Prognostic impact of hyponatraemia and hypernatraemia at admission and discharge in heart failure patients with preserved, mid-range and reduced ejection fraction.

BACKGROUND: Hyponatraemia is common in patients with acute heart failure (HF). AIMS: To determine the impact of sodium disturbances on mortality and readmissions in HF with reduced left ventricular ejection fraction (HFrEF), preserved ejection fraction (HFpEF) and mid-range ejection fraction (HFmrEF). METHODS: This study was a prospective multicentre consecutive registry in 20 hospitals, including patients admitted due to acute HF in cardiology departments. Sodium <135 mmol/L was considered hyponatraemia, >145 mmol/L hypernatraemia and 135-145 mmol/L normal. RESULTS: A total of 1309 patients was included. Mean age was 72.0 ± 11.9 years, and 810 (61.9%) were male. Mean serum sodium level was 138.6 ± 4.7 mmol/L at hospital admission and 138.1 ± 4.1 mmol/L at discharge. The evolution of sodium levels was: normal-at-admission/normal-at-discharge 941 (71.9%), abnormal-at-admission/normal-at-discharge 127 (9.7%), normal-at-admission/abnormal-at-discharge 155 (11.8%) and abnormal-at-admission/abnormal-at-discharge 86 (6.6%). Hyponatraemia at discharge was more common in HFrEF (109 (20.7%)) than in HFpEF (79 (13.9%)) and HFmrEF (27 (12%)), P = 0.003. The prevalence of hypernatraemia at discharge was similar in the three groups: HFrEF (10 (1.9%)), HFpEF (12 (2.1%)) and HFmrEF (4 (1.9%)), P = 0.96. In multivariate analysis, abnormal sodium concentrations at hospital admission (hazard ratio (HR) 1.42, 95% confidence interval (CI) 1.15-1.76, P = 0.001) and discharge (HR 1.33, 95% CI 1.08-1.64, P = 0.007) were both independently associated with increased mortality and readmissions at 12 months. CONCLUSIONS: Hyponatraemia and hypernatraemia at admission and discharge predict a poor outcome in patients with acute HF regardless of left ventricular ejection fraction. Hyponatraemia at discharge is more frequent in HFrEF than in the other groups.

Discharge treatment with angiotensin-converting enzyme inhibitor/angiotensin receptor blocker after a heart failure hospitalisation is associated with a better prognosis irrespective of left ventricular ejection fraction.

BACKGROUND: Medical therapy could improve the prognosis of real-life patients discharged after a heart failure (HF) hospitalisation. AIM: To determine the impact of discharge HF treatment on mortality and readmissions in different left ventricular ejection fraction (LVEF) groups. METHODS: Multicentre prospective registry in 20 Spanish hospitals. Patients were enrolled after a HF hospitalisation. RESULTS: A total of 1831 patients was included (583 (31.8%) HF with reduced ejection fraction (HFrEF); 227 (12.4%) HF with midrange ejection fraction (HFmrEF); 610 (33.3%) HF with preserved ejection fraction (HFpEF), and 411 (22.4%) with unknown LVEF). Angiotensin-converting enzyme (ACE) inhibitors/angiotensin II receptor blockers (ARB) at discharge were independently associated with a reduction in: (i) all-cause mortality: hazard ratio (HR) 0.55, 95% confidence interval (CI) 0.41-0.74, P < 0.001, with a similar effect in the four groups; (ii) mortality due to refractory HF HR 0.45, 95% CI 0.29-0.64, P < 0.001, with a similar effect in the three groups with known LVEF; (iii) mortality/HF admissions (HR 0.61; 95% CI: 0.50-0.74), more evident in HFrEF (HR 0.54; 95% CI: 0.38-0.78) compared with HRmEF (HR 0.64; 95% CI 0.40-1.02), or HFpEF (HR 0.70; 95% CI 0.53-0.92). In patients with HFrEF triple therapy (ACE inhibitor/ARB + beta blocker + mineralocorticoid receptor antagonist) was associated with the lowest mortality risk (HR 0.21; 95% CI: 0.08-0.57, P = 0.002) compared with patients that received none of these drugs. CONCLUSIONS: Discharge treatment with ACE inhibitor/ARB after a HF hospitalisation is associated with a reduction in all-cause and refractory HF mortality, irrespective of LVEF.

