Anticoagulants for stroke prevention in heart failure with reduced ejection fraction.

Impaired left-ventricular ejection-fraction (LV-EF) is a known risk factor for ischemic stroke and systemic embolism in patients with heart failure (HF) even in the absence of atrial fibrillation. While stroke risk is inversely correlated with LV-EF in HF patients with sinus rhythm, strategies using anticoagulation with Vitamin-K antagonists (VKA) were futile as the increase in major bleedings outweighed the potential benefit in stroke reduction. Non-Vitamin K oral anticoagulants (NOACs) proved to be an effective and in general safer approach for stroke prevention in patients with atrial fibrillation and may also have a favourable risk-benefit profile in HF patients. In HF patients with sinus rhythm, the COMPASS trial suggested a potential benefit for rivaroxaban, whereas the more dedicated COMMANDER-HF trial remained neutral on overall ischemic benefit owed to a higher mortality which was not influenced by anticoagulation. More recent data from subgroups in the COMMANDER-HF trial, however, suggest that there might be a benefit of rivaroxaban regarding stroke prevention under certain circumstances. In this article, we review the existing evidence for NOACs in HF patients with atrial fibrillation, elaborate the rationale for stroke prevention in HF patients with sinus rhythm, summarise the available data from anticoagulation trials in HF with sinus rhythm, and describe the patient who might eventually profit from an individualised strategy aiming to reduce stroke risk.

Unloading in Refractory Cardiogenic Shock After Out-Of-Hospital Cardiac Arrest Due to Acute Myocardial Infarction-A Propensity Score-Matched Analysis.

Aims: Unclear neurological outcome often precludes severely compromised patients after out-of-hospital cardiac arrest (OHCA) from mechanical circulatory support (MCS), while it may be considered as rescue therapy for patients with refractory cardiogenic shock (rCS) in the absence of OHCA. This analysis sought to investigate the role of left ventricular (LV) unloading in patients with rCS related to acute myocardial infarction (AMI) after OHCA. Methods: Of 273 consecutive patients receiving microaxial pumps in the Hannover Cardiac Unloading Registry between January 2013 and August 2018, 47 presented with AMI-rCS following successful resuscitation. Subsequently, the patients were compared by propensity score matching to patients with OHCA AMI-rCS without MCS. The patient data for OHCA without LV unloading was available from 280 patients of the Hannover Cooling Registry for the same time period. Furthermore, the patients with OHCA without rCS were compared to the patients with OHCA AMI-rCS and LV unloading. Results: In total, 15 OHCA AMI-rCS patients without MCS were matched to patients with AMI-rCS and Impella. Patients without LV support had a higher proportion of a cardiac cause of death (n = 7 vs. n = 3; p = 0.024). LV unloading with Impella counteract rCS status and was associated with a preferable 30-day survival (66.7 vs. 20%, p = 0.01) and a favorable neurological outcome after 30 days (Cerebral Performance Category ≤2, 47 vs. 27%). Impella support is associated with a higher 30-day survival (odds ratio, 2.67; 95% confidence interval, 1.02-13.66). Conclusion: In patients after OHCA with AMI-rCS, Impella support incorporated in a strict standardized treatment algorithm results in a preferable 30-day survival and counteracts severe rCS status.

Percutaneous dilatational tracheotomy in high-risk ICU patients.

