Assessment of right ventricular systolic function: Comparison between cardiac magnetic resonance derived ejection fraction and pulsed-wave tissue Doppler imaging of the tricuspid annulus

Systolic right ventricular (RV) function is an important predictor in the course of various congenital and acquired heart diseases. Its practical determination by echocardiography remains challenging. We compared routine assessment of lateral tricuspid annular systolic motion velocity (TV(lat), cm/s) using pulsed-wave tissue Doppler imaging from the apical 4-chamber view with cardiac magnetic resonance (CMR) as reference method.

Clinical outcome of high-risk patients with severe aortic stenosis and reduced left ventricular ejection fraction undergoing medical treatment or TAVI

Introduction Reduced left ventricular function in patients with severe symptomatic valvular aortic stenosis is associated with impaired clinical outcome in patients undergoing surgical aortic valve replacement (SAVR). Transcatheter Aortic Valve Implantation (TAVI) has been shown non-inferior to SAVR in high-risk patients with respect to mortality and may result in faster left ventricular recovery. Methods We investigated clinical outcomes of high-risk patients with severe aortic stenosis undergoing medical treatment (n = 71) or TAVI (n = 256) stratified by left ventricular ejection fraction (LVEF) in a prospective single center registry. Results Twenty-five patients (35%) among the medical cohort were found to have an LVEF≤30% (mean 26.7±4.1%) and 37 patients (14%) among the TAVI patients (mean 25.2±4.4%). Estimated peri-interventional risk as assessed by logistic EuroSCORE was significantly higher in patients with severely impaired LVEF as compared to patients with LVEF>30% (medical/TAVI 38.5±13.8%/40.6±16.4% versus medical/TAVI 22.5±10.8%/22.1±12.8%, p <0.001). In patients undergoing TAVI, there was no significant difference in the combined endpoint of death, myocardial infarction, major stroke, life-threatening bleeding, major access-site complications, valvular re-intervention, or renal failure at 30 days between the two groups (21.0% versus 27.0%, p = 0.40). After TAVI, patients with LVEF≤30% experienced a rapid improvement in LVEF (from 25±4% to 34±10% at discharge, p = 0.002) associated with improved NYHA functional class at 30 days (decrease ≥1 NYHA class in 95%). During long-term follow-up no difference in survival was observed in patients undergoing TAVI irrespective of baseline LVEF (p = 0.29), whereas there was a significantly higher mortality in medically treated patients with severely reduced LVEF (log rank p = 0.001). Conclusion TAVI in patients with severely reduced left ventricular function may be performed safely and is associated with rapid recovery of systolic left ventricular function and heart failure symptoms.

Value of age, creatinine, and ejection fraction (ACEF score) in assessing risk in patients undergoing percutaneous coronary interventions in the 'All-Comers' LEADERS trial

Background— The age, creatinine, and ejection fraction (ACEF) score (age/left ventricular ejection fraction+1 if creatinine >2.0 mg/dL) has been established as an effective predictor of clinical outcomes in patients undergoing elective coronary artery bypass surgery; however, its utility in “all-comer” patients undergoing percutaneous coronary intervention is yet unexplored. Methods and Results— The ACEF score was calculated for 1208 of the 1707 patients enrolled in the LEADERS trial. Post hoc analysis was performed by stratifying clinical outcomes at the 1-year follow-up according to ACEF score tertiles: ACEFlow ≤1.0225, 1.0225< ACEFmid ≤1.277, and ACEFhigh >1.277. At 1-year follow-up, there was a significantly lower number of patients with major adverse cardiac event–free survival in the highest tertile of the ACEF score (ACEFlow=92.1%, ACEFmid=89.5%, and ACEFhigh=86.1%; P=0.0218). Cardiac death was less frequent in ACEFlow than in ACEFmid and ACEFhigh (0.7% vs 2.2% vs 4.5%; hazard ratio=2.22, P=0.002) patients. Rates of myocardial infarction were significantly higher in patients with a high ACEF score (6.7% for ACEFhigh vs 5.2% for ACEFmid and 2.5% for ACEFlow; hazard ratio=1.6, P=0.006). Clinically driven target-vessel revascularization also tended to be higher in the ACEFhigh group, but the difference among the 3 groups did not reach statistical significance. The rate of composite definite, possible, and probable stent thrombosis was also higher in the ACEFhigh group (ACEFlow=1.2%, ACEFmid=3.5%, and ACEFhigh=6.2%; hazard ratio=2.04, P<0.001). Conclusions— ACEF score may be a simple way to stratify risk of events in patients treated with percutaneous coronary intervention with respect to mortality and risk of myocardial infarction.

