Effect of posture on the spatial vectorcardiogram of man

Changes of posture can cause rotation of the spatial QRS loop around its various axes and alter the voltage of the maximum QRS spatial vectors. These have been described in normal subjects and in patients with scalar ECG abnormalities in whom changes of posture may cause atypical changes in the spatial VCG. These atypical responses in patients with ventricular hypertrophy may have a value in diagnosis. Rotation of the spatial VCG with change of posture is partly the result of an altered anatomical position of the heart and partly caused by inherent errors in the method of recording the VCG.