Interdisciplinary consensus on indications for transfemoral transcatheter aortic valve implantation (TF-TAVI) : Joint Consensus Document of the Arbeitsgemeinschaft Leitende Kardiologische Krankenhausärzte e.V. (ALKK) and cooperating Cardiac Surgery Departments.

Indications for TF-TAVI (transfemoral transcatheter aortic valve implantation) are rapidly changing according to increasing evidence from randomized controlled trials. Present trials document the non-inferiority or even superiority of TF-TAVI in intermediate-risk patients (STS-Score 4-8%) as well as in low-risk patients (STS-Score < 4%). However, risk scores exhibit limitations and, as a single criterion, are unable to establish an appropriate indication of TF-TAVI vs transapical TAVI vs SAVR (surgical aortic valve replacement). The ESC (European Society of Cardiology)/EACTS (European Association for Cardio-Thoracic Surgery) guidelines 2017 and the German DGK (Deutsche Gesellschaft für Kardiologie)/DGTHG (Deutsche Gesellschaft für Thorax-, Herz- und Gefäßchirurgie) commentary 2018 offer a framework for the selection of the best therapeutic method, but the individual decision is left to the discretion of the heart teams. An interdisciplinary TAVI consensus group of interventional cardiologists of the ALKK (Arbeitsgemeinschaft Leitende Kardiologische Krankenhausärzte e.V.) and cardiac surgeons has developed a detailed consensus on the indications for TF-TAVI to provide an up-to-date, evidence-based, comprehensive decision matrix for daily practice. The matrix of indication criteria includes age, risk scores, contraindications against SAVR (e.g., porcelain aorta), cardiovascular criteria pro TAVI, additional criteria pro TAVI (e.g., frailty, comorbidities, organ dysfunction), contraindications against TAVI (e.g., endocarditis) and cardiovascular criteria pro SAVR (e.g., bicuspid valve anatomy). This interdisciplinary consensus may provide orientation to heart teams for individual TAVI-indication decisions. Future adaptations according to evolving medical evidence are to be expected. Interdisciplinary consensus on indications for transfemoral transcatheter aortic valve implantation (TF-TAVI).

Malignancies after heart transplantation: incidence, risk factors, and effects of calcineurin inhibitor withdrawal.

The objectives of the present study were to evaluate the incidence of malignancies and to describe the effects of immunosuppression on survival and recurrence of malignancies after heart transplantation (HTX). Data were analyzed in 211 cardiac allograft recipients, in whom HTX was performed between 1989 and 2005. All of these patients survived for more than 2 years after HTX and received induction therapy with antithymocyte globulin (RATG) guided by T-cell monitoring since 1994. An immunosuppressive regimen consisting of cyclosporine A (CsA) combined with azathioprine was followed by CsA and mycophenolate mofetil (MMF) in 2001; mammalian target of rapamycin (mTOR) inhibitors (everolimus/sirolimus) were used since 2003. Mean patient age at HTX was 51.4 ± 10.5 years; mean follow-up time after HTX 9.2 ± 4.7 years. Overall incidence of neoplasias was 30.8%. Individual risk factors associated with a higher risk of malignancy after HTX were higher age at transplantation (P = .003), male gender (P = .005) and ischemic cardiomyopathy before HTX (P = .04). Administration of azathioprine (P < .0001) or a calcineurin inhibitor (CNI) (P = .02) for more than 1 year was associated with development of malignancy, whereas significantly fewer malignancies were noticed in patients receiving an mTOR-inhibitor (P < .0001). Kaplan-Meier analysis demonstrated a strong statistical trend toward an improved survival in patients with a noncutaneous neoplasia switched to a CNI-free protocol (P = .05). This study demonstrated the impact of a variety of individual risk factors and immunosuppressive drugs on development of malignancy after HTX. Markedly fewer patients with noncutaneous malignancies died after switch to a CNI-free regimen, not quite reaching statistical significance by Kaplan-Meier analysis, however.

Myocardial protection with the use of L-arginine and N-alpha-acetyl-histidine.

