Given a passage, 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.

Example Input: Apelin has been shown ex vivo to be a potent cardiac inotrope. This study was undertaken to evaluate the in vivo effects of apelin on cardiac function in native and ischemic cardiomyopathic rat hearts using a novel combination of a perivascular flow probe and a conductance catheter.', 'Native rats (n =32) and rats in heart failure 6 weeks after left anterior descending coronary artery ligation (n =22) underwent median sternotomy with placement of a perivascular flow probe around the ascending aorta and a pressure volume conductance catheter into the left ventricle. Compared with sham-operated rats, the ligated rats had significantly decreased baseline Pmax and max dP/dt. Continuous infusion of apelin at a rate of 0.01 microg/min for 20 minutes significantly increased Pmax and max dP/dt compared with infusion of vehicle alone in both native and failing hearts. Apelin infusion increased cardiac contractility, indicated by a significant increase in stroke volume (SV) without a change in left ventricular end diastolic volume (102+/-16% change from initial SV versus 26+/-20% for native animals, and 110+/-30% versus 26+/-11% for ligated animals), as well as an increase in preload recruitable stroke work (180+/-24 mm Hg versus 107+/-9 mm Hg for native animals).
Example Output: Does apelin have in vivo inotropic effects on normal and failing hearts?

Example Input: The stress electrocardiogram (sECG) is routinely used to screen individuals for underlying cardiac pathology before an exercise programme is prescribed. The underlying assumption is that the cardiac responses elicited during the sECG test are similar to those achieved during participation in sporting activities. However, this premise may be incorrect since the physical demands of different modes of exercise vary substantially.', "Ten veteran league squash players (LSP), 10 social squash players (SSP), 10 league runners (LR), 10 social runners (SR) and 10 sedentary individuals (SED) were recruited for the study. All subjects completed a lifestyle questionnaire, a full medical examination and a routine sECG. Thereafter each subject's heart rate (HR) was monitored on two separate occasions while participating in sporting activity.", 'No sECG exercise-induced abnormalities were observed, although five subjects showed resting abnormalities. Maximal HR during the sECG, and maximal and mean HR during the field tests, were not significantly different between groups. However, maximal HR was significantly higher in all groups during their sporting activities than during stress testing in the laboratory (P < 0.01).
Example Output: Do veteran athletes exercise at higher maximum heart rates than are achieved during standard exercise ( stress ) testing?

Example Input: The conventional 12-lead electrocardiogram (cECG) derived from 10 electrodes using a cardiograph is the gold standard for diagnosing myocardial ischemia. This study tested the hypothesis that a new 5-electrode 12-lead vector-based ECG (EASI; Philips Medical Systems, formerly Hewlett Packard Co, Boeblingen, Germany) patient monitoring system is equivalent to cECG in diagnosing acute coronary syndromes (ACSs).', 'Electrocardiograms (EASI and cECG) were obtained in 203 patients with chest pain on admission and 4 to 8 hours later. Both types of ECGs were graded as ST-elevation myocardial infarction if at least 1 of the 2 consecutive recordings showed ST elevation more than 0.2 mV, as ACS if one or both showed ST elevation less than 0.2 mV, T-wave inversion, or ST depression. Otherwise, the ECG was graded negative.', 'Final diagnosis was identical in 177 patients (87%; 95% confidence interval [CI], 82%-91%; kappa = 0.81; SE = 0.035). ST-elevation myocardial infarction was correctly identified or excluded by EASI with a specificity of 94% (95% CI, 89%-97%) and a sensitivity of 93% (95% CI, 86%-97%; using cECG as the gold standard). Of 118 patients with enzyme elevations, an almost identical number (72 [61% by EASI] and 73 [62% by cECG]) had ST elevations. Both techniques were equivalent in predicting subsequent enzyme elevation (identical, 108/143; 75% of ACS and ST-elevation myocardial infarction ECGs by EASI and cECG). Thus, both ECG methods had exactly the same specificity of 59% (95% CI, 48%-69%) and sensitivity of 91% (95% CI, 85%-96%) for detecting myocardial injury.
Example Output:
Is a vector-based , 5-electrode , 12-lead monitoring ECG ( EASI ) equivalent to conventional 12-lead ECG for diagnosis of acute coronary syndromes?