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: Pulmonary vein (PV) isolation is a curative treatment for patients with atrial fibrillation. The aim of this study was to evaluate prospectively the effects of adenosine administration on the PV activity and atrio-venous conduction after PV isolation.', 'Twenty-nine patients (21 m; age: 55+/-8 years) were submitted to ostial PV isolation guided by basket catheter recordings. After successful isolation, the effects of a 12 mg intravenous bolus of adenosine were tested in 62 PVs. In 22/62 PVs (35%), left atrium (LA)-to-PV conduction was transiently (16.6+/-7.1 s, range: 3.8-27.9 s) or permanently (3 PVs) restored in response to adenosine administration. The prevalence of this phenomenon was 39% in left superior PVs, 43% in right superior PVs, and 22% in left inferior PVs (p=0.365). It occurred more frequently in the presence of dissociated PV activity (11/15 PVs, 73% vs. 11/47 PVs, 23%; p=0.002), whereas it was not influenced by the median duration of the radiofrequency current (RFC) delivery for each PV [19 (IQR: 12-26) min vs. 16 (IQR: 11-24) min: p=0.636]. A lengthening or shortening of the LA-PV conduction time was observed at LA-PV conduction appearance and disappearance in 36% and 55% of the cases, respectively. Further RFC applications (median: 5.5 min, IQR: 4-11 min) at the residual conduction breakthrough(s) indicated by the basket catheter recordings definitively eliminated adenosine-induced recovery of LA-PV conduction in all cases. Finally, when present, intrinsic PV discharge was invariably depressed by adenosine administration.
Answer: Adenosine may transiently or permanently re-establish LA-PV conduction after apparently successful PV isolation. This phenomenon is abolished by additional RFC delivery. However, its possible influence on the clinical results of PV ablation must be evaluated by properly designed, randomized studies.
[EX A]: Does adenosine restore atrio-venous conduction after apparently successful ostial isolation of the pulmonary veins?

[EX Q]: Context: It is recommended that dentists screen for dental anxiety (DA) so that fearful patients may be better managed. The main aim of this study was to determine what dentists are being taught in relation to DA as well as whether and how anxious patients are identified in the clinic.', 'Two hundred and forty-six practising dentists (adjusted response rate = 40.1%), from a random sample of registered Australian dentists, completed a mailed questionnaire.', "Dentists estimated that high DA affected 23.3% of children and 19.4% of adults seen. Only 3.7% of dentists reported using a published scale for screening DA, with the most common reason being lack of awareness (56.5%). Approximately one-half of responding dentists directly asked their patients about DA and this was more common among younger dentists (χ(2) = 7.75, p = 0.021). There were few differences in DA screening by other practitioner or practice characteristics (p > 0.05). Only one-third of dentists had received undergraduate training related to DA and only 41.7% considered this to be 'good' or better. Almost 37% of respondents expressed an interest in future training opportunities.
Answer: The use of formal, validated scales for screening DA is minimal. Training in anxiety management appears to be low and is an area that could be expanded upon.
[EX A]: Does dental anxiety screening practices and self-reported training need among Australian dentists?

[EX Q]: Context: The goals of the current study were to examine the incidence and severity of toxicity resulting from dexamethasone and prednisone during induction therapy for children with precursor B-cell acute lymphoblastic leukemia (ALL) and to determine whether the addition of daunomycin affected toxicity.', 'Medical records of patients with precursor B-cell ALL from January 1996 through June 2000 were reviewed retrospectively for toxicity during the 4-week induction phase and the 2 weeks after the induction phase.', 'One hundred seventy-six patients age < 14 years were diagnosed with precursor B-cell ALL from January 1996 through June 2000. Of the 156 evaluable patients, 106 were treated with prednisone and 50 with dexamethasone. Fifty-two patients received steroids, L-asparaginase, and vincristine, whereas 104 high-risk patients received daunomycin in addition to these 3 agents. The incidence of gastritis was significantly higher among patients receiving dexamethasone (P = 0.01); incidence rates of hyperglycemia, hypertension, and myopathy were similar for all treatment groups. Dexamethasone led to more weight gain than did prednisone (+11.9% vs. +5.4%; P = 0.002). Serious infections were observed in 27 (25.5%) and 18 (36%) patients receiving prednisone and dexamethasone, respectively (P < or = 0.2). Five patients, four of whom received prednisone and one of whom received dexamethasone, died of infection. The addition of daunomycin to treatment regimens increased overall toxicity (P < 0.01). When daunomycin was included in treatment regimens, toxicity was greater among patients receiving dexamethasone; in contrast, when daunomycin was not included, toxicity was equal for both treatment groups. Regardless of daunomycin use, there was no difference in the incidence of serious infection between the two groups. ALL treatment was not compromised by steroid-related toxicity in either group.
Answer: The addition of daunomycin led to a much larger increase in dexamethasone-related toxicity compared with the increase in prednisone-related toxicity. Although the use of daunomycin enhanced dexamethasone-related toxicity, this enhancement did not result in a higher mortality rate or the alteration of planned ALL therapy.
[EX A]:
Is dexamethasone-associated toxicity during induction chemotherapy for childhood acute lymphoblastic leukemia augmented by concurrent use of daunomycin?