A 38-year-old woman with a 3-month history of progressive fatigue, palpitations, and syncope on exertion is found to have a heart rate of 110 bpm at rest and a blood pressure of 95/60 mmHg. Electrocardiography shows sinus tachycardia with low voltage complexes. Chest X-ray reveals an enlarged cardiac silhouette. Which investigation would be most appropriate to assess the degree of ventricular dysfunction and determine the etiology of the cardiomyopathy?

Explanation

## Investigation of Choice for Cardiomyopathy Workup **Key Point:** Transthoracic echocardiography with Doppler and tissue Doppler imaging is the first-line, non-invasive investigation to assess ventricular dysfunction, chamber dimensions, systolic and diastolic function, and guide initial classification of cardiomyopathy in a hemodynamically compromised patient. ### Why Echocardiography is First-Line 1. **Quantifies LVEF and stroke volume** — essential for diagnosis and severity stratification 2. **Assesses chamber dimensions** — dilated vs restrictive vs hypertrophic pattern 3. **Evaluates diastolic dysfunction** — tissue Doppler E/e' ratio, LA volume index 4. **Identifies regional vs global dysfunction** — helps narrow differential diagnosis 5. **Non-invasive and safe** — appropriate for hemodynamically unstable patients 6. **Guides immediate therapy** — determines need for ACE-I, beta-blockers, diuretics, device therapy 7. **Cost-effective and repeatable** — allows serial monitoring ### Role of Other Investigations in Cardiomyopathy Workup | Investigation | Indication | Timing | |---|---|---| | **Transthoracic echo** | First-line; assess LV function, dimensions, diastolic function | Immediate | | Endomyocardial biopsy | Suspected myocarditis, infiltrative disease, or restrictive physiology | After echo if etiology unclear | | Cardiac CT angiography | Coronary artery disease exclusion; not for functional assessment | After echo if CAD suspected | | Holter/stress test | Arrhythmia detection, ischemic inducibility | After echo; not for acute dysfunction | **Clinical Pearl:** In this patient with syncope, hypotension, and tachycardia, echocardiography will immediately reveal LVEF and guide urgent initiation of neurohormonal blockade and consideration of device therapy (ICD if EF ≤ 35%). The low-voltage ECG and dilated silhouette suggest dilated cardiomyopathy, and echo will confirm global systolic dysfunction. **High-Yield:** Tissue Doppler imaging (E/e' ratio) is superior to conventional Doppler for detecting diastolic dysfunction and has prognostic significance in cardiomyopathy. An E/e' > 14 suggests elevated filling pressures and correlates with worse outcomes. **Mnemonic: ECHO FIRST** — **E**jection fraction, **C**hamber dimensions, **H**ypokinesis pattern, **O**verall function → **F**irst-line, **I**mmediate, **R**epeatable, **S**afe, **T**herapy-guiding.