SUMMARY To test the hypothesis that patients at risk of future cardiac events can be identified by submaximal exercise testing with radionuclide ventriculography (RVG), 61 patients were studied a mean of 19 ± 1.0 days (± SEM) after acute myocardial infarction (MI). RVGs were used to measure left ventricular ejection fraction (LVEF), wall motion score (WMS), end-diastolic volume (EDV) and end-systolic volume (ESV), and the ratio of systolic blood pressure to ESV (P/V index) at rest and during submaximal exercise. Frank lead ECGs were analyzed for ST-segment change and arrhythmias. These patients were followed for a mean of 9.6 months (60 for 6 months or more and one for 3 months) to determine the incidence of cardiac death, recurrent MI, unstable or medically refractory angina, persistent congestive heart failure (CHF) or limiting angina; these problems were considered to be important cardiac events. At the 6-month follow-up, 37 patients had important complications: four patients died, five had MI, seven had unstable or medically refractory angina, 11 had persistent CHF and 10 had severe limiting angina.The sensitivity and specificity of RVG in predicting the important postinfarct complications listed above were 95% and 96% for failure to increase LVEF by at least 5 units, 95% and 96% for an increase in ESV of more than 5%, 97% and 88% for failure of the P/V Index to increase by more than 35%, and 81% and 88%, respectively, for a decrease in WMS. The sensitivity and specificity of the ECG in predicting important complications were 54% and 58%, respectively.The rest and submaximal exercise RVG variables, the ECG, a history of MI, the location of the infarction, Killip class III, age, sex, and maximal work load performed were analyzed statistically to determine the best predictors of prognosis. The change with exercise in LVEF, ESV and the P/V index were the most significant variables in predicting prognosis during the 6-month follow-up period. When patients with subsequent cardiac events were separated into those with death, recurrent MI and unstable or medically refractory angina as major cardiac events, and patients with persistent CHF and limiting angina as less important ("minor") cardiac events, only the peak submaximal exercise LVEF and history of MI were significant in distinguishing these groups. In patients without important cardiac events during the 3-and 6-month follow-up, 70% and 88%, respectively, had no abnormality in the responses of LVEF, ESV, or P/V index to submaximal exercise. These results suggest that submaximal exercise testing with RVG is a highly sensitive means of classifying patients at the time of hospital discharge after MI according to the likelihood of having cardiac events during the ensuing 6 months. THE PROGNOSIS of patients after myocardial infarction (MI) has been studied extensively. Several clinical criteria and diagnostic procedures have been used to identify patients at risk for subsequent complications;'4 however, the sensitivity and specificity of these tests vary widely.7 ...

The purpose of this study was to test the hypothesis that downslope treadmill walking decreases spinal excitability. Soleus H-reflexes were measured in sixteen adults on 3 days. Measurements were taken before and twice after 20 min of treadmill walking at 2.5 mph (starting at 10 and 45 min post). Participants walked on a different slope each day [level (Lv), upslope (Us) or downslope (Ds)]. The tibial nerve was electrically stimulated with a range of intensities to construct the M-response and H-reflex curves. Maximum evoked responses (Hmax and Mmax) and slopes of the ascending limbs (Hslp and Mslp) of the curves were evaluated. Rate-dependent depression (RDD) was measured as the % depression of the H-reflex when measured at a rate of 1.0 Hz versus 0.1 Hz. Heart rate (HR), blood pressure (BP), and ratings of perceived exertion (RPE) were measured during walking. Ds and Lv walking reduced the Hmax/Mmax ratio (P = 0.001 & P = 0.02), although the reduction was larger for Ds walking (29.3 ± 6.2% vs. 6.8 ± 5.2%, P = 0.02). The reduction associated with Ds walking was correlated with physical activity level as measured via questionnaire (r = −0.52, P = 0.04). Us walking caused an increase in the Hslp/Mslp ratio (P = 0.03) and a decrease in RDD (P = 0.04). These changes recovered by 45 min. Exercise HR and BP were highest during Us walking. RPE was greater during Ds and Us walking compared to Lv walking, but did not exceed “Fairly light” for Ds walking. In conclusion, in healthy adults treadmill walking has a short-term effect on soleus H-reflex excitability that is determined by the slope of the treadmill surface.

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Objectives We developed a Pediatric Transport Triage Tool (PT3) to objectively guide selection of team composition and transport mode, thereby standardizing transport planning. Previously, modified Pediatric Early Warning Score for transport has been used to assess illness severity but not to guide transport decision making. Methods The PT3 was created for pediatric transport by combining objective evaluations of neurologic, cardiovascular, and respiratory systems with a systems-based medical condition list to identify diagnoses requiring expedited transport and/or advanced team composition not captured by neurologic, cardiovascular, and respiratory systems alone. A scoring algorithm was developed to guide transport planning. Transport data (mode, team composition, time to dispatch, patient disposition, and complications) were collected before and after PT3 implementation at a single tertiary care center over an 18-month period. Results We reviewed 2237 inbound pediatric transports. Transport mode, patient disposition, and dispatch time were unchanged over the study period. Fewer calls using a transport nurse were noted after PT3 implementation (33.9% vs 30%, P = 0.05), with a trend toward fewer rotor-wing transports and transports requiring physicians. The majority of users, regardless of experience level, reported improved transport standardization with the tool. Need to upgrade team composition or mode during transport was not different during the study period. No adverse patient safety events occurred with PT3 use. Conclusions The PT3 represents an objective triage tool to reduce variability in transport planning. The PT3 decreased resource utilization and was not associated with adverse outcomes. Teams with dynamic staffing models, various experience levels, and multiple transport modes may benefit from this standardized assessment tool.