Changing QRS Morphology: What is the mechanism?

ECG in sinus rhythm with ventricular preexcitation and changing QRS morphology was seen that was initially interpreted as the multiple accessory pathway from elsewhere. (Figure 1A). The following mechanisms are potentially involved in the electrogenesis of changing QRS morphology in WPW syndrome: 1) multiple accessory pathways1; 2) simultaneous occurrence of aberrant atrioventricular conduction with accessory pathway conduction 2; 3) ventricular fusion of preexcited sinus impulse with ectopic impulse. Electrophysiologic study showed short PR (75 ms) interval with wide QRS (152 ms) and negative HV (-12 ms) interval. No change in delta wave polarity was observed during HRA and CS pacing. In full preexcitation, no breakthrough was seen in the CS. During incremental ventricular pacing, atrial breakthrough site is initially recorded on the HRA catheter and then changed to distal pole of CS catheter with progressive decrease in pacing cycle length. During ventricular pacing at cycle length of 500 ms (S1), earliest atrial activity is recorded on HRA catheter. Changing QRS could not be explained by presence of multiple APs because only right-sided AP had bidirectional conduction and no distal CS breakthrough was seen simultaneous with changing QRS morphology. The possibility of aberrant conduction is excluded by presence of negative HV interval in the beats with differing QRS morphology. No sinus cycle length variation before and after the beats with different morphologies are against the occurrence of functional LBBB. The prematurity of ventricular electrogram in His recording catheter with variable HV (H-electrogram is recorded after V-electrogram in second beat and before V-electrogram in third beat) and fixed V-RB intervals (interval from ventricular electrogram in His to the RB potential) are compatible with ventricular fusion of preexcited sinus impulse with ectopic ventricular impulse originating from parahissian area (explaining LBBB and inferior axis morphology of the beats with changing QRS) but not from the His bundle or RBB itself (because H-electrogram and RB potential is recorded after V-electrogram in the second beat with greater degree of ventricular fusion)(Figure 1B)

Absence of isolated critical points with nonstandard critical exponents in the four-dimensional regularization of Lovelock gravity

Hyperbolic vacuum black holes in Lovelock gravity theories of odd order $N$ are known to have the so-called isolated critical points with nonstandard critical exponents (as $\alpha = 0$, $\beta = 1$, $\gamma = N-1$, and $\delta = N$), different from those of mean-field critical exponents (with $\alpha = 0$, $\beta = 1/2$, $\gamma = 1$, and $\delta = 3$). Motivated by this important observation, here, we explore the consequences of taking the $D \to 4$ limit of Lovelock gravity and the possibility of finding nonstandard critical exponents associated with isolated critical points in four-dimensions by use of the four-dimensional regularization, recently proposed by Glavan and Lin \cite{Glavan2020}. It is shown that the regularized $4D$ Einstein-Lovelock gravity theories of odd order $N > 3$ do not possess any physical isolated critical point. In fact, the critical (inflection) points of equation of state always occurs for the branch of black holes with negative entropy. The situation is quite different for the case of the regularized $4D$ Einstein-Lovelock gravity with cubic curvature corrections ($N=3$). In this case ($N=3$), although the entropy is non-negative and the equation of state of hyperbolic vacuum black holes has a nonstandard Taylor expansion about its inflection point, but there is no criticality associated with this special point. At this point, the physical properties of the black hole system change drastically, e.g., both the mass and entropy of the black hole vanishes, meaning that there do not exist degrees of freedom in order for a phase transition to occur. These results are in strong contrast to those findings in Lovelock gravity.Comment: 8 pages, 4 figures, 1 tabl

Comparison the Students’ Ability in Answering to Patient-Management Problem and Modified Essay Question Examination with Multiple-Choice Question Examination and its Association with Educational Promotion

