Abstract 15612: Intracoronary ECG is Novel Predictor of Myocardial Injury and Hyperemic Blood Flow Following Primary Coronary Intervention: Insights From a Cardiac MRI Study
Background: During treatment of acute ST-segment elevation myocardial infarction (STEMI), the achievement of hyperemic blood flow [defined as Corrected TIMI Frame Count (CTFC) of <14 frames] has been well described as a powerful predictor of left ventricular remodeling and mortality. Intracoronary electrocardiography (IC-ECG) is a simple and novel tool with the potential direct in-lab ‘real-time’ therapeutic decision making process. We assessed the hypothesis that IC-ECG is a valid surrogate of hyperemic blood flow (measured by CTFC), and the extent of myocardial injury by cardiac magnetic resonance (CMR) in STEMI.
Methods: Fifty three consecutive patients (age 60±10 years; 81% male) presenting with STEMI (anterior 40%) underwent IC-ECG ST-segment analysis prior to and immediately after achieving successful patency of the infarct related artery (IRA). The IC-ECGs were acquired by connecting an ECG monitor to the angioplasty guidewire whilst situated distally within the IRA. CTFC measurements were analysed offline. Peak creatine kinase (CK) levels were recorded. Delayed contrast enhancement CMR was performed at 3 and 90 days post primary coronary intervention.
Results: Despite restoration of TIMI 3 flow in 96% of patients, only 53% achieved a CTFC of <14. Hyperemic blood flow correlated with favorable post infarct left ventricular parameters of a [smaller infarct size (p=0.016) and non viable mass (p=0.006) on CMR at 3 days post STEMI. Furthermore favourable remodeling reflected in reduced diastolic (p=0.05) and systolic volumes (p=0.05) were also seen in this group at 90 days]. Immediate IC-ECG resolution greater than 1 mm successfully predicted 70% of patients with hyperemic blood flow (p=0.028). Immediate IC-ECG resolution also correlated with smaller infarct size (p=0.012) and non viable mass (p=0.001) on CMR, peak CK (p=0.021) as well as ejection fraction at 90 days (p=0.038)
Conclusions: In acute STEMI, IC-ECG is a novel and immediate “in-lab” predictor of myocardial injury, and correlates favorably with post infarct size and left ventricular remodeling. In addition, we found it to be strong predictor of hyperemic flow post primary coronary intervention. Further studies are necessary to determine its prognostic value in the STEMI population. .
- © 2010 by American Heart Association, Inc.