Predictive Value of Left Ventricular Response to Exercise in Patients with Dilated Cardiomyopathy - Assessment by Radionuclide Ventriculography

The objective of this study was to determine noninvasively the likelihood of recovery of the left ventricular ejection fraction (LVEF) in patients with dilated cardiomyopathy (DCM) verified by radionuclide ventriculography. Twenty patients with DCM were clas sified into two groups according to the LVEF by M-mode echocardiographic findings two years after ventriculographic examination. The LVEF recovered to ≥ 50% in 10 patients (Group A), while it was sustained at < 50% in 10 patients (Group B). The clinical features of each group were compared, based on results of physical examination, radionuclide ventriculography, and other diagnostic tests performed on their referral to hospital. Only the systolic blood pressure differed significantly between the two groups, being slightly, but significantly, increased in Group A over that in Group B (P < 0.05). LVEF at rest by radionuclide did not differ (Group A: 31.5 ±10.3% vs Group B: 26.5 ±9.4%). Peak exercise EF-EF at rest (peak Δ EF) in Group A was apparently increased (3.4 ±4.0%), while that in Group B was decreased (-4.4 ±5.2%). The positive peak Δ EF had a highly predictive value of 90% for patients with DCM whose LVEF will recover to more than 50%. The recovery EF-EF at rest did not differ significantly between groups (Group A: 8.4 ±4.7 vs Group B: 3.9 ±2.3, P < 0.05). Other clinical parameters such as functional class, cardiothoracic ratio, LVEF by echocardiography, cardiac index by Swan-Ganz catheter examination, and histologic examination of biopsied endocardium were indistinguish able in the two groups. The authors conclude that peak Δ EF of radionuclide ventricu lography on exercise indicates a preservation of LVEF and predicts a good clinical recovery in patients with DCM.