Hemodynamic and Functional Effects of 6-Week Cardio-Rehabilitation after Acute Miocardial Infarction, Identification of a NWE Functional Index: Meter/Heart Rate Rario

Introduction: The cardio-rehabilitation after acute myocardial infarction (AMI) is able to determine prognostic, hemodynamic and functional heart improvement. The 6-minute-walking-test Distance (6MWTD) is well known as prognostic and functional markers after AMI. Aim: To evaluate a new parameter (6MWTD/Heart Rate-HR) at the beginning (t0) of the cardio-rehabilitation could better predictthe final exercise capacity in patients with a recent AMI. Methods: We studied 34 patients (age 61 ± 10 years; 30 male) with the 6MWT at t0 and at the end of the rehabilitation program (after 20–25 session, t1) together with an ergometric test. Results: At t0 the Blood Pressure (BP) was 124/77 ± 15/ 6 mmHg, HR 63 ± 11 bpm and Ejection Fraction (EF) 55 ± 7 %. At the 6MWT the walked distance was 455 ± 100 m, with a max HR of 95 ± 13 (60 ± 9 % of the theoretical max HR). The 6MWTD/HR ratio was 4.8 ± 1. At the end of the rehabilitation program systolic BP was significantly reduced (112 ± 9 mmHg) and the walked distance increased (583 ± 106 m, 110 ± 21 % of the theoretical max HR). 6MWTD/HR at t0 significantly correlates with walked distance and the theoretical max HR at t1 (r = 0.67, p\0.001 and r = 0.53, p 0.001, respectively) and with the reached watt at the ergometric test (r = 0.57, \0.001). Nor the echocardiographic parameter or the HR and the BP correlate at t0 or at t1 with 6MWTD/HR ratio. Conclusions: The 6MWTD/HR ratio at t0 is a new index that correlates with the functional capacity at the end of the rehabilitation. It could be useful to set the program itself and as a predictor of functional outcome.