BACKGROUND: Percutaneous dilatational tracheotomy (PDT) has become an established procedure in intensive care units (ICU). However, the safety of this method has been under debate given the growing number of critically ill patients with high bleeding risk receiving anticoagulation, dual antiplatelet therapy (DAPT) or even a combination of both, i.e. triple therapy. Therefore, the purpose of this study, including such a high proportion of patients on antithrombotic therapy, was to investigate whether PDT in high-risk ICU patients is associated with elevated procedural complications and to analyse the risk factors for bleeding occurring during and after PDT. METHODS: PDT interventions conducted in ICUs at 12 European sites between January 2016 and October 2019 were retrospectively analysed for procedural complications. For subgroup analyses, patient stratification into clinically relevant risk groups based on anticoagulation and antiplatelet treatment regimens was performed and the predictors of bleeding occurrence were analysed. RESULTS: In total, 671 patients receiving PDT were included and stratified into four clinically relevant antithrombotic treatment groups: (1) intravenous unfractionated heparin (iUFH, prophylactic dosage) (n = 101); (2) iUFH (therapeutic dosage) (n = 131); (3) antiplatelet therapy (aspirin and/or P2Y12 receptor inhibitor) with iUFH (prophylactic or therapeutic dosage) except for triple therapy (n = 290) and (4) triple therapy (DAPT with iUFH in therapeutic dosage) (n = 149). Within the whole cohort, 74 (11%) bleedings were reported to be procedure-related. Bleeding occurrence during and after PDT was independently associated with low platelet count (OR 0.73, 95% CI [0.56, 0.92], p = 0.009), chronic kidney disease (OR 1.75, 95% CI [1.01, 3.03], p = 0.047) and previous stroke (OR 2.13, 95% CI [1.1, 3.97], p = 0.02). CONCLUSION: In this international, multicenter study bronchoscopy-guided PDT was a safe and low-complication airway management option, even in a cohort of high risk for bleeding on cardiovascular ICUs. Low platelet count, chronic kidney disease and previous stroke were identified as independent risk factors of bleeding during and after PDT but not triple therapy.

A DARPin targeting activated Mac-1 is a novel diagnostic tool and potential anti-inflammatory agent in myocarditis, sepsis and myocardial infarction.

The monocyte ß2-integrin Mac-1 is crucial for leukocyte-endothelium interaction, rendering it an attractive therapeutic target for acute and chronic inflammation. Using phage display, a Designed-Ankyrin-Repeat-Protein (DARPin) was selected as a novel binding protein targeting and blocking the αM I-domain, an activation-specific epitope of Mac-1. This DARPin, named F7, specifically binds to activated Mac-1 on mouse and human monocytes as determined by flow cytometry. Homology modelling and docking studies defined distinct interaction sites which were verified by mutagenesis. Intravital microscopy showed reduced leukocyte-endothelium adhesion in mice treated with this DARPin. Using mouse models of sepsis, myocarditis and ischaemia/reperfusion injury, we demonstrate therapeutic anti-inflammatory effects. Finally, the activated Mac-1-specific DARPin is established as a tool to detect monocyte activation in patients receiving extra-corporeal membrane oxygenation, as well as suffering from sepsis and ST-elevation myocardial infarction. The activated Mac-1-specific DARPin F7 binds preferentially to activated monocytes, detects inflammation in critically ill patients, and inhibits monocyte and neutrophil function as an efficient new anti-inflammatory agent.

Neuromarkers and neurological outcome in out-of-hospital cardiac arrest patients treated with therapeutic hypothermia-experience from the HAnnover COoling REgistry (HACORE).

BACKGROUND: Neuron-specific enolase (NSE) and S-100b have been used to assess neurological damage following out-of-hospital cardiac arrest (OHCA). Cut-offs were derived from small normothermic cohorts. Whether similar cut-offs apply to patients treated with hypothermia remained undetermined. METHODS: We investigated 251 patients with OHCA treated with hypothermia but without routine prognostication. Neuromarkers were determined at day 3, neurological outcome was assessed after hospital discharge by cerebral performance category (CPC). RESULTS: Good neurological outcome (CPC≤2) was achieved in 41%. Elevated neuromarkers, older age and absence of ST-segment elevation after ROSC were associated with increased mortality. Poor neurological outcome in survivors was additionally associated with history of cerebrovascular events, sepsis and higher admission lactate. Mean NSE was 33µg/l [16-94] vs. 119µg/l [25-406]; p<0.001, for survivors vs. non-survivors, and 21µg/l [16-29] vs. 40µg/l [23-98], p<0.001 for good vs. poor neurological outcome. S-100b was 0.127µg/l [0.063-0.360] vs. 0.772µg/l [0.121-2.710], p<0.001 and 0.086µg/l [0.061-0.122] vs. 0.138µg/l [0.090-0.271], p = 0.009, respectively. For mortality, thresholds of 36µg/l for NSE and 0.128µg/l for S-100b could be determined; for poor neurological outcome 33µg/l (NSE) and 0.123µg/l (S-100b), respectively. Positive predictive value for NSE was 81% (74-88) and 79% (71-85) for S-100b. CONCLUSIONS: Thresholds for NSE and S-100b predicting mortality and poor neurological outcome are similar in OHCA patients receiving therapeutic hypothermia as in those reported before the era of hypothermia. However, both biomarkers do not have enough specificity to predict mortality or poor neurological outcome on their own and should only be additively used in clinical decision making.

