Electrocardiographic prediction of the severity of posterior wall perfusion defects on rest technetium-99m Sestamibi myocardial perfusion imaging

To identify electrocardiogram (ECG) variables predicting the severity of previous posterior wall myocardial infarction as measured by technetium-99m-Sestamibi rest single-photon emission computed tomography, we assessed agreement between ECG criteria and posterior wall perfusion defects (PWPDs) in 236 patients. Established ECG criteria for posterior and posterolateral infarctions were present in 22% and 19% of patients, respectively, and did not predict severity of PWPD (P = NS). Univariate predictors of severity were the Selvester QRS score (SQS) (P = .001) and an upright T wave in V1 (UTV1) greater than 0.2 mV (P = .001). Regression analysis demonstrated that SQS (P = .0001) and UTV1 greater than 0.2 mV (P = .006) were highly predictive of severity (c statistic = 0.793). All severe PWPDs had an SQS of 2 or higher. Established ECG patterns for diagnosis of posterior infarction are insensitive and poor predictors of severity. The SQS and UTV1 are effective for the diagnosis of posterior infarction and useful for the estimation of infarct severity.