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Substrate-based catheter ablation approaches to ventricular tachycardia (VT) focus on low-voltage areas and abnormal electrograms. However, specific electrogram characteristics in sinus rhythm are not clearly defined and can be subject to variable interpretation. We analyzed the potential ablation target size using automatic abnormal electrogram detection and studied findings during substrate mapping in the VT isthmus area.Electrogram characteristics in 61 patients undergoing scar-related VT ablation using ultrahigh-density 3D-mapping with a 64-electrode mini-basket catheter were analyzed retrospectively. Forty-four complete substrate maps with a mean number of 10319 ± 889 points were acquired. Fractionated potentials detected by automated annotation and manual review were present in 43 ± 21% of the entire low-voltage area (1.0 mV), highly fractionated potentials in 7 ± 8%, late potentials in 13 ± 15%, fractionated late potentials in 7 ± 9% and isolated late potentials in 2 ± 4%, respectively. Highly fractionated potentials (10 ± 1 fractionations) were found in all isthmus areas of identified VT during substrate mapping, while isolated late potentials were distant from the critical isthmus area in 29%.The ablation target area varies enormously in size, depending on the definition of abnormal electrograms. Clear linking of abnormal electrograms with critical VT isthmus areas during substrate mapping remains difficult due to a lack of specificity rather than sensitivity. However, highly fractionated, low-voltage electrograms were found to be present in all critical VT isthmus sites.

Myocarditis is characterized by various clinical manifestations, with ventricular arrhythmia (VA) as a frequent symptom at initial presentation. Here, we investigated characteristics and prognostic relevance of VA in patients with myocarditis. The study population consisted of 76 patients with myocarditis, verified by biopsy and/or cardiac magnetic resonance (CMR) imaging, including 38 consecutive patients with VA (45 ± 3 years, 68% male) vs. 38 patients without VA (NVA) (38 ± 2 years, 84% male) serving as a control group. VA was monomorphic ventricular tachycardia in 55% of patients, premature ventricular complexes in 50% and ventricular fibrillation in 29%. The left ventricular ejection fraction at baseline was 47 ± 2% vs. 40 ± 3% in VA vs. NVA patients (p = 0.069). CMR showed late gadolinium enhancement more often in VA patients (94% vs. 69%; p = 0.016), incorporating 17.6 ± 1.8% vs. 8.2 ± 1.3% of myocardial mass (p < 0.001). Radiofrequency catheter ablation for VA was initially performed in nine (24%) patients, of whom five remained free from any recurrence over 24 ± 3 months. Taken together, in patients with myocarditis, reduced left ventricular ejection fraction does not predict VA occurrence but CMR shows late gadolinium enhancement more frequently and to a larger extent in VA than in NVA patients, potentially guiding catheter ablation as a reasonable treatment of VA in this population.

Purpose Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is an increasingly used treatment option for patients in need of mechanical cardiopulmonary support, while available outcome data is limited. The aim of this study was to identify predictors for 30-day in-hospital mortality. Material and methods We analyzed baseline characteristics and outcomes of 8351 VA-ECMO procedures performed in Germany from 2007 to 2015. Using a multivariable model, we identified the ten most important variables to allow for prediction of 30-day in-hospital mortality. Based on these variables, we created a mortality prediction score (ECMO-ACCEPTS score) to enhance decision making in patients considered for or treated with VA-ECMO support. Results Of 8351 patients (71.7% male) 3567 had prior CPR. Mean age was 62 years in the present cohort. The overall 30-day in-hospital mortality was 61%. The ECMO-ACCEPTS score, derived among randomly selected 4175 patients, included ten independent predictors for in-hospital mortality. Internal validation in the remaining 4176 patients confirmed strong differentiation between low and high risk of 30-day in-hospital mortality (r = 0.97 for correlation of predicted with observed mortality, p Conclusions The ECMO-ACCEPTS score might help clinicians to improve risk prediction among VA-ECMO patients for refractory cardiogenic shock.