Anti-thrombotic strategies in patients with atrial fibrillation undergoing PCI.

Triple anti-thrombotic therapy combining oral anticoagulation and dual anti-platelet therapy following percutaneous coronary intervention in patients with atrial fibrillation was considered as standard and recommended by guidelines. While bleeding risk is considerable with that approach, data for efficacy are scare. Several trials assessed the possibility of reducing anti-thrombotic treatment by mainly shortening the exposure to acetylsalicylic acid. Dropping one of the anti-platelet components might increase the risk of stent thrombosis, myocardial infarction or stroke. Despite that fear, the recent trials' primary endpoint was major and/or clinically-relevant non-major bleeding. We review data on major bleedings, intracranial bleedings and major adverse cardiovascular events from the published reports. We demonstrate that Non-Vitamin K oral anticoagulant (NOAC)-based strategies compared to VKA-based triple therapies significantly reduce the risk for TIMI-major bleedings by 39% and for intracranial bleedings by 66%, while they did not increase the risk for overall ischemic or embolic events. However, recent meta-analyses indicate an increased risk for stent thrombosis with less intense anti-thrombotic therapy. While the overall incidence rate for stent thrombosis is rather low, relative increases by about 30-60% are reported, but they did not translate into adverse clinical net-benefit ratios. This review highlights that using certain NOAC regimens proven effective for stroke prevention in AF can reduce the rate of bleeding without increasing ischemic or embolic events. Furthermore, additive ASA in triple anti-thrombotic regimens should be limited to 1 month and individual weighing of ischemic versus bleeding risk during the first 30 days seems to be reasonable.

Early use of hemoadsorption in patients after out-of hospital cardiac arrest - a matched pair analysis.

BACKGROUND: Pro- and anti-inflammatory mediators are released during and after cardiac arrest, which may be unfavourable. Small case-series and observational studies suggested that unselective hemoadsorption may reduce inadequately high cytokine levels during sepsis or cardiac surgery. We aimed to assess the effect of cytokine adsorbtion on mortality in patients following out-of-hospital cardiac arrest by comparing a patient cohort with hemoadsorption after resuscitation for out-of-hospital cardiac arrest to a control cohort without adsorption within the HAnnover COling REgistry (HACORE). METHODS: We adopted an early routine use of hemoadsorption in patients after out-of-hospital cardiac arrest with increased vasopressor need and performed a 1:2 match according to age, gender, time to return of spontaneous circulation, initial left-ventricular ejection fraction, extracorporeal membrane-oxygenation or left-ventricular unloading by Impella, need for renal replacement therapy, admission lactate, pH, glomerular filtration rate to patients without an adsorber from HACORE. The primary endpoint was 30-day mortality. RESULTS: Twenty-four patients receiving hemoadsorption were matched to 48 patients without hemoadsorption (mean age 62±13 years, 83% male). While there was no significant difference in baseline parameters, 30-day mortality was higher in patients treated with hemoadsorption than in the matched control group (83% vs 65%, Log rank p = 0.011). CONCLUSIONS: Routine use of hemoadsorption did not reduce, but seems to be associated with higher 30-day mortality in patients after OHCA. Prior to routine adoption in daily practice, hemoadsorption should be evaluated in properly sized randomized controlled trials.

