137 resultados para Heart Function Tests
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Extracorporeal membrane oxygenation (ECMO) was used to achieve temporary artificial support in cardiac and pulmonary function in 22 patients from 1987 to September 1990. Standard indications were postcardiotomy cardiogenic shock (n = 4), neonatal (n = 1) and adult respiratory distress syndrome (n = 4). ECMO was also used for extended indications, such as graft failure following heart (n = 11) or lung transplantation (n = 2). In six of these cases ECMO was instituted as a bridge device to subsequent retransplantation of either the heart (n = 4) or one lung (n = 2). One out of nine patients supported by ECMO for standard indications, and two out of 13 patients supported for extended indications are long-term survivors. This series illustrates the results with ECMO in emergency situations, in patients under immunosuppressive protocols, or in patients with advanced lung failure requiring almost complete artificial gas exchange. In such complex situations, ECMO does provide stabilization until additional therapeutic measures are in effect. ECMO cannot be recommended for postoperative cardiogenic shock but short-term ECMO support is an accepted method in most cases with graft failure or pulmonary failure or other origin.
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BACKGROUND: Exercise capacity after heart transplantation (HTx) remains limited despite normal left ventricular systolic function of the allograft. Various clinical and haemodynamic parameters are predictive of exercise capacity following HTx. However, the predictive significance of chronotropic competence has not been demonstrated unequivocally despite its immediate relevance for cardiac output. AIMS: This study assesses the predictive value of various clinical and haemodynamic parameters for exercise capacity in HTx recipients with complete chronotropic competence evolving within the first 6 postoperative months. METHODS: 51 patients were enrolled in this exercise study. Patients were included when at least >6 months after HTx and without negative chronotropic medication or factors limiting exercise capacity such as significant transplant vasculopathy or allograft rejection. Clinical parameters were obtained by chart review, haemodynamic parameters from current cardiac catheterisation, and exercise capacity was assessed by treadmill stress testing. A stepwise multiple regression model analysed the proportion of the variance explained by the predictive parameters. RESULTS: The mean age of these 51 HTx recipients was 55.4 +/- 13.2 yrs on inclusion, 42 pts were male and the mean time interval after cardiac transplantation was 5.1 +/- 2.8 yrs. Five independent predictors explained 47.5% of the variance observed for peak exercise capacity (adjusted R2 = 0.475). In detail, heart rate response explained 31.6%, male gender 5.2%, age 4.1%, pulmonary vascular resistance 3.7%, and body-mass index 2.9%. CONCLUSION: Heart rate response is one of the most important predictors of exercise capacity in HTx recipients with complete chronotropic competence and without relevant transplant vasculopathy or acute allograft rejection.
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BACKGROUND: Surfactant protein type B (SPB) is needed for alveolar gas exchange. SPB is increased in the plasma of patients with heart failure (HF), with a concentration that is higher when HF severity is highest. The aim of this study was to evaluate the relationship between plasma SPB and both alveolar-capillary diffusion at rest and ventilation versus carbon dioxide production during exercise. METHODS AND RESULTS: Eighty patients with chronic HF and 20 healthy controls were evaluated consecutively, but the required quality for procedures was only reached by 71 patients with HF and 19 healthy controls. Each subject underwent pulmonary function measurements, including lung diffusion for carbon monoxide and membrane diffusion capacity, and maximal cardiopulmonary exercise test. Plasma SPB was measured by immunoblotting. In patients with HF, SPB values were higher (4.5 [11.1] versus 1.6 [2.9], P=0.0006, median and 25th to 75th interquartile), whereas lung diffusion for carbon monoxide (19.7+/-4.5 versus 24.6+/-6.8 mL/mm Hg per min, P<0.0001, mean+/-SD) and membrane diffusion capacity (28.9+/-7.4 versus 38.7+/-14.8, P<0.0001) were lower. Peak oxygen consumption and ventilation/carbon dioxide production slope were 16.2+/-4.3 versus 26.8+/-6.2 mL/kg per min (P<0.0001) and 29.7+/-5.9 and 24.5+/-3.2 (P<0.0001) in HF and controls, respectively. In the HF population, univariate analysis showed a significant relationship between plasma SPB and lung diffusion for carbon monoxide, membrane diffusion capacity, peak oxygen consumption, and ventilation/carbon dioxide production slope (P<0.0001 for all). On multivariable logistic regression analysis, membrane diffusion capacity (beta, -0.54; SE, 0.018; P<0.0001), peak oxygen consumption (beta, -0.53; SE, 0.036; P=0.004), and ventilation/carbon dioxide production slope (beta, 0.25; SE, 0.026; P=0.034) were independently associated with SPB. CONCLUSIONS: Circulating plasma SPB levels are related to alveolar gas diffusion, overall exercise performance, and efficiency of ventilation showing a link between alveolar-capillary barrier damage, gas exchange abnormalities, and exercise performance in HF.