Background Neuron-specific-enolase (NSE) is frequently used to predict the neurologic outcome in persistently unconscious patients after cardiopulmonary resuscitation (CPR). However, its predictive value is unclear in the setting of veno-arterial extracorporeal membrane oxygenation therapy (ECMO). Aim of this project is to evaluate the predictive value of NSE in ECMO patients. Methods NSE was measured after 24, 48, and 72 h in post-CPR ECMO patients. Neurologic status was evaluated using the best Cerebral Performance Categories Score (CPC) during the hospital stay. Patients who deceased within the first 24 h and patients who were awake during the first 24 h were excluded. ROC curves were calculated to assess the discriminative ability of single NSE measurements. Trajectories of serial NSE values were investigated using latent class mixed models. Results The derivation cohort consisted of 65 patients, 30-day all-cause mortality was 47.7% and a poor neurological outcome with a CPC score of 4–5 was seen 30.7%. NSE measurement after 48 h showed the best discrimination for poor neurological outcome (AUC of 0.87 in the ROC curve; cut-off value of 70 μg/L). Specificity was highest if using serial NSE measurements at all three time points. These results could be validated in an external cohort of 64 patients. Conclusion In post-CPR patients on ECMO, NSE can be used to assess the neurologic outcome. Importantly, specificity was highest if using serial NSE measurements. Further research using prospective datasets is needed to verify these findings.

Objectives: This report relates the authors' ongoing experience with percutaneous left ventricular (LV) unloading by using a transaortic LV assist device in combination with venoarterial ex...

Experimental data indicate that stimulation of the nitric oxide-soluble guanylate cyclase(sGC)-cGMP-PKG pathway can increase left ventricular (LV) capacitance via phosphorylation of the myofilamental protein titin. We aimed to test whether acute pharmacological sGC stimulation with BAY 41-8543 would increase LV capacitance via titin phosphorylation in healthy and deoxycorticosteroneacetate (DOCA)-induced hypertensive pigs. Nine healthy Landrace pigs and 7 pigs with DOCA-induced hypertension and LV concentric hypertrophy were acutely instrumented to measure LV end-diastolic pressure-volume relationships (EDPVRs) at baseline and during intravenous infusion of BAY 41-8543 (1 and 3 μg·kg−1·min−1 for 30 min, respectively). Separately, in seven healthy and six DOCA pigs, transmural LV biopsies were harvested from the beating heart to measure titin phosphorylation during BAY 41-8543 infusion. LV EDPVRs before and during BAY 41-8543 infusion were superimposable in both healthy and DOCA-treated pigs, whereas mean aortic pressure decreased by 20–30 mmHg in both groups. Myocardial titin phosphorylation was unchanged in healthy pigs, but total and site-specific (Pro-Glu-Val-Lys and N2-Bus domains) titin phosphorylation was increased in DOCA-treated pigs. Bicoronary nitroglycerin infusion in healthy pigs ( n = 5) induced a rightward shift of the LV EDPVR, demonstrating the responsiveness of the pathway in this model. Acute systemic sGC stimulation with the sGC stimulator BAY 41-8543 did not recruit an LV preload reserve in both healthy and hypertrophied LV porcine myocardium, although it increased titin phosphorylation in the latter group. Thus, increased titin phosphorylation is not indicative of increased in vivo LV capacitance. NEW & NOTEWORTHY We demonstrate that acute pharmacological stimulation of soluble guanylate cyclase does not increase left ventricular compliance in normal and hypertrophied porcine hearts. Effects of long-term soluble guanylate cyclase stimulation with oral compounds in disease conditions associated with lowered myocardial cGMP levels, i.e., heart failure with preserved ejection fraction, remain to be investigated.

Background Ablation of scar-related ventricular tachycardia (VT), especially in non-inducible VT or hemodynamically unstable patients, can be challenging. Thus, we evaluated feasibility of an ultra high-density 3D-mapping approach to characterize the ventricular substrate and, if possible, to map VT. Methods and results Twenty-two patients (67±2 years, mean LV-EF 36±3%) with both ischemic and non-ischemic cardiomyopathy and documented VT underwent mapping and catheter ablation using a 64-electrode mini-basket catheter. Substrate characterization included ultra high-density voltage maps, identification of areas of slow conduction and late potentials. Whenever VT was inducible activation mapping was performed. In 13/22 patients the presumed clinical VT (in 16/22 any VT) was inducible. A total of 50 maps were generated (22 substrate maps, 28 during VT), mapping time was 33±4 minutes, number of points was 10937±1923. Low voltage areas were related with the site of origin in all mapped VT. Isochronal maps indicated areas of slow conduction in 14/22 patients, all in border zone scar. In 95% of patients late potentials were found. Mapping time during VT was 9±2 minutes, number of points 6740±1140. Covered cycle length was 82±5% (16 re-entry, 10 focal and 2 undetermined). During 4 months follow-up 90% remained free from VT recurrence. Conclusion Ultra high-density mapping in patients with scar-related VT is feasible, safe and enables detailed insight into tachycardia mechanisms. Critical sites can be identified (1) by precise substrate characterization when VT is not inducible or hemodynamically not tolerated and (2) during short lasting episodes of VT in order to guide catheter ablation. This article is protected by copyright. All rights reserved

