of MR was graded according to American Society of Echocardiography guideline [12] MR jet area (< 4.0 cm2 was defined as mild MR, MR jet area > 10 cm2 as severe MR, and MR jet area in-between as moderate MR).
Statistical Analysis
Echocardiographic parameters included change in LVEDV, LVESV, LVEF, LV sphericity index, and mitral regurgitation. Comparison of changes from baseline to 36 months were evaluated with longitudinal regression analysis, using a mixed effects model in which follow-up visit was the repeated measure and the baseline values of the response was included as a covariant. All differences were considered significant at the p < 0.05 level (two-sided).
|
Results
|
|---|
The study enrolled 300 patients and the last patient was enrolled on June 20, 2003. As of June 15, 2006, the median duration of follow-up was 40.9 months, with a range of 0 to 71.9 months. There was a total of 944 patient-years of follow-up. Baseline demographics of enrolled patients are described in detail in Table 1
of a previous reference [10]. In brief, enrolled patients had advanced heart failure, as evidenced by increased LV end-diastolic dimensions, decreased LVEF, reduced baseline peak oxygen consumption, and reduced Minnesota Living with Heart Failure scores.
Mortality
Over the entire duration of follow-up, there were 41 deaths among 152 patients in the control group (crude mortality rate: 27.0%) and 38 deaths among 148 patients (crude mortality rate: 25.7%) in the treatment group (Fig 1). This resulted in a relative risk reduction of 4.8% favoring the treatment group. Although this small difference was not statistically significant, there was no late adverse effect on mortality associated with implantation of the CorCap CSD. This study was not powered to detect a mortality benefit.
View larger version (11K):
[in this window]
[in a new window]
|
Fig 1. Mortality: June 2006. Kaplan-Meier mortality curves for the CorCap cardiac support device (CSD: Acorn Cardiovascular) treatment group (solid line) and the control group (dotted line) for patients followed out to four years. The CorCap CSD treatment group had a lower crude mortality rate (25.7%) when compared to the control group (27.0%, risk reduction of 4.8%) but this difference was not significant. (--- = control [C]; — = treatment [T; cardiac support device].)
|
|
LV End Diastolic Volume
Figure 2
summarizes the longitudinal regression analyses for the changes in LV end diastolic volume. Table 1 summarizes the baseline values. When compared with the control group, the treatment group showed a significantly greater decrease that averaged 18.8 mL (p = 0.005). Thus the effect of the CSD to reduce LV volume was evident early and was maintained throughout the follow-up period.
View larger version (13K):
[in this window]
[in a new window]
|
Fig 2. All Patients: June 2006. Changes in left ventricular end-diastolic volume (LVEDV) for the CorCap cardiac support device (Acorn Cardiovascular) treatment group (solid line) and the control group (dotted line). When compared with the control group, the treatment group showed a significantly greater decrease in LVEDV (average difference = 18.8 mL; p = 0.005). The effect of the CorCap CSD to reduce LVEDV was evident early and was maintained throughout the follow-up period.
|
|
Figure 3
summarizes the changes in LVEDV in the two strata. In the MVR stratum (left hand panel) the control group (MVR surgery alone) demonstrated a progressive reduction in LVEDV, indicating that MV surgery alone can result in reverse remodeling, as evidenced by the smaller LVEDV. The treatment group (MV surgery plus CorCap CSD) shows incremental benefit. Thus, the addition of the CorCap CSD to MV surgery results in a smaller ventricle; the treatment effect averaged 16 mL over the 36 month follow-up period (p = 0.032).
