Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

[EX Q]: Context: Cardiac resynchronization therapy (CRT) by simultaneous biventricular pacing is now widely accepted as a new therapeutic option for patients with severe congestive heart failure (CHF). Recent studies have shown comparable hemodynamic benefits of left ventricular (LV) pacing alone. The clinical usefulness of CRT, however, might be compromised by potential exaggeration of arrhythmogenic substrates through a modification of ventricular repolarization.', 'We compared ECG parameters during sinus rhythm (SR), atrioventricular synchronous pacing at the right ventricular apex (RV(end)P), at LV epicardium (LV(epi)P), and at both sites (BiVP) in acute homodynamic studies of 14 CHF patients scheduled for CRT (QRS duration = 144 +/- 23 msec, LVEF = 27 +/- 10%). The maximum rate of increase in LV pressure (LVdp/dt(max)) was decreased significantly during RV(end)P, whereas it was increased similarly during LV(epi)P and BiVP compared with SR. QTc was increased during RV(end)P (by 10.2%) and LV(epi)P (by 26.1%). QTc dispersion (QTc(max)-QTc(min) in the six precordial leads) was also increased during LV(epi)P (by 66.5%). These parameters were unaffected during BiVP. JTc was unchanged, and the interval from the peak to the end of the T wave (Tc(peak-end)) was increased slightly (by 19.3%) during RV(end)P. Both JTc and Tc(peak-end) were increased dramatically during LV(epi)P (by 18.2% and 55.4%, respectively), but increased only modestly during BiVP (by 6.6% and 15.8%, respectively).
Answer: LV(epi)P causes much greater increase in spatial dispersion of ventricular repolarization than BiVP in CHF patients. BiVP may have a substantial advantage over LV(epi)P to minimize the proarrhythmic perturbation of ventricular repolarization in association with CRT.
[EX A]: Does biventricular pacing have an advantage over left ventricular epicardial pacing alone to minimize proarrhythmic perturbation of repolarization?

[EX Q]: Context: To study the prevalence and age dependency of senile plaques (SP) and neurofibrillary tangles (NFT), the brain changes characteristic of Alzheimer disease (AD), and their association with apolipoprotein E (APOE) genotypes in a community-dwelling normal population.', 'This neuropathological study used both silver staining and A beta immunohistochemistry in brain tissue microarrays, including SP coverage and NFT counts from frontal cortex and hippocampus, and APOE genotyping, and was performed on a consecutive prospective series of 603 subjects (aged between 0 and 97 years) of an unselected population living outside of institutions. Cases were subjected to autopsy following sudden or unexpected out-of-hospital death, covering 22.1% of the mortality of Tampere, Finland and its surroundings. None died of AD, although 22 (3.7%) were demented and 10 (1.7%) had memory problems.', 'Of the series, 30.8% had SP, and 42.1% had NFT; these occurred more commonly among females and showed a strong relationship with age. Both changes had already appeared at around 30 years of age, reaching an occurrence of almost 100% in the oldest. SP were more frequent in APOE epsilon 4-carriers compared with noncarriers in every age group except the oldest (>90 years). The difference was most evident during the ages 50 to 59 years, where 40.7% of epsilon 4-carriers had SP, compared with 8.2% in noncarriers (odds ratio, 8.39; 95% confidence interval, 2.55-27.62). The difference in NFT prevalence between APOE genotypes was not statistically significant in any age group.
Answer: The brain changes associated with AD may already begin developing early in middle age, especially among APOE epsilon 4 carriers.
[EX A]: Does apolipoprotein E-dependent accumulation of Alzheimer disease-related lesions begin in middle age?

[EX Q]: Context: Programs seek to expose trainees to research during residency. However, little is known in any formal sense regarding how to do this effectively, or whether these efforts result in more or better-quality research output.', 'The objective of our study was to evaluate a dedicated resident research program in terms of the quantity and quality of resident research peer-reviewed publications. Specifically we asked: (1) Did residents mentored through a dedicated resident research program have more peer-reviewed publications in higher-impact journals with higher citation rates compared with residents who pursued research projects under a less structured approach? (2) Did this effect continue after graduation?', 'In 2006, our department of orthopaedic surgery established a dedicated resident research program, which consisted of a new research policy and a research committee to monitor quality and compliance with this policy. Peer-reviewed publications (determined from PubMed) of residents who graduated 6 years before establishing the dedicated resident research program were compared with publications from an equal period of the research-program-directed residents. The data were assessed using descriptive statistics and regression analysis. Twenty-four residents graduated from 2001 to 2006 (before implementation of the dedicated resident research program); 27 graduated from 2007 to 2012 (after implementation of the dedicated resident research program). There were 74 eligible publications as defined by the study inclusion and exclusion criteria.', "Residents who trained after implementation of the dedicated resident research program published more papers during residency than did residents who trained before the program was implemented (1.15 versus 0.79 publications per resident; 95% CI [0.05,0.93]; p = 0.047) and the journal impact factor was greater in the group that had the research program (1.25 versus 0.55 per resident; 95% CI [0.2,1.18]; p = 0.005). There were no differences between postresidency publications by trainees who graduated with versus without the research program in the number of publications, citations, and average journal impact factor per resident. A regression analysis showed no difference in citation rates of the residents' published papers before and since implementation of the research program.
Answer: Currently in the United States, there are no standard policies or requirements that dictate how research should be incorporated in orthopaedic surgery residency training programs. The results of our study suggest that implementation of a dedicated resident research program improves the quantity and to some extent quality of orthopaedic resident research publications, but this effect did not persist after graduation.
[EX A]:
Does a dedicated research program increase the quantity and quality of orthopaedic resident publications?