Background & Objective: The present study aimed to compare the students’ ability in answering to patient management problem (PMP) and modified essay question (MEQ) examination with multiple-choice question (MCQ) examination and its association with educational promotion. Methods: This research carried out in two sections descriptive-analytic and qualitative on 76 nutrition students of Kerman University of Medical Sciences, Iran, who were selected by census. The first and second examinations were PMP-MEQ and MCQ, respectively. Educational promotion variables were grade point average (GPA) in 5 sequence semesters and GPA in current semester. The other variables were the grade in food toxicology course, the scores in PMP-MEQ, PMP and MEQ exams and MCQ exam. The second section was designed with the aim of comparing the overview of students in regard to PMP-MEQ and MCQ exams. Data were analyzed by descriptive and analytic statistics. Results: The association between educational promotion variables and mark of food toxicology course and MCQ exam were statistically significant (P < 0.001); however, there was not a statistically significant association between these variables and the other variables. Mean differences scores of MCQ and food toxicology course were significant (P < 0.001); however, scores of PMP-MEQ test and PMP and MEQ sections in two students groups based on categorized GPA were not statistically significant. Conclusion: Therefore, the students’ inability in answering to PMP and MEQ examination in comparing to the MCQ examination format was showed students’ incapability in evaluation of clinical competence even with regard to their high GPA and scientific knowledge. Keywords Patient management problem (PMP) Modified essay question (MEQ) Multiple-choice question (MCQ) Educational promotion Clinical competenc

White blood cell count to mean platelet volume ratio as a novel non-invasive marker predicting long-term outcomes in patients with non-ST elevation acute coronary syndrome

Background: Total white blood cell (WBC) count and mean platelet volume have previously been shown to predict outcomes in acute coronary syndrome (ACS) patients. In this prospective study, we sought to determine the prognostic value of baseline WBC count to mean platelet volume ratio (WMR) in patients with non-ST elevation acute coronary syndrome (NSTE-ACS). Methods: A total of 490 patients with NSTE-ACS were prospectively enrolled. The relationship between baseline WMR and major adverse cardiovascular events (MACE) incidence was assessed during a mean follow-up of 330.8 ± 38 days. Results: The patients’ mean age was 60.4 ± 12.9 year, 59% of them were male. The patients were categorized into two groups based on WMR values, high- and low-WMR groups (&lt; 755 vs. ≥ 755). The incidence of MACE was significantly higher in high-WMR compared with that of low-WMR group (22.4% vs. 10.7%, p &lt; 0.001). Total WBC counts (median 7.9 vs. 6.9 ×103/μL, p = 0.004), neutrophil count (median 4.6 vs. 4.2 ×103/μL, p = 0.021), and WMR (median 863.2 vs. 731.5, p = 0.001) were significantly higher in the MACE-positive than MACE-negative group. The high-WMR was found to be significantly associated with the MACE-free survival rate (p &lt; 0.001). In an adjusted cox regression model, the elevated WMR was independently predicted the incidence of MACE (hazard ratio 2.419, 95% CI 1.515–3.862, p &lt; 0.001). Conclusions: The elevated baseline WMR independently predicted the MACE incidence in patients with NSTE-ACS during long-term follow-up.

The effect of distance and dimensions of magnets on nonlinear behavior of piezomagnetoelastic bimorph energy harvester

This paper presents the effect of distance and dimensions of magnetson chaotic behavior and voltage level of a vibratory piezo-magneto-elastic bimorph energy harvesting system. The bimorph model comprises two iezoelectriclayers on a cantilever base structure with one tip magnet as well as two external magnets. The mathematical model is extracted by using distributed model. The validity of the extracted model verified by previously published experimental results.In order to study the nonlinear dynamic of the bimorph, bifurcation diagram, phase plane portrait, time history response, Poincare map, power spectra diagram, and maximum Lyapunov exponents are used. In the bifurcation diagrams, the control parameters are the distances and dimensions of the magnets. It is shown that in the specific region of the control parameters, the sub-harmonic or super-harmonic behavior has minimum harvested voltage and irregular regions has maximum voltage. Also specific dimensions of tip magnet can influence greatly the dynamic behavior as well as output voltage. So these obtained results can give good insights about parameters identification and realization of the nonlinear behavior to reach the broadband higher harvested voltage of the system</span

Effect of Nitrogen and Two Types of Green Manure on the Changes in Percentage and Yield of Peppermint (Mentha piperita) Essential Oil