Mechanical circulatory support in refractory cardiogenic shock due to influenza virus-related myocarditis.

BACKGROUND: There is scarce evidence for mechanical circulatory support (MCS) in patients with influenza-related myocarditis complicated by refractory cardiogenic shock (rCS). We sought to investigate the impact of MCS using combined veno-arterial extracorporeal membrane oxygenation (VA-ECMO) and micro-axial flow pumps (the ECMELLA concept) in influenza-related myocarditis complicated by rCS. METHODS: This is a prospective, observational analysis from the single centre HAnnover Cardiac Unloading REgistry (HACURE) from two recent epidemic influenza seasons. We analysed patients with verified influenza-associated myocarditis complicated by rCS who were admitted to our intensive care unit (ICU) on MCS. Subsequently, we performed a propensity score (PS) matched analysis to patients with acute myocardial infarction (AMI) complicated by rCS and non-ischaemic cardiomyopathy (DCM) related rCS. RESULTS: We describe a series of seven patients with rCS-complicated influenza-related myocarditis (mean age 56±10 years, 58% male, influenza A (n=2)/influenza B (n=5)). No patient had been vaccinated prior to the influenza season. MCS was provided using combined VA-ECMO and Impella micro-axial flow pump. In two patients with out-of-hospital cardiac arrest, VA-ECMO had been implanted for extracorporeal cardiopulmonary resuscitation. All patients died within 18 days of hospital admission. By PS-based comparison to patients with AMI- or DCM-related rCS and combined MCS, 30-day mortality was significantly higher in influenza-related rCS. CONCLUSION: Despite initial stabilisation with combined MCS in patients with rCS-complicated influenza-related myocarditis, the detrimental course of shock could not be stopped and all patients died. Influenza virus infection potentially critically affects other organs besides the heart, leading to irreversible end-organ damage that MCS cannot compensate for and, therefore, results in a devastating outcome.

Anticoagulants for Stroke Prevention in Atrial Fibrillation in Elderly Patients.

Ischaemic stroke and systemic embolism are the major potentially preventable complications of atrial fibrillation (AF) leading to severe morbidity and mortality. Anticoagulation using vitamin K antagonists (VKA) or non-vitamin K oral anticoagulants (NOACs) is mandatory for stroke prevention in AF. Following approval of the four NOACs dabigatran, rivaroxaban, apixaban, and edoxaban, the use of VKA is declining steadily. Increasing age with thresholds of 65 and 75 years is a strong risk factor when determining annual stroke risk in AF patients. Current recommendations such as the "2016 Guidelines for the management of atrial fibrillation" of the European Society of Cardiology and the "2019 AHA/ACC/HRS Focused Update" by the American College of Cardiology, the American Heart Association, and the Heart Rhythm Society strengthen the importance of anticoagulation and detection of bleeding risks, of which older age is an important one. While patients aged ≥ 75 years are usually underrepresented in randomised clinical trials, they represent almost 40% of the trial populations in the large NOAC approval studies. Therefore, a sufficient amount of data is available to assess the efficacy and safety for this patient cohort in that specific indication. In this article, the evidence for stroke prevention in AF using either VKA or NOACs is summarised with a special focus on efficacy compared to bleeding risk in patients aged ≥ 75 years. Specifically, we used a model of increased weighing of intracranial bleeding to illustrate the potential benefit of NOACs over VKA in the elderly population. In brief, there are at least two tested strategies with apixaban and edoxaban which even confer an additional clinical net benefit compared with VKA. Furthermore, elderly subgroups of trials for combined antithrombotic treatment following percutaneous coronary interventions in anticoagulated patients are analysed.

Early Escalation of Mechanical Circulatory Support Stabilizes and Potentially Rescues Patients in Refractory Cardiogenic Shock.

