RS Configuration Research Articles

The Significance of rS Change in the V2 Lead for Diagnosing Ventricular Tachycardia Deserves Attention: A Case Report

Abstract Occasionally, incessant ventricular tachycardia (VT) exhibits a narrow QRS complex pattern that could be misdiagnosed as supraventricular tachycardia. In this case, a 66-year-old woman was referred to the emergency department due to the worsen hemodynamic and incessant VT manifesting as a narrow QRS complex pattern that was initially misdiagnosed as supraventricular tachycardia, which was unresponsive to antiarrhythmic drugs. The electrocardiogram manifestation of VT was characterized by an rS configuration in lead V2 with Rs pattern in leads V1 and V3, and the R-wave amplitude of lead V1 and V3 was greater than that of lead V2, which was different from the typical electrocardiogram features of right bundle branch block. The patient was subsequently found to have suspected acute myocarditis when the cause of the disease was investigated. A combination of high-dose methylprednisolone, immunoglobulin and intra-aortic balloon pump was given immediately. Hemodynamics gradually stabilized, and ventricular tachycardia did not recur. The rS change in the V2 lead may be helpful to distinguish VT from supraventricular tachycardia.

Global R-wave peak time for diagnosis of left bundle branch capture

BackgroundQRS axis deviation and rS configuration in V6 affect the ability of V6 R-wave peak time (RWPT) criterion to discriminate capture type during left bundle branch area pacing (LBBAP). ObjectiveWe hypothesized that combining RWPTs from lateral leads: I, aVL, V5, and V6 may better reflect left ventricular activation time and that such a global RWPT may be insensitive to changes in QRS configuration. MethodsThe analysis included 519 electrocardiograms (ECGs) with nonselective left bundle branch pacing (nsLBBP) and 176 ECGs with left ventricular septal pacing (LVSP). Optimal RWPT cutoffs and area under the receiver operating curve (AUC) were determined for each lead and combinations of leads, to find the best RWPT criterion for discriminating nsLBBP from LVSP. Values were reported separately for healthy and diseased left conduction system groups. ResultsThe highest AUC of 97.1/89.2% was obtained for the global RWPT, which combined leads I and V6. The AUC for single-lead RWPT, was highest for lead I, followed by V6, V5, and aVL with AUC of 95.1/87.4%, 93.6/87.1%, 93.0/86.5%, and 84.8/74.6%, respectively. The global RWPT criterion was not affected by variations in QRS configuration, as V6 and I RWPTs often showed opposite responses to changes in axis. In contrast, all single-lead RWPT criteria were sensitive to axis deviation and QRS configuration. Diagnostically optimal RWPT cutoffs for global RWPT and lead I RWPT were 162.5/187.5 ms, and 81.5/90.5 ms, respectively. ConclusionThe global RWPT criterion allows a more accurate diagnosis of LBBAP capture type independent of QRS configuration and axis.

(SC,RS)-Bromido-(N-{4-methyl-1-[(4-methyl-phenyl)sul-fan-yl]-pentan-2-yl}-N'-(pyridin-2-yl)imidazol-2-yl-idene)palladium(II) bromide.

The mol-ecule of the title NCNHCS pincer N-heterocyclic carbene palladium(II) complex, [PdBr(C21H25N3S)]Br, exhibits a slightly distorted square-planar coordination at the palladium(II) atom, with the five-membered chelate ring nearly planar. The six-membered chelate ring adopts an envelope conformation. Upon chelation, the sulfur atom becomes a stereogenic centre with an RS configuration induced by the chiral carbon of the precursor imidazolium salt. There are intra-molecular C-H⋯Br-Pd hydrogen bonds in the structure. The two inter-stitial Br atoms, as the counter-anion of the structure, are both located on crystallographic twofold axes and are connected to the complex cations via C-H⋯·Br hydrogen bonds.