BACKGROUND Extensive and repeated substrate modification (SM) is frequently performed as an ablation strategy in persistent atrial fibrillation (persAF). The effect of these extended ablation strategies on atrial function has not been investigated sufficiently so far. The purpose was to assess atrial function by cardiac magnetic resonance (CMR) and its association with left atrial (LA) scar burden by electroanatomical voltage-mapping after multiple persAF ablation procedures. METHODS We included 16 persAF patients who had ≥2 SM procedures and a control group (CG) of 21 persAF patients without prior ablation. CMR was performed in sinus rhythm at least 4 weeks after the last cardioversion. Active left and right (RA) atrial emptying fractions (AEF) as well as peak active left atrial appendage (LAA) emptying velocities were obtained by CMR flow measurements. Furthermore, LA scar burden was quantified on electroanatomical voltage maps by the portion of points with local voltage amplitude

Heart failure is a consequence of various cardiovascular diseases and associated with poor prognosis. Despite progress in the treatment of heart failure in the past decades, prevalence and hospitalisation rates are still increasing. Heart failure is typically associated with cardiac remodelling. Here, inflammation and fibrosis are thought to play crucial roles. During cardiac inflammation, immune cells invade the cardiac tissue and modulate tissue-damaging responses. Cardiac fibrosis, however, is characterised by an increased amount and a disrupted composition of extracellular matrix proteins. As evidence exists that cardiac inflammation and fibrosis are potentially reversible in experimental and clinical set ups, they are interesting targets for innovative heart failure treatments. In this context, animal models are important as they mimic clinical conditions of heart failure patients. The advantages of mice in this respect are short generation times and genetic modifications. As numerous murine models of heart failure exist, the selection of a proper disease model for a distinct research question is demanding. To facilitate this selection, this review aims to provide an overview about the current understanding of the pathogenesis of cardiac inflammation and fibrosis in six frequently used murine models of heart failure. Hence, it compares the models of myocardial infarction with or without reperfusion, transverse aortic constriction, chronic subjection to angiotensin II or deoxycorticosterone acetate, and coxsackievirus B3-induced viral myocarditis in this context. It furthermore provides information about the clinical relevance and the limitations of each model, and, if applicable, about the recent advancements in their methodological proceedings.

Obesity is a risk factor for heart failure (HF) and identification of symptomatic, and obese HF patients are challenging, because obesity can mimic HF symptoms. We aimed to evaluate novel biomarkers for HF in obese subjects of the general population. Midregional proadrenomedullin (MR-proADM), growth differentiation factor-15 (GDF-15), midregional pro-atrial natriuretic peptide (MR-proANP), and NT-proBNP were measured in 5000 individuals of the population-based Gutenberg Health Study (GHS), including 1204 obese individuals (BMI ≥ 30 kg/m2) and 107 individuals with HF. NT-proBNP and MR-proANP were lower in obese vs. non-obese HF individuals (p = 0.013 and p = 0.01, respectively), whereas GDF-15 was similar and MR-proADM was higher in obese vs. non-obese HF individuals. All biomarkers increased the odds ratio (OR) for prevalent HF. For NT-proBNP and MR-proANP, this increase was lower in obese vs. non-obese individuals, whereas it was comparable for MR-proADM and GDF-15. All biomarkers were associated with increased all-cause mortality (median follow-up 7.3 years, 211 events). Results were validated in 8373 individuals (n = 1734 with BMI ≥ 30 kg/m2) of the FINRISK study with a median follow-up of 13.8 years (1030 events). Using a dichotomized biomarker cutoff for HF, the best predictor for all-cause mortality in obese subjects was GDF-15 (p