Patient-Associated Predictors of 15- and 30-Day Readmission After Hospitalization for Acute Heart Failure.

BACKGROUND: Identifying readmission predictors in heart failure (HF) patients may help guide preventative efforts and save costs. We aimed to identify 15- and 30-day readmission predictors due to cardiovascular reasons. METHODS AND RESULTS: A total of 1831 patients with acute HF admission were prospectively followed during a year. Patient-associated variables were gathered at admission/discharge and events during follow-up. A multivariate Fine and Gray competing risk regression model and a cumulative incidence function were used to identify predictors and build a risk score model for 15- and 30-day readmission. The 15- and 30-day readmission rates due to cardiovascular reasons were 7.1% and 13.9%. Previous acute myocardial infarction, congestive signs at discharge, and length of stay > 9 days were predictors of 15- and 30-day readmission, while much weight loss and large NT-ProBNP reduction were protective factors. The NT-ProBNP reduction was larger at 30 days (> 55%) vs 15 days (> 40%) to protect from readmission. Glomerular filtration rate at discharge < 60 mL/min/1.73m2 and > 1 previous admissions due to HF were predictors of 30-day readmission, while first post-discharge control at an HF unit was a protective factor. CONCLUSIONS: Previous identified factors for early readmission were confirmed. The NT-ProBNP reduction should be increased (> 55%) to protect from 30-day readmission.

Identification of new biophysical markers for pathological ventricular remodelling in tachycardia-induced dilated cardiomyopathy.

Our aim was to identify biophysical biomarkers of ventricular remodelling in tachycardia-induced dilated cardiomyopathy (DCM). Our study includes healthy controls (N = 7) and DCM pigs (N = 10). Molecular analysis showed global myocardial metabolic abnormalities, some of them related to myocardial hibernation in failing hearts, supporting the translationality of our model to study cardiac remodelling in dilated cardiomyopathy. Histological analysis showed unorganized and agglomerated collagen accumulation in the dilated ventricles and a higher percentage of fibrosis in the right (RV) than in the left (LV) ventricle (P = .016). The Fourier Transform Infrared Spectroscopy (FTIR) 1st and 2nd indicators, which are markers of the myofiber/collagen ratio, were reduced in dilated hearts, with the 1st indicator reduced by 45% and 53% in the RV and LV, respectively, and the 2nd indicator reduced by 25% in the RV. The 3rd FTIR indicator, a marker of the carbohydrate/lipid ratio, was up-regulated in the right and left dilated ventricles but to a greater extent in the RV (2.60-fold vs 1.61-fold, P = .049). Differential scanning calorimetry (DSC) showed a depression of the freezable water melting point in DCM ventricles - indicating structural changes in the tissue architecture - and lower protein stability. Our results suggest that the 1st, 2nd and 3rd FTIR indicators are useful markers of cardiac remodelling. Moreover, the 2nd and 3rd FITR indicators, which are altered to a greater extent in the right ventricle, are associated with greater fibrosis.

Comparison between endocardial and epicardial cardiac resynchronization in an experimental model of non-ischaemic cardiomyopathy.