Comparison of in hospital outcome of patients with and without distorted terminal portion of QRS complex on initial electrocardiogram in ST segment elevation myocardial infarction with GRACE scoring assessment

Distorted terminal portion of QRS complex on initial electrocardiogram in ST segment elevation myocardial infarction is a strong predictor of in hospital adverse outcome This observational prospective study was carried out in the department of cardiology, BSMMU, Dhaka from July 2014 to June 2015 to analyse admission ECG in patients of STEMI based on terminal portion of QRS complex and find out inhospital death, heart failure, cardiogenic shock and recurrent myocardial infarction, with GRACE scoring assessment. Total 60 patients with STEMI (age 54.33±10.37, 55M/5/F) were included in this study after analysing the selection criteria. We defined two ECG groups according to absence of distortion of terminal QRS (Group-I) and presence of distorted terminal QRS (Group-II) in two or more adjacent leads. Group-II further divided into pattern-A – J point originating at ³50% of height of R wave in leads with qR configuration and pattern B- S wave is absent in leads with RS configuration. Global Registry of Acute Coronary Events (GRACE) risk score was evaluated and compared in between two groups. Out of 60 patients of STEMI, 30 patients had distortion of QRS complex. There were 7 deaths, 16 heart failure, 3 cardigenic shock and no recurrent myocardial infarction. Hospital mortality and heart failure were found to be significantly higher in distorted QRS group (1 vs. 6 patients p=0.04; 4 vs. 12 patients p=0.02; respectively), cardiogenic shock of both groups did not show significant difference (0 vs. 3 patients p=0.075). Multiple logistic regression analysis using hospital mortality as dependable variable and all studied risk factors were independent variables, QRS distortion on admission ECG and Killip class were only variable found to be statistically significant (OR=7.25, p value < 0.05 ; OR=16.25, p value< 0.05 respectively). GRACE risk score was significantly high in distorted QRS group and low in without QRS distorted group (6 vs 15 patients p=0.014; 6 vs 16 patients p=0.007; respectively). Intermediate GRACE score did not show any statistically significant difference between two groups (p=0.77). Careful analysis of ECG which is simple, cheap, universally available bed side investigation may offer important prognostic information in patients with STEMI and would help in deciding which patients should go urgent myocardial revascularization procedure. Assessment of GRACE risk scoring is strongly encourage in everyday clinical practice as it provides reliable identification of STEMI patients who are at high risk of death. Bangladesh Medical Res Counc Bull 2022; 48(3): 211-218

Intramural Purkinje fibers facilitate rapid ventricular activation in the equine heart.

The Purkinje fibers convey the electrical impulses at much higher speed than the working myocardial cells. Thus, the distribution of the Purkinje network is of paramount importance for the timing and coordination of ventricular activation. The Purkinje fibers are found in the subendocardium of all species of mammals, but some mammals also possess an intramural Purkinje fiber network that provides for relatively instantaneous, burst-like activation of the entire ventricular wall, and gives rise to an rS configuration in lead II of the ECG. To relate the topography of the horse heart and the distribution and histology of the conduction system to the pattern of ventricular activation as a mechanism for the unique electrical axis of the equine heart. The morphology and distribution of the cardiac conduction system was determined by histochemistry. The electrical activity was measured using ECG in the Einthoven and orthogonal configuration. The long axis of the equine heart is close to vertical. Outside the nodal regions the conduction system consisted of Purkinje fibers connected by connexin 43 and long, slender parallel running transitional cells. The Purkinje fiber network extended deep into the ventricular walls. ECGs recorded in an orthogonal configuration revealed a mean electrical axis pointing in a cranial-to-left direction indicating ventricular activation in an apex-to-base direction. The direction of the mean electrical axis in the equine heart is determined by the architecture of the intramural Purkinje network, rather than being a reflection of ventricular mass.

Global gyro-kinetic study of magnetic shaping effects on linear trapped electron mode instability in normal/reversed magnetic shear plasmas

