sinus rhythm at 63 bpm with no ST segment changes and persistence of anteroseptal Q waves, but disappearance of inverted T-waves on apical and lateral leads. An X-ray of his chest was normal without cardiomegaly; transthoracic echocardiography showed normal LV size and function with 62% of ejection fraction and normal segmental contractility.

Discussion {#Sec3}
==========

Our observation had several specificities: first, total occlusion of LMCA is very rare; second, there was no parallelism between the severity of the pathology and the relatively non-threatening clinical presentation; third, the LV size and function were preserved despite an associated stenosis of a dominating RCA; and fourth, we report the surgery contribution to the therapeutic arsenal.

Total occlusion of LMCA is lethal usually by sudden cardiac death after massive myocardial infarction and cardiogenic shock \[[@CR9], [@CR10]\]. Samadov *et al.* suggested that the high probability of out-of-hospital cardiac arrest might preclude the true estimation of the prevalence of LMCA occlusion \[[@CR7]\].

On clinical examination, the patients are often strongly symptomatic with complaints of recurrent typical chest pain, or a disabling exercise angina occurring at the slightest effort of daily life or even during rest. They may have a history of myocardial infarction or present symptoms of heart failure with advanced exertional dyspnea or even rest dyspnea \[[@CR8]\]. According to Su *et al.,* cardiogenic shock has been described in LMCA occlusion, and timely mechanical support should be considered for emergency revascularization in such cases \[[@CR11]\]. In our case, symptoms were less severe and even less suggestive of the seriousness of the pathology.

Since the main artery cannot ensure LV vascularization, two conditions are required for both patient survival and maintenance of LV function: a dominant RCA, and a massive and rich collateral circulation allowing retrograde vascularization of the entire left coronary network \[[@CR5]\]. This noti