Differences in phenotypes, symptoms, and survival in patients with cardiomyopathy-a prospective observational study from the Sahlgrenska CardioMyoPathy Centre

Introduction

Cardiomyopathy is the fourth most common cause of heart failure. The spectrum of cardiomyopathies may be impacted by changes in environmental factors and the prognosis may be influenced by modern treatment. The aim of this study is to create a prospective clinical cohort, the Sahlgrenska CardioMyoPathy Centre (SCMPC) study, and compare patients with cardiomyopathies in terms of phenotype, symptoms, and survival.

Methods

The SCMPC study was founded in 2018 by including patients with all types of suspected cardiomyopathies. This study included data on patient characteristics, background, family history, symptoms, diagnostic examinations, and treatment including heart transplantation and mechanical circulatory support (MCS). Patients were categorized by the type of cardiomyopathy on the basis of the diagnostic criteria laid down by the European Society of Cardiology (ESC) working group on myocardial and pericardial diseases. The primary outcomes were death, heart transplantation, or MCS, analyzed by Kaplan-Meier and Cox proportional regression, adjusted for age, gender, LVEF and QRS width on ECG in milliseconds.

Results

In all, 461 patients and 73.1% men with a mean age of 53.6 ± 16 years were included in the study. The most common diagnosis was dilated cardiomyopathy (DCM), followed by cardiac sarcoidosis and myocarditis. Dyspnea was the most common initial symptom in patients with DCM and amyloidosis, while patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) presented with ventricular arrythmias. Patients with ARVC, left-ventricular non-compaction cardiomyopathy (LVNC), hypertrophic cardiomyopathy (HCM), and DCM had the longest time from the debut of symptoms until inclusion in the study. Overall, 86% of the patients survived without heart transplantation or MCS after 2.5 years. The primary outcome differed among the cardiomyopathies, where the worst prognosis was reported for ARVC, LVNC, and cardiac amyloidosis. In a Cox regression analysis, it was found that ARVC and LVNC were independently associated with an increased risk of death, heart transplantation, or MCS compared with DCM. Further, female gender, a lower LVEF, and a wider QRS width were associated with an increased risk of the primary outcome.

Conclusions

The SCMPC database offers a unique opportunity to explore the spectrum of cardiomyopathies over time. There is a large difference in characteristics and symptoms at debut and a remarkable difference in outcome, where the worst prognosis was reported for ARVC, LVNC, and cardiac amyloidosis.

Heart failure and long-term prognosis in patients with congenital heart disease: a nationwide, register-based cohort study

Introduction

Heart failure (HF) is associated with high morbidity and severe prognosis. The aim of this study was to investigate the risk of HF in patients with congenital heart disease (CHD) and to determine the prognosis after HF diagnoses in patients with CHD compared to HF controls without CHD.

Methods

We identified 89,532 patients with CHD born between 1930 and 2017 from the National Patient Register in Sweden and matched with 10 controls without CHD by gender and birth year from the National Population Register. The study population was followed-up until 2017, through the Swedish Patient Register and Cause of Death Register.

Results

Altogether, 7,013 (7.8%) patients with CHD and 9,681 (1.1%) controls developed HF. The overall incidence rate of HF was 31.6 per 104 person-years in patients with CHD and 4.0 per 104 person-years in controls. The mean age for HF diagnoses was 40.3 (± 28.8) in patients with CHD and 66.4 (± 13.6) for controls. The risk for developing HF was significantly higher in complex than non-complex CHD lesion groups, HR 28.7 (26.5–31.0) and HR 6.9 (6.7–7.2) respectively. Mortality incidence rate was twice as high in controls with HF compared to CHD with HF (IR 9.7 (9.4–10.0) and 4.74 (4.6–4.9), respectively). The mortality incidence was higher within all age groups except for 18–39 years and there was no difference between complex and non complex lesions

Conclusion

One out of thirteen CHD patients will develop HF. The highest risk for HF is within CHD patients with complex lesions. CHD patients develops HF at a considerably younger age, reflecting their slightly better prognosis after development of HF compared to controls with HF.

Funding Acknowledgement

Type of funding sources: None.

Comparative Effectiveness of CABG versus PCI in Patients with Ischemic Heart Disease: insights from SWEDEHEART Registry

Background

Several studies have compared CABG to PCI as revascularization treatment in patients with ischemic heart disease (IHD). However, it remains unclear which revascularization strategy carries survival benefits in the long-term.

Methods

We used data from the SWEDEHEART (Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies) registry for all hospital admissions at 13 cardiac care centers within Västra Götaland County in Sweden (∼20% of all SWEDEHEART data). The database contains >1000 clinical variables documenting the entire process of acute coronary hospital care. All patients hospitalized for stable angina or NSTE-ACS during the period 2000–2018 were included in the analysis. We used a propensity score-adjusted Cox proportional-hazards regression with hospitals as random-effect variables. We adjusted for patients' demographics, socio-economic status, traditional risk factors, comorbidities, the severity of coronary artery disease, left ventricular function, calendar year and medication at discharge. For sensitivity analysis, we used the instrumental variable estimator for the Cox proportional-hazards model (with treating hospital as a treatment-preference instrument) to simultaneously deal with the problems of unmeasured confounding and censoring of the outcome. The primary outcome was all-cause mortality.

