A 62-year-old man with hypertension and diabetes mellitus presents to the emergency department with palpitations and dyspnea for 6 hours. On examination, heart rate is 128/min, irregular, and blood pressure is 148/92 mmHg. ECG shows atrial fibrillation with rapid ventricular response. Chest X-ray is normal. Troponin is negative. What is the most appropriate immediate next step in management?

Explanation

## Clinical Scenario Analysis This patient presents with **symptomatic atrial fibrillation with rapid ventricular response (RVR)** — heart rate 128/min with hemodynamic stability (normal BP, no cardiogenic shock, negative troponin). ## Management Approach in AF with RVR **Key Point:** In haemodynamically stable AF with RVR, the first-line management is **rate control**, not rhythm control or cardioversion. ### Rate Control Agents — Comparison | Agent | Route | Onset | Use in AF-RVR | Notes | |-------|-------|-------|---------------|-------| | **IV Diltiazem / Verapamil** | IV | 2–5 min | **First-line** | Non-dihydropyridine CCB; rapid AV nodal blockade; safe in stable AF | | IV Amiodarone | IV | 10–15 min | Rhythm control agent | Used when rate control fails or for rhythm conversion; not first-line for rate control | | Oral Digoxin | PO | 30–60 min | Slow onset | Vagomimetic; slower onset; useful for maintenance but not acute RVR | | DC Cardioversion | Electrical | Immediate | **Unstable AF only** | Reserved for haemodynamic instability, acute heart failure, or ACS | **High-Yield:** In haemodynamically **stable** AF with RVR, use **IV calcium channel blockers (diltiazem or verapamil)** for rapid rate control. Amiodarone is reserved for rhythm conversion or when rate control fails. ## Why This Patient Needs IV CCB 1. **Rapid onset** (2–5 minutes) — patient is symptomatic with palpitations and dyspnea 2. **Effective AV nodal blockade** — reduces ventricular rate by 20–30% 3. **Haemodynamically stable** — no shock, hypotension, or acute heart failure 4. **No contraindications** — normal cardiac function on CXR, negative troponin **Clinical Pearl:** Always assess haemodynamic stability first. If the patient had signs of cardiogenic shock, acute pulmonary edema, or ACS, DC cardioversion would be the next step. ## Subsequent Management (After Rate Control) 1. Check TSH, electrolytes, renal function 2. Assess CHA₂DS₂-VASc score for anticoagulation 3. Decide on rhythm control (if recurrent or persistent AF) vs. rate control strategy 4. Initiate anticoagulation (DOAC or warfarin based on CHA₂DS₂-VASc ≥1 in males, ≥2 in females) **Mnemonic:** **RATE** = **R**ate control first (stable), **A**ssess haemodynamics, **T**hromboembolic risk (CHA₂DS₂-VASc), **E**lectrolytes & echo.