OBJECTIVE: Effective myocardial preservation is an important condition for cardiac surgery, especially in heart transplantation with long ischemia times. During ischemia and reperfusion, myocardial function is altered by cold-induced ischemic injury. Cold-induced ischemic injury is triggered by cold storage and the amino acid histidine, a main component of the storage solution histidine-tryptophan-ketoglutarate (HTK). Cold-induced ischemic injury generates free oxygen radicals in an iron-dependent way. We investigated the efficacy of new modifications with the addition of L-arginine and N-alpha-acetyl-histidine to the well-established HTK solution (Custodiol) using a rat heart transplant model. MATERIALS AND METHODS: Heterotopic transplantation was performed in Lewis rats (n = 20). After 1 hour of ischemic preservation and 1 hour of reperfusion, we assessed myocardial function and energy charge potential. The modifications of HTK solution included the addition of L-arginine, partial replacement of histidine with acetyl-histidine, and reduction of chloride concentration (HTK-1). In a second group, Custodiol served as the control. RESULTS: After 1 hour of reperfusion, left ventricular systolic pressure (106 +/- 33 vs 69 +/- 9 mm Hg; P < .05) and minimum rate of pressure development (dP/dt) (-1388 +/- 627 vs -735 +/- 219 mm Hg/s; P < .05) were significantly higher among the HTK-1 group compared with the control group. Energy charge potential did not differ significantly between the groups. CONCLUSION: This study showed that the novel modified HTK-1 solution improved myocardial contractility and relaxation after heart transplantation.

Interstitial leukocytes in right ventricular endomyocardial biopsies after heart transplantation in patients with complicated versus uneventful postoperative course.

BACKGROUND: Infections and rejections play key roles in morbidity and mortality in the early postoperative period after orthotopic heart transplantation (HTX). The aim of this study was to evaluate whether qualitative and quantitative analyses of various interstitial leukocytes in endomyocardial biopsies during the first 2 weeks after HTX provided early information on these complications. PATIENTS AND METHODS: During and after HTX, endomyocardial biopsies were obtained in 51 patients. By immunohistochemistry we determined the CD3-, CD4-, CD8-, CD15-, CD20-, CD57-, and CD68-positive cell numbers projected to planimetrically measured areas. To compare morbidity in the postoperative course, the patients were subdivided into complicated versus uncomplicated after 3 months. RESULTS: In the uncomplicated group, the cell counts of CD3-, CD8-, CD57-, and CD68-positive cells were significantly lower than in the complicated group. CD3-, CD4-, and CD8-positive cell numbers showed a significant decrease in the first week among the uncomplicated group. In the complicated group, the cell counts increased significantly in the second week. The numbers of CD57-positive cells were significantly lower during the first and second weeks among the uncomplicated group. CONCLUSIONS: Increased T lymphocytes, natural killer cells, and macrophages observed in the second week after HTX indicated increased morbidity. A reduction in CD3-positive cells in the first week indicated a low morbidity risk; an increase indicated a higher risk.

Coronary fistula of right coronary artery to vena cava superior and ectasia of pulmonary artery.

We report on a patient with coronary heart disease, a coronary fistula of right coronary artery to vena cava superior and pulmonary hypertension. Combined with coronary artery revascularization, the coronary fistula was closed successfully.

Dopexamine attenuates microvascular perfusion injury of the small bowel in pigs induced by extracorporeal circulation.

BACKGROUND: Cardio-thoracic surgery with the use of extracorporeal circulation may lead to an impairment of splanchnic perfusion. The aim of this study was to investigate the effect of dopexamine on gastrointestinal microvascular perfusion failure due to extracorporeal circulation. METHODS: Twenty landrace pigs served as laboratory animals. A loop of the terminal ileum was exteriorized for microscopic observation. In 13 animals a partial left-heart bypass (pLHB), with a non-pulsatile pump flow of approximately 50% of the cardiac output, was established for 2 h. Seven animals received a continuous i.v. infusion of 3 micrograms kg-1 min-1 dopexamine from the beginning of pLHB to the end of the experiment. Seven sham-operated animals served as controls. The microcirculatory network was analysed by means of intra-vital microscopy prior to, during pLHB, and 2 h after bypass. RESULTS: Despite normal haemodynamics measured by arterial pressure and cardiac output, pLHB led to significant impairment of microvascular perfusion characterized by arteriolar vasoconstriction, reduction of functional capillary density (FCD) to 30% 2 h after weaning off bypass and diminished blood-cell velocities in submucous venules. Dopexamine attenuated this perfusion impairment, preventing arteriolar vasoconstriction. FCD remained normal. CONCLUSION: Our data demonstrate that treatment with the vasoactive drug dopexamine leads to a significant reduction of the perfusion injury of the small bowel.

A novel perfusion catheter for hybrid procedures in minimally invasive bypass surgery.