Results

In total, 11,896 patients were included in the study. Of these, 3,129 (26.3%) were women. 20.4% had diabetes and 10.4% had a previous myocardial infarction. The mean age was 66.7±10.7, and 42.9% were >70 years old. 61.5% had three-vessel and/or left main disease. Median follow-up time was 5.7 years (range 1 day-18.2 years). Revascularization therapy after coronary angiography was PCI in 9449 (79.4%) and CABG in 2,447 (20.6%) patients. CABG patients were more likely to have diabetes, left main/multivessel disease and heart failure. The number of revascularized patients with PCI increased by 6.4% per calendar year (P<0.001). There were 2,481 (20.9%) deaths. CABG was associated with a lower risk of death compared to PCI (HR 0.81; 95% CI 0.69–0.95; P=0.011. We found no evidence for treatment heterogeneity between the revascularization strategy and age, gender, diabetes, heart failure and indication for revascularization (all P-interaction >0.05). Results from the sensitivity analysis support the conclusions from the primary model.

Conclusions

In hospitalized patients due to IHD, revascularization with CABG was associated with superior long-term survival compared to PCI.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): Heart and Lung Foundation, ALF Västra Götaland, Swedish Scientific Council

Trends in outcome and patient composition in dilated cardiomyopathy in Sweden over time

Background

We studied prognosis and patient composition over time in dilated cardiomyopathy (DCM): a well-defined category of heart failure (HF), often affecting younger individuals. We expected improved prognosis over time, due to emerging diagnostic and therapeutic options.

Methods

All patients from the Swedish Heart Failure Registry (SwedeHF) fulfilling criteria for DCM (exclusion of ischemic, valvular, or alcoholic etiology and affirmed by clinical judgment in the protocol) (n=3739), were analyzed with respect to three time periods of inclusion in the registry, 2003–2007 (n=814), 2008–2011 (n=1448), 2012–2016 (n=1477), regarding mortality, transplantations, and hospital admissions during one year after inclusion.

Results

Over the three time periods, registered cohorts were older with time (mean 59.3 years/ 60 years/ 61.0 years, p=0.0035), and the proportion of females incresased (24.1% / 27.2% / 30.7%, p=0.0006).

For clinical variables, the distribution of left ventricular ejection fraction (LVEF) with time showed significantly higher LVEF (p=0.0024), and functional classification (NYHA) showed lower class (p=0.0011). Hypertension as a comorbidity (i.e. not judged to be responsible for HF) was more frequently occurring with time: (34.0%/ 40.6%/ 44.1%, p<0.0001). As for HF treatment: use of device increased (p<0.0001 for categorical combinations), mineralocorticoid receptor antagonists (MRA) increased (41.9%/ 37.3%/ 46.7%, p=0.0023), and diuretics dropped (76.1%/ 71.1%/ 67.0%, p≤0.0001) in the different cohorts with time.

Mortality (6.9%, 5.1%, 5.5%), transplantation (0.5%, 0.8%, 0.6%) and hospital admissions for HF (28.4%, 26.3%, 24.6%) were stable over time (ns for all), whereas cardiovascular (CV) (33.8%, 33.8%, 29.7%, p=0.043) and all cause admissions (39.1%, 38.8%, 33.7%, p=0.0099) decreased. After adjustment for age, sex, LVEF, NYHA, hypertension and device treatment only all cause admissions remained significantly decreased.

Conclusion

In this nationwide study between 2003–2016, one-year outcome in DCM in Sweden remained stationary over time, despite advances in HF therapy. During the time period, we observed a continuous change in the clinical profile in the DCM population.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Region Västra Götaland agreement concerning research and education of physicians.

P6340Mortality and prognostic factors in dilated cardiomyopathy versus ischaemic heart disease in patients with heart failure with reduced ejection fraction - a Swedish population-based study

Background

In heart failure with left ventricular ejection fraction reduction <40% (HFrEF) the increased mortality in patients with underlying ischaemic heart disease (IHD) compared to multi-aetiological non-ischaemic HFrEF is established. The prognostic difference over time in comparison with dilated cardiomyopathy (DCM) is less clear.

Purpose

To evaluate the difference in mortality between IHD and DCM in HFrEF, overall, in specific subgroups and over time.

Methods

By applying multivariable Cox regression analyses on Swedish Heart Failure Registry data from the years 2000 to 2012 (including 51,060 patients), the incidence of mortality in 8,982 patients with non-valvular clinical IHD-HFrEF was compared to 2,220 patients with DCM-HFrEF overall and for subgrouping variables of age category, sex and EF group (<30% and 30–39%), adjusted for additional 23 baseline variables.