Aims: Pacing from the left ventricular (LV) endocardium might increase the likelihood of response to cardiac resynchronization therapy. However, experimental and clinical data supporting this assumption are limited and controversial. The aim of this study was to compare the acute response of biventricular pacing from the LV epicardium and endocardium in a swine non-ischaemic cardiomyopathy (NICM) model of dyssynchrony. Methods and results: A NICM was induced in six swine by 3 weeks of rapid ventricular pacing. Biventricular stimulation was performed from 16 paired locations in the LV (8 epicardial and 8 endocardial) with two different atrioventricular (80 and 110 ms) intervals and three interventricular (0, +30, -30 ms) delays. The acute response of the aortic blood flow, LV and right ventricular (RV) pressures, LVdP/dtmax and LVdP/dtmin and QRS complex width and QT duration induced by biventricular stimulation were analysed. The haemodynamic and electrical beneficial responses to either LV endocardial or epicardial biventricular pacing were similar (ΔLVdP/dtmax: +7.8 ± 2.2% ENDO vs. +7.3 ± 1.5% EPI, and ΔQRS width: -16.8 ± 1.3% ENDO vs. -17.1 ± 1.9% EPI; P = ns). Pacing from LV basal regions either from the epicardium or endocardium produced better haemodynamic responses as compared with mid or apical LV regions (P < 0.05). The LV regions producing the maximum QRS complex shortening did not correspond to those inducing the best haemodynamic responses (EPI: r2 = 0.013, P = ns; ENDO: r2 = 0.002, P = ns). Conclusion: Endocardial LV pacing induced similar haemodynamic changes than pacing from the epicardium. The response to endocardial LV pacing is region dependent as observed in epicardial pacing.

Electrophysiological Effects of Selective Atrial Coronary Artery Occlusion in Humans.

BACKGROUND: The arrhythmogenesis of ventricular myocardial ischemia has been extensively studied, but models of atrial ischemia in humans are lacking. This study aimed at describing the electrophysiological alterations induced by acute atrial ischemia secondary to atrial coronary branch occlusion during elective coronary angioplasty. METHODS AND RESULTS: Clinical data, 12-lead ECG, 12-hour Holter recordings, coronary angiography, and serial plasma levels of high-sensitivity troponin T and midregional proatrial natriuretic peptide were prospectively analyzed in 109 patients undergoing elective angioplasty of right or circumflex coronary arteries. Atrial coronary branches were identified and after the procedure patients were allocated into two groups: atrial branch occlusion (ABO, n=17) and atrial branch patency (non-ABO, n=92). In comparison with the non-ABO, patients with ABO showed: (1) higher incidence of periprocedural myocardial infarction (20% versus 53%, P=0.01); (2) more frequent intra-atrial conduction delay (19% versus 46%, P=0.03); (3) more marked PR segment deviation in the Holter recordings; and (4) higher incidence of atrial tachycardia (15% versus 41%, P=0.02) and atrial fibrillation (0% versus 12%, P=0.03). After adjustment by a propensity score, ABO was an independent predictor of periprocedural infarction (odds ratio, 3.4; 95% confidence interval, 1.01-11.6, P<0.05) and atrial arrhythmias (odds ratio, 5.1; 95% confidence interval, 1.2-20.5, P=0.02). CONCLUSIONS: Selective atrial coronary artery occlusion during elective percutaneous transluminal coronary angioplasty is associated with myocardial ischemic damage, atrial arrhythmias, and intra-atrial conduction delay. Our data suggest that atrial ischemic episodes might be considered as a potential cause of atrial fibrillation in patients with chronic coronary artery disease.

Early detection of acute transmural myocardial ischemia by the phasic systolic-diastolic changes of local tissue electrical impedance.

