This study aimed to determine the role of global longitudinal
strain (GLS) in early diagnosis and detection of severity of coronary
artery disease (CAD) in non-diabetic patients with preserved
left ventricular ejection fraction (EF) without regional
wall motion abnormalities presented with chronic coronary syndrome,
and to identify the role of territorial longitudinal strain
(TLS) in detection of the affected coronary artery. We enrolled
60 non-diabetic patients with suspected CAD who underwent
resting echocardiography and speckle tracking imaging and
subsequently coronary angiography then results were correlated
together. Patients with family history of CAD (68.3%), hypertension
(68.3%), smokers (43.3%), and dyslipidemia (81.6%). All
participants had normal left ventricular systolic function with
mean EF of 64.02±6.15% and no regional wall motion abnormalities
at rest. Patients were classified angiographically according
to the number of the diseased vessels into: 3 vessels disease
(43.3%), 1-2 vessels disease (35%), and normal coronary
angiography (21.7%) with GLS mean values of -13.69±1.94%,
-15.4±1.74%, and -18.80±2.14%, respectively. There was a negative
significant correlation between GLS values and the number
of diseased vessels (P=0.001). The values of TLS were significantly
lower in myocardial regions supplied by stenotic arteries than
those supplied by non-stenotic arteries. Mean TLS values for
stenotic left anterior descending, left circumflex, and right coronary
arteries were -15.51±3.19, -13.06±2.90, -13.27±2.60 with
P=0.011, 0.001, and 0.001, respectively. Speckle tracking derived
GLS is an effective non-invasive method in predicting presence
and severity of CAD and in locating the affected vessels based
on the distribution of segments affected in TLS.