In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

Q: Context: T-wave alternans (TWA) is an indicator of vulnerability to ventricular arrhythmias and is useful for predicting sudden cardiac death (SCD) in patients with various structural heart diseases. We evaluated whether high levels of time-domain TWA on ambulatory ECG (AECG) are associated with a history of ventricular fibrillation (VF) in Brugada syndrome (BrS) patients.', 'We examined the associations among VF history, family history of SCD, spontaneous type 1 electrocardiogram (ECG), late potentials, VF induction by programmed electrical stimulation, and TWA in 45 BrS patients (44 males; mean age, 45 15 years). TWA analyzed from 24-h AECG recordings using the modified moving average method was positive in 13 of 43 patients (30%). Patients with a history of VF had a significantly higher incidence of a positive TWA test (82% vs. 13%; P < 0.001) and spontaneous type 1 ECG (92% vs. 38%; P = 0.007) than those without VF history. Multivariate analysis indicated that positive TWA (OR 7.217; 95% CI 2.503-35.504; P = 0.002) and spontaneous type 1 ECG (OR 5.530; 95% CI 1.651-34.337; P = 0.020) were closely associated with VF history. Spontaneous type 1 ECG had high sensitivity (92%) but low specificity (63%). Positive TWA was a reliable marker with high sensitivity and specificity (82% and 88%, respectively).\Question: Is time-domain T-wave alternans strongly associated with a history of ventricular fibrillation in patients with Brugada syndrome?

A: Elevated time-domain TWA on AECG confirms arrhythmia risk in symptomatic BrS patients without the need for provocative stimuli.
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Q: Context: Studies over many years have demonstrated that preoptimization and attention to appropriate perioperative care is associated with a substantial decrease in surgical mortality. This review discusses ways in which patient preparation and perioperative support can minimize surgical mortality and morbidity.', 'Scoring systems continue to be developed in order to classify categories of surgical risk. Objective physiologically based assessments can also identify high-risk groups of patients. Debate continues over the indications for specific interventions such as beta-blockade or statin therapy. There is continuing interest in perioperative optimization of oxygen delivery. A multimodality approach paying attention to a range of possible interventions appears to be beneficial. Audit, training, experience and a sufficient volume of procedures are all factors associated with surgical mortality.\Question: Does excellent anaesthesia need patient preparation and postoperative support to influence outcome?

A: The provision of a high-quality service throughout the perioperative period is vital for a successful outcome. Patients need to be assessed well before major elective surgery to determine if they fall into a high-risk category. Some patients may benefit from a change in management. Postoperatively, critical-care support should be available backed by level 1 (enhanced ward) care with input from outreach or medical emergency teams 24 hours per day, seven days a week.
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Q: Context: The purpose of this study was to examine the osteotomy gap filling rate with new bone after open wedge high tibial osteotomy (HTO) without bone graft and the effects of smoking, lateral hinge fracture, and early full weight bearing.', 'A prospective series (N= 70) of open wedge HTOs with the TomoFix plate (DePuy Synthes, Umkirch, Germany) was performed. Radiologic follow-up examinations took place postoperatively, after 6 and 12 weeks, and after 6, 12, and 18 months to measure osteotomy gap filling at each follow-up. Bone healing was compared in smokers versus nonsmokers who underwent open wedge HTOs with intact lateral hinges. Fractured lateral hinges were classified according to the Takeuchi classification and separately analyzed regarding bone healing. Patients were randomly assigned to undergo early (11 days) or standard (6 weeks) full-weight-bearing rehabilitation.', 'A delay in the osteotomy gap filling rate between smokers and nonsmokers could be observed at all follow-up periods, but differences were not significant. A fracture of the lateral hinge was found in 39% of the patients. A type I fracture was observed in 14% of patients, a type II fracture was observed in 13%, and a type III fracture was found in 6%. The highest increase in the osteotomy gap filling rate was observed between 12 weeks and 6 months after surgery in patients with intact lateral hinges. For patients with unstable type II fractures, the highest increase in the gap filling rate was delayed until 6 to 12 months. Early full weight bearing had no effect on the gap filling rate in any of the patient groups evaluated.\Question: Do smoking and unstable hinge fractures cause delayed gap filling irrespective of early weight bearing after open wedge osteotomy?

A:
This study shows that osteotomy gap filling after open wedge HTO is delayed in smokers and in patients in whom opening of the gap resulted in unstable lateral hinge fractures. Early full weight bearing did not have a significant effect on the gap filling rate.
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