BACKGROUND: Combined off-pump bypass grafting and percutaneous coronary intervention (hybrid procedures) is supposed to be beneficial for high-risk patients. We developed a novel perfusion catheter to facilitate these hybrid interventions. METHODS: First, we tested coagulatory activation in vitro. Afterwards, 6 landrace pigs underwent active coronary perfusion of the LAD. In a second study, 15 pigs underwent off-pump bypass surgery (LIMA to LAD grafting) and the catheter was used to provide myocardial perfusion and prevent bleeding at the site of the coronary anastomosis. RESULTS: In the in vitro perfusion studies, no activation of coagulation or clotting occurred. Active coronary perfusion was feasible without signs of regional myocardial ischemia or coagulation over a 50-minute period. During off-pump bypass surgery, the catheter prevented bleeding in the operation field and facilitated the surgical procedure. CONCLUSION: The new perfusion catheter can optimize the conditions of off-pump bypass surgery by preventing bleeding in the operation field, maintaining myocardial perfusion and allowing direct angiographic control of the anastomosis. Therefore, this new technique could be an important tool to facilitate hybrid interventions.

Capillary endothelia and cardiomyocytes differ in vulnerability to ischemia/reperfusion during clinical heart transplantation.

OBJECTIVE: The development of accelerated graft arteriosclerosis is a major cause of late death after orthotopic heart transplantation. The influence and the extent of peritransplant injury, especially of cardiomyocyte or capillary endothelial cell edema is discussed. METHODS: A morphometric ultrastructural analysis of myocardial biopsies from 29 donor hearts (21 male, age 34+/-11 years) was performed. Right ventricular biopsies were obtained before cardioplegia (A), immediately following cardioplegia (B) (Custodiol, Dr. F. Köhler Chemie GmbH, Alsbach-Hähnlein, Germany), before implantation (C), after 30 (D) or 60 (E) min of reperfusion and 1 week after transplantation (F). Mean ischemic time was 185+/-68 min. Quantitative electron microscopy was carried out in five samples per heart and time point and in 30 test fields per sample by 'random systematic sampling' and 'point and intersection counting'. As parameters for cell edema the volume density of myofibrils in cardiomyocytes and the mean barrier thickness of capillary endothelia were analyzed. P-values of less than 0.05 were regarded as significant. Significant differences in contrast to the previous values are marked by *. RESULTS: The volume density of myofibrils (vol.%) was as follows: (B) 63.6+/-3.2, (C) 61.8+/-3.2, (D) 62.9+/-3.2, (E) 63.6+/-4.5. The mean barrier thickness (nm) was as follows: (A) 353+/-21, (B) 376+/-59, (C) 416+/-71*, (D) 473+/-45*; (E) 453+/-50*, (F) 379+/-39. CONCLUSIONS: Apart from a generally accepted edema of cardiomyocytes a relevant capillary endothelial cell edema develops during clinical heart transplantation. In contrast to cardiomyocytes the cell edema of endothelia shows a more pronounced and significant progression during cold ischemia and early reperfusion. After 60 min of reperfusion it is still significantly more pronounced than at the onset of ischemia. After 1 week there are no statistical differences compared to the initial values. Thus, an edema of capillary endothelia probably will trigger inhomogeneities in capillary perfusion. Peritransplant injury of endothelia may contribute to the later development of accelerated allograft arteriosclerosis.

Influence of steroids on microvascular perfusion injury of the bowel induced by extracorporeal circulation.

BACKGROUND: Extracorporeal circulation is associated with gastrointestinal complications. By means of intravital microscopic methods, we investigated whether preoperative treatment with steroids can attenuate the impairment of the bowel microcirculation. METHODS: In 20 pigs, a partial left heart bypass (pLHB) was established. A loop of the terminal ileum was exteriorized for intravital-microscopic observation. Seven sham-operated animals served as controls. In 13 animals, pLHB was established for 2 hours with a flow rate of 2,000 mL per minute; 7 of the animals received 20 mg/kg body weight prednisolone preoperatively. The microcirculatory network was analyzed before, during pLHB, and 2 hours after bypass. RESULTS: Despite unchanged macro-hemodynamics, pLHB resulted in a significant microvascular perfusion injury of the small bowel. Arteriolar vasoconstriction and a reduction of perfused capillaries per unit area (functional capillary density) to 30% of prebypass values could be found. Blood cell velocities were reduced in submucuous collecting venules. In the steroid-treated animals, the functional capillary density remained normal. In addition, arteriolar vasoconstriction could be prevented. CONCLUSIONS: Treatment with prednisolone largely prevents the microcirculatory alterations in the small bowel induced by extracorporeal circulation.