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OBJECTIVE: Recent studies have shown that mechanically unloading a failing heart may induce reverse remodeling and functional improvement. However, these benefits may be balanced by an unloading-related remodeling including myocardial atrophy that might lead to decrease in function. Using a model of heterotopic heart transplantation, we aimed to characterize the myocardial changes induced by long-term unloading. MATERIAL AND METHODS: Macroscopic as well as cellular and functional changes were followed in normal hearts unloaded for a 3-month period. Microscopic parameters were evaluated with stereologic methodology. Myocardial contractile function was quantified with a Langendorff isolated, perfused heart technique. RESULTS: Atrophy was macroscopically obvious and accompanied by a 67% reduction of the myocyte volume and a 43% reduction of the interstitial tissue volume, thus accounting for a shift of the myocyte/connective tissue ratio in favor of noncontractile tissue. The absolute number of cardiomyocyte nuclei decreased from 64.7 +/- 5.1 x 10(7) in controls to 22.6 +/- 3.7 x 10(7) (30 days) and 21.6 +/- 3.1 x 10(7) (90 days) after unloading (P < .05). The numeric nucleic density in the unloaded myocardium, as well as the mean cardiomyocyte volume per cardiomyocyte nucleus, remained constant throughout the 90 days of observation. Functional data indicated an increase in ventricular stiffness, although contractile function was preserved, as confirmed by unaltered maximal developed pressure and increased contractility (maximum rate of left ventricular pressure development) and relaxation (minimum rate of left ventricular pressure development). CONCLUSION: Atrophic remodeling involves both the myocyte and interstitial tissue compartment. These data suggest that although there is decreased myocardial volume and increased stiffness, contractile capacity is preserved in the long-term unloaded heart.
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Objective assessments of subjective complaints such as sleepiness, tiredness or fatigue using sleepiness and vigilance tests aim to identify its causes and to judge the fitness to drive or to work of the affected person. "Vigilance" comprises wakefulness, alertness and attention and is therefore not merely reciprocal to sleepiness. Since it is a complex phenomenon with several dimensions it is unlikely to be appropriately assessed by one single "vigilance test". One important dimension of vigilance discussed here is wakefulness with its counterpart of overt sleep and the whole spectrum of various levels in between. The transit zone between full wakefulness and overt sleep is mainly characterised by the subjective complaint of sleepiness, which cannot be measured directly. Only the consequences of reduced wakefulness such as a shortened sleep latency, slowed cognitive function and prolonged reaction time can be measured objectively. It is, therefore, more promising to combine a battery of subjective and objective tests to answer a specific question in order to achieve the most appropriate description for a given clinical or medicolegal situation. However even then we must keep in mind that many other important aspects of fitness to drive / fitness to work such as neurological, psychiatric and neuropsychological functions including risk taking behaviour are not covered by vigilance tests. A comprehensive, multidisciplinary approach is essential in such situations.