Myocardial electrical impedance is influenced by the mechanical activity of the heart. Therefore, the ischemia-induced mechanical dysfunction may cause specific changes in the systolic-diastolic pattern of myocardial impedance, but this is not known. This study aimed to analyze the phasic changes of myocardial resistivity in normal and ischemic conditions. Myocardial resistivity was measured continuously during the cardiac cycle using 26 different simultaneous excitation frequencies (1 kHz-1 MHz) in 7 anesthetized open-chest pigs. Animals were submitted to 30 min regional ischemia by acute left anterior descending coronary artery occlusion. The electrocardiogram, left ventricular (LV) pressure, LV dP/dt, and aortic blood flow were recorded simultaneously. Baseline myocardial resistivity depicted a phasic pattern during the cardiac cycle with higher values at the preejection period (4.19 ± 1.09% increase above the mean, P < 0.001) and lower values during relaxation phase (5.01 ± 0.85% below the mean, P < 0.001). Acute coronary occlusion induced two effects on the phasic resistivity curve: 1) a prompt (5 min ischemia) holosystolic resistivity rise leading to a bell-shaped waveform and to a reduction of the area under the LV pressure-impedance curve (1,427 ± 335 vs. 757 ± 266 Ω·cm·mmHg, P < 0.01, 41 kHz) and 2) a subsequent (5-10 min ischemia) progressive mean resistivity rise (325 ± 23 vs. 438 ± 37 Ω·cm at 30 min, P < 0.01, 1 kHz). The structural and mechanical myocardial dysfunction induced by acute coronary occlusion can be recognized by specific changes in the systolic-diastolic myocardial resistivity curve. Therefore these changes may become a new indicator (surrogate) of evolving acute myocardial ischemia.

Prevention of adenosine A2A receptor activation diminishes beat-to-beat alternation in human atrial myocytes.

Atrial fibrillation (AF) has been associated with increased spontaneous calcium release from the sarcoplasmic reticulum and linked to increased adenosine A2A receptor (A2AR) expression and activation. Here we tested whether this may favor atrial arrhythmogenesis by promoting beat-to-beat alternation and irregularity. Patch-clamp and confocal calcium imaging was used to measure the beat-to-beat response of the calcium current and transient in human atrial myocytes. Responses were classified as uniform, alternating or irregular and stimulation of Gs-protein coupled receptors decreased the frequency where a uniform response could be maintained from 1.0 ± 0.1 to 0.6 ± 0.1 Hz; p < 0.01 for beta-adrenergic receptors and from 1.4 ± 0.1 to 0.5 ± 0.1 Hz; p < 0.05 for A2ARs. The latter was linked to increased spontaneous calcium release and after-depolarizations. Moreover, A2AR activation increased the fraction of non-uniformly responding cells in HL-1 myocyte cultures from 19 ± 3 to 51 ± 9 %; p < 0.02, and electrical mapping in perfused porcine atria revealed that adenosine induced electrical alternans at longer cycle lengths, doubled the fraction of electrodes showing alternation, and increased the amplitude of alternations. Importantly, protein kinase A inhibition increased the highest frequency where uniform responses could be maintained from 0.84 ± 0.12 to 1.86 ± 0.11 Hz; p < 0.001 and prevention of A2AR-activation with exogenous adenosine deaminase selectively increased the threshold from 0.8 ± 0.1 to 1.2 ± 0.1 Hz; p = 0.001 in myocytes from patients with AF. In conclusion, A2AR-activation promotes beat-to-beat irregularities in the calcium transient in human atrial myocytes, and prevention of A2AR activation may be a novel means to maintain uniform beat-to-beat responses at higher beating frequencies in patients with atrial fibrillation.

Retinol-binding protein 4 levels and susceptibility to ischaemic events in men.

