Attenuated responses of Doppler-derived hemodynamic parameters during supine bicycle exercise in heart transplant recipients

The aim of this study was to characterize Doppler-derived hemodynamic param eters in heart transplant recipients at rest and during symptom-limited sup ine bicycle exercise. Eighteen sedentary patients aged 54.0 +/- 2 years, 1. 6 +/- 1.0 years following cardiac transplantation, and 18 sedentary healthy volunteers aged 51.8 +/- 4 years were investigated. Basic hemodynamic para meters and Doppler-derived parameters were recorded at rest and at peak dyn amic exercise. Resting heart rate, blood pressure and rate-pressure product were higher in the transplanted patients (p < 0.001). However, in comparis on with the resting state, the increase in these parameters at exercise was lower in heart transplant recipients. In the healthy, dynamic exercise ind uced an increase in peak flow velocity, mean acceleration, flow velocity in tegral, stroke volume, cardiac output and cardiac index (p < 0.001 for all) while systemic Vascular resistance, ejection time and acceleration time de creased (p < 0.001 for all). The following parameters increased in the tran splanted patients at dynamic exercise: peak flow velocity, cardiac output a nd ca rd iac index (p < 0.001), mean acceleration (p < 0.01) and flow veloc ity integral (p < 0.05). Ejection time decreased (p < 0.05) and acceleratio n time and systemic vascular resistance remained unchanged. In conclusion, at rest peak flow velocity, mean acceleration, flow velocity integral and s troke volume are lower in the transplanted than in the healthy controls, wh ile cardiac output, cardiac index and systemic vascular resistance are equa l. Our study demonstrates attenuated responses of basic hemodynamic paramet ers and Doppler-derived cardiovascular indices at symptom-limited supine bi cycle exercise in heart transplant recipients compared to healthy volunteer s. Copyright (C) 2000 S. Karger AG, Basel.