## Rationale for 12-Lead ECG **Key Point:** In ASA PS II–III patients with cardiac risk factors (diabetes, hypertension, dyspnea on exertion) undergoing elective non-cardiac surgery, a resting 12-lead ECG is the standard initial investigation of choice for pre-anesthetic cardiac assessment. ### Why ECG is Indicated Here This patient meets criteria for baseline ECG: - Age ≥ 45 years - Presence of diabetes mellitus (major risk factor) - Hypertension (risk factor) - Symptoms suggestive of possible cardiac disease (dyspnea on exertion) - Elective surgery (allows time for investigation) **High-Yield:** ECG is non-invasive, rapid, inexpensive, and detects: - Ischemic changes - Arrhythmias - Left ventricular hypertrophy - Conduction abnormalities ### Role of Other Investigations | Investigation | Indication | Timing | |---|---|---| | **12-lead ECG** | All patients with risk factors; baseline assessment | Initial screening | | **Transthoracic echo** | Suspected structural disease, dyspnea of unclear etiology | If ECG abnormal or clinical suspicion high | | **Stress testing** | Intermediate risk, multiple risk factors, poor functional capacity | If ECG abnormal or high clinical suspicion | | **Coronary angiography** | Acute coronary syndrome, high-risk findings on stress test | Therapeutic/diagnostic for unstable disease | **Clinical Pearl:** In stable patients with controlled risk factors and normal ECG, further cardiac investigation is often unnecessary for low-to-intermediate risk surgery. This patient's dyspnea warrants baseline ECG; further testing depends on findings. **Mnemonic — ECG Indications in Pre-op:** **CHARD** - **C**ardiac symptoms (chest pain, dyspnea, syncope) - **H**ypertension (uncontrolled or on medication) - **A**ge > 45 years with risk factors - **R**enal disease (chronic kidney disease) - **D**iabetes mellitus [cite:Barash Clinical Anesthesia 8e Ch 7]
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