Results

The overall mortality was higher in IHD-HFrEF with the crude mortality of 42.1% and the event rate 15.4 (95% confidence interval [CI]: 14.9 - 15.9) per 100 person years compared with 19.4% and 5.5 (95% CI: 5.0–6.1) in DCM-HFrEF. The probability of survival in IHD-HFrEF was lower than in DCM-HFrEF (Figure). After multivariable adjustment the risk for mortality in IHD-HFrEF remained increased with a hazard ratio (HR) of 1.34 (95% CI: 1.18–1.50). The adjusted HR was higher in all groups of age <80 years and in both sexes, with a significantly higher risk in women than in men (HR 1.85 vs 1.22, p for interaction = 0.002). Overall, HR was increased regardless of EF group but analyses by both age group and EF group revealed significantly increased mortality in EF <30% only for age groups <80 years. No significant temporal trend was seen between IHD-HFrEF and DCM-HFrEF.

Probability of survival

Conclusions

In patients with heart failure and reduced ejection fraction, ischaemic heart disease compared to dilated cardiomyopathy was associated with increased mortality in all age groups below 80 years of age, throughout the 13-year study period.

Acknowledgement/Funding

The Swedish Heart-Lung Foundation. The regional ALF agreement between Västra Götalandsregionen and University of Gothenburg (ALFGBG-72196, prof.Fu)

P1635A risk score for prediction of TIA/ischemic stroke in patients with heart failure and sinus rhythm

Background

Prediction of ischemic cerebral events in patients with heart failure (HF) in the absence of atrial fibrillation (AF) is challenging.

Purpose

To prospectively test a staged approach to identify patients with HF and sinus rhythm who are at high risk of developing TIA/ischemic stroke (TIA/IS) during the first two years after diagnosis.

Methods

The analysis is based on patient data reported in the Swedish Heart Failure Register from January 2003 until December 2013. Patients with AF and those treated with anticoagulants were excluded. The study population was categorized in two groups according to left ventricular ejection fraction: LVEF ≤40% and LVEF >40%. Factors associated with TIA/IS were determined by univariate proportional hazard regression. The risk score included: age (1p for 65–74y; 2p for 75–84y; 3p for ≥85y), previous ischemic heart disease (1p), hypertension (1p), diabetes mellitus (1p), TIA/IS (2p), and kidney dysfunction (1p). Two-year hazard ratios with death as competing risk were computed. The probability of observing the outcome was calculated using the cumulative incidence function.

Results

A total of 16,865 patients (mean age 72.1±13.2y) were included in the study, 39.9% women; 59.7% had LVEF ≤40%. The two-year crude rate of TIA/IS, hemorrhagic stroke, and all-cause mortality were 3.3%, 0.3%, and 26%, respectively.

An incremental absolute risk for TIA/IS was observed for patients with LVEF ≤40% and score 1- ≥6: 1.6, 2.3, 3.6, 2.9, 6.3, and 7.1%, respectively. The corresponding HRs with 95% confidence interval (CI) and the patients with 0 points as reference group were: 2.8 (1.1–7.3), 4.0 (1.6–10.1), 6.6 (2.7–16.2), 5.5 (2.2–13.8), 14.4 (5.8–35.9) for score 1- ≥6, where all p-values were less than 0.05 and Wald χ2 for overall model fit <0.0001. The cumulative incidence per 1000 person-years was: 8.2 (5.4–12.5), 11.8 (8.3–16.7), 19.4 (15.1–24.8), 16.3 (12.6–21.1), 36.6 (29.4–45.4), and 42.1 (33.0–53.8), respectively.

In patients with LVEF >40% and score 1–≥6, the absolute TIA/IS risk was: 1.3, 3.1, 3.1, 3.3, 4.6, and 5.3%, respectively. The corresponding HRs with 95% CI and patients with 1 point as reference group was: 2.4 (1.1–5.2), 2.5 (1.2–5.3), 2.7 (1.3–5.7), 3.9 (1.8–8.2); and 4.6 (2.2–9.8), for score 1- ≥6 (all p<0.05 and Wald χ2 for overall model fit p=0.0002). The cumulative incidence per 1000 person-year was: 6.7 (3.4–13.2), 16.0 (10.8–23.8), 16.7 (12.5–22.2), 18.0 (13.9–23.4), 25.8 (19.4–34.3), and 30.6 (21.7–43.0), for score 1- ≥6, respectively.

Conclusion

In the current study, a risk score compiling age and specific comorbidity was shown to predict increased risk of TIA/IS, regardless of LVEF, during the first two years after diagnosis in patients with incident HF in sinus rhythm.