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OBJECTIVES: Obstructive sleep apnea (OSA) can have adverse effects on cognitive functioning, mood, and cardiovascular functioning. OSA brings with it disturbances in sleep architecture, oxygenation, sympathetic nervous system function, and inflammatory processes. It is not clear which of these mechanisms is linked to the decrease in cognitive functioning. This study examined the effect of inflammatory parameters on cognitive dysfunction. MATERIALS AND METHODS: Thirty-nine patients with untreated sleep apnea were evaluated by polysomnography and completed a battery of neuropsychological tests. After the first night of evaluation in the sleep laboratory, blood samples were taken for analysis of interleukin 6, tumor necrosis factor-alpha (TNF-alpha), and soluble TNF receptor 1 (sTNF-R1). RESULTS: sTNF-R1 significantly correlated with cognitive dysfunction. In hierarchical linear regression analysis, measures of obstructive sleep apnea severity explained 5.5% of the variance in cognitive dysfunction (n.s.). After including sTNF-R1, percentage of variance explained by the full model increased more than threefold to 19.6% (F = 2.84, df = 3, 36, p = 0.05). Only sTNF-R1 had a significant individual relationship with cognitive dysfunction (beta = 0.376 t = 2.48, p = 0.02). CONCLUSIONS: sTNF-R1 as a marker of chronic inflammation may be associated with diminished neuropsychological functioning in patients with OSA.
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Background Left atrium (LA) dilation and P-wave duration are linked to the amount of endurance training and are risk factors for atrial fibrillation (AF). The aim of this study was to evaluate the impact of LA anatomical and electrical remodeling on its conduit and pump function measured by two-dimensional speckle tracking echocardiography (STE). Method Amateur male runners > 30 years were recruited. Study participants (n = 95) were stratified in 3 groups according to lifetime training hours: low (< 1500 h, n = 33), intermediate (1500 to 4500 h, n = 32) and high training group (> 4500 h, n = 30). Results No differences were found, between the groups, in terms of age, blood pressure, and diastolic function. LA maximal volume (30 ± 5, 33 ± 5 vs. 37 ± 6 ml/m2, p < 0.001), and conduit volume index (9 ± 3, 11 ± 3 vs. 12 ± 3 ml/m2, p < 0.001) increased significantly from the low to the high training group, unlike the STE parameters: pump strain − 15.0 ± 2.8, − 14.7 ± 2.7 vs. − 14.9 ± 2.6%, p = 0.927; conduit strain 23.3 ± 3.9, 22.1 ± 5.3 vs. 23.7 ± 5.7%, p = 0.455. Independent predictors of LA strain conduit function were age, maximal early diastolic velocity of the mitral annulus, heart rate and peak early diastolic filling velocity. The signal-averaged P-wave (135 ± 11, 139 ± 10 vs. 148 ± 14 ms, p < 0.001) increased from the low to the high training group. Four episodes of non-sustained AF were recorded in one runner of the high training group. Conclusion The LA anatomical and electrical remodeling does not have a negative impact on atrial mechanical function. Hence, a possible link between these risk factors for AF and its actual, rare occurrence in this athlete population, could not be uncovered in the present study.
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OBJECTIVE This study tested the hypotheses that intermittent coronary sinus occlusion (iCSO) reduces myocardial ischaemia, and that the amount of ischaemia reduction is related to coronary collateral function. DESIGN Prospective case-control study with intraindividual comparison of myocardial ischaemia during two 2-min coronary artery balloon occlusions with and without simultaneous iCSO by a balloon-tipped catheter. SETTING University Hospital. PATIENTS 35 patients with chronic stable coronary artery disease. INTERVENTION 2-min iCSO. MAIN OUTCOME MEASURES Myocardial ischaemia as assessed by intracoronary (i.c.) ECG ST shift at 2 min of coronary artery balloon occlusion. Collateral flow index (CFI) without iCSO, that is, the ratio between mean distal coronary occlusive (Poccl) and mean aortic pressure (Pao) both minus central venous pressure. RESULTS I.c. ECG ST segment shift (elevation in all) at the end of the procedure with iCSO versus without iCSO was 1.33±1.25 mV versus 1.85±1.45 mV, p<0.0001. Regression analysis showed that the degree of i.c. ECG ST shift reduction during iCSO was related to CFI, best fitting a Lorentzian function (r(2)=0.61). Ischaemia reduction with iCSO was greatest at a CFI of 0.05-0.20, whereas in the low and high CFI range the effect of iCSO was absent. CONCLUSIONS ICSO reduces myocardial ischaemia in patients with chronic coronary artery disease. Ischaemia reduction by iCSO depends on coronary collateral function. A minimal degree of collateral function is necessary to render iCSO effective. ICSO cannot manifest an effect when collateral function prevents ischaemia in the first place.
