Applying Cardiopulmonary Exercise Testing to the Evaluation of Left Ventricular Function for Patients Ventricular Assist Device Therapy

Abstract

HISTORY: Patient with severe heart failure and presence of a left ventricular assist device (LVAD). PHYSICAL EXAMINATION: A patient with severe heart failure and LVAD (29 y, male, BMI 26 kg/m2, INR > 2.0) was examined on two separate occasions two weeks apart with CPX on a cycle ergometer (continuous ramp, 20 Watts per minute). DIFFERENTIAL DIAGNOSIS: n/a TEST AND RESULTS: The first CPX was performed with the LVAD on at its prescribed speed. The second test was performed at the lowest LVAD speed setting, at which point the LVAD was effectively not supportive. Both tests were performed to volitional exhaustion.The LVAD speeds for the first and second tests were 2400 rpm and 1800 rpm. Peak respiratory exchange ratios were 1.20 and 1.16, respectively. For the CPX with LVAD support, VO2peak was 24.4 ml/kg/min and peak workload was 167 Watts For the CPX without LVAD support VO2peak was 27.7 ml/kg/min and peak load was 190 Watts. FINAL WORKING DIAGNOSIS: Patient seems to have recovered a substantial amount of functionality, so that the LVAD may be unnecessary. Furthermore, the LVAD may be a hindrance to exercise performance and therefore adequate ventricular recovery. TREATMENT AND OUTCOMES: Patient is being considered for reevaluation for need of LVAD. Focus is on further recovery and improvement of quality of life.