An experiment was conducted during 2015-2016 as a split factorial in a randomized complete block design (RCBD) with three replications. Experimental factors were nitrogen fertilizer at four levels 0, 50, 100 and 150 kg/ha as the main factor and two types of green manure. Alfalfa (Medicago sativa) and secale (Secale montanum) in two states (use and non-use) were considered as sub-factors. Medicago sativa and Secale montanum were cultivated as green manure in September 2015 and returned into the soil by ploughing at the fall of 2015. Thereafter, Mentha piperita was planted and the crop was taken care of in order to collect the samples. The highest increase of peppermint essential oil percentage and essential oil yield in different treatments resulted from the application of 150 kg/ha of pure nitrogen with 0.35% and 45.60 kg/ha, as well as the use of M. sativa with 0.43% and 55.80 kg/ha, the use of S. montanum with 0.44% and 49.50 kg/ha, respectively. The highest essential oil percentage and essential oil yield were recorded under the influence of the double interaction use of 150 kg/ha of pure nitrogen and use of green manure of M. sativa with average 0.62% and 80.30 kg/ha, respectively. The triple interaction of experimental factors on traits tested showed that nitrogen treatment of 150 kg/ha with M. sativa and S. montanum produced the highest percentage of essential oil and essential oil yield of average 0.73% and 91.65 kg/ha, respectively

Scabies contamination status in Iran: A review

Background and aims: Scabies is a common worldwide parasitic contagious disease caused by Sarcoptes scabiei of the order of Astigmata of the family of Sarcoptidae. Therefore, this review is to determine the exact status of scabies in Iran in order to manage it better. Methods: On the whole, out of the 120 articles and books, 56 ones were covered based on items such as study purpose, date of publication, journal’s credibility, indication of the subject in them, transmittance, way of prevention, diagnosis, and treatment. Results: Due to the non-uniform geographical distribution of scabies in Iran, diagnosis and treatment of the disease is different. Studies show that scabies is on increase in Iran. Thus, scabies is a burden to the economy and the health care system. Prevalence of this disease has been rather high in Iran during war, prisons, and geographical humid areas which are variable in different provinces due to various climates. Conclusion: By regular monitoring and controlling the way the disease spreads, health of the population at risk can be maintained in order to bring health to the society that is among the main aims of every organizations and health providing institutions. This review focuses on scabies in Iran and other countries the entire world over to find ways for preventing and giving health care to control the diseas

Effect of oral vitamin C on atrial fibrillation development after isolated coronary artery bypass grafting surgery: A prospective randomized clinical trial

Background: Some evidences have shown the role of antioxidant vitamins in preventing atrial fibrillation (AF) after coronary artery bypass grafting (CABG) surgery. We sought to determine the effect of oral vitamin C on the incidence of postoperative AF in patients undergoing elective isolated on-pump CABG surgery. Methods: One-hundred patients who underwent isolated CABG surgery were prospectively assigned into two groups: Group 1 — 50 patients received 2 g of oral vitamin C before and 500 mg twice daily lasting for 5 days after surgery; Group 2 — 50 patients as the control group did not receive any. All patients were continuously monitored after surgery in the intensive careunit (ICU), and then Holter monitoring was implemented for 72 h. Results: The mean of patients’ age was 61.31 ± 6.42 years. Postoperative AF occurred in 16 and 4 patients in control and treatment groups, respectively (32% vs. 8%, p = 0.003). The ICU stay was 1.79 ± 0.313 and 2.10 ± 0.61 days for vitamin C and control groups, respectively (p = 0.002). The hospital stay was significantly lower in vitamin C group compared with that of the control group (5.32 ± 0.59 vs. 5.74 ± 1.30 days, respectively, p = 0.041). Baseline erythrocyte sedimentation rate (OR 1.030, 95% CI 1.003–1.058, p = 0.030) and taking vitamin C (OR 8.068, 95% CI 1.783–36.517, p = 0.007) were the independent predictors of postoperative AF. Conclusions: Oral vitamin C can be safely used to decrease the incidence of postoperative AF in patients undergoing elective isolated on-pump CABG surgery.