Intracoronary electrocardiogram ST segment shift evaluation during intravenous adenosine infusion: a comparison with fractional flow reserve.

BACKGROUND

By measuring the pressure decline caused by coronary narrowing, fractional flow reserve (FFR) is an index of the physiological significance of a vessel stenosis. Intracoronary electrocardiogram (IC-ECG) recording from an angioplasty guidewire is more sensitive than standard ECG in detecting regional myocardial ischemia. The aim of the study was to assess if unipolar IC-ECG ST segment recording from angioplasty guidewire during maximal pharmacologic vasodilation could be used as an indirect estimation of FFR results.

METHODS

Forty-eight clinically stable patients with intermediate stenosis underwent FFR evaluation and IC-ECG recording during intravenous adenosine infusion.

RESULTS

FFR values were ≤ 0.80 in 26 (54%) patients and > 0.80 in 22 (46%). After adenosine, standard ECG was abnormal in only nine (19%) patients, while IC-ECG showed a significant ST segment shift (IST) in 24 (50%) patients: ST elevation in 19 patients and depression in five). IST was documented in 21/26 patients with FFR ≤ 0.80 (81%) and in 3/22 with FFR > 0.80 (p < 0.001). Sensitivity of IST for predicting an abnormal FFR value was 81%, specificity 86%, positive and negative predictive accuracies were 88% and 79%, respectively.

CONCLUSIONS

Intracoronary ST segment shift evaluation during adenosine infusion may be of value in assessing the functional significance of a borderline stenosis. The presence of IST during adenosine infusion could obviate the need for additional FFR evaluation.