You are configuring continuous intraoperative ECG monitoring for a 66-year-old woman with triple vessel coronary disease undergoing open gastrectomy. Which modified bipolar lead configuration provides the best sensitivity for detecting left ventricular myocardial ischaemia?

• A Lead II
• B CR7
• C CB1
• D CM5 ✓

Explanation

CM5 places the negative electrode at the right sternal border (manubrium) and the positive electrode at the V5 position, approximating the V5 vector over the anterolateral left ventricle. It detects the large majority of perioperative ischaemic episodes, which occur predominantly in the left ventricular territory. Lead II is excellent for arrhythmia recognition and for detecting inferior wall (right coronary) ischaemia, which explains why it is the tempting but incorrect choice for this question.

Reference: Miller's Anesthesia, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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