BACKGROUND: Limited progress has been made in the management of cardiogenic shock (CS). Morbidity and mortality of refractory CS remain high. The effects of mechanical circulatory support (MCS) are promising, although many aspects are elusive. We evaluated efficacy and safety of early combined MCS (Impella microaxial pump + venoarterial extracorporeal membrane oxygenation [VA-ECMO]) in refractory CS and aimed to determine factors for decision-making in combined MCS. METHODS AND RESULTS: We analyzed 69 consecutive patients with refractory CS from our registry requiring combined MCS. In 12 cases, therapy was actively withdrawn according to patient's will. Patients were severely sick (Survival After Venoarterial ECMO score mean±SD, -8.9±4.4) predicting 30% in-hospital survival; ventilation 94%, dialysis 56%. Impella pumps and VA-ECMO were combined early (duration of combined MCS: median 94 hours; interquartile range, 49-150 hours). Early MCS escalation stabilized patients rapidly, reducing number and doses of catecholamines (P<0.05 versus baseline) while hemodynamics improved. Reflecting an improved microcirculation, lactate levels normalized within 24 hours (P<0.05 versus baseline). Despite refractory CS and disease severity, survival was favorable (on MCS 61%, 30 days 49%, 6 months 40%). In multivariate Cox-regression, duration of shock-to-first device (hours, hazard ratio, 1.05 [95% CI, 1.01-1.08]; P=0.007) and lactate levels after 12 hours of MCS (hazard ratio, 1.28 [95% CI, 1.09-1.51]; P=0.002) independently predicted survival. Additional right ventricular failure predisposed to futility (hazard ratio, 8.48 [95% CI, 1.85-38.91]; P=0.006). CONCLUSIONS: The early and consequent combination of MCS by Impella microaxial pumps and VA-ECMO enables stabilization and may rescue high-risk patients with refractory CS at low overall risk. Independent predictors of survival may guide prognostication, decision-making, and allocation of medical resources.

Successful renal denervation decreases the platelet activation status in hypertensive patients.

AIMS: To determine whether renal denervation (RDN) in hypertensive patients affects the platelet activation status. METHODS AND RESULTS: We investigated the effect of RDN on the platelet activation status in 41 hypertensive patients undergoing RDN. Ambulatory blood pressure (BP), plasma sympathetic neurotransmitter Neuropeptide Y, and platelet activation markers were measured at baseline, at 3 months, and 6 months after RDN. RDN significantly decreased BP at 3 months (150.6 ± 11.3/80.9 ± 11.4 mmHg to 144.7 ± 12.0/77.1 ± 11.1 mmHg; P < 0.01) and at 6 months (144.3 ± 13.8/78.3 ± 11.1 mmHg; P < 0.01). Plasma levels of the sympathetic neurotransmitter Neuropeptide Y, an indicator of sympathetic nerve activity, were significantly decreased at 3 months (0.29 ± 0.11 ng/mL to 0.23 ± 0.11 ng/mL; P < 0.0001) and at 6 months (0.22 ± 0.12 ng/mL; P < 0.001) after RDN. This was associated with a reduction in platelet membrane P-selectin expression (3 months, P < 0.05; 6 months, P < 0.05), soluble P-selectin (6 months, P < 0.05), circulating numbers of platelet-derived extracellular vesicles (EVs) (3 months, P < 0.001; 6 months, P < 0.01), and phosphatidylserine expressing EVs (3 months, P < 0.001; 6 months, P < 0.0001), indicative of a reduction in platelet activation status and procoagulant activity. Only patients who responded to RDN with a BP reduction showed inhibition of P-selectin expression at 3 months (P < 0.05) and 6 months (P < 0.05) as well as reduction of glycoprotein IIb/IIIa activation at 3 months (P < 0.05). Notably, 13 patients who took aspirin did not show significant reduction in platelet P-selectin expression following RDN. CONCLUSION: Our results imply a connection between the sympathetic nervous system and the platelet activation status and provide a potential mechanistic explanation by which RDN can have favourable effects towards reducing cardiovascular complications.

Anti-thrombotic strategies in elderly patients receiving platelet inhibitors.