BACKGROUND: Many efforts in cardiovascular medicine have been focused in the identification of patients at risk of developing an acute ischaemic event. Biomarker discovery studies have become an essential research area, being proteomic technologies an excellent tool for biomarker identification. By applying proteomic approaches, we have detected changes in retinol-binding protein 4 (RBP4) in acute new-onset myocardial infarction patients (AMI) and in high-risk patients with heterozygous familial hypercholesterolaemia (FH). MATERIALS AND METHODS: Differential serum proteome was analysed by two-dimensional electrophoresis and MALDI-TOF/TOF. Validation studies were performed by ELISA, and functional effects of RBP4 were tested in cell culture experiments. RESULTS: Retinol-binding protein 4 proteomic characterization depicted two spots (pI = 5·4;Mw = 23·01/22·78 kDa) with decreased intensity in AMI patients. Total serum RBP4 levels were decreased in AMI patients (N = 68) compared with controls (N = 132; P < 0·0001). RBP4 was also decreased in FH patients who had an ischaemic event 2 years (±0·3) after their inclusion compared with FH patients without any cardiovascular episode at follow-up (P < 0·001; N = 187). In both cases, changes were limited to men. RBP4 induced a significant increase in eNOS expression in human endothelial vascular cells and in prostaglandin I2 release in coronary vascular smooth muscle cells. CONCLUSIONS: We show decreased serum RBP4 levels in men in the acute phase of AMI, being this decrease already detected in men with FH previous to the presentation of an ischaemic event. The decrease in RBP4 levels could confer an increased susceptibility to the precipitation of an ischaemic event that could be mediated by the decrease in its vasculoprotective properties through NO and PGI2 .

Effects of open-irrigated radiofrequency ablation catheter design on lesion formation and complications: in vitro comparison of 6 different devices.

INTRODUCTION: Open-irrigated radiofrequency ablation catheters with slight differences in tip architecture are widely used, although limited comparative data are available. The purpose of this study was to compare the lesion size and potential complications produced by commercially available open-irrigated catheters in an in vitro porcine heart model. METHODS AND RESULTS: Six catheters were tested (Biosense Webster Thermocool, Boston Scientific Open irrigated, St. Jude CoolPath, St. Jude CoolPath Duo, Biosense Webster Thermocool SF, St. Jude Cool Flex) at 20 and 35 W power-control, under 2 different blood flows (0.1 and 0.5 m/s) and at 2 target durations (30 and 60 seconds). A total of 601 lesions were made in 26 in vitro preparations. The tip temperature profile showed significant differences between the catheters (P < 0.001) with the Thermocool SF registering the lowest. Only the surface diameter and the depth at maximum diameter of the lesion were influenced by the design of the ablation electrode. The lesion volume did not show significant differences between catheters for any power, application duration or blood flow condition. Char and pops occurred more often at 35 W with only slight differences between the catheters. CONCLUSIONS: Tip design of the 6 different irrigated catheters does not affect the lesion total volume, although a slight difference in lesion geometry in terms of surface diameter and depth at maximum diameter is present. The catheters show a slight different in vitro safety profile.

Spatial Distribution of Calcium Sparks Determines Their Ability to Induce Afterdepolarizations in Human Atrial Myocytes.

Analysis of the spatio-temporal distribution of calcium sparks showed a preferential increase in sparks near the sarcolemma in atrial myocytes from patients with atrial fibrillation (AF), linked to higher ryanodine receptor (RyR2) phosphorylation at s2808 and lower calsequestrin-2 levels. Mathematical modeling, incorporating modulation of RyR2 gating, showed that only the observed combinations of RyR2 phosphorylation and calsequestrin-2 levels can account for the spatio-temporal distribution of sparks in patients with and without AF. Furthermore, we demonstrate that preferential calcium release near the sarcolemma is key to a higher incidence and amplitude of afterdepolarizations in atrial myocytes from patients with AF.

Beta-blocker treatment of patients with atrial fibrillation attenuates spontaneous calcium release-induced electrical activity.