Circulating interleukin-1 receptor antagonist (IL-1RA) serum levels in patients undergoing orthotopic heart transplantation.

In a pilot study we determined the serum levels of circulating interleukin-1 receptor antagonist (IL-1ra) in patients undergoing orthotopic heart transplantation and in control patients scheduled for open heart surgery without allograft transplantation. Blood samples were obtained from 12 transplant recipients and 7 controls prior to the operative procedures to determine baseline values. Serum levels of IL-1ra were measured within 12 h of decrossclamping of the aorta and every 24 h for the following 14 days. Endomyocardial biopsies were obtained weekly for the 1st month after transplantation. Compared to baseline values, IL-1ra serum levels 12 h after decrossclamping of the aorta were significantly higher both in the control group (507 +/- 165 vs 3980 +/- 452 pg/ml, P < 0.01) and among the transplant recipients (413 +/- 180 vs 4117 +/- 459 pg/ml, P < 0.01) IL-1ra levels remained significantly elevated for 2 and 5 days, respectively. There were no significant differences in the IL-1ra serum levels between the two groups throughout the observation period. Endomyocardial biopsies of two patients showed acute allograft rejection, Billingham grade IIIa and IIIb, respectively. In both cases, the rejection episodes were accompanied by a renewed and more pronounced elevation in the IL-1ra serum levels beyond 4000 pg/ml for at least 2 days. These preliminary results indicate that IL-1ra may be a nonspecific immune marker during the first few days after orthotopic heart transplantation and cardiopulmonary bypass. Moreover, renewed, prolonged increases in IL-1ra appear to be associated with rejection. Further studies are needed to confirm the predictive value of IL-1ra in the detection of acute allograft rejection.

Elevated serum concentrations of cardiac troponin T in acute allograft rejection after human heart transplantation.

OBJECTIVES: This study evaluates the concept and diagnostic efficacy of using serum troponin T for the detection of cardiac graft rejection. BACKGROUND: Cardiac troponin T is a cardiospecific myofibrillar protein, which is only detectable in the circulation after cardiac myocyte damage. It might be expected to be released during acute heart allograft rejection, allowing noninvasive rejection diagnosis. METHODS: In 35 control subjects and in 422 samples from 95 clinically unremarkable heart allograft recipients more than 3 months postoperatively, troponin T serum concentrations were compared to the histological grade of acute graft rejection in concurrent endomyocardial biopsies. RESULTS: Mean troponin T serum concentrations were identical in control subjects (23.2 +/- 1.4 ng/liter) and in heart transplant recipients without graft rejection (International Society for Heart and Lung Transplantation [ISHLT] grade 0; 22.4 +/- 1.7 ng/liter). Mean troponin T concentrations increased in parallel with the severity of graft rejection (ISHLT grade 1: 27.8 +/- 1.8 ng/liter; grade 2: 33.2 +/- 2.7 ng/liter; grade 3A: 54.6 +/- 6.5 ng/liter; grade 3B and 4: 105.4 +/- 53.7 ng/liter; p < 0.001 for grades 3 and 4 vs. grades 0 and 1). The proportion of positive samples also increased in parallel with rejection severity, reaching 100% in rejections of grade 3B and 4. Sensitivity and specificity for the detection of significant graft rejection (ISHLT grade 3/4) were 80.4% and 61.8%, respectively. The negative predictive value was most remarkable with 96.2%. Intraindividual longitudinal analysis of troponin T levels and biopsy results in 15 patients during long-term follow-up confirmed these findings. CONCLUSIONS: The present data demonstrate that acute allograft rejection after human heart transplantation is often associated with increased serum concentrations of troponin T. All cases of serious forms of graft rejection would have been detected before the development of clinical symptoms. Measurement of troponin T levels may become a useful ancillary parameter for noninvasive rejection diagnosis, being most valuable in the exclusion of severe cardiac graft rejection.

Transferral of extrathoracic donor neoplasm by the cardiac allograft.