Acetyl-salicylic acid is the basic anti-thrombotic therapy used for single anti-platelet therapy in primary as well as secondary prevention of atherosclerotic disease. Dual anti-platelet therapy (DAPT) is the cornerstone of maintenance medication following elective percutaneous coronary intervention or acute coronary syndromes (ST elevation myocardial infarction, non-ST elevation myocardial infarction, unstable angina). DAPT duration has been frequently discussed. Currently, guideline recommendations strengthen the importance of individualized treatment to reduce bleeding risk based on clinical predictors, of which older age is an important one. Patients aged ≥75 years are often underrepresented in randomized clinical trials, but present a patient cohort deemed both at heightened ischaemic as well as bleeding risk. We aimed to summarize the evidence or the lack of evidence for anti-platelet treatment strategies in patients aged ≥75 years including combinations with anticoagulants in secondary prevention or coronary interventions in elderly patients with atrial fibrillation. This review article represents the author's interpretation of available data and is not discussed by a formal task force; it is intended to point out missing evidence and to provide age-specific data for individualized decision making, which is currently encouraged by the guidelines.

Mortality in patients with cardiogenic shock treated with the Impella CP microaxial pump for isolated left ventricular failure.

AIMS: Cardiogenic shock is still associated with high mortality rates of around 50%. Intra-aortic counterpulsation had been frequently used in cardiogenic shock, but was previously found to provide no mortality benefit. We investigated the effect of an interdisciplinary and multiprofessional routine strategy of early invasive haemodynamic support in combination with complete revascularization in patients with cardiogenic shock before admission to our intensive care unit. METHODS AND RESULTS: We analysed all cardiogenic shock patients (mean age 62±13 years) presenting at our institution between 2013 and mid 2016, who received an Impella CP microaxial pump for isolated left ventricle support (n=61). Sixty-one per cent (n=37) had been resuscitated before Impella insertion. Overall mortality was 48% (n=29/61) at 30 days. Thirty-day mortality was higher in resuscitated patients (resuscitated: 65% (n=24/37); non-resuscitated: 21% (n=5/24)). When applying the inclusion/exclusion criteria of the SHOCK-II trial, eligible patients (n=25) had a markedly lower mortality (24% (n=6/25) at 30 days) compared with the published trial (~40% in both arms). The observed mortality of SHOCK-II-like patients in the registry was also lower compared with their predicted mortality using IABP-Shock II score (49%) and CardShock score (36%). CONCLUSION: The results of this registry suggest that using a standardized protocol including early active haemodynamic support with Impella CP in cardiogenic shock in patients with isolated left ventricle failure may be associated with improved outcomes and lower than previously reported or predicted mortality rates. Pre-implantation cardiac arrest critically influences observed mortality. The results support the case for a randomized trial.

Safe Exchange of a Transfemoral Impella Pump.

Mechanical circulatory support with the Impella pump is established in many centers treating patients with cardiogenic shock. While Impella pumps usually run very stable, it may still be possible that one needs to remove the pump for using the same vascular access for different reasons. Unfortunately, until now it had been nearly impossible to remove the pump while preserving arterial access without severe bleeding. Here we describe a prototypical approach of exchanging an Impella pump in a 47-year-old female supported with veno-arterial ECMO for cardiogenic shock from myocarditis. The dysfunctional Impella pump was safely removed and replaced by a new one through the same arterial access site. Continuation of active LV unloading resolved pulmonary edema, and the patient was finally bridged to ventricular assist device surgery with favorable outcome. In general, the described approach is applicable for virtually all large-bore devices with arterial access.

Mortality in Patients With Out-of-Hospital Cardiac Arrest Undergoing a Standardized Protocol Including Therapeutic Hypothermia and Routine Coronary Angiography: Experience From the HACORE Registry.

