Relationship between T-wave normalization on exercise ECG and myocardial functional recovery in patients with acute myocardial infarction

Myocardial Viability: From Proof of Concept to Clinical Practice

Ischaemic left ventricular (LV) dysfunction can arise from myocardial stunning, hibernation, or necrosis. Imaging modalities have become front-line methods in the assessment of viable myocardial tissue, with the aim to stratify patients into optimal treatment pathways. Initial studies, although favorable, lacked sufficient power and sample size to provide conclusive outcomes of viability assessment. Recent trials, including the STICH and HEART studies, have failed to confer prognostic benefits of revascularisation therapy over standard medical management in ischaemic cardiomyopathy. In lieu of these recent findings, assessment of myocardial viability therefore should not be the sole factor for therapy choice. Optimization of medical therapy is paramount, and physicians should feel comfortable in deferring coronary revascularisation in patients with coronary artery disease with reduced LV systolic function. Newer trials are currently underway and will hopefully provide a more complete understanding of the pathos and management of ischaemic cardiomyopathy.

Normalization of abnormal T-waves during stress testing does not identify patients with reversible perfusion defects

OBJECTIVE

To determine if T-wave normalization during exercise or dobutamine stress testing identified patients with myocardial ischemia as indicated by reversible perfusion defects.

METHODS

Exercise or dobutamine stress tests with perfusion scintigraphy were performed in 1,173 patients with abnormal T-waves on their baseline electrocardiograms. The results of perfusion scintigraphy were compared in patients with and without stress-induced T-wave normalization.

RESULTS

Only 33 of 270 patients with reversible perfusion defects (12.2%) had T-wave normalization during stress while 76.4% of 140 patients who had T-wave normalization during stress did not have a reversible perfusion defect. Results were similar for patients who did or did not reach 85% of their maximal predicted heart rate, for patients with and without Q-wave infarction on the baseline EKG and for patients who did or did not have ischemic ST-segment depression during stress.

CONCLUSIONS

T-wave normalization during stress testing has low sensitivity and poor positive predictive value for stress-induced reversible myocardial ischemia.