The transference of neoplasm from the donor to the recipient is a rare but recognized complication of organ transplantation. It has been reported after kidney transplantation from cadaver donors. We report a case in which an extrathoracic tumor was transmitted by the donor heart. The donor heart was harvested from a 46-year-old local donor and immediately transplanted to a 62-year-old female recipient. While implantation was performed, a hypernephroma was detected in the multiorgan donor. The ongoing heart transplantation could not be stopped. Four weeks after operation, the patient was discharged from the hospital. During the first year after transplantation, the clinical course was uneventful. One year after operation, the patient was admitted to the hospital with symptoms of weakness and fever. A right facial hemiparesis occurred, and a soft tumor was palpable subcutaneously in the right supraorbital region. Histologic examination revealed a malignant tumor with characteristics identical to the donor hypernephroma. In spite of chemotherapy and radiation therapy, dramatic tumor progression occurred with multiorgan metastases, which led to the death of the patient 2 months after admission.

Endothelin plasma levels in acute graft rejection after heart transplantation.

BACKGROUND: Endothelin is an oligopeptide of endothelial origin with potent vasoconstrictive and mitogenic properties, implicated in the pathogenesis of cyclosporine-induced hypertension, graft vasculopathy, and renal failure. Experimental animal data suggest a role for endothelin in allograft rejection also. METHODS: To determine the role of endothelin in acute graft rejection after heart transplantation, we determined endothelin plasma levels in 165 blood samples from 79 cardiac allograft recipients (2 to 81 months after the operation) with normal graft function and correlated our findings with the histologic severity of acute graft rejection according to International Society for Heart and Lung Transplantation grading. For comparison endothelin levels were determined in 30 healthy controls and in 22 early postoperative transplant recipients (< 2 months after the operation). RESULTS: Endothelin plasma levels were significantly higher in transplant recipients than in controls (early postoperative: 7.97 = 7.53 pg/ml; late postoperative: 3.68 +/- 1.72 pg/ml; controls: 1.55 +/- 0.89 pg/ml). Endothelin plasma levels were not significantly different between groups of rejection grades 0 to 4. In the comparison of two groups of no rejection or lower (International Society for Heart and Lung Transplantation grade 0 and 1, n = 134) and higher (International Society for Heart and Lung Transplantation grade > or = 2, n = 31) rejection severity or comparing patients requiring rejection therapy (n = 20) with those not requiring therapy (n = 145), endothelin levels did not differ significantly between the groups. In 22 patients with three to six available consecutive biopsy scores and endothelin levels, intraindividual longitudinal analysis did also not show any significant correlation. The only positive correlation of endothelin levels with other laboratory parameters was found with serum creatinine concentrations (p < 0.001). In the early postoperative recipients, no correlation of endothelin plasma levels with rejection severity was seen; furthermore the only significant association was found with time after operation. CONCLUSIONS: In this study endothelin plasma levels were not influenced by acute allograft rejection after heart transplantation. Therefore endothelin levels do not appear to be a useful marker for noninvasive rejection diagnosis. Furthermore, a relevant pathogenetic role of endothelin in the rejection process cannot be derived from these data.

Treatment of dilated cardiomyopathy with dynamic cardiomyoplasty: the Heidelberg experience.

BACKGROUND: Data concerning the efficacy of dynamic cardiomyoplasty are still inconsistent, especially in terms of improvement of left ventricular function. METHODS: Between August 1990 and February 1994, eight isolated cardiomyoplasty procedures were performed in patients with cardiomyopathy (ejection fraction, 0.14 to 0.32; New York Heart Association class III) and contraindications to heart transplantation. RESULTS: Follow-up was 41.1 +/- 14.1 months. One patient died 2 months and another 3 years after operation. Considerable symptomatic improvement was found in 6 of 7 patients, 3 of whom went back to work. One patient with severe pulmonary hypertension exhibited no improvement. Mean New York Heart Association-class decreased from 3.0 to 1.9 (p < 0.001). Echocardiography showed an increase in fractional shortening and in peak aortic flow velocity in all patients. Left ventricular ejection fraction increased from 0.21 +/- 0.05 to 0.38 +/- 0.16 (n = 7, p < 0.015) at 1 year, to 0.37 +/- 0.18 (n = 6, p < 0.05) at 2 years, and to 0.36 +/- 0.19 (n = 5, not significant) at 3 years. Pulmonary artery pressure tended to decrease over time. No significant change in exercise level or maximal oxygen consumption during treadmill testing was observed. CONCLUSIONS: Our preliminary results show that patients may exhibit an impressive clinical improvement after cardiomyoplasty, with only moderate changes in objective hemodynamic indices. We do not consider cardiomyoplasty an alternative to heart transplantation, but reserve it for patients with contraindications to heart transplantation.