A linear δf version of the gyro-kinetic Vlasov code GKNET (Gyro-Kinetic Numerical Experiment of Tokamak) is extended to the global cylindrical coordinates (R, φ, Z) and includes the kinetic electron response, to study the shaping effect on linear drift-wave instabilities in Tokamak plasmas. Cross-verifications are performed between three GKNET versions that use different electron models, i.e. the adiabatic electron model, hybrid electron model (only trapped electrons are calculated kinetically) and full-kinetic electron model (all electrons are calculated kinetically). A destabilizing effect of non-adiabatic passing electrons is observed in the full-kinetic case for the ion temperature gradient (ITG) mode in the short wavelength region and the trapped electron mode (TEM). The ion-to-electron mass ratio and the electron–electron collisionality have weak impacts on the destabilization of ITG/TEM. Utilizing magnetohydrodynamic equilibria designed with normal and reversed magnetic shear (NS and RS), the characteristics of linear TEMs and the corresponding impact of plasma shaping are studied based on the GKNET code with full-kinetic electrons. Due to the change in temperature/density gradient and magnetic shear either measured locally in the low field side (LFS) or averaged over the flux surface, plasma shaping shows different impacts on linear TEMs in NS and RS configurations. For the elongation κ, the increase in κ always stabilizes linear TEMs due to the reduction in the effective profile gradient over the flux surface. For the triangularity δ, in the NS case, the change in δ shows weak dependence on TEM linear growth rates due to the balance between variations of profile gradients and magnetic shear in the LFS. In the RS case, local magnetic shear in the peak gradient region is nearly zero. Thus, the variation in local profile gradient plays a dominant role on the linear growth in a plasma shaping scan. Consequently, the negative triangularity (δ < 0) has a destabilizing effect on the linear TEMs in the RS configuration mainly due to the upshift in local profile gradient in the LFS.

Miniseries 2-Septal and paraseptal accessory pathways-Part II: Para-Hisian accessory pathways-so-called anteroseptal pathways revisited.

Surgeons, when dividing bypass tracts adjacent to the His bundle, considered them to be 'anteroseptal'. The area was subsequently recognized to be superior and paraseptal, although this description is not entirely accurate anatomically, and conveys little about the potential risk during catheter interventions. We now describe the area as being para-Hisian, and it harbours two types of accessory pathways. The first variant crosses the membranous septum to insert into the muscular ventricular septum without exiting the heart, and hence being truly septal. The second variant inserts distally in the paraseptal components of the supraventricular crest, and consequently is crestal. The site of ventricular insertion determines the electrocardiographic expression of pre-excitation during sinus rhythm, with the two types producing distinct patterns. In both instances, the QRS and the delta wave are positive in leads I, II, and aVF. In crestal pathways, however, the QRS is ≥ 140 ms, and exhibits an rS configuration in V1-2. The delta wave in V1-2 precedes by 20-50 ms the apparent onset of the QRS in I, II, III, and aVF. In the true septal pathways, the QRS complex occupies ∼120 ms, presenting a QS, W-shaped, morphology in V1-2. The delta wave has a simultaneous onset in all leads. Our proposed terminology facilitates the understanding of the electrocardiographic manifestations of both types of para-Hisian pathways during pre-excitation and orthodromic tachycardia, and informs on the level of risk during catheter ablation.

Numerical study of the effects of pin geometry and configuration in micro-pin-fin heat sinks for turbulent flows

This study numerically investigates a micro-pin-fin heat sink (MPFHS) to improve cooling capability and productivity of MPFHS. It was assumed that the flow is turbulent, steady, and incompressible. Turbulence was modeled using the k−ε turbulence model. For this purpose, the effects of different pin-fin configurations, including RS, ET, and ES, height, fluid velocity, in terms of heat transfer, pressure drop, as well as temperature variation between the inlet and outlet were studied in detail. Moreover, a comparison investigation with experimental results was carried out. Finally, it is found that the RS configuration possessed maximum heat transfer while yielding the maximum pressure drop. Smaller distances between the pins improved heat transfer but enhanced the convective heat transfer coefficient and increased pressure drop. Contrarily, an increased pin length and diameter enhanced pressure drop and heat transfer for all the configurations. This was more obvious in the RS configuration.

Terminal QRS Distortion on Admission ECG as a Predictor for Major Cardiovascular Adverse Events during Hospitalization in Patient with ST Segment Elevation Myocardial Infarction in Haji Adam Malik General Hospital