Aims Left-ventricular (LV) remodelling impacts on the LV end-diastolic pressure–volume relationship (EDPVR), which is different in heart failure (HF) with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). In a large-scale, population-based cohort (Gutenberg Health Study), we aimed to investigate alterations of the EDPVR in HF patients and their association to risk factors and all-cause mortality in non-HF individuals. Methods and results Based on clinical and echocardiographic data, participants were divided into ‘No HF’ ( n = 14487), HFrEF ( n = 215), and HFpEF ( n = 79). We estimated the position of the EDPVR and its stiffness-coefficient β from echocardiographic data using a single-beat method. The EDPVR was shifted rightward in HFrEF and leftward in HFpEF compared with ‘No HF’, while the stiffness-coefficient β was increased in both HFrEF and HFpEF. In ‘No HF’, a higher stiffness-coefficient β was associated with age, female gender, hypertension, diabetes, and obesity, while age and female gender were associated with a leftward shift of the EDPVR, whereas dyslipidaemia, obesity, smoking, and impaired renal function were associated with a rightward shift of the EDPVR. Both changes of the EDPVR were associated with increased all-cause mortality. Conclusion In a large-scale, population-based cohort, we show distinct alterations of the EDPVR in HFrEF and HFpEF. Already in non-HF individuals, the presence of risk factors for HF is linked alterations of the EDPVR, which are associated with increased mortality.

Background Percutaneous mitral valve edge‐to‐edge repair ( pMVR ) with a MitraClip is beneficial for the clinical symptoms of patients irrespective of the ejection fraction ( EF ). Nevertheless, the consequences on hemodynamics are poorly understood. Therefore, we used data from noninvasive pressure‐volume loops to investigate the left ventricular (LV) remodeling of patients after pMVR dependent on their baseline EF. Methods and Results In 130 patients with successful pMVR , the end‐diastolic pressure‐volume relationship (EDPVR) and end‐systolic pressure‐volume relationship were estimated noninvasively from echocardiographic data. We compared EDPVR and end‐systolic pressure‐volume relationship at discharge and follow‐up between patients with a reduced EF (EF (≥40%). Reduced EF was present in 71 patients (54%). Mean follow‐up duration was 277±117 days. We observed a significant reduction in degree of mitral regurgitation and an improvement in functional status at follow‐up irrespective of baseline EF . In patients with a mid‐ranged or preserved EF , the EDPVR and end‐systolic pressure‐volume relationship were shifted leftwards, suggesting an improvement in LV function. In contrast, in patients with a reduced EF , EDPVR and end‐systolic pressure‐volume relationship remained stable, although comparison with the baseline data indicates a rightward shift of the EDPVR . This indicates that there is no improvement in LV function after pMVR in patients with reduced EF. Conclusions The pMVR is associated with improved clinical symptoms in all patient subgroups. However, it leads to different hemodynamic responses. In patients with mid‐ranged or preserved EF , we found reverse remodeling with reduced LV dilatation and increased contractility. In contrast, in patients with reduced EF , we observed no reverse remodeling and no improvement in LV function.

BACKGROUND Aorto-ostial lesions as well as bifurcation lesions still provide challenges in percutaneous coronary intervention (PCI), as meticulous stent placement is needed. The Szabo-technique, which uses a second wire to anchor the stent at the ostium, may be helpful here. In this article, we will provide detailed information on the technique including video material as well as procedural and long-term follow-up data of a cohort of patients treated with this technique. METHODS A retrospective single-centre study was performed in patients undergoing Szabo-PCI from 2014 to 2016 (N.=28). RESULTS Indications for PCI were elective in 53% and urgent/emergent in 47%. Target vessel was the ostial right coronary artery in 43%, the ostial left main artery in 7%, the proximal left anterior descending artery in 29% and the proximal circumflex artery in 21% of the cases. Primary success rate was 86%. In the other 14%, delivery of the stent failed due to a high-grade calcification. There were no periprocedural complications. During the follow-up time (mean 308 days) there was one case of cardiovascular and one case of non-cardiovascular death without any stroke events. In one case target lesions revascularisation was necessary. CONCLUSIONS The Szabo-technique offers a feasible and safe approach for PCI of ostial and bifurcation lesions. Calcified lesions seem to be a challenging aspect.

