Arrhythmia Management

Systematic Approach to ECG in CVICU

• Rate: Normal 60–100 bpm; post-transplant baseline often 90–110 (denervated)
• Rhythm: Sinus vs atrial (AF/flutter/MAT) vs junctional vs ventricular; assess regularity
• Axis: Normal −30° to +90°; new left axis deviation → LAHB; new right axis → RVH, PE, or lateral MI
• Intervals: PR (normal 120–200 ms), QRS (<120 ms), QTc (<470 ms women, <450 ms men)
• New LBBB: Post-TAVR (15–25%), post-SAVR, acute MI (Sgarbossa criteria); assess need for permanent pacemaker
• ST Changes Post-Op: Expect non-specific ST-T changes; new ST elevation → consider graft occlusion, pericarditis, or coronary air embolism
• Paced Rhythm Analysis: Identify pacing spikes, capture (QRS after spike), sensing (appropriate inhibition)

Epidemiology & Prevention

• Incidence: 20–40% after CABG, up to 50% after valve surgery; peaks POD 2–3
• Risk factors: Age >65, prior AF, LA enlargement, COPD, obesity, electrolyte imbalance
• Prevention: Beta-blockers (continue preoperative; start postoperatively if not contraindicated), amiodarone prophylaxis in high-risk, maintain K⁺ >4.0, Mg²⁺ >2.0
• Posterior pericardiotomy may reduce incidence
• Colchicine: COPPS-2 trial showed reduction in post-pericardiotomy syndrome and POAF

Treatment Algorithm

• Hemodynamically Unstable: Synchronized cardioversion (biphasic 120–200 J)
• Rate Control (first-line): IV esmolol or metoprolol; diltiazem if beta-blocker contraindicated (avoid in low EF)
• Rhythm Control: Amiodarone (150 mg IV bolus → 1 mg/min × 6h → 0.5 mg/min × 18h); consider vernakalant where available
• Anticoagulation: Start heparin if AF persists >48h or patient has high CHA₂DS₂-VASc; balance bleeding risk post-surgery
• Atrial Pacing: Overdrive atrial pacing (via epicardial wires) may terminate organized atrial flutter

VT/VF Management in CVICU

• Pulseless VT/VF: Defibrillation → ACLS/CALS protocol; in post-sternotomy patients, emergency resternotomy within 5 min if initial ACLS fails
• Stable Monomorphic VT: Amiodarone 150 mg IV over 10 min; lidocaine 1–1.5 mg/kg if amiodarone fails; procainamide alternative
• Polymorphic VT (normal QT): Treat as ischemia until proven otherwise — urgent angiography; amiodarone, beta-blockers
• Torsades de Pointes (prolonged QT): Magnesium 2 g IV bolus; overdrive pacing to shorten QT; isoproterenol temporizing
• Post-Op VT Causes: Ischemia (graft failure), electrolyte abnormalities (K⁺ <4, Mg²⁺ <2), proarrhythmic drugs, reperfusion, myocardial irritation from sutures/air
• VT Storm: Amiodarone infusion + deep sedation (propofol/intubation); consider stellate ganglion block, catheter ablation

Post-Operative Conduction Disorders

Epicardial Pacing Algorithm (Post-Cardiac Surgery)

• Step 1: Identify underlying rhythm and hemodynamic status
• Step 2: If bradycardic with hemodynamic compromise → initiate VVI pacing at 80–90 bpm immediately
• Step 3: If sinus rhythm present but slow → AAI mode to preserve AV synchrony
• Step 4: If AV block → DDD mode with AV delay 150–200 ms; atrial pacing preserves atrial kick (~20% of CO)
• Step 5: If AF + slow ventricular rate → VVI or VVIR mode
• Step 6: Daily threshold checks (both atrial and ventricular); set output at 2× threshold
• Step 7: If no pacing need by POD 5–7, wires removed (check INR <1.5, platelets adequate)
• Step 8: If persistent AVB at POD 5–7, consult electrophysiology for permanent pacemaker