20. Post-Operative Pediatric Cardiac Surgical ECGs
Surgical intervention for congenital heart defects disrupts specialized myocardial conduction pathways, creates surgical ventriculotomy scars, and alters post-operative mechanical and electrical properties.
1. Post-Surgical Lesion-Specific Conduction & Arrhythmia Patterns
| Congenital Surgical Procedure | Surgical Lesion / Anatomical Injury | Post-Operative Electrocardiographic Signature | Long-Term Clinical & Arrhythmia Risks |
|---|---|---|---|
| Repair of Tetralogy of Fallot (TOF) | Right ventriculotomy, infundibulectomy, VSD patch closure. | Complete Right Bundle Branch Block (RBBB) with variable QRS prolongation. | QRS Duration $\ge 180\text{ ms}$ is a marker of severe RV dilatation, late monomorphic VT, and sudden cardiac death $\to$ triggers Pulmonary Valve Replacement (PVR). |
| Fontan Operation (Single Ventricle) | Total cavopulmonary connection with extensive atrial suture lines. | Sinus node dysfunction (junctional escape rhythm), loss of sinus P waves. | Intra-Atrial Reentrant Tachycardia (IART / Incisional Atrial Flutter) with $1:1$ or $2:1$ AV conduction; hemodynamic collapse. |
| Mustard / Senning (Atrial Switch) | Complex intra-atrial baffles redirecting systemic/pulmonary venous flow. | Severe sinus bradycardia, junctional rhythm, slow atrial escape. | High incidence of Sick Sinus Syndrome ($>50\%$ at 10 years) requiring permanent pacemaker implantation. |
| Arterial Switch Operation (ASO) | Translocation and coronary button reimplantation into neoaorta. | ST segment elevation/depression in lateral or inferior leads. | Acute Coronary Kinking or Stenosis causing acute myocardial infarction in the immediate post-op period. |
| Perimembranous VSD / AVSD Repair | Patch placement along postero-inferior rim of defect near His bundle. | Transient or permanent Complete Third-Degree AV Block. | Permanent epicardial pacemaker indicated if complete heart block persists beyond $7-10$ days post-operatively. |
2. Evidence-Based Management Protocols
- Temporary Epicardial Pacing: All open-heart pediatric surgical patients leave the operating room with temporary atrial and ventricular epicardial pacing wires.
- Junctional Ectopic Tachycardia (JET) is managed with surface cooling ($34-35^\circ\text{C}$), sedation, withdrawal of catecholamines, and IV Dexmedetomidine or IV Amiodarone.
- Permanent Pacemaker Implantation Timing: Post-operative AV block that does not recover by day $7-10$ requires permanent pacemaker placement prior to hospital discharge.