Growth hormone receptor deficiency in mice results in reduced systolic blood pressure and plasma renin, increased aortic eNOS expression, and altered cardiovascular structure and function

To study the role of the growth hormone receptor (GHR) in the development of cardiovascular structure and function, female GHR gene-disrupted or knockout (KO) and wild-type (WT) mice at age 18 wk were used. GHR KO mice had lower plasma renin levels (12 +/- 2 vs. 20 +/- 4 mGU/ml, P < 0.05) and increased aortic endothelial NO synthase (eNOS) expression (146%, P < 0.05) accompanied by a 25% reduction in systolic blood pressure (BP, 110 +/- 4 vs. 147 +/- 3 mmHg, P < 0.001) compared with WT mice. Aldosterone levels were unchanged, whereas the plasma potassium concentration was elevated by 14% (P < 0.05) in GHR KO. Relative left ventricular weight was 14% lower in GHR KO mice (P < 0.05), and cardiac dimensions as analyzed by echocardiography were similarly reduced. Myograph studies revealed a reduced maximum contractile response in the aorta to norepinephrine (NE) and K(+) (P < 0.05), and aorta media thickness was decreased in GHR KO (P < 0.05). However, contractile force was normal in mesenteric arteries, whereas sensitivity to NE was increased (P < 0.05). Maximal acetylcholine-mediated dilatation was similar in WT and GHR KO mice, whereas the aorta of GHR KO mice showed an increased sensitivity to acetylcholine (P < 0.05). In conclusion, loss of GHR leads to low BP and decreased levels of renin in plasma as well as increase in aortic eNOS expression. Furthermore, GHR deficiency causes functional and morphological changes in both heart and vasculature that are beyond the observed alterations in body size. These data suggest an important role for an intact GH/IGF-I axis in the maintenance of a normal cardiovascular system.

Prenatal Multivitamin Supplementation and Rates of Pediatric Cancers: A Meta-Analysis

Prenatal supplementation of folic acid has been shown to decrease the risk of several congenital malformations. Several studies have recently suggested a potential protective effect of folic acid on certain pediatric cancers. The protective role of prenatal multivitamins has not been elucidated. We conducted a systematic review and meta-analysis to assess the potential protective effect of prenatal multivitamins on several pediatric cancers. Medline, PubMed, EMBASE, Toxline, Healthstar, and Cochrane databases were searched for studies published in all languages from 1960 to July 2005 on multivitamin supplementation and pediatric cancers. References from all articles collected were reviewed for additional articles. Two blinded independent reviewers assessed the articles for inclusion and exclusion. Rates of cancers in women supplemented with multivitamins were compared with unsupplemented women using a random effects model. Sixty-one articles were identified in the initial search, of which, seven articles met the inclusion criteria. There was an apparent protective effect for leukemia (odds ratio (OR)=0.61, 95% confidence interval (CI)=0.50-0.74), pediatric brain tumors (OR=0.73, 95% CI=0.60-0.88) and neuroblastoma (OR=0.53, 95% CI=0.42-0.68). In conclusion, maternal ingestion of prenatal multivitamins is associated with a decreased risk for pediatric brain tumors, neuroblastoma, and leukemia. Presently, it is not known which constituent(s) among the multivitamins confer this protective effect.

Cardiac concentric remodelling induced by non-aromatizable (dihydro-)testosterone is antagonized by oestradiol in ovariectomized rats

Previous studies on the cardiovascular effects of androgens in females, most of them using testosterone treatment, have yielded conflicting results. Testosterone is metabolized into oestradiol (E2) and dihydrotestosterone (DHT) within cardiovascular tissues. The aim of the present study was to explore the cardiovascular effects exerted by E2 and the non-aromatizable androgen DHT and to study possible interactions between these in female rats. Ovariectomized rats were treated with DHT, E2, or DHT+E2 for 6 weeks. DHT increased left-ventricular posterior wall thickness, assessed by echocardiography, whereas left-ventricular dimension, as well as total heart weight and calculated left-ventricular mass, were unchanged. DHT also increased the levels of insulin-like growth factor-I mRNA in the left ventricle. E2 abolished the effect of DHT on left-ventricular remodelling and insulin-like growth factor-I mRNA when the two treatments were given in combination. E2 also reduced androgen receptor mRNA levels in the heart. Neither E2 nor DHT changed blood pressure measured by telemetry. In conclusion, treatment with the endogenous non-aromatizable androgen DHT causes cardiac concentric remodelling in ovariectomized rats, possibly mediated by increased local levels of insulin-like growth factor-I. The effect of DHT on cardiac wall thickness was antagonized by E2, possibly through downregulation of cardiac androgen receptors. These mechanisms may be of importance for the concentric left-ventricular geometric pattern developing in women after menopause.

