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 Input:
Context: The etiology of reduced left ventricular (LV) ejection fraction after exercise, without obstructive coronary artery disease or other established causes, is unclear. The aims of this study were to determine whether patients undergoing treadmill stress echocardiography with this abnormal LV contractile response to exercise (LVCRE) without established causes have resting LV long-axis dysfunction or microvascular dysfunction and to determine associations with this abnormal LVCRE.', 'Of 5,275 consecutive patients undergoing treadmill stress echocardiography, 1,134 underwent cardiac computed tomography angiography or invasive angiography. Having excluded patients with obstructive coronary artery disease, hypertensive response, submaximal heart rate response, resting LV ejection fraction < 50%, and valvular disease, 110 with "abnormal LVCRE" and 212 with "normal LVCRE" were analyzed. Resting mitral annular velocities were measured to assess LV long-axis function. Myocardial blush grade and corrected Thrombolysis In Myocardial Infarction frame count were determined angiographically to assess microvascular function.', "Comparing normal LVCRE with abnormal LVCRE, age (mean, 59.7 ± 11.1 vs 61.4 ± 10.0 years), hypertension (53% vs 55%), diabetes (16% vs 20%), and body mass index (mean, 29.1 ± 5.4 vs 29.5 ± 6.4 kg/m(2)) were similar (P > .05). Abnormal LVCRE had reduced resting LV long-axis function with lower septal (mean, 6.1 ± 1.9 vs 7.7 ± 2.2 cm/sec) and lateral (mean, 8.1 ± 2.9 vs 10.4 ± 3.0 cm/sec) e' velocities (P < .001) and larger resting left atrial volumes (mean, 37.3 ± 10.1 vs 31.1 ± 7.2 mL/m(2), P < .001). On multivariate analysis, female gender (odds ratio [OR], 1.21; 95% confidence interval [CI], 1.15-1.99; P < .001), exaggerated chronotropic response (OR, 1.49; 95% CI, 1.09-2.05; P < .001), resting left atrial volume (OR, 2.38; 95% CI, 1.63-3.47; P < .001), and resting lateral e' velocity (OR, 1.70; 95% CI, 1.22-2.49; P = .003) were associated with abnormal LVCRE, but not myocardial blush grade or corrected Thrombolysis In Myocardial Infarction frame count.
Answer: An abnormal LVCRE in the absence of established causes is associated with resting LV long-axis dysfunction and is usually seen in women.

Ex Output:
Is abnormal left ventricular contractile response to exercise in the absence of obstructive coronary artery disease associated with resting left ventricular long-axis dysfunction?


Ex Input:
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 Output:
Does biventricular pacing have an advantage over left ventricular epicardial pacing alone to minimize proarrhythmic perturbation of repolarization?


Ex Input:
Context: The optimal type of mesh for complex abdominal wall reconstruction has not been elucidated. We hypothesized that AWRs using acellular dermal matrix (ADM) experience low rates of surgical site occurrence (SSO) and surgical site infection, despite increasing degrees of wound contamination.', 'We retrospectively reviewed prospectively collected data from consecutive abdominal wall reconstructions with ADM over a 9-year period. Outcomes of abdominal wall reconstructions were compared between patients with different CDC wound classifications. Univariate and multivariate logistic regression and Cox proportional hazard regression analyses identified potential associations and predictive/protective factors.', 'The 359 patients had a mean follow-up of 28.3 ± 19.0 months. Reconstruction of clean wounds (n\xa0= 171) required fewer reoperations than that of combined contaminated (n\xa0=\xa0188) wounds (2.3% vs 11.2%; p\xa0= 0.001) and trended toward experiencing fewer SSOs (19.9% vs 28.7%, p\xa0= 0.052). There were no significant differences between clean and combined contaminated cases in 30-day SSI (8.8% vs 8.0%), hernia recurrence (9.9% vs 10.1%), and mesh removal (1.2% vs 1.1%) rates. Independent predictors of SSO included body mass index ≥30 kg/m(2) (odds ratio [OR] 3.6; p < 0.001), 1 or more comorbidities (OR 2.5; p\xa0= 0.008), and defect width ≥15 cm (OR 1.8; p\xa0= 0.02).
Answer: Complex abdominal wall reconstructions using ADM demonstrated similar rates of complications between the different CDC wound classifications. This is in contradistinction to published outcomes for abdominal wall reconstruction using synthetic mesh that show progressively higher complication rates with increasing degrees of contamination. These data support the use of ADM rather than synthetic mesh for complex abdominal wall reconstruction in the setting of wound contamination.

Ex Output:

Are outcomes of abdominal wall reconstruction with acellular dermal matrix affected by wound contamination?