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.

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?
Elevated time-domain TWA on AECG confirms arrhythmia risk in symptomatic BrS patients without the need for provocative stimuli.

Context: The aim of this study was to evaluate the effect of local injection of vasopressin on blood loss and secondary impact on complications during cesarean section in patients with placenta previa.', 'We retrospectively reviewed the medical records of all patients diagnosed with placenta previa admitted to our hospital. Two consecutive periods were compared. During period B, 59 patients underwent the local injection of a vasopressin solution (4 U in 20 mL of saline) into the placental implantation site after placental delivery. During period A, 50 patients underwent cesarean section without vasopressin injection, and were analyzed as a control group. The estimated blood loss was recorded, as were the complications during surgery. In addition, the expression of the vasopressin V1 receptor in uterine smooth muscle was evaluated by immunohistochemistry.', 'The mean estimated blood loss was significantly lower in the vasopressin group than in the control group. There were no statistically significant differences with surgical complications. The vasopressin V1 receptor was highly expressed in smooth muscle cells in the lower segment of the uterine body, whereas the immunoreactivity for the oxytocin receptor was faint in the lower segment.\Question: Does local injection of vasopressin reduce the blood loss during cesarean section in placenta previa?
The local injection of vasopressin into the placental implantation site significantly reduced the blood loss without increasing the morbidity.

Context: The influence of different types of exercise on risk factors for cardiovascular diseases has rarely been investigated. The aim of the present work was to evaluate the effect of adding resistance exercise to aerobic activities on lipid-lipoprotein profile, in a representative sample of men and women from the province of Attica, Greece.', 'We randomly enrolled 1514 and 1528 healthy men and women, respectively, stratified by city, age and gender distribution. Participants were classified as inactive (INA), sufficiently active (SA) and highly active for either aerobic activities (HAA) alone or a combination of aerobic plus resistance exercise (HAC). The main outcome measures are lipid-lipoprotein profile [total, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, apolipoprotein-A1, apolipoprotein-B] and anthropometric indices.', 'From those participating in aerobic activities, 480 (31.7%) men and 502 (32.9%) women were classified as SA, 100 men (6.6%) and 93 women (6.1%) as HAA and 90 men (5.9%) and 49 women (3.2%) as HAC. After various adjustments were made, men from the HAC group had an average of 23% lower plasma triacylglycerol concentration (P = 0.04) and 10% lower LDL-cholesterol (P = 0.01) when compared with the HAA group. Moreover, women from the HAC group had 13% lower LDL-cholesterol when compared with HAA group (P = 0.051).\Question: Is resistance exercise plus to aerobic activities associated with better lipids ' profile among healthy individuals : the ATTICA study?
These data suggest that combining aerobic and resistance-type activities may confer a better effect on lipoprotein profile in healthy individuals than aerobic activities alone.