Speckle Tracking Imaging Parameters in non Ischemic Stress Echocardiography

Objectives: This work aimed to elaborate accepted speckle tracking imaging parameters during non ischemic exercise stress echocardiography.

Background: Exercise stress echocardiography is a widely used modality for diagnosis and follow up of patients with coronary artery disease. During the last decade speckle tracking imaging has been increasingly used for accurate evaluation of cardiac function. Speckle tracking imaging can improve accuracy of exercise stress echocardiography.

Methods: During 2012-2014 were selected 53 patients, who completed exercise stress echocardiography, had normal resting left ventricular function and non-ischemic response, with frame rate ≥40 frames per second and satisfactory image quality. These echocardiography exams were analyzed with speckle tracking imaging software at rest and at peak exercise. Clinical follow up included telephone contact 1 - 4 years after stress echo exam and confirming freedom from coronary events during this time. Peak strain and time to peak strain were measured at rest and after the exercise.

Results: Global and regional peak strain increased in all the segments except the basal segments of the postero-lateral and anterior walls. Time-to-peak global and regional strain and time-to-peak strain adjusted to the heart rate were significantly shorter in all segments after exercise. Rest to stress ratio of time-to-peak strain adjusted to the heart rate was 2.1-2.7. Dispersion of time to peak strain relatively to the aortic valve closure was maximal at basal and minimal at apical segments at rest and at stress.

Conclusion: Global and regional peak strain rise during normal exercise echocardiography. Peak global and regional strain may occur before or after aortic valve closure at rest and after the exercise, the delay more apparent at basal segments. Time-to-peak strain normally shortens significantly during exercise, after adjustment to heart rate it shortens 2.1-2.7 times. These data may be useful for interpretation of future exercise stress speckle tracking echocardiography studies.