ECG is poor in detecting ischemia in areas supplied by which of the following vessels:

Answer is B (Left Circumflex (LCx) Ischemia in the distribution of Left Circumflex Aery is difficult to detect on standard 12 lead ECG `Circumflex distribution ischemia is notoriously silent on an ECG as the posterolateral wall is under-represented on a conventional 12 lead ECG' -- 'Manual of cardiovascular medicine' by Griffin 3rd/528 'A normal ECG does not exclude acute MI especially when the Left circumflex is the culprit vessel because most of the area supplied by the LCx is not represented in the standard 12 lead ECG' -- 'Basic and Bedside Electrocardiography' by Baltazar (Lippincott Williams, 2009) Jst /344 `Acute Myocardial Infarctions in the distribution of the circumflex aery are likely to have non diagnostic ECG' -- 'Management of Acute Coronary Syndromes' by Cannon (2003) /213 There are areas of the hea that are difficult to 'see' with the ECG paicularly in the left circumflex distribution Small areas of ischemia may be missed altogether -- 'Cardiovascular Biomarkers' by Morrow (2006)/182 `The posterolateral wall of the LV tends to be electrocardiographically silent. Occlusion of a small circumflex aery may not cause ST segment elevation in lateral leads (Leads I, aVL and / or V5_6).Occasional patients with posterolateral MI have no ECG changes at all. Infact patients who are having MI without ECG changes usually have a posterolateral infarction' -- Primary Care Cardiology' by Taylor 2"d/I39 `ECG may be normal in high lateral wall infarctions as this area may be electrocardiographically 'Silent' -- 'Critical care Medicine : The Essentials' (2009)/385