Background: Mortality in patient with acute myocardial infarction has decreased due to evolution in management system in patient with acute coronary syndrome, but mortality rate during hospitalization remains high, especially STEMI. Electrocardiography (ECG) has a role for diagnosing and predict prognosis in acute myocardial infarction. Terminal QRS distortion defined as J point elevation more than 50% of R wave in lead with qR configuration and/or loss of S wave with RS configuration. Changes of terminal QRS segment believed to be caused by electrical conduction elongation in Purkinje fiber or myocardial ischemic zone that represent severe ischemia. The purpose of this study is to assess the role of terminal QRS distortion as one of the parameter to predict major adverse cardiovascular events during hospitalization in ST elevation myocardial infarction in RSUP H. Adam Malik&#x0D; Methods: This is a ambispective observational study consist of STEMI patients who were hospitalized from Mei 2019 to September 2019. All subjects diagnosed with STEMI and already fulfilled the inclusion and exclusion criterias. The terminal QRS distortion on the ECGs was assessed when the patient came to emergency departement. Then during hospitalization, the patients will undergo intervention and then observed during hospitalization for MACE occurrence.&#x0D; Results: Of the 78 STEMI patients, 44 people had terminal QRS distortion and 34 did not have terminal QRS distortion. In group with terminal QRS distortion, 27 people experiences MACE. From the correlation analysis, there is positive correlation between terminal QRS distortion with MACE with correlation coefficient 0.317 (p value &lt; 0.001). Multivariate analysis for most significant variable for MACE occurrence shows that terminal QRS distortion can predict MACE (OR 3.66 [1.317-10.166], 95% CI, p = 0.013)&#x0D; Conclusion: Terminal QRS distortion found in ECG at admission in STEMI patient correlate with major adverse cardiovascular event during hospitalization.

Investigation of peripheral vortex reverse flow (PVRF) combustor for gas turbine engines

In a reverse flow combustor air is injected from the exit side so that the bulk gas flow reverses its direction while exiting the combustor. In the combustor investigated here, a dominant peripheral vortex away from the exit is stabilized by carefully choosing the location of the air jet. Combustion is stabilized due to internally recirculated hot product gases in this peripheral vortex. The fuel is injected in the peripheral vortex region at high velocity and rapid mixing of injected fuel with the oxidizer results in avoidance of hot spot regions and leads to overall lean combustion and low pollutant emissions. Due to reverse flow geometry, along with the presence of the peripheral vortex, favourable residence time distribution of gases is achieved (shown numerically). This resulted in lower CO emissions (confirmed experimentally). In the non-premixed mode, fuel injection port is either placed on the exit/air port side (named as RS configuration) or on the opposite side of the exit/air port (named as RO configuration). The combustor operating in RO configuration displayed wider lean operational limit, and lower CO emissions as compared to the RS configuration, while NOx emissions were almost same in both the cases.

Atypical Surface ECG Complicating the Diagnosis of Bundle Branch Reentry Tachycardia

Typical left bundle branch block (LBBB) during ventricular tachycardia (VT) is a diagnostic criterion of bundle branch reentry tachycardia (BBRT) with activation of the right bundle in the anterograde direction. Eleven patients (seven male, 60 ± 12 years) with nonischemic cardiomyopathy (left ventricular ejection fraction 37 ± 16%) presenting with BBRT were successfully treated by ablation of the right bundle. Among them, five patients had atypical surface electrocardiograms (ECGs) differing from a typical LBBB during the VT. Three patients with severe enlargement and dysfunction of the left ventricle had broadened irregular QRS complexes with rR or RS configuration in lead V6 during the BBRT. Two patients with enlargement and/or hypokinesia of the right ventricle had entirely or almost entirely negative complexes (QS) in the chest leads (V1-V6) during the VT. Activation mapping in these two patients revealed that the exit site of the BBRT was in the anterior right ventricle generating a negative concordance in the precordial leads. Atypical surface ECGs with broadened irregular QRS complexes or negative concordance in the precordial leads can complicate the correct diagnosis of BBRT in patients with severe left ventricular dysfunction and involvement of the right ventricle.

The Prevalence of distorted terminal portion of QRS complex in patients of CKD with STEMI and its effect on their Outcome

