Two-dimensional speckle tracking echocardiography derived post systolic shortening in patients with unstable angina and normal left ventricular systolic function oleh Srinivasan Giridharan, Selvaraj Karthikeyan, Arumugam Aashish, Balasubramaniyan Amirtha Ganesh, Palamalai Arun Prasath, Pandiyan Usha