Shamim W, Iqbal M, Chaudhry AH. EFFECTS OF QRS DURATION ON MYOCARDIAL PERFORMANCE AS ASSESSED BY Z-RATIO AND TEI-INDEX IN CHRONIC HEART FAILURE PATIENTS. Pak Heart J [Internet]. 2013Jun.13 [cited 2024Nov.23];46(1). Available from: https://pakheartjournal.com/index.php/pk/article/view/607