The Influence of Symptom-to-reperfusion-time on Left Ventricular Strain and Extent of Infarction in Patients with STEMI: a 3-Dimensional View on the Wavefront Phenomenon

Aims Data on the relationship between time-to-reperfusion and left ventricular (LV) function and infarct characteristics after ST-segment elevation myocardial infarction (STEMI) are inconsistent and not completely understood. Therefore, we examined the association between the symptom-to-reperfusion-time and cardiovascular magnetic resonance (CMR) derived global strain parameters and infarct extent in STEMI patients. Methods and results The study included 108 STEMI patients who underwent successful primary percutaneous coronary intervention (PPCI). Patients were categorized according to the median symptom-to-reperfusion-time: shorter (<160min, n=54) and longer times (>160min, n=54). CMR was performed 2-7 days after PPCI and at 1-month. CMR cine imaging was performed for functional assessment and late gadolinium enhancement (LGE) to evaluate infarct extent. Myocardial feature-tracking was used for global LV strain analysis. Mean transmural extent score was quantified per patient as the average of infarct percentages for all segments containing hyperenhanced tissue. Baseline clinical and angiographic characteristics were comparable between the groups. Patients with shorter reperfusion time had more favorable baseline and follow-up LV circumferential and radial strain (p=0.049, p=0.01, p=0.047, p<0.01, respectively), while LV longitudinal strain appeared comparable for both baseline and follow-up (p>0.05 for both, Figure 1). Mean transmural extent score at follow-up was lower in patients with shorter reperfusion time (p<0.01). In multivariable regression analysis including all 3 strain directions, baseline LV circumferential strain was independently associated with mean transmural extent score at follow-up (β=1.89, p<0.001). Conclusion In STEMI patients, time-to-reperfusion was significantly associated with smaller extent of infarction and better LV circumferential and radial strain but not with longitudinal strain. Moreover, infarct transmurality and residual LV circumferential strain are closely linked.Comparison of BL and FU global LV strainGraphical abstract