OBJECTIVES: This study sought to analyze the impact of mandatory therapeutic hypothermia and cardiac catheterization in the absence of overt noncardiac cause of arrest as part of the Hannover Cardiac Resuscitation Algorithm before intensive care admission. BACKGROUND: Despite advanced therapies, out-of-hospital cardiac arrest (OHCA) is still associated with high mortality rates. Recently, the TTM (Target Temperature Management 33°C Versus 36°C After Out-of-Hospital Cardiac Arrest)-trial caused severe uncertainty about the efficacy of and need for therapeutic hypothermia. Furthermore, the role of early coronary angiography in OHCA survivors without ST-segment elevation remains undetermined. METHODS: In the HACORE (HAnnover Cooling REgistry) we investigated 233 consecutive patients (median age 64 [interquartile range: 53 to 74] years) with OHCA admitted to our institution between January 2011 and December 2015 who were treated according to the algorithm. RESULTS: A total of 73% had ventricular fibrillation as primary rhythm. Return of spontaneous circulation was achieved after 20 (interquartile range: 10 to 30) min. Immediate percutaneous coronary angiography was performed in 96% and coronary angioplasty in 59% of all cases. ST-segment elevation was present in 47%. Critical coronary stenosis requiring percutaneous coronary intervention was present in 67% of patients with and 52% of patients without ST-segment elevation. Overall 30-day intrahospital mortality in this real-world registry was 37%. Patients in our local registry who matched the inclusion/exclusion criteria of the TTM-trial (n = 145) had a markedly lower 30-day mortality (27%) compared with the published trial (44%). CONCLUSIONS: Standardized treatment of patients with OHCA following a strict protocol incorporating computed tomography, cardiac catheterization and revascularization, liberal use of active hemodynamic support in presence of shock, and mandatory therapeutic hypothermia results in mortality rates lower than previously reported.

The effect of oxygen in Sirt3-mediated myocardial protection: a proof-of-concept study in cultured cardiomyoblasts.

Sirtuin 3 is a nicotinamide adenine dinucleotide dependent mitochondrial deacetylase that governs mitochondrial metabolism and oxidative defense. The demise in myocardial function following myocardial ischemia has been associated with mitochondrial dysfunction. Sirt3 maintains myocardial contractile function and protects from cardiac hypertrophy. The role of Sirt3 in ischemia is controversial. Our objective was to understand, under what circumstances Sirt3 is protective in different facets of ischemia, using an in vitro proof-of-concept approach based on simulated ischemia in cultured cardiomyoblasts. Cultured H9c2 cardiomyoblasts were subjected to hypoxia and/or serum deprivation, the combination of which we refer to as simulated ischemia. Apoptosis, as assessed by Annexin V staining in life-cell imaging and propidium-iodide inclusion in flow cytometry, was enhanced following simulated ischemia. Interestingly, serum deprivation was a stronger trigger of apoptosis than hypoxia. Knockdown of Sirt3 further increased apoptosis upon serum deprivation, whereas no such effect occurred upon additional hypoxia. Similarly, only upon serum deprivation but not upon simulated ischemia, silencing of Sirt3 led to a deterioration of mitochondrial function in extracellular flux analysis. In the absence of oxygen these Sirt3-dependent effects were abolished. These data indicate, that Sirt3-mediated myocardial protection is oxygen-dependent. Thus, mitochondrial respiration takes center-stage in Sirt3-dependent prevention of stress-induced myocardial damage.

One symptom, two arrhythmias: the rare and the even rarer.

BACKGROUND: Wolff-Parkinson-White (WPW) syndrome and idiopathic left ventricular tachycardia (ILVT) are rare and up to now the coexistence of both entities has rarely been reported. In patients with ventricular preexcitation the underlying mechanism of paroxysmal tachycardia most likely is atrioventricular reentrant tachycardia (AVRT). However, without ECG documentation of the tachycardia diagnosis of the underlying mechanism cannot be made due to similar clinical presentation of AVRT and ILVT. CASE PRESENTATION: We report a case of a two-staged occurrence of two rare arrhythmias in a young adult, who was admitted to our hospital twice within 6 months because of paroxysmal tachycardia. WPW syndrome and ILVT as underlying arrhythmias have been diagnosed and were ablated successfully. CONCLUSIONS: This case highlights the diagnostic defiance of rare tachycardia entities and the paramount importance of ECG documentation and analysis of all available tachycardia ECGs.