Changes in electrical vectors correlated with coronary insufficiency with recent symptoms

Vectorcardiography (VCG) enables measurement of voltages and directions of resultant spatial vectors in the heart that are altered by myocardial ischemia. To validate the ability of VCG to detect electrophysiological effects of regional myocardial ischemia and identify blood vessels that obstruct blood flow significantly, VCG records of 37 patients who presented with unstable symptoms of ischemia requiring coronary angiography (CA) were processed and analyzed. The difference in magnitude and direction of electrical vectors were measured before and after percutaneous coronary intervention (PCI) to study the significance of changes after revascularization. Bio amplifiers recorded 3 simultaneous orthogonal lead ECG signals with low-pass frequency of 150 Hz without electronic filtration. The analogue signals were digitized and recorded for analysis. The numerical output was processed by algorithms to calculate and display the state of vectors. 36 of 37 patients showed congruence between VCG and CA results: 34 of the 36 showed changes in electrical vectors and insufficient blood supply. 2 showed no changes in electrical vectors and non-obstructive arteries on CA. 1 patient had ischemia detected by VCG, but CA was negative. Blood vessels that were opened with PCI corresponded with regions of myocardial ischemia and expected coronary blood supply on VCG interpretation.