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine known to play a major role in inflammatory diseases such as myocardial infarction (MI), where its expression increases. Cardio protective functions of MIF during ischemia have been reported. Recently, the structurally related MIF-2 was identified and similar effects are assumed. We wanted to further investigate the role of MIF and MIF-2 on inflammatory processes during MI. Therefore, we subjected mice to experimentally induced MI by coronary occlusion for one and five days. During the acute phase of MI, the gene expression of Mif was upregulated in the infarct zone, whereas Mif-2 was downregulated, suggesting a minor role of MIF-2. Simulating ischemic conditions or mechanical stress in vitro, we demonstrated that Mif expression was induced in resident cardiac cells. To investigate possible auto /paracrine effects, cardiomyocytes and cardiac fibroblasts were individually treated with recombinant murine MIF, which in turn induced Mif expression and the expression of pro-inflammatory genes in cardiac fibroblasts. Cardiomyocytes did not respond to recombinant MIF with pro-inflammatory gene expression. While MIF stimulation alone did not change the expression of pro-fibrotic genes in cardiac fibroblasts, ischemia reduced their expression. Mimicking the increased MIF levels during MI, we exposed cardiac fibroblasts to simulated ischemia in the presence of MIF, which led to further reduced expression of pro-fibrotic genes. The presented data show that MIF was expressed by resident cardiac cells during MI. In vitro, Mif expression was induced by different external stimuli in cardiomyocytes and cardiac fibroblasts. Addition of recombinant MIF protein increased the expression of pro-inflammatory genes in cardiac fibroblasts including Mif expression itself. Thereby, cardiac fibroblasts may amplify Mif expression during ischemia promoting cardiomyocyte survival.

Heart failure (HF) incidence is rising worldwide and HF with preserved ejection fraction (HFpEF) represents nearly half of all cases. Treatment options are still limited in HFpEF in comparison to HF with reduced ejection fraction (HFrEF).We analyzed biomarkers in the general population to characterize HFpEF and HFrEF and defined a biomarker index to differentiate HFpEF from HFrEF. Growth differentiation factor-15 (GDF-15), soluble source of tumorigenicity 2 (sST2), C-reactive protein (CRP) and NT-proBNP were measured in 5000 individuals of the population-based Gutenberg Health Study (GHS). The median follow-up time for all-cause mortality was 7.3years with 213 events.Identification of subjects with HF was improved by GDF-15 (p0.001) in addition to NT-proBNP with an odds ratio (OR) of 1.4 (95% confidence interval [CI]:1.1-1.7). Discrimination of subjects with and without HF was slightly higher for GDF-15 (area under the ROC curve [AUC]:0.79 [95%CI:0.75-0.83]) compared to NT-proBNP (AUC:0.77 [95% CI:0.72-0.82]). For subjects with HF, differentiating HFpEF from HFrEF was feasible with the index ((CRP+GDF-15+sST2)/NT-proBNP) with an OR of 3.7 (95% CI:1.9-8.5) (p0.001). The best biomarkers predicting all-cause mortality were NT-proBNP and GDF-15 with a hazard ratio (HR) of 1.9 (95% CI:1.6-2.2) and 1.7 (95%CI:1.6-1.9) (both p0.001), respectively.GDF-15 was useful to detect prevalent HF in addition to NT-proBNP and was elevated in HFrEF and HFpEF, whereas NT-proBNP was higher in HFrEF than in HFpEF. All biomarkers were useful to predict mortality in the general population. The index of ((CRP+GDF-15s+sST2)/NT-proBNP) was able to discriminate HFpEF from HFrEF.

Extensive and repeated substrate modification (SM) is frequently performed as an ablation strategy in persistent atrial fibrillation (persAF). The effect of these extended ablation strategies on atrial function has not been investigated sufficiently so far. The purpose was to assess atrial function by cardiac magnetic resonance (CMR) and its association with left atrial (LA) scar burden by electroanatomical voltage-mapping after multiple persAF ablation procedures.We included 16 persAF patients who had ≥2 SM procedures and a control group (CG) of 21 persAF patients without prior ablation. CMR was performed in sinus rhythm at least 4 weeks after the last cardioversion. Active left and right (RA) atrial emptying fractions (AEF) as well as peak active left atrial appendage (LAA) emptying velocities were obtained by CMR flow measurements. Furthermore, LA scar burden was quantified on electroanatomical voltage maps by the portion of points with local voltage amplitude0.2 mV.We found median LA-AEF to be lower (13 [9-22] vs 32 [26-36] %, P0.001) and median LA scar burden to be higher (40 [20-68] vs nine [3-18] %, P0.05) in the SM group compared with the CG. Furthermore, a significant correlation was found between mean LA voltage and LA-AEF (rActive LA function is preserved but significantly impaired and associated with ablation-related LA scar burden after multiple extensive persAF ablations.

