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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).

Background: Understanding the predictors of appropriate implantable cardioverter defibrillator (ICD) therapy could help to better identify candidates for ICD implantation. Methods: One hundred and sixty two patients with ICD (111 with coronary artery disease [CAD] and 51 with dilated cardiomyopathy [DCM]) were included in the study. Clinical, electrocardiographic, and ICD stored data and electrograms were collected. Results: During mean follow up of 15±11 months 54 patients (33%) received ≥ 1 appropriate ICD therapy (AICDT). We used binary logistic regression analysis with forward selection method to find the potential predictors of appropriate ICD therapy after device implantation. Male gender (odds ratio [OR] = 2.76, 95% confidence interval [CI] = 1.1 – 7.1, P=0.021), DCM as underlying heart disease (OR = 4.2, 95% CI = 1.9 – 9.5, P=0.001), and QRS width > 100 ms (OR = 2.58, 95% CI = 1.2 – 5.4, P=0.010) were correlated with increased likelihood of AICDT during the follow up period. In subgroup analysis of the patients with CAD and DCM, QRS duration > 100 ms was correlated with the probability of ≥ 1 AICDT. In our patients indication of ICD implantation (primary versus secondary prevention) did not influence probability of ≥ 1 AICDT (adjusted OR = 1.66, 95% CI = 0.7 – 4.0, Mantel-Haenszel P value P=0.355.) Conclusion: QRS width could be used as an additional simple risk stratifier beyond EF to identify potential candidates who would benefit more from ICD implantation. This may have practical implications for patient selection especially in developing countries. Indication of ICD implantation (primary versus secondary prevention) did not affect the probability of ≥ 1 AICDT during the follow up period.

The effects of ventilation and sucrose concentration on proliferation and organogenesis of pistachio cutting and photosynthetic performance of two in vitro cultures of pistachio rootstocks have been assessed. The apical leaf buds (Qazvini and UCB1 cultivars) were cultured in filter vessels containing Murashige and Skoog medium supplemented with 0, 10, 15, and 30 g L−1 of sucrose. The plants treated with 10, 15, and 30 g L−1 sucrose showed no significant differences regarding the measured traits; therefore, this treatment was set aside from the final statistical analyses. Use of different ventilation systems showed to be suitable for increasing the growth of pistachio. Referring to root production difficulties under in vitro cultivation of pistachio, ventilation increased the root production and length. However, the full ventilation system was more effective in improving the growth properties. Regression between fluorescence feature vs root length showed that F v/F m had a significant positive relationship with root length. Stomata of cell parameters under ventilation systems improved compared to no ventilation, which was highly similar to the trend in the greenhouse. The overall results indicated that low concentrations of sucrose (e.g., 10 g L−1) and full ventilation are recommended for producing high quality and vigorous pistachio plantlets under in vitro conditions.

Abstract Background To evaluate the scientific reasoning in basic science among undergraduate medical students, we established the National Medical Science Olympiad in Iran. In this Olympiad, the drawing of a concept map was used to evaluate a student's knowledge framework; students' ability in hypothesis generation and testing were also evaluated in four different steps. All medical students were invited to participate in this program. Finally, 133 undergraduate medical students with average grades ≥ 16/20 from 45 different medical schools in Iran were selected. The program took the form of four exams: drawing a concept map (Exam I), hypothesis generation (Exam II), choosing variables based on the hypothesis (Exam III), measuring scientific thought (Exam IV). The examinees were asked to complete all examination items in their own time without using textbooks, websites, or personal consultations. Data were presented as mean ± SE of each parameter. The correlation coefficient between students' scores in each exam with the total final score and average grade was calculated using the Spearman test. Results Out of a possible score of 200, the mean ± SE of each exam were as follows: 183.88 ± 5.590 for Exam I; 78.68 ± 9.168 for Exam II; 92.04 ± 2.503 for exam III; 106.13 ± 2.345 for Exam IV. The correlation of each exam score with the total final score was calculated, and there was a significant correlation between them (p < 0.001). The scatter plot of the data showed a linear correlation between the score for each exam and the total final score. This meant that students with a higher final score were able to perform better in each exam through having drawn up a meaningful concept map. The average grade was significantly correlated with the total final score (R = 0.770), (p < 0.001). There was also a significant correlation between each exam score and the average grade (p < 0.001). The highest correlation was observed between Exam I (R = 0.7708) and the average grade. This means students with higher average grades had better grades in each exam, especially in drawing the concept map. Conclusions We hope that this competition will encourage medical schools to integrate theory and practice, analyze data, and read research articles. Our findings relate to a selected population, and our data may not be applicable to all medical students. Therefore, further studies are required to validate our results.

The effects of ventilation and sucrose concentration on proliferation and organogenesis of pistachio cutting and photosynthetic performance of two in vitro cultures of pistachio rootstocks have been assessed. The apical leaf buds (Qazvini and UCB1 cultivars) were cultured in filter vessels containing Murashige and Skoog medium supplemented with 0, 10, 15, and 30 g L−1 of sucrose. The plants treated with 10, 15, and 30 g L−1 sucrose showed no significant differences regarding the measured traits; therefore, this treatment was set aside from the final statistical analyses. Use of different ventilation systems showed to be suitable for increasing the growth of pistachio. Referring to root production difficulties under in vitro cultivation of pistachio, ventilation increased the root production and length. However, the full ventilation system was more effective in improving the growth properties. Regression between fluorescence feature vs root length showed that Fv/Fm had a significant positive relationship with root length. Stomata of cell parameters under ventilation systems improved compared to no ventilation, which was highly similar to the trend in the greenhouse. The overall results indicated that low concentrations of sucrose (e.g., 10 g L−1 ) and full ventilation are recommended for producing high quality and vigorous pistachio plantlets under in vitro conditions. [ABSTRACT FROM AUTHOR]

Introduction: Fragmented QRS (fQRS) complex on routine 12‐lead electrocardiogram (ECG) predicts adverse outcomes in patients with cardiovascular diseases. In addition, it has been found to be associated with subclinical myocardial dysfunction in chronic diseases. We sought to investigate the relationship between the presence of fQRS with the myocardial functions in individuals free from known systemic cardiovascular diseases. Methods: In a case‐control study, we evaluated normal individuals from March 2017 to February 2018. All participants underwent a 2‐dimensional transthoracic echocardiographic examination using tissue Doppler imaging (TDI) and speckle‐tracking echocardiography. In addition, all participants were examined using a 12‐lead surface ECG, and patients with fQRS and a group of age‐ and sex‐matched controls without fQRS were enrolled in our study. Results: The patients' mean age was 40.3 ± 10.7 and 35.4 ± 11.2 years in fQRS‐positive and fQRS‐negative groups, respectively (P =.110). Patients with fQRS had significantly lower values of apical left ventricular global longitudinal strain (LV GLS) in 2‐chamber (16.9 ± 2.5 vs. 20.5 ± 3.3, P <.001), 4‐chamber (16.9 ± 3.4 vs. 20.1 ± 3, P =.001), LAX views (17.7 ± 2.8 vs. 20.8 ± 3.5, P =.001), and averaged LV GLS (17 ± 2.6 vs. 20.4 ± 2.7, P <.001) values compared to patients without fQRS. In a multivariate analysis, averaged LV GLS and smoking history were independent predictors for positive fQRS. Conclusion: The presence of fQRS on 12‐lead ECG in healthy population was associated with lower values of LV GLS compared to normal individuals without fQRS. [ABSTRACT FROM AUTHOR]