Phenotype of early cardiomyopathic changes induced by active immunization of rats with a synthetic peptide corresponding to the second extracellular loop of the human beta-adrenergic receptor

In the failing human heart, due to idiopathic dilated cardiomyopathy, it has been suggested that the beta1-adrenergic receptor (beta1AR) is a potential pathogenic autoantigen. The aim of the present study was to investigate whether immunization of rats with a synthetic peptide corresponding to the second extracellular loop of the beta1AR (beta1AR EC(II)) was able to induce the early stage of cardiomyopathy and also to investigate immunological and receptor functional parameters at a transcriptional level to permit insights into the autoimmune mechanism in cardiomyopathy. Eleven Whistar Fur rats were immunized with a beta1AR EC(II) peptide (H26R) once a month during 12 months and seven control rats were injected with vehicle according to the same procedure used for the immunized group. Cardiac function, beta1AR autoantibodies and their functional effects on cardiomyocytes were analysed. beta1AR receptor signalling, immunological and cardiomyocyte stretch markers were determined on transcriptional level. In H26R immunized rats, beta1AR autoantibodies were shown to be present and functionally active, cardiac functions in terms of fractional shortening were decreased and beta1-adrenergic receptor kinase (GRK2) mRNA were increased compared with the control group. These data have shown that immunization of rats with a putative antigenic peptide was able to induce an early stage phenotype of cardiomyopathy in the form of cardiac dysfunction and up-regulation of GRK2 as the first step in the desensitization process of the beta1AR, implying the pathological importance of the beta1AR autoantibody.

SSRI'S and other antidepressant use during pregnancy and potential neonatal adverse effects: impact of a public health advisory and subsequent reports in the news media

BACKGROUND

On Aug 9th 2004 Health Canada released an advisory, which followed a similar one from the FDA regarding the use of SSRI's and other antidepressants during pregnancy and potential adverse effects on newborns. In neither advisory was it stated that women should discontinue their antidepressant. In the seven days following the release of this advisory, The Motherisk Program received 49 calls from anxious women in response to the media reporting of this information.

OBJECTIVE

To examine the impact of the advisory and subsequent reporting in the media, on the decision-making of women, currently taking an antidepressant, who called The Motherisk Program after becoming aware of this information.

METHODS

We attempted to follow up all the women who had called us who were alarmed by this advisory and asked them to complete a specially designed questionnaire.

RESULTS

We were able to complete 43/49 (88%) follow-ups of the women who contacted us. All of the callers reported that the messages in the media caused a great deal of anxiety. Seven misunderstood the advisory, ie their children were more than 1 year old, five had discontinued their antidepressant (3 abruptly (2 later restarted after speaking with Motherisk counsellors)and 2 with some form of tapering off) and(6) were considering discontinuation, but decided to continue following reassurance from Motherisk

CONCLUSION

Medical information regarding fetal and infant safety, disseminated in the public domain, should be transferred in a way that does not influence a pregnant woman to make decisions that may not be in the best interest of hers or her child's health.

Selective cerebral overexpression of growth hormone alters cardiac function, morphology, energy metabolism and catecholamines in transgenic mice

BACKGROUND

Growth hormone (GH) has important regulatory effects on cardiac morphology and function both during normal development as well as in pathophysiological settings such as myocardial infarction (MI) and congestive heart failure (CHF). In order to investigate in more detail the interaction between GH and sympathetic nervous system (SNS) system we studied the effects of selective cerebral GH overexpression on myocardial content of catecholamines, myocardial and brain energy metabolism as well as on cardiac function during resting and stress conditions in a transgenic mouse model.

METHODS

Transgenic mice with selective bovine GH overexpression under control of glial fibrillary acidic protein promoter in the brain (GFAP-bGH, n=15) were created and compared to genetically matched non-transgenic mates (Control, n=15). Cardiac morphology and function were evaluated in vivo using transthoracic echocardiography during resting and stress conditions induced pharmacologically by dopamine (D) and isoprotenolol (ISO). Myocardial and brain energy metabolism were evaluated non-invasively using in vivo volume-selective phosphorus magnetic resonance spectroscopy ((31)P MRS). Myocardial content of catecholamines was analyzed by means of HPLC.

RESULTS

Compared to the C animals, the GFAP-bGH mice have showed several differences in the cardiac phenotype. Systolic (fractional shortening) and diastolic function (E/A wave ratio of mitral flow) was disturbed in the GFAP-bGH mice (both p<0.05). During the dopamine stress, there was chronotropic insufficiency in the GFAP-bGH group (p<0.01) while no difference was observed in response to isoprotenolol. Left ventricular dimensions were increased in GFAP-bGH mice (p<0.05). There was a tendency for higher body weight in GFAP-bGH compared to the control group (p=0.06) while no difference was observed in heart weight and brain weight when normalized for body weight. Myocardial content of noradrenaline was lower in the GFAP-bGH group (p<0.05). PCr/ATP ratio was higher (p<0.05) in the brain and lower in the heart (p<0.05) in the GFAP-bGH mice.

CONCLUSIONS

Selective cerebral overexpression of GH results in alterations of cardiac function, morphology and metabolism in transgenic mice. Decreased myocardial content of catecholamines in the GFAP-bGH mice suggests central interaction between GH and sympathetic nervous system.

Selective β1-blockade attenuates post-infarct remodelling without improvement in myocardial energy metabolism and function in rats with heart failure

OBJECTIVE

To investigate in vivo effects of long-term selective beta1-blockade on cardiac energy metabolism, remodelling, function and plasma cytokines in a rat model of post-infarct congestive heart failure (CHF).