Background: Distorted terminal portion of QRS complex on initial electrocardiogram ( ECG) in patients with ST segment elevation myocardial infarction ( STEMI) is a strong predictor of adverse outcome. Objectives: Our purpose of this study was to assess the relationship of distortion of QRS on initial ECG in STEMI with chronic kidney diseases (CKD). Methods: We evaluated 60 patients of STEMI admitted within 12 hours and receiving thrombolytic therapy. Patients having serum creatinine &lt; 1.5 mg/dl were group-I and ?1.5 mg/dl were group-II. We defined two ECG groups according to absence of distortion of terminal QRS and presence of distorted terminal QRS in two or more adjacent leads. Distorted QRS group further divided into pattern-A – J point originating at ?50% of height of R wave in leads with qR configuration and pattern B- S wave is absent in leads with RS configuration. Additionally study population was divided into two groups on the basis of serum creatinine level. Results: CKD patients had more QRS distortion (43.2% vs 68.8%, p=0.008) and worse inhospital outcome. Out of 60 patients 7(11.6%) death, 16(26.7%) heart failure and 37(61.7%) uneventful recovery. Hospital mortality and heart failure were significantly higher in STEMI with CKD group (4.5% vs 31%, p=0.004; 16% vs 56%, p=0.001; respectively), uneventful recovery was significantly higher in STEMI without CKD group(12.5% vs 80%, p=&lt;0.001). In multiple logistic regression analysis, CKD ( serum creatinine ?1.5) and Killip class ?II were independent predictors of QRS distortion (OR= 5.702, p=0.014; OR= 3.578,p=0.036; respectively). Conclusion: Among the CKD patients with STEMI the distorted terminal portion of QRS complex on initial ECG is more frequent and significantly related to adverse prognosis. Careful analysis of ECG which is simple, chief, universally available, bed side investigation may offer important information regarding prompt risk stratification and management in patients of CKD with STEMI.University Heart Journal Vol. 11, No. 1, January 2015; 7-12

The static electrocardiogram in clinically healthy, anesthetized, zoo-kept black-tailed prairie dogs (Cynomys ludovicianus)

ObjectivesThe goal of this study was to evaluate the static electrocardiograms of clinically healthy black-tailed prairie dogs (Cynomys ludovicianus), and suggest normal values. AnimalsThirteen clinically healthy black-tailed prairie dogs were included in the study. They were anesthetized for physical examination, and complete laboratory data including troponin I concentration, thoracic radiographs, echocardiograms, and static ECG were recorded. Material and methodsStatic electrocardiograms were recorded using standard, six-limb leads from each of the 13 apparently healthy prairie dogs. Each prairie dog was anesthetized with isoflurane via facemask. Electrocardiograms were recorded in right lateral recumbency. The data were retrospectively analyzed. Lead II was used for waveform analysis. ResultsThe median heart rate was 250 bpm (range 147–320). Median P-wave amplitude was 0.05 mV (range 0.01–0.06) and P-wave duration was 0.03 s (range 0.02–0.03). The PR interval was 0.06 s (range 0.04–0.06). The R-wave amplitude was 0.5 mV (range 0.1–1.15) and the QRS duration was 0.02 s (range 0.02–0.03). The QT interval was 0.12 s (range 0.1–0.14). Sixty-two percent of the QRS complexes were of Rs configuration. ConclusionsStatic electrocardiograms can be performed and evaluated in anesthetized prairie dogs. This report provided normal values in clinically healthy black-tailed prairie dogs.

Estudo eletrocardiográfico de éguas da raça Crioula

A eletrocardiografia constitui ferramenta indispensável no diagnóstico de arritmias e distúrbios de condução elétrica do coração de equinos, bem como na determinação do prognóstico de cardiopatias, do desempenho atlético, da eficiência do treinamento, além de sugerir distúrbios eletrolíticos. No entanto, as variáveis eletrocardiográficas em equinos podem sofrer influência de diversos fatores como a idade, sexo, raça e constituição morfofuncional, dentre outas, tornando-se necessário conhecer as características de normalidade para as diferentes raças e fases do desenvolvimento. Descendentes dos cavalos da Península Ibérica, a raça Crioula foi trazida ao continente americano há mais de quatro séculos, resultando em características físicas e de resistência únicas, dada por sua seleção natural. Desta forma, objetivou-se com o presente trabalho avaliar e comparar os aspectos eletrocardiográficos de fêmeas da raça Crioula, em diferentes idades, bem como avaliar possíveis alterações eletrocardiográficas secundárias a prenhes. Para tanto, 84 éguas hígidas (34 prenhes e 50 não prenhes) da raça Crioula foram submetidas à avaliação eletrocardiográfica digital na derivação ápice-base, e os registros eletrocardiográficos subdivididos quanto à idade em G1 (até 4 anos), G2 (5 a 9 anos), G3 (acima de 10 anos). Não foram observadas arritmias cardíacas fisiológicas ou patológicas e distúrbios de condução elétrica do coração nas 84 éguas. Houve predomino de taquicardia sinusal, ondas P bífidas, complexos QRS do tipo rS e ondas T bifásicas em todos os grupos. Apenas a duração média do complexo QRS foi superior no grupo G1 (110,65±8,49) quando comparadas aos grupos G2 (101,98±10,02) e G3 (100,92±10,72). As variáveis autonômicas mensuradas (ITV, NNmédio e SDNN) foram inferiores nas éguas prenhes em relação às não prenhes, sugerindo maior participação do sistema nervoso autônomo simpático e ou menor participação parassimpática. Conclui-se, portanto, que a idade influenciou apenas na duração do complexo QRS , e que a prenhes foi capaz de diminuir as variáveis de variabilidade da frequência cardíaca no domínio do tempo e, possivelmente, influenciar na avaliação eletrocardiográfica das éguas Crioulas aqui testadas.

