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This Article Full Text Full Text (PDF) All Versions of this Article: 296/3/H645    most recent 00313.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lyseggen, E. Articles by Smiseth, O. A. Search for Related Content PubMed PubMed Citation Articles by Lyseggen, E. Articles by Smiseth, O. A.

A novel echocardiographic marker of end systole in the ischemic left ventricle: "tug of war" sign

Institute for Surgical Research and Department of Cardiology, University of Oslo, Rikshospitalet University Hospital, Oslo, Norway

Submitted 25 March 2008 ; accepted in final form 25 December 2008

The present study introduces a new clinical method to define left ventricular (LV) end systole (ES) during tissue Doppler imaging (TDI). Preliminary experiments showed a sharp inflection point in strain traces (S_IP) from ischemic borderzones, which coincided with onset of a postsystolic shortening wave (V_PS) in the velocity trace. In a single-vessel disease model, we investigated whether S_IP and V_PS may serve as markers of global ES and their mechanism. In six anesthetized dogs we measured LV pressure and myocardial long-axis function by using TDI and sonomicrometry. Ischemia was induced by left anterior descending coronary artery occlusion. ES was defined by the minimum first derivative of LV pressure. TDI and sonomicrometry demonstrated a sharp S_IP and V_PS at ES in the ischemic borderzone (defined as moderately ischemic myocardium by pressure-dimension loop analysis). Time differences relative to ES ( ± SD) were –0.1 ± 2.3 (intraclass correlation coefficient R_IC = 0.996) and 6.8 ± 10.7 ms (R_IC = 0.89) for S_IP as shown by sonomicrometry and TDI, respectively. There was a strong inverse relationship between postsystolic shortening in the borderzone and simultaneous lengthening of nonischemic myocardium. In 30 patients with acute myocardial infarction, S_IP and V_PS evaluated by TDI were compared with ES defined by aortic valve closure. Time differences were –4 ± 14 (R_IC = 0.94) and –2 ± 11 ms (R_IC = 0.96), respectively. In the ischemic borderzone, S_IP and V_PS identified global ES with high accuracy. The force balance or "tug of war" between borderzone and nonischemic myocardium is a likely underlying mechanism for these markers. The method may be used as an "all in one heart beat" approach for TDI analysis in acute myocardial ischemia.

echocardiography; infarction; reperfusion; ventricular function; tissue Doppler imaging