Economic evaluation of a randomised trial of early return to normal activities versus cardiac rehabilitation after acute myocardial infarction

Background: Although there have been a number of economic evaluations of cardiac rehabilitation after acute myocardial infarction (AMI), none has considered only low-risk patients or control groups with no rehabilitation at all. Methods: An economic evaluation was included in a randomised controlled trial of patients following uncomplicated AMI. Eligible patients were randomised to return to normal activities after 6 weeks of standard rehabilitation (REHAB, n = 70) or to early return to normal activities 2 weeks after AMI with no formal rehabilitation (ERNA, n = 72). Outcomes were assessed weekly for 6 weeks, then 3, 6 and 12 months post-AMI. Outcomes included four quality of life (QOL) measures (physical abilities, distress, usual/social activities, self-care) and four measures of return to normal activities (paid and unpaid return to any work and to pre-AMI level of work). Statistical analysis included repeated-measures regression (QOL outcomes) and survival analysis (work outcomes). Results: There were no statistically significant differences between the two groups in any of the outcomes measured or in the use of other health services. The net cost that could be saved by the health service by targeting rehabilitation to high-risk patients was approximately $300 (Australian, 1999) per low-risk patient. Conclusions: Early return to normal activities without formal rehabilitation is cost-effective for low-risk patients

Return to full normal activities including work at two weeks after acute myocardial infarction

Patients are generally advised to return to full normal activities, including work, 6 to 8 weeks after acute myocardial infarction (AMI). We assessed the outcomes of early return to normal activities, including work at 2 weeks, after AMI in patients who were stratified to be at a low risk for future cardiac events. Patients were considered for randomization before discharge if they had no angina, had left ventricular ejection fraction >40%, a negative result from a symptom-limited exercise stress test for ischemia (7 METs. Patients with left ventricular ejection fraction <40% were included only if they did not have inducible ventricular tachycardia at electrophysiologic studies. Seventy-two patients were randomized to return to normal activities at 2 weeks and 70 patients to undergo standard cardiac rehabilitation and return to normal activities at 6 weeks after AMI. There were no deaths or heart failure in either group. There was no significant difference in the incidence of reinfarction, revascularization, left ventricular function, lipids, body mass index, smoking, or exercise test results at 6 months. In conclusion, return to full normal activities, including work at 2 weeks, after AMI appears to be safe in patients who are stratified to a low-risk group. This should have significant medical and socioeconomic implications. © 2006 Elsevier Inc. All rights reserved

Late Potentials in a Porcine Model of Anterior Wall Myocardial Infarction and Their Relation to Inducible Ventricular Tachycardia

In this study, normal values for signal averaged electrocardiographic parameters were assessed in healthy pigs (n = 100) and the development of late potentials after myocardial infarction (n = 41) in relation to inducible ventricular tachycardia was investigated. Normal values are: filtered QRS duration (QRS) less-than-or-equal-to 70 msec; root mean square voltage of the averaged QRS complex (V(tot)) greater-than-or-equal-to 51 muV, and duration of terminal activity below 30 muV (D30) less-than-or-equal-to 37 msec. The distribution of the root mean square voltage in the last 30 msec (V30) Was biphasic. Two weeks after myocardial infarction, QRS was prolonged from 55 +/- 10 to 66 +/- 19 msec (P <0.002). D30 was prolonged from 19 +/- 6 msec to 28 +/- 13 (P <0.002). V30 was decreased from 107 +/- 135 muV to 45 +/- 77 (P <0.02). The total voltage (V(tot)) was decreased from 195 +/- 78 to 123 +/- 61 muV (P <0.002). In four pigs (19%) late potentials developed. Sustained ventricular tachycardia was inducible in 11 pigs (52%), ventricular fibrillation in two pigs (10%) and eight pigs (38%) were noninducible. Three of 11 inducible pigs and one of the noninducible pigs had a late potential. The incidence of late potentials and their relation to inducible sustained ventricular tachycardia is comparable to the situation in man. Therefore, this pig model is an attractive alternative to the commonly used dog models