Dynamic cardiomyoplasty: indication, surgical technique, and results.

The efficacy of dynamic cardiomyoplasty is still controversial. To date more than 400 patients have been operated worldwide. In recent years the indication and the surgical technique have become more uniform, which makes results from different centers eligible for comparison. We performed cardiomyoplasty exclusively in patients with contraindications for heart transplantation, such as chronic and recurrent infections or severe, irreversible sequelae of diabetes. Between August 1990 and October 1994, 8 isolated cardiomyoplasty procedures were performed in patients with cardiomyopathy (EF 14-32%, all in NYHA III). One patient died 2 months after surgery. Reported are the results of 7 patients after a mean follow-up of 41.1 +/- 14.1 months. Considerable symptomatic improvement was found in 6 or 7 patients, 3 of whom went back to work. One patient with severe pulmonary hypertension exhibited no improvement. In the others NYHA class improved by at least one. Echocardiography showed an increase in fractional shortening in all patients. LVEF increased from 21.2 +/- 5.2% to 38.1 +/- 15.9% (n = 7, p < 0.015) at 1 year, to 36.6 +/- 17.6% (n = 6, p < 0.05) at two years, and to 36.4 +/- 18.9% (n = 5, NS) at three years. Pulmonary artery pressure tended to decrease at rest over time. Resting lung function showed no change of vital capacity and FEV1. No significant change in exercise level and maximal O2-consumption during treadmill testing was observed. One patient died 34 months after the operation from sudden death. Our preliminary results show that patients after cardiomyoplasty may exhibit an impressive clinical improvement with less striking changes of objective hemodynamic parameters. This data is in agreement with the results of all other investigators. Some possible mechanisms of action are discussed and a risk profile suggested. According to the current state of experience with cardiomyoplasty, we do not consider this method an alternative to heart transplantation, but reserve it for patients with contraindications for heart transplantation.

Superiority of endocardial versus epicardial implantation of the implantable cardioverter defibrillator (ICD).

The implantable cardioverter-defibrillator (ICD) has proved to be an efficient device for the treatment of severe ventricular tachyarrhythmias (VT). From May 1985 to August 1991, the ICD was implanted in 107 patients of whom 72% suffered from coronary artery disease, 17% from cardiomyopathy, 5% from long QT-syndrome and 6% from other heart disease. All patients had a life threatening episode of VT or at least one episode of ventricular fibrillation. Of 107 implants, 12% were combined with other heart surgery, 55% were isolated epicardial implantations (epi I) and in 33%, the novel endocardial (endo I) approach was chosen. Between epi I and endo I we found no difference in operation time, but time for ICU and in-hospital stay was significantly shorter using the transvenous approach. In addition, sensing and pacing capability of the endocardial screw-in electrode was superior and the need for thoracotomy was avoided, a particular advantage in patients with previous heart surgery. Complications after epi I were: temporary low cardiac output, 1; perioperative death, 2; infection, 3, and after endo I: electrode dislocation, 2. Hence, endo I may become the method of choice for patients without concomitant surgery.

Performance of dynamic cardiomyoplasty related to the functional state of the heart.

Cardiomyoplasty (CMP) was performed with the left Latissimus dorsi in five beagles (group 1) with intact hearts and seven foxhounds (group 2) in whom the left ventricle was enlarged by 31 +/- 11.9% of cross-sectional area. Ventricular function curves were constructed at filling pressures ranging from 15-40 mmHg (group 2). Myocardial contraction patterns were investigated by epicardial 2-D echocardiography. Skeletal muscle contraction caused a significant increase in aortic pressure, dP/dt, stroke volume, work and performance in all animals. Function curves were shifted upward in a parallel manner. Echocardiography showed an increase of the LV cross-sectional delta area of 14.8% +/- 5.8% (group 1) and of 39.5% +/- 15.1%, and approximation of the edges of the wall defects (group 2). In conclusion, dynamic CMP as applied in this acute model, increased the performance of normal canine hearts and hence, a model of cardiac failure may not be a prerequisite for the investigation of certain technical aspects of CMP. In the failing heart, a parallel upward shift of myocardial function curves suggested increased performance of the heart/skeletal muscle complex over a wide range of filling pressures. However, the descending limb of the function curve with increasing filling pressures was observed despite skeletal muscle contraction. Hence, similar to other assist systems, the residual function of the heart may be of considerable importance in the overall performance of dynamic CMP.