Abstract 16142: Grad 3-Ischemia (QRS Complex Distortion) as a Predictor of Myocardial Damage as Assessed by Cardiac Magnetic Resonance Imaging and Clinical Prognosis in Patients With ST-Elevation Myocardial Infarction

Introduction: Predicting the extent of myocardial damage on early electrocardiographic (ECG) findings could be helpful for improved risk stratification in patients with acute reperfused ST-elevation myocardial infarction (STEMI). Distortion in the terminal portion of the QRS complex (so called grade 3 ischemia, G3I) has been associated with adverse outcomes in STEMI patients. The correlation of G3I with infarct size and microvascular injury is not well defined. Objective: To studied the relation of G3I with myocardial damage as assessed by CMR and the association of G3I with adverse clinical outcomes in a STEMI population treated by primary percutaneous coronary intervention (PCI). Methods: We analyzed the ECGs of 572 consecutive STEMI patients regarding the presence or absence of G3I. G3I was defined as: 1) complete loss of S waves in 2 adjacent leads with typical Rs configuration (i.e. V1-V3), or 2) ST-J point to R wave amplitude ratio &gt;0.5 in other leads with qR configuration. CMR was performed within 1 week after infarction for comprehensive assessment of myocardial damage using a standardised protocol. The primary clinical end-point was major adverse cardiac events (MACE) defined as death, reinfaction and readmission for congestive heart failure within 12 months after the index event. Results: G3I was present in 186 (32%) patients. The presence of G3I was associated with larger infarct size (18.3%LV [10.4 to 27.6] versus 16.5%LV (8.2 to 23.5), p=0.01), late microvascular obstruction (0.4%LV [0 to 2.7] versus 0%LV [0 to 1.5], p= 0.05, presence of intramyocardial hemorrhage (41 versus 32%, p=0.04) and less myocardial salvage (47 [28 to 64] versus 53 (35 to 68), p=0.01). G3I was associated with a significant higher incidence of MACE (p=0.01) and was identified as an independent predictor of MACE in Cox regression analysis (Hazard ratio 2.19 [1.10 to 4.38], p=0.03). Conclusions: This largest study to date correlating G3I on the admission ECG with CMR markers of myocardial damage demonstrates that G3I is significantly associated with infarct size, myocardial salvage and reperfusion injury in a STEMI population reperfused by primary PCI. Moreover, G3I was independently associated with MACE.

Prognostic significance of the distortion of terminal portion of QRS complex on admission electrocardiogram in ST segment elevation myocardial infarction