AIMS: Atrial fibrillation (AF) has been associated with excessive spontaneous calcium release, linked to cyclic AMP (cAMP)-dependent phosphorylation of calcium regulatory proteins. Because ß-blockers are expected to attenuate cAMP-dependent signaling, we aimed to examine whether the treatment of patients with ß-blockers affected the incidence of spontaneous calcium release events or transient inward currents (ITI). METHODS: The impact of treatment with commonly used ß-blockers was analyzed in human atrial myocytes from 371 patients using patch-clamp technique, confocal calcium imaging or immunofluorescent labeling. Data were analyzed using multivariate regression analysis taking into account potentially confounding effects of relevant clinical factors RESULTS: The L-type calcium current (ICa) density was diminished significantly in patients with chronic but not paroxysmal AF and the treatment of patients with ß-blockers did not affect ICa density in any group. By contrast, the ITI frequency was elevated in patients with either paroxysmal or chronic AF that did not receive treatment, and ß-blocker treatment reduced the frequency to levels observed in patients without AF. Confocal calcium imaging showed that ß-blocker treatment also reduced the calcium spark frequency in patients with AF to levels observed in those without AF. Furthermore, phosphorylation of the ryanodine receptor (RyR2) at Ser-2808 and phospholamban at Ser-16 was significantly lower in patients with AF that received ß-blockers. CONCLUSION: Together, our findings demonstrate that ß-blocker treatment may be of therapeutic utility to prevent spontaneous calcium release-induced atrial electrical activity; especially in patients with a history of paroxysmal AF displaying preserved ICa density.

Time course, factors related to, and prognostic impact of venoarterial extracorporeal membrane flow in cardiogenic shock.

AIMS: Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is currently one of the most used devices in refractory cardiogenic shock. However, there is a lack of evidence on how to set the 'optimal' flow. We aimed to describe the evolution of VA-ECMO flows in a cardiogenic shock population and determine the risk factors of 'high-ECMO flow'. METHODS AND RESULTS: A 7 year database of patients supported with VA-ECMO was used. Based on the median flow during the first 48 h of the VA-ECMO run, patients were classified as 'high-flow' or 'low-flow', respectively, when median ECMO flow was ≥3.6 or <3.6 L/min. Outcomes included rates of ventilator-associated pneumonia, ECMO-related complications, days on ECMO, days on mechanical ventilation, intensive care unit and hospitalization lengths of stay, and in-hospital and 60 day mortality. Risk factors of high-ECMO flow were assessed using univariate and multivariate cox regression. The study population included 209 patients on VA-ECMO, median age was 51 (40-59) years, and 78% were males. The most frequent aetiology leading to cardiogenic shock was end-stage dilated cardiomyopathy (57%), followed by acute myocardial infarction (23%) and fulminant myocarditis (17%). Among the 209 patients, 105 (50%) were classified as 'high-flow'. This group had a higher rate of ischaemic aetiology (16% vs. 30%, P = 0.023) and was sicker at admission, in terms of worse Simplified Acute Physiology Score II score [40 (26-58) vs. 56 (42-74), P < 0.001], higher lactate [3.6 (2.2-5.8) mmol/L vs. 5.2 (3-9.7) mmol/L, P < 0.001], and higher aspartate aminotransferase [97 (41-375) U/L vs. 309 (85-939) U/L, P < 0.001], among others. The 'low-flow' group had less ventilator-associated pneumonia (40% vs. 59%, P = 0.007) and less days on mechanical ventilation [4 (1.5-7.5) vs. 6 (3-12) days, P = 0.009]. No differences were found in lengths of stay or survival according to the ECMO flow. The multivariate analysis showed that risk factors independently associated with 'high-flow' were mechanical ventilation at cannulation [odds ratio (OR) 3.9, 95% confidence interval (CI) 2.1-7.1] and pre-ECMO lactate (OR 1.1, 95% CI 1.0-1.2). CONCLUSIONS: In patients with refractory cardiogenic shock supported with VA-ECMO, sicker patients had higher support since early phases, presenting thereafter higher rates of ventilator-associated pneumonia but similar survival compared with patients with lower flows.

Influence of heart failure on nucleolar organization and protein expression in human hearts.