View larger version (29K):
[in this window]
[in a new window]
|
Fig 3. Changes in left ventricular end-diastolic volume (LVEDV) in the two strata. In the mitral valve replacement (MVR) stratum (top), the control group (MVR surgery alone) demonstrated a progressive reduction in LVEDV. The treatment group (MVR surgery plus CorCap cardiac support device [CSD; Acorn Cardiovascular) show incremental benefit (average difference = 16.0 mL; p = 0.032). In the no-MVR stratum (bottom), the control group (medical therapy alone) shows no consistent change in LVEDV until an apparent increase during late follow-up. The treatment group (CorCap CSD) shows consistently smaller LV size (average treatment effect = 24.7 mL; p = 0.042).
|
|
In the no-MVR stratum (Fig 3; right hand panel), the control group (medical therapy alone) shows no consistent change in LVEDV until an apparent increase in LV size during the late follow-up period. This progressive LV enlargement could reflect the relentless natural history of heart failure. In contrast, the CSD treatment group shows a consistently smaller LV size. At the three year follow-up point, the differences between the control and treatment groups appear to be larger. The average treatment effect was 24.7 mL over the 36 month follow-up period (p = 0.042).
LV End Systolic Volume
A similar pattern of change was observed for LV end systolic volume (LVESV) (Fig 4, and baseline values in Table 1). When compared with the control group, the treatment group showed a significantly greater decrease of approximately 15.6 mL (p = 0.013). The smaller LVESV in the treatment group was evident early and was maintained throughout the follow-up period.
View larger version (13K):
[in this window]
[in a new window]
|
Fig 4. All patients: June 2006. Changes in left ventricular end-systolic volume (LVESV) for the CorCap cardiac support device (CSD; Acorn Cardiovascular) treatment group (solid line) and the control group (dotted line). The treatment group showed a significantly greater decrease of approximately 15.6 mL when compared with the control group (p = 0.013). The effect of the CorCap CSD to reduce LVESV was indicated early and was maintained throughout the follow-up period.
|
|
Figure 5
summarizes the changes in LVESV in the two strata. In the MVR stratum (left hand panel), the control group (MV surgery alone) demonstrated a progressive reduction in LVESV. In the treatment group, the addition of the CorCap CSD to MV surgery led to a significantly smaller LVESV (average difference of 13.8 mL; p = 0.048). In the no-MVR stratum (right hand panel), the control group (medical therapy alone) showed no consistent change in LVESV with an apparent increase during the late follow-up period. In contrast, the CorCap CSD group shows consistently smaller LVESV with an average difference of 22.2 mL, which was trending toward statistical significance (p = 0.054).
View larger version (28K):
[in this window]
[in a new window]
|
Fig 5. Changes in left ventricular end-systolic volume (LVESV) in the two strata. In the mitral valve replacement (MVR) stratum (top), the control group (MV surgery alone) demonstrated a progressive reduction in LVESV. In the treatment group, the addition of the CorCap cardiac assist device (CSD; Acorn Cardiovascular) to MV surgery led to a significantly smaller LVESV (average difference of 13.8 mL; p = 0.048). In the no-MVR stratum (bottom), the control group (medical therapy alone) showed no consistent change in LVESV. In contrast, the CorCap CSD group shows a smaller LVESV with an average difference of 22.2 mL (p = 0.054).
|
|
LV Ejection Fraction
Changes in LVEF for the entire group of 300 patients are shown in Figure 6
and baseline values in Table 1. There were no consistent differences in EF between the treatment and control groups. In the MVR stratum (Fig 7; left hand panel), the treatment group tended to have a higher LVEF when compared with the control group but this difference was not maintained during all follow-up periods and was not statistically significant. In the no-MVR stratum (Fig 7; right hand panel), there were no consistent differences in LVEF between the treatment and control groups.
View larger version (11K):
[in this window]
[in a new window]
|
Fig 6. Changes in left ventricular ejection fraction (LVEF) for the entire group of 300 patients. There were no consistent differences in EF between the treatment (solid line) and control (dotted line) groups.
|
|
View larger version (24K):
[in this window]
[in a new window]
|
Fig 7. Changes in left ventricular ejection fraction (LVEF) for the two strata. In the mitral valve replacement (MVR) stratum (top) the treatment group tended to have a higher LVEF when compared with the control group, but this difference was not maintained during all follow-up periods and was not statistically significant. In the no-MVR stratum (bottom), there were no consistent differences in LVEF between the treatment and control groups.
