Thomas W. Schlosser MD, Presenter: Nothing to Disclose

Christoph Jensen, Abstract Co-Author: Nothing to Disclose

Holger Eberle, Abstract Co-Author: Nothing to Disclose

Oliver Bruder, Abstract Co-Author: Nothing to Disclose

Kai Nassenstein, Abstract Co-Author: Nothing to Disclose

To examine the association of early reduction of QT dispersion (QTd) and microvascular obstruction (MVO) in patients with non-ST-segment myocardial infarction (NSTEMI) assessed by contrast-enhanced cardiac magnetic resonance imaging (CMR).

Sixty-nine consecutive patients with first NSTEMI (45males, mean age 61.9±11.8 years) treated with primary PCI were included into this study. QTd was calculated prior to PCI and within 90 minutes after. The ratio of QTd reduction (QTd-R) was defined as follows: [(QTd prior - QTd post PCI)/QTd prior PCI] x 100. CMR was performed within four days after PCI on a 1.5 Tesla MR System. The imaging protocol included SSFP cine sequences for the calculation of LV function, volumes and mass. Total MVO volumes were calculated on early post-contrast images. MVO were expressed as percent of LV Mass (MVO%). Continuous variables were compared by Mann-Whitney test and correlation of QTd-R and MVO% was performed using Pearson testing. A receiver operating characteristics (ROC) analysis was used to detect the best cut-off point and was used for the analysis of the diagnostic accuracy of QTd-R for detection of microvascular obstruction.

Mean QTd-R was 44%±18%. The ratio of QTd reduction was significantly related to the extent of MVO% (r: 0.41; p=0.01). ROC analysis revealed an area under the curve (AUC) for QTd-R of 0.70 with a cut-off point of 39% for the detection of microvascular obstruction. The sensitivity and specificity of <39% QTd-R to detect microvascular obstruction was 70% and 86% with positive and negative predictive values of 84% and 62%, respectively. Patients with <39% QTd-R had a significantly lower ejection fraction (p=0.02), higher end-systolic volumes (p=0.05) and greater MVO% (p=0.003).

The relative change of QT dispersion calculated from ECG prior and early post PCI in NSTEMI is significantly correlated to microvascular obstruction as assessed by CMR and allows for prediction of reperfusion at the microvascular level.

The relative change of QT dispersion prior and early post PCI is significantly correlated to microvascular obstruction as assessed by CMR.

Schlosser, T, Jensen, C, Eberle, H, Bruder, O, Nassenstein, K, Association between Early Reduction of QT Dispersion and Microvascular Obstruction in Patients with Acute Non-ST-Segment Myocardial Infarction Assessed by Cardiac Magnetic Resonance Imaging.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9010502.html