We investigate for the first time the influence of heart failure (HF) on nucleolar organization and proteins in patients with ischemic (ICM) or dilated cardiomyopathy (DCM). A total of 71 human hearts from ICM (n=38) and DCM (n=27) patients, undergoing heart transplantation and control donors (n=6), were analysed by western-blotting, RT-PCR and cell biology methods. When we compared protein levels according to HF etiology, nucleolin was increased in both ICM (117%, p<0.05) and DCM (141%, p<0.01). Moreover, mRNA expression were also upregulated in ICM (1.46-fold, p<0.05) and DCM (1.70-fold, p<0.05. Immunofluorescence studies showed that the highest intensity of nucleolin was into nucleolus (p<0.0001), and it was increased in pathological hearts (p<0.0001). Ultrastructure analysis by electron microscopy showed an increase in the nucleus and nucleolus size in ICM (17%, p<0.05 and 131%, p<0.001) and DCM (56%, p<0.01 and 69%, p<0.01). Nucleolar organization was influenced by HF irrespective of etiology, increasing fibrillar centers (p<0.001), perinucleolar chromatin (p<0.01) and dense fibrillar components (p<0.01). Finally, left ventricular function parameters were related with nucleolin levels in ischemic hearts (p<0.0001). The present study demonstrates that HF influences on morphology and organization of nucleolar components, revealing changes in the expression and in the levels of nucleolin protein.

Low density lipoprotein receptor-related protein 1 expression correlates with cholesteryl ester accumulation in the myocardium of ischemic cardiomyopathy patients.

Our hypothesis was that overexpression of certain lipoprotein receptors might be related to lipid accumulation in the human ischemic myocardium. Intramyocardial lipid overload contributes to contractile dysfunction and arrhythmias in cardiomyopathy. Thus, the purpose of this study was to assess the effect of hypercholesterolemic LDL and hypertrigliceridemic VLDL dose on LRP1 expression in cardiomyocytes, as well as the potential correlation between LRP1 expression and neutral lipid accumulation in the left ventricle tissue from ischemic cardiomyopathy patients. Cell culture experiments include control and LRP1-deficient cardiomyocytes exposed to lipoproteins under normoxic and hypoxic conditions. Explanted hearts from 18 ICM patients and eight non-diseased hearts (CNT) were included. Low density lipoprotein receptor-related protein 1 (LRP1), very low density lipoprotein receptor (VLDLR) and low density lipoprotein receptor (LDLR) expression was analyzed by real time PCR and Western blotting. Cholesteryl ester (CE), triglyceride (TG) and free cholesterol (FC) content was assess by thin layer chromatography following lipid extraction. Western blotting experiments showed that protein levels of LRP1, VLDLR and HIF-1α were significantly upregulated in ischemic hearts. Immunohistochemistry and confocal microscopy analysis showed that LRP1 and HIF-1α were upregulated in cardiomyocytes of ICM patients. In vitro studies showed that VLDL, LDL and hypoxia exerted an upregulatory effect on LRP1 expression and that LRP1 played a major role in cholesteryl ester accumulation from lipoproteins in cardiomyocytes. Myocardial CE accumulation strongly correlated with LRP1 levels in ischemic hearts. Taken together, our results suggest that LRP1 upregulation is key for myocardial cholesterol ester accumulation in ischemic human hearts and that LRP1 may be a target to prevent the deleterious effects of myocardial cholesterol accumulation in ischemic cardiomyopathy.

Common pitfalls in the interpretation of electrocardiograms from patients with acute coronary syndromes with narrow QRS: a consensus report.

Acute coronary syndromes (ACS) with narrow QRS are divided into 2 groups: ST-elevation ACS that requires emergency percutaneous coronary intervention, and non-ST elevation ACS. The classification of ACS into these 2 groups is not always straightforward. In this document, we discuss several electrocardiogram patterns of acute ischemia that are often misinterpreted. We suggest that any new recommendations or guidelines from the Scientific Societies should acknowledge these aspects of electrocardiogram interpretation by including appropriate diagnostic criteria that should prove helpful for the optimal management of patients with ACS.

