Cited 14 times since 2013 (1.3 per year) source: EuropePMC Journal of electrocardiology, Volume 46, Issue 4, 14 2 2013, Pages 302-311 Difference vectors to describe dynamics of the ST segment and the ventricular gradient in acute ischemia. ter Haar CC, Maan AC, Warren SG, Ringborn M, Horáček BM, Schalij MJ, Swenne CA
Background
The ECG is important in the diagnosis and triage of the acute coronary syndrome (ACS), especially in the hyperacute phase, the "golden hours," during which myocardial salvage possibilities are largest. An important triaging decision to be taken is whether or not a patient requires primary PCI, for which, as mentioned in the guidelines, the presence of an ST elevation (STE) pattern in the ECG is a major criterion. However, preexisting non-zero ST amplitudes (diagnostic, but also non-diagnostic) can obscure or even preclude this diagnosis.
Methods
In this study, we investigated the potential diagnostic possibilities of ischemia detection by means of changes in the ST vector, ΔST, and changes in the VG (QRST integral) vector, ΔVG. We studied the vectorcardiograms (VCGs) synthesized of the ECGs of 84 patients who underwent elective PTCA. Mean±SD balloon occlusion times were 260±76s. The ECG ischemia diagnosis (ST elevation, STE, or non-ST-elevation, NSTE), magnitudes and orientations of the ST and VG vectors, and the differences ΔST and ΔVG with the baseline ECG were measured after 3min of balloon occlusion.
Results
Planar angles between the ΔST and ΔVG vectors were 14.9±14.0°. Linear regression of ΔVG on ΔST yielded ΔVG=324·ΔST (r=0.85; P<0.0001, ΔST in mV). We adopted ΔST>0.05mV, and the corresponding ΔVG>16.2mV·ms as ischemia thresholds. The classical criteria characterized the ECGs of 46/84 (55%) patients after 3min of occlusion as STE ECGs. Combined application of the ΔST and ΔVG criteria identified 73/84 (87%) of the patients as ischemic.
Conclusion
Differential diagnosis by ΔST and ΔVG (requiring an earlier made non-ischemic baseline ECG) could dramatically improve ECG guided detection of patients who urgently require catheter intervention.