METHODS

Myocardial infarction (MI) was induced in male rats by ligation of the left coronary artery. Three different groups of rats were studied, MI rats treated with metoprolol (n=17), MI rats treated with saline (n=14) and sham-operated rats (n=12). The treatment with metoprolol 1 mg/kg/h was initiated in the third week post-infarct for a period of 6 weeks. All rats were investigated non-invasively with volume-selective 31P magnetic resonance spectroscopy and echocardiography for evaluation of left ventricular (LV) energy metabolism, morphology and function. Plasma concentration of IL-1beta and IL-6 and density of beta-adrenergic receptors were analyzed.

RESULTS

Metoprolol attenuated the increase in LV dimensions and volumes. Treatment with metoprolol had no effect on PCr/ATP and LV function. Plasma level of IL-1beta was higher and IL-6 was lower in the metoprolol group. Density of beta-adrenergic receptors was similar in all three groups.

CONCLUSION

Selective beta1-blockade in rats with chronic CHF attenuates post-infarct structural remodelling, without concomitant improvement in myocardial energy metabolism and function. Improvements in myocardial energy metabolism and function do not precede and are not a prerequisite for an anti-remodelling effect of beta1-blockade in the setting of chronic CHF.

Different responses to dobutamine in the presence of carvedilol or metoprolol in patients with chronic heart failure

OBJECTIVE

To determine whether patients with congestive heart failure on different beta adrenoreceptor blocking drugs have similar haemodynamic responses to dobutamine.

DESIGN

Single centre, single blind, randomised, two period crossover study comparing carvedilol with metoprolol CR/XL.

PATIENTS

Ten patients with stable chronic congestive heart failure (ejection fraction < 40%) on chronic treatment with metoprolol CR/XL.

METHODS

Patients were treated with carvedilol or metoprolol CR/XL (target dose 50 mg twice daily and 200 mg once daily, respectively) for eight weeks. Stress echocardiography was undertaken at the end of each maintenance period, using dobutamine 5 and 15 microg/kg/min.

RESULTS

No significant haemodynamic differences were seen at rest on the two treatments. There was a more pronounced increase in heart rate and cardiac output during dobutamine infusion when the patients were on metoprolol than when they were on carvedilol. Mean arterial pressure increased significantly when the patients were on carvedilol, and cardiac output increased during low dose dobutamine, without further change during high dose dobutamine. During the dobutamine infusion, there was no significant difference in ejection fraction between carvedilol and metoprolol treatment.

CONCLUSIONS

Patients with congestive heart failure on a non-selective beta adrenoreceptor blocker or beta1 selective blocker responded differently to the inotropic drug dobutamine: the beta1 blockade caused by metoprolol could be counteracted by dobutamine, whereas with carvedilol a low dose of dobutamine increased cardiac output, and a higher dose of dobutamine caused a pressor effect. These findings may be clinically relevant when choosing an inotropic drug.

Growth hormone alone or combined with metoprolol preserves cardiac function after myocardial infarction in rats

BACKGROUND AND OBJECTIVE

Beta-adrenoreceptor blocking agents are important for the treatment of myocardial infarction (MI). Accumulating evidence also indicates that growth hormone (GH) improves cardiac function after MI in rats. We aimed to investigate the cardiovascular effects of combined treatment in an animal model of MI.

METHODS

MI was induced in rats by ligation of the left coronary artery. Three days after MI, animals were randomly assigned to one of four groups: controls (C) (n=19); GH (n=19) receiving s.c. 2 mg/kg per day rhGH; metoprolol (M) group (n=19) receiving 24 mg/kg per day and combined group (GHM) (n=20) treated with both GH (2 mg/kg per day s.c.) and M (24 mg/kg per day) for 9 days. Transthoracic echocardiography was performed before and after treatment.

RESULTS

Serum levels of insulin-like growth factor I were significantly elevated in the GH-group but not in the GHM group compared to controls. Left ventricular volumes, cardiac index, systolic blood pressure, were similar in all groups. Percent changes in ejection fraction compared to baseline were; GH (6.1+/-5.0%) and GHM (6.1+/-4.2%) vs. C (-12.5+/-3.0%), P<0.01, M (-7.3+/-4.2%). The occurrence of aneurysms was not significantly different between the various treatment regimes.

CONCLUSION

Treatment with growth hormone alone or in combination with metoprolol preserved left ventricular function after MI.

Selective beta(1)-blockade improves cardiac bioenergetics and function and decreases neuroendocrine activation in rats during early postinfarct remodeling

