The significance of early post-exercise ST segment normalization.

Area of Science:

• Cardiology
• Diagnostic Imaging
• Exercise Physiology

Background:

• Persistent ST segment depression post-exercise treadmill test (ETT) signifies a strongly positive result.
• The prognostic implications of early ST segment recovery in ETT are not well-defined.
• This study investigates the correlation between ST segment recovery patterns and myocardial ischemic burden assessed by myocardial perfusion imaging (MPI).

Purpose of the Study:

• To determine if early ST segment recovery in ETT correlates with a lower ischemic burden on MPI.
• To compare the ischemic burden between patients with persistent ST depression, early ST recovery, and normal ETT results.

Main Methods:

• Retrospective analysis of 853 patients undergoing exercise MPI.
• Patients stratified into three groups: normal ETT, early ST recovery (<1mm depression at 1 min), and persistent ST depression (>1mm depression at 1 min).
• Summed Stress Scores (SSS) from MPI and coronary anatomy (from angiograms) were analyzed.

Main Results:

• The persistence group showed significantly higher SSS (8.48±7.77) compared to early normalization (4.34±4.98) and normal groups (4.47±5.31).
• SSS in early normalization and normal groups were not statistically different, meeting non-inferiority criteria.
• Significant three-vessel or left main disease was more prevalent in the persistence group (39.3%) versus normal (5.9%) and early normalization (7.4%) groups.

Conclusions:

• Early ST segment recovery within 1 minute post-ETT is associated with a lower ischemic burden on MPI.
• Early ST recovery confers an ischemic burden similar to that of a negative ETT.
• A positive ETT with early ST segment recovery may represent a false positive finding, indicating a less significant ischemic burden.