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AIM As technological interventions treating acute myocardial infarction (MI) improve, post-ischemic heart failure increasingly threatens patient health. The aim of the current study was to test whether FADD could be a potential target of gene therapy in the treatment of heart failure. METHODS Cardiomyocyte-specific FADD knockout mice along with non-transgenic littermates (NLC) were subjected to 30 minutes myocardial ischemia followed by 7 days of reperfusion or 6 weeks of permanent myocardial ischemia via the ligation of left main descending coronary artery. Cardiac function were evaluated by echocardiography and left ventricular (LV) catheterization and cardiomyocyte death was measured by Evans blue-TTC staining, TUNEL staining, and caspase-3, -8, and -9 activities. In vitro, H9C2 cells transfected with ether scramble siRNA or FADD siRNA were stressed with chelerythrin for 30 min and cleaved caspase-3 was assessed. RESULTS FADD expression was significantly decreased in FADD knockout mice compared to NLC. Ischemia/reperfusion (I/R) upregulated FADD expression in NLC mice, but not in FADD knockout mice at the early time. FADD deletion significantly attenuated I/R-induced cardiac dysfunction, decreased myocardial necrosis, and inhibited cardiomyocyte apoptosis. Furthermore, in 6 weeks long term permanent ischemia model, FADD deletion significantly reduced the infarct size (from 41.20 ± 3.90% in NLC to 26.83 ± 4.17% in FADD deletion), attenuated myocardial remodeling, improved cardiac function and improved survival. In vitro, FADD knockdown significantly reduced chelerythrin-induced the level of cleaved caspase-3. CONCLUSION Taken together, our results suggest FADD plays a critical role in post-ischemic heart failure. Inhibition of FADD retards heart failure progression. Our data supports the further investigation of FADD as a potential target for genetic manipulation in the treatment of heart failure.
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OBJECTIVES The aim of this study was to compare the right (RV) and left (LV) ventricular Tei indices obtained by pulsed-wave Doppler (PD) and tissue Doppler (TD) methods in fetuses with structurally normal and abnormal hearts. METHODS This was a retrospective cross-sectional study of 147 fetuses that had a fetal echocardiogram and Tei index measured during a 2-year period. The RV and LV Tei indices were measured using both PD and TD methods. The difference between the two methods of Tei index measurement was tested using paired sample t-test, Pearson correlation coefficient was used to examine their relationship, and the agreement between the methods was tested using Bland-Altman analysis. RESULTS A total of 87 fetuses had normal hearts and 60 had a congenital heart defect. Both PD and TD Tei indices were measured successfully from at least one ventricle in 123 cases and from both ventricles in 110 cases. The mean TD Tei index was significantly higher than the mean PD Tei index for both ventricles (P < 0.0001). There was a weak but statistically significant correlation between the PD and TD Tei indices of the right ventricle (r = 0.20, P = 0.029), whereas the PD and TD Tei indices of the left ventricle did not correlate significantly (r = 0.04, P = 0.684). When pairs of Tei indices measured by two different methods (123 pairs for the right ventricle and 111 for the left ventricle) were tested with Bland-Altman analysis, the bias and precision were 0.147 and 0.254, respectively, for the right ventricle, and 0.299 and 0.276, respectively, for the left ventricle. CONCLUSIONS Correlation between Tei indices measured by PD and TD methods is weak and the agreement between individual measurements is poor. Therefore, they should not be used interchangeably in the assessment of fetal cardiac function.
