Non-Invasive Imaging After Exercise Detects Heart Disease
Strain imaging measures post-ischemic left ventricular delayed relaxation
WEDNESDAY, Feb. 18 (HealthDay News) -- Using strain imaging to quantify regional heart function after treadmill exercise is an effective and non-invasive way to detect coronary artery disease, researchers report in the Feb. 24 issue of the Journal of the American College of Cardiology.
Katsuhisa Ishii, M.D., and colleagues from Kansai Electric Power Hospital in Osaka, Japan, examined whether post-ischemic left ventricular delayed relaxation during early diastole, a sensitive sign of acute myocardial ischemia, could be detected after an exercise test using strain imaging derived from two-dimensional speckle-tracking echocardiography in 162 patients with stable effort angina.
The investigators found that 117 patients had significant coronary stenoses (at least 50 percent of the luminal diameter). After five minutes of treadmill exercise, the mean strain imaging diastolic index (SI-DI) fell significantly (from 78 to 27.6 percent) in vascular territories perfused by arteries with significant stenoses but not in territories perfused by arteries without significant stenoses. This trend continued 10 minutes after exercise, the researchers report. Using an SI-DI ratio (the ratio of SI-DI before and after exercise) cutoff of 0.74 detected significant coronary stenosis with a sensitivity of 97 percent and a specificity of 93 percent, the authors note.
The study "amplifies the drum roll for incorporation of diastolic phase mechanics in the assessment of stress echocardiography," according to the authors of an accompanying editorial.
An author of the editorial has a financial relationship with GE Healthcare.