ECG on admission has been used in predicting prognosis and risk stratification in ST segment elevation acute myocardial infarction (STEMI). To analyze the admission ECG in STEMI based on abnormality observed in terminal portion of QRS and its correlation to hospital mortality. 160 consecutive patients of STEMI were classified into subjects without (Group I) and with distortion of terminal QRS (Group II), Pattern A--Emergence of J point at ≥50% of the R wave amplitude in leads with qR configuration or Pattern B--Absence of the S waves, in leads with Rs configuration in two consecutive leads. Out of 160 patients of STEMI, 69 (43.1%) had distortion of QRS. There were 13 deaths (8.1%). Hospital mortality was found to be significantly more in subjects with distortion than those without (15.9% V/S 2.1%, p < 0.001). Patients with QRS distortion tended to have larger infarction as assessed by Killip class on admission (p < 0.05), anterior location of MI (p < 0.01) and presence of significant Q waves in leads with ST segment elevation (p < 0.0001). With multiple logistic regression analysis using hospital mortality as a dependent variable and all studied risk factors as independent variables, QRS distortion on admission ECG was the only variable found to be statistically significant (Adjusted OR = 7.161, p < 0.05). ECG on admission is a simple, cheap, universally available investigation that can predict the short term prognosis in STEMI and would help in deciding which patients should go for other myocardial revascularization procedures.

Stereodivergent Synthesis of Iminosugars from Stannylated Derivatives of (S)-Vinylglycinol

An original access to iminosugars from a cis/trans mixture of stannylated oxazolidinones 5 is reported. The dehydropiperidines 7-trans and 7-cis were obtained stereoselectively with an RS and SS configuration depending on the order of the Sn-Li transmetalation (followed by electrophilic trapping) and of the ring closing metathesis reactions due to the stereoselective epimerization of the α-aminoanion intermediate. The dehydropiperidines 7-trans and 7-cis were subsequently used for the synthesis of enantiopure homonojirimycin analogs.

The Impact of Preinfarction Angina on Electrocardiographic Ischemia Grades in Patients with Acute Myocardial Infarction Treated with Primary Percutaneous Coronary Intervention

Grade 3 ischemia (G3I) is defined as ST elevation with distortion of the terminal portion of the QRS (emergence of the J point > 50% of the R wave in leads with qR configuration, or disappearance of the S wave in leads with an Rs configuration). Patients with G3I on the presenting electrocardiogram (ECG) had worse prognosis than the patients with lesser (grade 2-G2I) ischemia. The aim of this study is to examine the effects of preinfarct angina (PIA) on electrocardiographic ischemia grades. One hundred forty-eight consecutive patients with ST-segment myocardial infarction (STEMI) were included in this study. All patients underwent primary percutaneous coronary intervention. The admission ECGs was analyzed retrospectively for electrocardiographic ischemia grades and compared with the presence of PIA. Study population consisted of 110 patients with G2I (88 men, mean age = 63 +/- 6 years) and 38 patients with G3I (32 men, mean age = 61 +/- 8 years). Baseline characteristics of the groups were the same except for patients with G3I had significantly longer pain to balloon time and higher admission creatine kinase MB isoenzyme (CK-MB) levels. Tissue myocardial perfusion grade (TMPG) was better in patients with G2I. While 18 patients (47%) with G3I had PIA, 81 patients (70%) with G2I had PIA (P = 0.005). Although pain to balloon time and admission CK-MB were independent predictor of worse electrocardiographic ischemia grade (OR 1.69, 95% CI 1.09-2.62; P = 0.01; OR 1.01, 1.00-1.02, P = 0.04), PIA and left ventricular ejection time (LVEF) were independent predictors of better electrocardiographic ischemia grade (OR 0.4, 95% CI 0.17-0.90; P = 0.02, OR 0.92, 95% CI 0.85-0.99; P = 0.03, respectively) in multivariate logistic regression analysis. PIA is one of the most important clinical predictors of better ischemia grades especially when combined with the pain to balloon time, LVEF, and admission CK-MB levels in patients with STEMI. This study provided another evidence for the protective effects of PIA.

Conformational Analysis of R207910, a New Drug Candidate for the Treatment of Tuberculosis, by a Combined NMR and Molecular Modeling Approach

R207910 is an enantiomeric compound from a new class of antimycobacterial agents, the diarylquinolines [Science; 307:223 (2005)]. As enantiospecific interaction is required for biologic activity, we have undertaken a combined nuclear magnetic resonance and molecular modeling study to gain new insights into its conformation in solution and its absolute configuration. A conformational analysis using a Monte-Carlo method has been performed on each of the four possible stereomers of this compound leading to the identification of their most stable conformation. Additional ab initio calculation was performed with emphasis on the strength of the observed intramolecular hydrogen bond. Simultaneously, a complete structural identification has been carried out by a set of monodimensional and bidimensional (1)H-(13)C-NMR experiments. Determination of inter-proton distances has been achieved by a series of (1)H-(1)H ROESY NMR experiments with different mixing times followed by a volume quantification of the correlations peaks. These experimental data were compared with the theoretical distances obtained from the conformational analysis. The remarkable match shows that R207910 adopts one of the low-energy conformations predicted by molecular modeling and belongs to the (RS, SR) couple of diastereoisomers. A posteriori validation of our approach has been performed by X-ray structure determination that concluded for the RS configuration.