Varying spin state composition by the choice of capping ligand in a family of molecular chains: detailed analysis of magnetic properties of chromium(III) horseshoes

We report a detailed physical analysis on a family of isolated, antiferro-magnetically (AF) coupled, chromium(III) finite chains, of general formula (Cr(RCO(2))(2)F)(n) where the chain length n = 6 or 7. Additionally, the chains are capped with a selection of possible terminating ligands, including hfac (= 1,1,1,5,5,5-hexafluoropentane-2,4-dionate(1-)), acac (= pentane-2,4-dionate(1-)) or (F)(3). Measurements by inelastic neutron scattering (INS), magnetometery and electron paramagnetic resonance (EPR) spectroscopy have been used to study how the electronic properties are affected by n and capping ligand type. These comparisons allowed the subtle electronic effects the choice of capping ligand makes for odd member spin 3/2 ground state and even membered spin 0 ground state chains to be investigated. For this investigation full characterisation of physical properties have been performed with spin Hamiltonian parameterisation, including the determination of Heisenberg exchange coupling constants and single ion axial and rhombic anisotropy. We reveal how the quantum spin energy levels of odd or even membered chains can be modified by the type of capping ligand terminating the chain. Choice of capping ligands enables Cr-Cr exchange coupling to be adjusted by 0, 4 or 24%, relative to Cr-Cr exchange coupling within the body of the chain, by the substitution of hfac, acac or (F)(3) capping ligands to the ends of the chain, respectively. The manipulation of quantum spin levels via ligands which play no role in super-exchange, is of general interest to the practise of spin Hamilton modelling, where such second order effects are generally not considered of relevance to magnetic properties.

Best combination of pre-stimulation and latency period duration before cluster attachment for efficient oxytocin release and milk ejection in cows with low to high udder-filling levels

Experiments were designed to investigate the suitability of a combination of a short manual teat stimulation with a short latency period before teat cup attachment to induce and maintain oxytocin release and milk ejection without interruption. In Experiment 1, seven dairy cows in mid lactation were manually pre-stimulated for 15, 30 or 45 s, followed by either 30 s or 45 s of latency period. It was shown that all treatments induced a similar release of oxytocin without interruption until the end of milking. In particular, the latency period of up to 45 s did not cause a transient decrease of oxytocin concentration. In Experiment 2, milking characteristics were recorded in seven cows each in early, mid, and late lactation, respectively. Because the course of milk ejection depends mainly on the degree of udder filling, individual milkings were classified based on the actual degree of udder filling which differs between lactational stages but also between morning and evening milkings. All animals underwent twelve different udder preparation treatments, i.e. 15, 30, or 45 s of pre-stimulation followed by latency periods of 0, 30, 45, or 60 s. Milking characteristics were recorded. Total milk yield, main milking time and average milk flow rate did not differ between treatments if the degree of udder filling at the start of milking was >40% of the maximum storage capacity. However, if the udder filling was <40%, main milking time was decreased with the duration of a latency period up to 45 s, independent of duration of pre-stimulation. Average milk flow at an udder filling of <40% was highest after a pre-stimulation of 45 s followed by a latency period of another 45 s. In contrast, average milk flow reached its lowest values at a pre-stimulation of 15 s without additional latency period. However, average milk flow after a 15-s pre-stimulation increased with increasing latency period. In conclusion, a very short pre-stimulation when followed by a latency period up to 45 s before teat cup attachment remains a suitable alternative for continuous stimulation to induce milk ejection.

Suitability of low-dosage oxytocin treatment to induce milk ejection in dairy cows

Chronic use of high oxytocin (OT) dosages can cause a reduced response to endogenous OT. In this study the OT dosages used in the milking practice of 82 dairy cow farms were recorded. The OT dosages per cow used were high, especially when injected i.m. (23+/-2 IU) compared with i.v. (7+/-1 IU). In addition, the minimum OT dosages needed to obtain normal milk removal in cows with disturbed milk ejection were investigated. Seventeen cows routinely treated with OT during milking (group T) and 17 cows without previous OT treatment were used (group C). After cessation of spontaneous milk flow, both T and C groups were injected i.v. with a low dosage of OT (0.2 or 0.5 IU/cow). The time from injection until cessation of the OT-induced milk flow was recorded (response phase). The response phase and the amounts of removed milk by effect of the OT injection increased with increasing OT dosage. Values for 0.2 and 0.5 IU/cow of OT injected i.v. were (response phase and amount of milk removed) 198+/-27 and 302+/-18s and 3.4+/-0.7 kg and 6.5+/-1.3 kg, respectively, for the C group, and 157+/-15 and 221+/-16s and 3.2+/-0.5 and 5.5+/-1.0 kg, respectively, for the T group. Within 20 min of the OT injection, plasma concentrations returned to basal levels. The threshold OT concentration at cessation of milk flow after injection of 0.2 or 0.5 IU/cow of OT was calculated based on the OT plasma half-life. The threshold increased with increasing dosages of OT and was higher in group T (8+/-1 and 14+/-1 pg/mL for 0.2 and 0.5 IU/cow, respectively) than in group C (7+/-1 and 11+/-1 pg/mL for 0.2 and 0.5 IU/cow, respectively). In conclusion, desensitization of the udder toward OT occurs when the udder is exposed to elevated OT plasma concentrations, both short-term during the actual milking and long-term due to chronic high-dosage OT treatment. However, low-dosage OT treatments to induce normal milk removal can minimize the observed side effects.

Effects of right ventricular pacing on left ventricular ejection fraction in a pacemaker clinic

The aim of this study was to evaluate whether a change of left ventricular ejection fraction (LVEF) depending on percentage of right ventricular pacing is found in a real-life setting of a pacemaker clinic.