|
|
LV Sphericity Index
An increase in sphericity index is consistent with the left ventricle returning to a more elliptical shape. For all patients (Fig 8), both the control and treatment groups demonstrated an increase in LV sphericity index. However, the increase was greater in the treatment group (average difference of 0.045 units; p = 0.018). In the MVR stratum (Fig 9; left hand panel), the control group demonstrated an increase in LV sphericity index, suggesting that MVR surgery could result in a more elliptical-shaped ventricle. However, the addition of the CorCap CSD to MV surgery (treatment group) led to a significantly greater increase in sphericity index (p = 0.002). In the no-MVR stratum, the control group demonstrated an early increase in sphericity index that returned to baseline levels by three years. In contrast, the treatment group tended to have a higher sphericity index, although this difference was not statistically significant.
View larger version (12K):
[in this window]
[in a new window]
|
Fig 8. All Patients: June 2006. Changes in left ventricular sphericity index. Both the control (dashed line) and treatment (solid line) groups demonstrated an increase in LV sphericity index. However, the increase was greater in the treatment group (average difference of 0.045 units; p = 0.018).
|
|
View larger version (27K):
[in this window]
[in a new window]
|
Fig 9. In the mitral valve replacement (MVR) stratum (top), the control group demonstrated an increase in left ventricular sphericity index, suggesting that MVR surgery by itself could result in a more elliptical shaped ventricle. However, the addition of the CorCap cardiac support device (CSD; Acorn Cardiovascular) to MV surgery (treatment group) led to a significantly greater increase in sphericity index (p = 0.002). In the no-MVR stratum (bottom), the control group demonstrated an early increase in sphericity index that returned to baseline levels by three years. In contrast, the treatment group tended to have a higher sphericity index, although this difference was not statistically significant.
|
|
Mitral Regurgitation
In the MVR stratum, both the treatment and control groups receive MV repair or replacement surgery, which resulted in a dramatic reduction in the severity of mitral regurgitation. During long-term follow-up, the treatment group (MVR plus CorCap CSD) compared with the control group (MVR alone) tended to have a lower score for MR (–0.19 grade) but this difference was not statistically significant (p = 0.10). In the no-MVR stratum there were no significant changes in the MR grade in either the control (medical therapy alone) or treatment groups (medical therapy plus CorCap CSD).
Adverse Events
Table 2
contains the serious adverse events (AEs) in the MVR (left hand panel) and no-MVR stratum (right hand panel). Overall, the total number of AEs were similar between the treatment and control groups in both the MVR stratum (89.0% vs 85.3%; p = 0.40) and the no-MVR stratum (82.5% vs 80%; p = 0.74). In the MVR stratum, the treatment group had a greater incidence of neurologic deficit-stroke (17.6% vs 7.8%; p = 0.039) but this difference was not confirmed and in fact was reversed in the no-MVR stratum (5.3% vs 10%; p = 0.39). In the MVR stratum, there was a trend for an increase in hemodynamic compromise (hemodynamic compromise was defined as signs or symptoms of vital organ hypoperfusion or deterioration in cardiac performance) (67.0% vs 53.9%; p = 0.06). In the no-MVR stratum, the treatment group tended to have a higher incidence or pulmonary compromise (15.8% vs 10.0%; p = 0.35) and renal compromise (14.0% vs 4.0%; p = 0.08). These differences are likely related to the fact that in the no-MVR stratum, the treatment group undergoes implant surgery while the control group does not.
The most common cited concern about CorCap CSD implantation is the long-term risk of pericardial constriction. During this extended follow-up, there have been no cases of constriction detected either clinically or during the surveillance echocardiograms read using standardized criteria. However, since constriction may take many years to develop, further monitoring is indicated.
|
Comment
|
|---|
The principal finding from this three year follow-up study of echocardiograms from patients enrolled in the Acorn Randomized Trial is that implantation of the CorCap Cardiac Support Device is safe in patients with heart failure and leads to beneficial cardiac remodeling that is characterized by reduced LV volume and a more elliptical LV shape. These data also suggest that the beneficial changes reported previously [10] were durable and maintained throughout the three year follow-up period. These findings provide important new information that addresses the long-term efficacy of the CorCap Cardiac Support Device. Further, there were no safety concerns with the device at three years and no clinically significant device-related complications.
