Assessment of global and regional myocardial function using the Minnesota Q/QS codes. A comparison with clinical ECG interpretation.

The authors investigated 244 consecutive patients with suspected coronary artery disease by coronary angiography and quantitative left ventriculography to compare the Minnesota Q/QS code (MC) with clinical electrocardiographic (ECG) interpretation. Patients who were suspected to have wall motion abnormalities for reasons other than coronary artery disease for possible regional wall motion abnormalities were excluded. Out of 244 patients, 159 (65%) had wall motion abnormalities. The sensitivity for detecting wall motion abnormalities was 21% for MC 1.1 and 51% for MC 1.1-3, whereas clinical ECG interpretation showed a sensitivity of 73%. Specificity for MC 1.1 was 93% and for MC 1.1-3 it was 84%. Specificity of clinical ECG interpretation (84%) was comparable. Compared to the MC, clinical ECG interpretation showed a stronger association with left ventricular ejection fraction, number of segments with abnormal wall motion, and severity of wall motion abnormality. Anterior myocardial infarction presented more often with clinical ECG changes (71%) and with a Q/QS code (50%) than inferior myocardial infarction (61% and 41%, respectively). In summary, in contrast to clinical ECG criteria, the MC has high specificity at the expense of a low sensitivity.