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BACKGROUND J-wave syndromes have emerged conceptually to encompass the pleiotropic expression of J-point abnormalities including Brugada syndrome (BrS) and early repolarization syndrome (ERS). KCNJ8, which encodes the cardiac K(ATP) Kir6.1 channel, recently has been implicated in ERS following identification of the functionally uncharacterized missense mutation S422L. OBJECTIVE The purpose of this study was to further explore KCNJ8 as a novel susceptibility gene for J-wave syndromes. METHODS Using polymerase chain reaction, denaturing high-performance liquid chromatography, and direct DNA sequencing, comprehensive open reading frame/splice site mutational analysis of KCNJ8 was performed in 101 unrelated patients with J-wave syndromes, including 87 with BrS and 14 with ERS. Six hundred healthy individuals were examined to assess the allelic frequency for all variants detected. KCNJ8 mutation(s) was engineered by site-directed mutagenesis and coexpressed heterologously with SUR2A in COS-1 cells. Ion currents were recorded using whole-cell configuration of the patch-clamp technique. RESULTS One BrS case and one ERS case hosted the identical missense mutation S422L, which was reported previously. KCNJ8-S422L involves a highly conserved residue and was absent in 1,200 reference alleles. Both cases were negative for mutations in all known BrS and ERS susceptibility genes. K(ATP) current of the Kir6.1-S422L mutation was increased significantly over the voltage range from 0 to 40 mV compared to Kir6.1-WT channels (n = 16-21; P <.05). CONCLUSION These findings further implicate KCNJ8 as a novel J-wave syndrome susceptibility gene and a marked gain of function in the cardiac K(ATP) Kir6.1 channel secondary to KCNJ8-S422L as a novel pathogenic mechanism for the phenotypic expression of both BrS and ERS.
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AIMS Loss-of-function mutations in the SCN5A-encoded sodium channel SCN5A or Nav1.5 have been identified in idiopathic ventricular fibrillation (IVF) in the absence of Brugada syndrome phenotype. Nav1.5 is regulated by four sodium channel auxiliary beta subunits. Here, we report a case with IVF and a novel mutation in the SCN3B-encoded sodium channel beta subunit Navbeta3 that causes a loss of function of Nav1.5 channels in vitro. METHODS AND RESULTS Comprehensive open reading frame mutational analysis of KCNQ1, KCNH2, SCN5A, KCNE1, KCNE2, GPD1L, four sodium channel beta subunit genes (SCN1-4B), and targeted scan of RYR2 was performed. A novel missense mutation, Navbeta3-V54G, was identified in a 20-year-old male following witnessed collapse and defibrillation from VF. The ECG exhibited epsilon waves, and imaging studies demonstrated a structurally normal heart. The mutated residue was highly conserved across species, localized to the Navbeta3 extracellular domain, and absent in 800 reference alleles. We found that HEK-293 cells had endogenous Navbeta3, but COS cells did not. Co-expression of Nav1.5 with Navbeta3-V54G (with or without co-expression of the Navbeta1 subunit) in both HEK-293 cells and COS cells revealed a significant decrease in peak sodium current and a positive shift of inactivation compared with WT. Co-immunoprecipitation experiments showed association of Navbeta3 with Nav1.5, and immunocytochemistry demonstrated a dramatic decrease in trafficking to the plasma membrane when co-expressed with mutant Navbeta3-V54G. CONCLUSION This study provides molecular and cellular evidence implicating mutations in Navbeta3 as a cause of IVF.
