A 58-year-old man with a 3-year history of hypertension presents with progressive dyspnea on exertion, orthopnea, and peripheral edema for 2 weeks. Physical examination reveals elevated JVP, bibasal crackles, and a third heart sound. Chest X-ray shows pulmonary edema and cardiomegaly. Which investigation is most appropriate to determine the etiology and guide further management?

## Investigation of Choice in Heart Failure Workup **Key Point:** Transthoracic echocardiography (TTE) is the single most important and first-line investigation in all patients with suspected heart failure. It provides comprehensive structural and functional assessment. ## Role of Echocardiography in HF TTE enables: 1. **Determination of ejection fraction** — classifies HF as HFrEF (EF ≤40%), HFmrEF (EF 41–49%), or HFpEF (EF ≥50%) 2. **Assessment of wall motion abnormalities** — identifies ischemic vs. non-ischemic etiology 3. **Evaluation of diastolic function** — essential for HFpEF diagnosis 4. **Valvular pathology** — detects primary valve disease or secondary MR/TR 5. **Chamber dimensions and wall thickness** — suggests hypertensive heart disease, restrictive cardiomyopathy, or dilated cardiomyopathy 6. **Estimation of pulmonary artery pressure** — prognostic significance **High-Yield:** TTE is non-invasive, widely available, reproducible, and has no radiation or contrast risk. It is the **gateway investigation** that directs all subsequent testing. ## When Other Investigations Are Indicated | Investigation | Indication | |---|---| | **Cardiac catheterization + CAG** | Suspected coronary artery disease; positive stress test; HFrEF with angina | | **Cardiac MRI** | Suspected infiltrative/inflammatory disease; arrhythmogenic RV cardiomyopathy; scar characterization | | **Endomyocardial biopsy** | Suspected myocarditis, amyloidosis, or other infiltrative disease (rarely used; high risk) | **Clinical Pearl:** In this case, TTE will immediately show whether the patient has systolic dysfunction (dilated chambers, reduced EF) or diastolic dysfunction (normal EF, impaired relaxation), and whether there is evidence of prior MI (regional wall motion abnormality) or primary valve disease. This finding guides the next step: if CAD is suspected, proceed to angiography; if infiltrative disease is suspected, consider MRI or biopsy. **Mnemonic: ECHO-FIRST** — **E**jection fraction, **C**hamber size, **H**ypertrophy/wall thickness, **O**pening pressures (diastolic), **F**unction (regional), **I**schemia (wall motion), **R**egurgitation (valve), **S**tructure (masses, thrombus), **T**amponade (pericardial).