The background for the Acorn Trial was based on extensive preclinical experience in three different animal models of heart failure, including heart failure induced by intracoronary microembolism in the dog, rapid ventricular pacing in the sheep, and coronary ligation in the dog. Data from all three models showed a consistent effect of the CSD in reducing LV diastolic wall stress and a reversal or regression of LV remodeling. Further, mechanistic studies have provided evidence that the CSD leads to fundamental changes in the biology of the myocyte, including reversal of fetal gene expression, increased adrenergic sensitivity, decreased interstitial fibrosis, increased capillary density, and reduced myocyte hypertrophy [13, 14]. It is important to note that studies of isolated cardiomyocytes have shown that the muscle cells are smaller, thus supporting the argument that the decrease in LV size is not due to a corset-like effect. Finally, safety studies using both echocardiography and electron beam tomography have shown that implantation of the CSD, either alone or with concomitant surgery, will result in a favorable change in the shape and size of the ventricle. The present study confirms all of these changes on reverse remodeling in a prospective, randomized, and controlled trial, with patients now followed out to three years.
One of the strengths of the study is that all echocardiograms were read in a core laboratory using standardized measurement techniques, and with each reader blinded to treatment status (CorCap CSD is not visible during echocardiography). The standardized techniques of a core lab increase the ability of the echocardiography to detect important changes in LV structure. Further, few studies in heart failure have followed patients for three years so this study provides useful data on the natural history of LV structure and function.
The Acorn Trial was comprised of two strata. The no-MVR stratum was the purer test of the CorCap CSD hypothesis because it compared medical therapy alone (no-MVR control group) to the CorCap CSD treatment (no-MVR treatment group) (see right hand panels of Figs 3; 5; 7; and 9). The control group demonstrated a progressive increase in LV size, as expected during the progressive natural history of heart failure. In contrast, the treatment group showed a persistent effect on reducing LV size throughout the follow-up period.
In the MVR stratum, it is worth noting that standard MV surgery with either a MV ring or MVR (control group) also leads to a progressive improvement in LV size and shape. Adding the CorCap CSD on top of MV surgery leads to an additional improvement in LV size and shape.
A similar study reported by St. John Sutton [15] showed durability of reverse remodeling with cardiac resynchronization therapy, but follow-up was for only 12 months. The implications from this study are that a CSD can provide beneficial remodeling when used independently and incremental benefit when used with concomitant therapies.
This study is limited by the fact that additional studies of patient functional status, including quality of life, six-minute walk test, peak exercise oxygen consumption, and levels of brain naturietic peptide were not performed during long-term follow-up. However, patient functional status can be affected by many additional factors and comorbidities during long-term follow-up. Further, data on repeat hospitalizations was not routinely collected during follow-up. This study included only a small number of patients with ischemic heart disease. Additional studies will be necessary to make conclusions about the effects of CorCap in this patient population. Finally, it is important to note that, despite the improvements in left ventricular structure, there was no improvement in survival at three years. A larger sample size and extended follow-up may be required to show a survival advantage. Advantageous reverse remodeling may take years to translate into clinical benefit (reduced hospitalizations) and improved survival. Although additional cardiac surgery will be more tedious in patients receiving the CorCap as is true in any repeat sternotomy, numerous uneventful repeat surgeries have been performed to date in CorCap patients.