Abnormal calcium handling in atrial fibrillation is linked to up-regulation of adenosine A2A receptors.

AIMS: Atrial fibrillation (AF) is associated with abnormal sarcoplasmic reticulum (SR) calcium release, which is promoted by adenosine A(2A) receptor (A(2A)R) activation. Here, we tested the hypothesis that abnormal calcium release in AF is linked to A(2A)R remodelling. METHODS AND RESULTS: Western blotting and quantitative real-time PCR were used to determine A(2A)R mRNA and protein levels in right atrial samples from patients with and without AF. Effects of A(2A)R activation on calcium handling were assessed with patch-clamp technique and confocal calcium imaging. A(2A)R mRNA levels and functional A(2A)Rs were moderately up-regulated in patients with atrial dilation and markedly up-regulated in those with AF. Accordingly, A(2A)R stimulation significantly increased ryanodine receptor phosphorylation in AF patients, and spontaneous calcium waves increased moderately in myocytes from patients with atrial dilation and strongly in patients with AF (2.2 ± 2.1 to 14.3 ± 8.8 min(-1), n = 6, P = 0.01). Moreover, the high baseline level of calcium waves in AF was reduced by A(2A)R antagonists (3.5 ± 2.0 to 1.3 ± 1.3 min(-1), n = 6, P = 0.007) or adenosine deaminase (1.7 ± 1.5 to 0.5 ± 0.6 min(-1), n = 10, P = 0.02) suggesting that A(2A)Rs are activated by endogenous adenosine. Indeed, intracellular perfusion with adenosine significantly increased the calcium wave frequency (1.1 ± 0.8 to 8.2 ± 3.3 min(-1), n = 8), whereas adenosine removal from the cytosol decreased it (2.1 ± 0.9 to 0.3 ± 0.3 min(-1), n = 8, P = 0.04). CONCLUSIONS: Atrial fibrillation patients show increased A(2A)R expression that may account for the high baseline level of spontaneous SR calcium release seen in myocytes from these patients, and the ability of A(2A)R antagonists to reduce this abnormal calcium release points to the A(2A)R as a novel molecular target in AF.

ß2-adrenergic stimulation potentiates spontaneous calcium release by increasing signal mass and co-activation of ryanodine receptor clusters.

AIMS: It is unknown how ß-adrenergic stimulation affects calcium dynamics in individual RyR2 clusters and leads to the induction of spontaneous calcium waves. To address this, we analysed spontaneous calcium release events in green fluorescent protein (GFP)-tagged RyR2 clusters. METHODS: Cardiomyocytes from mice with GFP-tagged RyR2 or human right atrial tissue were subjected to immunofluorescent labelling or confocal calcium imaging. RESULTS: Spontaneous calcium release from single RyR2 clusters induced 91.4% ± 2.0% of all calcium sparks while 8.0% ± 1.6% were caused by release from two neighbouring clusters. Sparks with two RyR2 clusters had 40% bigger amplitude, were 26% wider, and lasted 35% longer at half maximum. Consequently, the spark mass was larger in two- than one-cluster sparks with a median and interquartile range for the cumulative distribution of 15.7 ± 20.1 vs 7.6 ± 5.7 a.u. (P < .01). ß2-adrenergic stimulation increased RyR2 phosphorylation at s2809 and s2815, tripled the fraction of two- and three-cluster sparks, and significantly increased the spark mass. Interestingly, the amplitude and mass of the calcium released from a RyR2 cluster were proportional to the SR calcium load, but the firing rate was not. The spark mass was also higher in 33 patients with atrial fibrillation than in 36 without (22.9 ± 23.4 a.u. vs 10.7 ± 10.9; P = .015). CONCLUSIONS: Most sparks are caused by activation of a single RyR2 cluster at baseline while ß-adrenergic stimulation doubles the mass and the number of clusters per spark. This mimics the shift in the cumulative spark mass distribution observed in myocytes from patients with atrial fibrillation.