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BACKGROUND Prognostic classification of congestive heart failure (CHF) is difficult and only possible with the help of additional diagnostic tools. B-type natriuretic peptide (BNP) has been used as a diagnostic and prognostic marker for patients (pts) with CHF. In this study, the clinical value of BNP for stratification and treatment of pts with CHF was evaluated. PATIENTS AND METHODS 33 out-pts with CHF (age 57 +/- 12 years) were included. Left-ventricular (LV) ejection fraction (EF) was 27 +/- 8% (mean +/- SD) and NYHA-class 2.4 +/- 0.7. Following parameters were measured: BNP and sodium from blood samples, exercise performance from 6-minute walking test (6MWT, meters) (n = 18), LV end-diastolic diameter (LVEDD) and LV mass (LVM) from 2D-echocardiography (n = 33), as well as LV end-diastolic pressure (LVEDP, n = 23) and systemic vascular resistance (SVR, n = 20) from heart-catheterisation. Ten pts were hospitalised in the preceding 6 months because of worsening CHF or for optimisation of medical therapy. BNP was measured at the beginning and end of the hospital-stay. Follow-up was for 1 year. RESULTS Pts with a high NYHA-class had a higher BNP (pg/ml) than those with a low NYHA- class: NYHA I 51 +/- 20, II 281 +/- 223, III 562+/-346 and IV 1061 +/- 126 pg/ml (p = 0.002). BNP correlated with LVEDP (r = 0.50, p <0.02), SVR (r =0.49, p <0.03) and inversely with 6MWT (r =-0.60, p <0.009), LVEF (r = -0.49, p <0.004) and sodium (r = -0.36, p = 0.04). In the hospitalised pts, mean BNP (pg/ml) was 881 +/- 695 at admission,and 532 +/- 435 at discharge (n.s.). Decrease in BNPduring hospitalisation paralleled weight-loss and was significantly greater in patients with >1000 pg/ml BNP at admission (n = 5) as compared to the 5 patients with BNP <1000 (p <0.03). Patients with an adverse event during 1-year follow-up had significantly higher BNP both at steady-state (603 +/-359 pg/ml) and at time of decompensation than patients with a favourable outcome (227 +/- 218 pg/ml,p <0.001). CONCLUSIONS BNP correlates well with the clinical severity of CHF (NYHA-class) and is directly related to filling pressure (LVEDP), LV function(LVEF) and exercise performance (6 MWT). Furthermore, BNP has prognostic impact with regard to adverse clinical events.
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OBJECTIVES To assess prevalence of anemia and its correlation with NYHA-class in patients with congestive heart failure. BACKGROUND Recently, it was reported that anemia in congestive heart failure patients is common and correlated with the severity of disease. In these patients with anemia, treatment with erythropoietin and intravenous iron improved cardiac function significantly. METHODS 193 patients from a tertiary heart failure outpatient clinic (mean age 54 years) were included in a retrospective analysis. Fourteen patients were in NYHA-class I, 69 class II, 79 class III, and 31 class IV. All patients had clinical and laboratory evaluation, echocardiography and coronary angiography. Patients with secondary anemia or on hemodialysis were excluded. Etiology of heart failure was ischemic in 41%. RESULTS Anemia (hemoglobin<120 g/l) was present in 28 of 193 patients (15%). There was an inverse relationship between NYHA-class and left ventricular ejection fraction (NYHA-class I 45%, class II 32%, class III 25%, class IV 25%). Serum creatinine increased with NYHA-class. Hemoglobin levels were similar in all four NYHA-classes but there were significantly more patients with anemia in NYHA-class III and IV (19%) compared with class I and II (8%, P<0.05). Hemoglobin was similar in surviving patients (mean 140 g/l) and those who died or were transplanted (mean 136 g/l, ns). CONCLUSIONS The prevalence of anemia in our heart failure service is 15% (compared with 56% in the literature) and is correlated to NYHA-class.
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The efficacy of everolimus with reduced cyclosporine in de novo heart transplant patients has been demonstrated convincingly in randomized studies. Moreover, everolimus-based immunosuppression in de novo heart transplant recipients has been shown in two randomized trials to reduce the increase in maximal intimal thickness based on intravascular ultrasound, indicating attenuation of cardiac allograft vasculopathy (CAV). Randomized trials of everolimus in de novo heart transplantation have also consistently shown reduced cytomegalovirus infection versus antimetabolite therapy. In maintenance heart transplantation, conversion from calcineurin inhibitors to everolimus has demonstrated a sustained improvement in renal function. In de novo patients, a renal benefit may only be achieved if there is an adequate reduction in exposure to calcineurin inhibitor therapy. Delayed introduction of everolimus may be appropriate in patients at high risk of wound healing complications, e.g. diabetic patients or patients with ventricular assist device. The current evidence base suggests that the most convincing reasons for use of everolimus from the time of heart transplantation are to slow the progression of CAV and to lower the risk of cytomegalovirus infection. A regimen of everolimus with reduced-exposure calcineurin inhibitor and steroids in de novo heart transplant patients represents a welcome addition to the therapeutic armamentarium.