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: β1-Adrenergic receptor (β1-AR) stimulation modulates the antiarrhythmic activities of sodium channel blockers. The β1-AR Gly389 variant shows a marked decrease in agonist-stimulated cyclic AMP production compared with that of the wild-type Arg389 in vitro. We investigated whether the Arg389Gly polymorphism affects the efficacy of flecainide, a typical sodium channel blocker, in patients with or without coadministration of β-blockers.', 'The effects of the β1-AR Arg389Gly polymorphism on the antiarrhythmic efficacy of flecainide were compared between with and without coadministered β-blockers in 159 patients with supraventricular tachyarrhythmia. The antiarrhythmic efficacy of flecainide was assessed for at least 2 months by evaluating symptomatology, 12-lead ECGs, and Holter monitoring results.', 'Genetic differences in the antiarrhythmic efficacy of flecainide were observed in patients with coadministration of β-blockers. Tachyarrhythmia was well controlled in 60% of Arg389-homozygotes, 30% of Gly389-heterozygotes, and 0% of Gly389-homozygotes (P=0.001). In contrast, no difference in the antiarrhythmic efficacy was observed among the three genotypes in the patients without coadministration of β-blockers (64, 70, and 60%, respectively). Heart rate in tachyarrhythmia in patients treated with flecainide was significantly higher in Gly389 carriers than in Arg389-homozygotes (P=0.013).
Answer: The Gly389 polymorphism decreased the antiarrhythmic efficacy of flecainide when coadministered with β-blockers. The results indicate that the Arg389Gly polymorphism may play an important role in predicting the efficacy of flecainide in patients with coadministration of β-blockers.
[EX A]: Does β1-Adrenergic receptor Arg389Gly polymorphism affect the antiarrhythmic efficacy of flecainide in patients with coadministration of β-blockers?

[EX Q]: Context: The aim of the present study was to evaluate baseline regional cerebral oxygen saturation (rSO2) values and identify factors influencing preoperative rSO2 in elective minor surgery.', 'Observational analysis post-hoc.', 'Observational post-hoc analysis of data for the patient sample (n=50) of a previously conducted clinical trial in patients undergoing tumourectomy for breast cancer or inguinal hernia repair. Exclusion criteria included pre-existing cerebrovascular diseases, anaemia, baseline pulse oximetry <97% and low quality rSO2 sensor signals. Demographic data, comorbidities, and ASA physical status as well as height and weight were collected prospectively from all patients. Baseline rSO2 values were recorded while the patient breathed room air, using the INVOS 5100C monitor™ (Covidien, Dublin, Ireland).', 'Thirty-seven women (72%) and 13 men (28%) 48 ± 13 years of age were enrolled in this study. Baseline rSO2 was 62.01 ± 10.38%. Baseline rSO2 was significantly different between men (67.6 ± 11.2%) and women (60 ± 9.4%), (P=0.023). There were also differences between baseline rSO2 and ASA physical status (ASA I: 67.6 ± 10.7%, ASA II: 61.6 ± 8.4%, ASA III: 55.8 ± 13.9%, P=0.045). Baseline rSO2 had a positive correlation with body weight (r=0.347, P=0.014) and height (r=0.345, P=0.014). We also found significant differences in baseline rSO2 among patients with and without chronic renal failure (P=0.005). No differences were found in any other studied variables.
Answer: Non-modifiable patient characteristics (ASA physical status, sex, chronic renal failure, body weight and height) influence baseline rSO2.
[EX A]: Do baseline cerebral oximetry values depend on non-modifiable patient characteristics?

[EX Q]: Context: Large-artery stiffness and arterial wave reflections have been identified as independent markers and prognosticators of cardiovascular risk. Mental stress is a novel risk factor for coronary artery disease and has been associated with left ventricular dysfunction, myocardial ischemia and infarction, and sudden cardiac death. The purpose of this study was to assess the effect of acute mental stress on aortic stiffness and wave reflections.', 'The effect of a mental arithmetic test was assessed in 19 healthy individuals using a randomized, sham-procedure-controlled, crossover design. Carotid-femoral pulse wave velocity and augmentation index were measured as indices of aortic stiffness and wave reflections, respectively.', 'Mental stress induced a sustained increase in central systolic and pulse pressure throughout the whole study (systolic: by 7.5 mm Hg, p < .05; pulse: by 5.7 mm Hg, p < .01). The increase in peripheral systolic and pulse pressure was not significant throughout the study, but only when their peak values were compared with baseline (systolic: by 6.2 mm Hg, peak at 0 minutes; pulse: by 6.6 mm Hg, peak at 5 minutes, p < .05 for both). There was a sustained increase in pulse wave velocity (by 0.57 m/s, p < .005) throughout the study denoting a sustained increase in aortic stiffness. Similarly, augmentation index showed a sustained increase with mental stress (by 6.16%, p < .05) denoting increased wave reflections from the periphery.
Answer: Acute mental stress results in a prolonged increase in aortic stiffness and wave reflections. Given the important pathophysiologic and prognostic role of these parameters, our results provide important mechanistic links between acute mental stress and increased cardiovascular risk.
[EX A]:
Does acute mental stress have a prolonged unfavorable effect on arterial stiffness and wave reflections?