Compounds of nickel(II) with 5 RS,7 RS,12 SR,14 SR-5,12-dimethyl-7,14-diphenyl-1,4,8,11-tetraazacyclotetradecane, mmL 2; the structures of δ-[Ni(mmL 2)](ClO 4) 2, trans-β-[Ni(mmL 2)(NO 2- N) 2] and cis-α-[Ni(mmL 2)(acac)]ClO 4

Reduction of the imine functions of 7 RS,14 SR-(5,12-dimethyl-7,14-diphenyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene)nickel(II) gives the meso–meso (5 RS,7 RS,12 SR,14 SR) and rac-meso (5 RS,7 RS,12 RS,14 SR) isomers of (5,12-dimethyl-7,14-diphenyl-1,4,8,11-tetraazacyclotetradecane)nickel(II), [Ni(mmL 2)] 2+ and [Ni(rmL 2)] 2+, in approximately 6:1 proportions. Most compounds of [Ni(mmL 2)] 2+ have the amine in planar coordination with the 1 RS,4 RS,8 SR,11 SR N-configuration III (labelled β) of the nitrogen centres as square-planar singlet ground state salts β-[Ni(mmL 2)]X 2 (X −=ClO 4 − , 1/2[ZnCl 4] 2−) or as octahedral triplet ground state compounds trans-β-[Ni(mmL 2)X 2] (X −=Cl −, Br −, I −, N 3 − NO 3 − , HCO 3 − , MeCO 3 − , NCS −, NO 2 − , CN −), trans-β-Ni(mmL 2)(CN)(ClO 4), bis-adducts trans-β-[Ni(mmL 2)Y 2](ClO 4) 2 (Y=MeCN, DMSO, DMF, pyridine, MeNO 2, NH 3) and trans-μ-anion polymeric compounds β-[Ni(mmL 2)Z] (Z 2−=C 2O 4 2− , SO 4 2− , CO 3 2− , [Ni(CN) 4] 2−). Centrosymmetrical trans-β-[Ni(mmL 2)(NO 2- N) 2] has N-configuration III, with all chelate rings in optimum chair or gauche conformations, with all substituents equatorially oriented and with mean distances NiN amine=2.083(2), NiN nitro=2.183(2) Å. Reaction of trans-β-[Ni(mmL 2)(HCO 3) 2]·H 2O with alcohols form compounds of mono-alkyl carbonate esters, trans-β-[Ni(mmL 2)(CO 2OR) 2]. Compounds cis-α-[Ni(mmL 2)(A)]ClO 4 (A=pentane-2,4-dionato −, 1/2C 2O 4 2− ) have the macrocycle folded. The acac − compound has the 1 RS,4 RS,8 RS,11 RS N-configuration V with mean distances NiN=2.121(3), NiO=2.042(3) Å and angles N(4)NiN(11)=173.2(1), N(1)NiN(8)=95.1(1)°, with one six-membered chelate ring in a chair conformation with the substituents equatorially oriented and the other in a boat conformation that orients the substituents pseudo-equatorially. The folded macrocycle compounds react with acid to form a metastable [Ni(mmL 2)] 2+ cation, isolated as the perchlorate salt δ-[Ni(mmL 2)](ClO 4) 2 with the 1 RS,4 RS,5 SR,7 SR,8 SR,11 RS,12 RS,14 RS configuration, N-configuration II. The square-planar cation is tetrahedrally twisted with N-atoms ±0.103 Å and Ni atom 0.043 Å from the best N 4 plane, with mean NiN=1.933(6) Å. One six-membered chelate ring is in a chair conformation with the substituents equatorially oriented, and the other in a twist conformation with the methyl substituent axially and the phenyl substituent equatorially oriented. Relative strain energies for the isomeric cations were calculated by molecular mechanics.