In spite of the solid evidence that beta-blockade reduces mortality and morbidity in congestive heart failure (CHF) this therapy continues to be underused in clinical praxis. The reason for this may lie in scarcity of knowledge about the mechanisms of beta-blockade action. The major aim of this study was to investigate in vivo whether selective beta(1)-blockade may improve cardiac energy metabolism in rats with myocardial infarction in early postinfarct remodeling phase. Myocardial infarction (MI) was induced in male Sprague-Dawley rats by ligation of the left coronary artery. Two different groups of rats were studied, rats with MI treated with metoprolol (5 mg/kg/h; n = 9) and rats with MI saline treated (n = 9). The treatment with metoprolol was given by subcutaneously implanted minipumps and was initiated at 3 days postinfarct and during the period of 4 weeks. All rats were investigated with noninvasive methods (31)P magnetic resonance spectroscopy (MRS) and transthoracic echocardiography 3 days after induction of MI and 4 weeks later. Phosphocreatine/ATP ratio was normalized after the treatment with metoprolol while it was 50% lower in the saline group (p < 0.001). In the metoprolol group stroke volume and ejection fraction increased while deceleration time of mitral early filling was longer (all p < 0.05). Left ventricular weight as well as volumes and dimensions were similar between the groups. Plasma levels of noradrenaline (p = 0.058), adrenaline (p < 0.01) and brain natriuretic peptide (p = 0.09) were lower in the metoprolol group. Selective beta(1)-blockade with high dose of metoprolol initiated in the early postinfarct phase improves myocardial energy metabolism and function and prevents overactivation of sympathetic system. The beneficial effect on myocardial bioenergetics may be an important mode of action of beta-blockers which contributes to the clinical benefits of the therapy in CHF.

Growth hormone improves bioenergetics and decreases catecholamines in postinfarct rat hearts

The aims of this study were to examine, in vivo, the effects of GH treatment on myocardial energy metabolism, function, morphology, and neurohormonal status in rats during the early postinfarct remodeling phase. Myocardial infarction (MI) was induced in male Sprague Dawley rats. Three different groups were studied: MI rats treated with saline (n = 7), MI rats treated with GH (MI + GH; n = 11; 3 mg/kg x day), and sham-operated rats (sham; n = 8). All rats were investigated with 31P magnetic resonance spectroscopy and echocardiography at 3 days after MI and 3 weeks later. After 3 weeks treatment with GH, the phosphocreatine/ATP ratio increased significantly, compared with the control group (MI = 1.69 +/- 0.09 vs. MI + GH = 2.42 +/- 0.05, P < 0.001; sham = 2.34 +/- 0.08). Treatment with GH significantly attenuated an increase in left ventricular end systolic volume and end diastolic volume. A decrease in ejection fraction was prevented in GH-treated rats (P < 0.05 vs. MI). Myocardial and plasma noradrenaline levels were significantly lower in MI rats treated with GH. These effects were accompanied by normalization of plasma brain natriuretic peptide levels (sham = 124.1 +/- 8.4; MI = 203.9 +/- 34.7; MI + GH = 118.3 +/- 8.4 ng/ml; P < 0.05 vs. MI). In conclusion, GH improves myocardial energy reserve, preserves left ventricular function, and attenuates pathologic postinfarct remodeling in the absence of induction of left ventricular hypertrophy in postinfarct rats. The marked decrease in myocardial content of noradrenaline, after GH treatment, may protect myocardium from adverse effects of catecholamines during postinfarct remodeling.

Induction of cardiomyopathy in severe combined immunodeficiency mice by transfer of lymphocytes from patients with idiopathic dilated cardiomyopathy

Growing evidence suggests that autoimmune mechanisms play an important role in the pathogenesis of idiopathic dilated cardiomyopathy (DCM). The aim of the study was to evaluate the effects of transfer of lymphocytes from patients with DCM into severe combined immunodeficiency (SCID) mice on the heart structure and function. Thirty CB-17 SCID (6-8 weeks old) mice were used and divided into 3 groups (n = 10). Mice were injected intraperitoneally with up to 25 x 10(6) peripheral blood lymphocytes (PBL) from either patients with DCM which contain human autoantibodies against cardiac beta1-adrenergic receptors and M2-muscarinic receptors (DCM group) or PBL from healthy controls (control-H group). Ten mice did not receive any injections and were used as baseline controls (control-N group). Echocardiography and morphological studies were performed seventy five days after the transfer. Results showed that in DCM group, left ventricle dimensions (LVD) in diastole were increased (4.2 +/- 0.1mm) as compared to both control-H group (3.8 +/- 0.1mm) and control-N group (3.6 +/- 0.1 mm) (p < 0.01). Further, there was a trend for increased LVD in systole. Fractional shortening was not different between groups. Histological evaluation revealed accumulation of human lymphocytes in the capillaries and scarce infiltration of the lymphocytes in the hearts from DCM group. Diffuse fibrosis was significant increased in DCM mice as compared to mice receiving PBL from normal subjects (2.2 +/- 0.3% vs. 0.8 +/- 0.1%, p < 0.01). In conclusion, transfer of the PBL from the patients with DCM was able to induce early stage of heart dilatation in SCID mice. These data provide for the first time the direct evidence supporting that the autoimmune mechanism is important in the pathogenesis of human DCM.

