Comparison of standard EKG criteria and EKG-derived Sylvester Score for quantification of infarct size with SPECT myocardial perfusion imaging (MPI)

Objectives EKG’s are routinely used in clinical practice to assess presence of old (chronic) myocardial infarction (MI). Our aim was to compare the ability of standard EKG criteria to predict chronic MI and also compare the EKG derived Sylvester Score, used to quantify MI size, to MI size measured by SPECT MPI.

Methods We retrospectively reviewed SPECT MPI and EKG’s of 38 patients with a history of at least one year or old MI. EKG’s with LVH, RBBB, LBBB, pacemaker, intra-ventricular conduction delay, left and right fascicular block and pre-excitation were excluded to enable calculation of Sylvester Score. Standard Q and R wave criteria per joint ESC/ACCF/AHA/WHF task force were used to determine presence or absence of old MI. Additionally EKG-derived Sylvester Score was calculated to quantify MI size. The MI size was measured by rest MPI using automated polar maps and expressed as percentage of LV myocardium.

Results There are 34 men and 4 women aged 66 ± 8 years. The MPI infarct size was 26 ± 17% (range 5 to 70%). The LVEF was 54 ± 10% (range 26 to 70%). Of the 38 patients with evidence of MI on SPECT MPI, only 14 (37%) met the standard EKG criteria of chronic MI (inferior/lateral or anterior/septal/lateral). The Sylvester score ranged between 0 and 11(median score 5 out of a possible maximum score of 32). There was no statistically significant correlation between the Sylvester Score and MPI in assessment of infarct size (p value 0.16).

Conclusions Standard EKG criteria as per joint ESC/ACCF/AHA/WHF task force are poor predictors of presence of old MI as determined by rest MPI. Further, the EKG-derived Sylvester Score is not useful in quantifying the MI size