In summary, data for the three year follow-up of echocardiogram studies from the Acorn Trial show that implantation of the CorCap Cardiac Support Device, both with and without concomitant MV surgery, lead to beneficial reverse remodeling and that this beneficial effect is sustained during long-term follow-up. Extended follow-up beyond three years will determine the relevance of these observations and whether structural improvement translates, as expected, into improved clinical outcomes.
|
Acknowledgments
|
|---|
The Acorn trial was funded by Acorn Cardiovascular (St. Paul, Minnesota).
|
Footnotes
|
|---|
* On behalf of the Acorn Trial Principal Investigators and Study Coordinators. 
|
References
|
|---|
- Cohn JN. Structural basis for heart failure: ventricular remodeling and its pharmacological inhibition Circulation 1995;91:2504-2507.[Free Full Text]
- Mann DL, Bristow MR. Mechanisms and models in heart failure: the biomechanical model and beyond Circulation 2005;111:2837-2849.[Free Full Text]
- Saavedra WF, Tunin RS, Paolocci N, et al. Reverse remodeling and enhanced adrenergic reserve from a passive external ventricular support in experimental dilated heart failure J Am Coll Cardiol 2002;39:2069-2076.[Abstract/Free Full Text]
- Sabbah HN, Sharov VG, Gupta RC, et al. Reversal of chronic molecular and cellular abnormalities due to heart failure by passive mechanical ventricular containment Circ Res 2003;93:1095-1101.[Abstract/Free Full Text]
- Power JM, Raman J, Dornom A, et al. Passive ventricular constraint amends the course of heart failure: a study in an ovine model of dilated cardiomyopathy Cardiovasc Res 1999;44:549-555.[Abstract/Free Full Text]
- Pilla JJ, Blom AS, Brockman DJ. Passive ventricular constraint improves myocardial left ventricular function and mechanics in a model of heart failure secondary to acute myocardial infarction Circulation 2002;106(suppl I):I-20711.
- Lembcke A, Dushe S, Dohmen PM, et al. Early and late effects of passive epicardial constraint on left ventricular geometry: ellipsoidal re-shaping confirmed by electron-beam computed tomography J Heart Lung Transplant 2006;25:90-98.[Medline]
- Lembcke A, Dushe S, Enzweiler CN, et al. Passive external cardiac constraint improves segmental left ventricular wall motion and reduces akinetic area in patients with non-ischemic dilated cardiomyopathy Eur J Cardiothorac Surg 2004;25:84-90.[Abstract/Free Full Text]
- Starling RC, Jessup M. Worldwide experience with the CorCap Cardiac Support Device J Card Fail 2004;10(6 suppl):S225-S233.[Medline]
- Mann DL, Acker MA, Jessup M, Sabbah HN, Starling RC, Kubo SH. Clinical evaluation of the CorCap Cardiac Support Device in patients with dilated cardiomyopathy Ann Thorac Surg 2007;84:1226-1235.[Abstract/Free Full Text]
- Mann DL, Acker MA, Jessup M, et al. Rationale, design and methods for a pivotal randomized clinical trial for the assessment of the CorCap Cardiac Support Device in patients with NYHA II–IV heart failure J Card Fail 2004;10:185-192.[Medline]
- Zoghbi WA, Enriquez-Sarano M, Foster E, et al. American Society of Echocardiography Recommendations for evaluation of the severity of native valvular regurgitation with two-dimensional and Doppler echocardiography J Am Soc Echocardiogr 2003;16:777-802.[Medline]
- Sabbah HN. Global left ventricular remodeling with the Acorn Cardiac Support Device: hemodynamic and angiographic findings in dogs with heart failure Heart Fail Rev 2005;10:109-115.[Medline]
- Blom AS, Mukherjee R, Pilla JJ, et al. Cardiac support device modifies left ventricular geometry and myocardial structure after myocardial infarction Circulation 2005;112:1274-1283.[Abstract/Free Full Text]
- St. John Sutton MG, Plappert T, Hilpisch KE, Abraham WT, Hayes DL, Chinchoy E. Sustained reverse left ventricular reverse structural remodeling with cardiac resynchronization at one year is a function of etiology Circulation 2006;113:266-277.[Abstract/Free Full Text]
Top
Abstract
Introduction