Impairment of cardiac function and bioenergetics in adult transgenic mice overexpressing the bovine growth hormone gene

Cardiovascular abnormalities represent the major cause of death in patients with acromegaly. We evaluated cardiac structure, function, and energy status in adult transgenic mice overexpressing bovine GH (bGH) gene. Female transgenic mice expressing bGH gene (n = 11) 8 months old and aged matched controls (n = 11) were used. They were studied with two-dimensional guided M-mode and Doppler echocardiography. The animals (n = 6) for each group were examined with 31P magnetic resonance spectroscopy to determine the cardiac energy status. Transgenic mice had a significantly higher body weight (BW), 53.2+/-2.4 vs. 34.6+/-3.7 g (P < 0.0001) and hypertrophy of left ventricle (LV) compared with normal controls: LV mass/BW 5.6+/-1.6 vs. 2.7+/-0.2 mg/g, P < 0.01. Several indexes of systolic function were depressed in transgenic animals compared with controls mice such as shortening fraction 25+/-3.0% vs. 39.9+/-3.1%; ejection fraction, 57+/-9 vs. 77+/-5; mean velocity of circumferential shortening, 4.5+/-0.8 vs. 7.0+/-1.1 circ/sec, p < 0.01. Creatine phosphate-to-ATP ratio was significantly lower in bGH overexpressing mice (1.3+/-0.08 vs. 2.1+/-0.23 in controls, P < 0.05). Ultrastructural examination of the hearts from transgenic mice revealed substantial changes of mitochondria. This study provides new insight into possible mechanisms behind the deteriorating effects of long exposure to high level of GH on heart function.

In vivo metabolic imaging of cardiac bioenergetics in transgenic mice

Recent advances in transgenic technology have made the mouse a particularly interesting small animal in cardiovascular research. Increasingly sophisticated experimental methods and tools are needed for detailed characterization of cardiovascular physiology and biochemistry in the mice. The objective of this study was to develop a method for noninvasive evaluation of cardiac energy metabolism in the mouse. Cardiac gated (31)P magnetic resonance spectroscopy using Image Selected in Vivo Spectroscopy (ISIS) method was applied in old mice overexpressing bovine growth hormone (bGH) (n = 5) and control mice (n = 5). The localized volumes of interest were 128 and 112 microL, respectively. Phosphocreatine-to-ATP ratio was 1.5 +/- 0.13 in the bGH mice and 2.1 +/- 0.04 in the control group (P < 0.01). The study demonstrates the feasibility of application of volume-selective (31)P MRS for evaluation of cardiac energy metabolism in the mouse under maintained physiological conditions.

The growth hormone secretagogue hexarelin improves cardiac function in rats after experimental myocardial infarction

Several studies have shown that GH can enhance cardiac performance in rats after experimental myocardial infarction and in humans with congestive heart failure. In the present study, the hemodynamic effects of hexarelin (Hex), an analog of GH-releasing peptide-6 and a potent GH secretagogue, were compared with the effects of GH. Four weeks after ligation of the left coronary artery male rats were treated sc twice daily with hexarelin [10 microg/kg x day (Hex10) or 100 microg/kg x day (Hex100)], recombinant human GH (2.5 mg/kg x day), or 0.9% NaCl for 2 weeks. Transthoracic echocardiography was performed before and after the treatment period. GH, but not Hex, increased body weight gain. GH and Hex100 decreased total peripheral resistance (P < 0.05) and increased stroke volume (P < 0.05 and P < 0.01, respectively) and stroke volume index (P = 0.06 and P < 0.01, respectively) vs. NaCl. Cardiac output was increased by GH and Hex100 (P < 0.05), and cardiac index was increased by Hex100 with a borderline significance for GH (P = 0.06). In conclusion, Hex improves cardiac function and decreases peripheral resistance to a similar extent as exogenous GH in rats postmyocardial infarction. The mechanisms of these effects are unclear; they could be mediated by GH or a direct effect of Hex on the cardiovascular system.

Bioenergetic, functional and morphological consequences of postinfarct cardiac remodeling in the rat

Despite recent advances in the treatment, severe chronic heart failure (CHF) remains a syndrome associated with high mortality. Therefore, the search for new agents to improve both patient symptoms and survival, as well as the pursuit for detailed knowledge about pathophysiology of the failing heart, will continue to depend on relevant animal models. Large acute myocardial infarction (MI) initiates complex changes in the geometrical, structural, and biochemical architecture of both infarcted and non-infarcted regions of ventricular myocardium, which can profoundly affect left ventricular function and prognosis. In this paper we present a new model for non-invasive cardiac (31)P MRS in the rat. Volume-selective (31)P magnetic resonance spectroscopy and echocardiography were used for evaluation of myocardial energy metabolism, cardiac morphology and function in rats 3 days and 3 weeks after induction of large MI. The phosphocreatine:adenosine triphosphate (PCr:ATP) ratio was decreased in rats with MI comparing with controls both at 3 days (1.6+/-0.06 vs 2.7+/-0.04; mean+/-s.e.m. P<0.0001) and 3 weeks (1.6+/-0.07 v 2.7+/-0.02 P<0.0001) postinfarct. The results from the study demonstrate that postinfarct cardiac remodeling is a rapid process of changes not only in cardiac geometry, structure and function but also in myocardial energy metabolism after large transmural MI in the rat.