Reassessment of the diagnostic value of the vectorcardiogram in cystic fibrosis. (Correlation with clinical score, pulmonary function tests and echocardiogram)

In 21 children with cystic fibrosis, the vectorcardiogram (VCG) was correlated with various indices of the severity of the disease. The best correlation was found between (1) the azimuth angle of the spatial QRS loop area, representing the rightward and posterior shift of the main electrical forces, and pulmonary function tests (PFT), i.e. FEV₁% predicted (r=-0.671, P<0.005) and VC% predicted (r=-0.607, P<0.005), and (2) the right ventricular anterior wall index measured echocardiographically (r=0.472, P<0.05). More VCG parameters correlated significantly with PFT than with the echocardiogram. This shows the major influence of pulmonary changes on the VCG of those patients. In several subgroups with different clinical scores, the VCG were analyzed and compared to normal limits of age- and sex-matched controls. In this small series, the VCG was a specific but not very sensitive method for predicting the degree of severity of the disease. Echocardiography and vectorcardiography can be considered as two complementary techniques in the evaluation of cystic fibrosis.