Die Therapie des akuten Myokardinfark­tes hat in den vergangenen Dekaden durch die Etablierung der Akut-PTCA, der Stents und die Fortentwicklung der medi­kamentosen Therapie (zuletzt die neuen Thrombozytenaggregationshemmer Pra­sugrel und Ticagrelor) grose Fortschritte erzielt. Wahrend die initiale Einfuhrung von Stents zu einer massiven Verbesse­rung des Ergebnisses gegenuber der allei­nigen Ballondilatation gefuhrt hat, waren die weiteren Schritte hin zu einer besse­ren Stentstruktur in Summe sehr nutzlich, jedoch in den einzelnen Schritten nur noch von geringem Zusatznutzen.

Mechanisms underlying atrial remodeling toward atrial fibrillation (AF) are incompletely understood. We induced AF in 16 pigs by 6weeks of rapid atrial pacing (RAP, 600bpm) using a custom-built, telemetrically controlled pacemaker. AF evolution was monitored three times per week telemetrically in unstressed, conscious animals. We established a dose-response relationship between RAP duration and occurrence of sustained AF >60minutes. Left atrial (LA) dilatation was present already at 2weeks of RAP. There was no evidence of left ventricular heart failure after 6weeks of RAP. As a proof-of-principle, arterial hypertension was induced in 5/16 animals by implanting desoxycorticosterone acetate (DOCA, an aldosterone-analog) subcutaneously to accelerate atrial remodeling. RAP+DOCA resulted in increased AF stability with earlier onset of sustained AF and accelerated anatomical atrial remodeling with more pronounced LA dilatation. This novel porcine model can serve to characterize effects of maladaptive stimuli or protective interventions specifically during early AF.

Introduction: The RELAX in Acute Heart Failure (RELAX-AHF) trial was done in patients admitted for acute decompensated heart failure to evaluate the efficacy of Serelaxin (human recombinant relaxin-2) on dyspnoea relief, as well as its safety and tolerability. Interestingly, the 180-day mortality was significantly better in the Serelaxin group compared to placebo. The pathophysiology of these beneficial effects remains elusive. Methods and results: To induce heart failure in mice, they were treated with Angiotensin II in absence or in presence of relaxin. After 21 days hemodynamic measurements revealed an improved hemodynamic function in relaxin treated animals with AngII-induced heart failure compared to mice without relaxin treatment. To further investigate the , cardiac fibroblasts were stimulated with pro-fibrotic TGF-β in the presence or in the absence of relaxin. Additionally as a control cardiac fibroblasts were treated with relaxin alone. The treatment with TGF-β induced an increased gene expression of connective tissue growth factor (CTGF) as well as monocyte chemotactic protein 1 (MCP-1) in cardiac fibroblasts, whereas treatment with relaxin alone decreased the gene expression level of CTGF as well as MCP-1 . To investigate a potential inhibitory function of relaxin during TGF-β induced pro-fibrotic gene expression regulation, cardiac fibroblasts were pre-incubated with relaxin 1 hour prior to TGF-β treatment. After the following 6 hours of TGF-β treatment no decreased gene expression was observed in relaxin pre-treated cardiac fibroblasts compared to TGF-β stimulated fibroblasts without relaxin treatment. Conclusion: In this study we could demonstrate no inhibitory effect of relaxin during the pro-fibrotic TGF-β-induced signaling pathway. Nevertheless, relaxin alone induced anti-fibrotic function. Therefore, we conclude that the anti-fibrotic function is not due to an influence on the TGF-β induced pro-fibrotic signaling.

Aim Mild hypothermia (MH) decreases left ventricular (LV) end-diastolic capacitance. We sought to clarify whether this results from incomplete relaxation. Methods Ten anaesthetized pigs were cooled from normothermia (NT, 38 °C) to MH (33 °C). LV end-diastolic pressure (LVPed), volume (LVVed) and pressure–volume relationships (EDPVRs) were determined during stepwise right atrial pacing. LV capacitance (i.e. LVVed at LVPed of 10 mmHg, LV VPed10) was derived from the EDPVR. Pacing-induced changes of diastolic indices (LVPed, LVVed and LV VPed10) were analysed as a function of (i) heart rate and (ii) the ratio between diastolic time interval (t-dia) and LV isovolumic relaxation constant τ, which was calculated using a logistic fit (τL) and monoexponential fit with zero asymptote (τZ) and nonzero asymptote (τNZ). Results Mild hypothermia decreased heart rate (85 ± 4 to 68 ± 3 bpm), increased τL (22 ± 1 to 57 ± 4 ms), τZ (26 ± 2 to 56 ± 5 ms) and τNZ (41 ± 1 to 96 ± 5 ms), decreased t-dia/τ ratios, and shifted the EDPVR leftwards compared to NT (all P