Cardiac Assessment in the Operating Room

1. Cardiac Assessment in the Operating Room Allison K. Cabalka, MD Associate Professor of Pediatrics Consultant, Pediatric Cardiology Mayo Clinic

2. Objectives • Rhythm issues encountered in the operating room • Discuss the use of echocardiography in the OR

3. Objectives • Rhythm issues encountered in the operating room • Discuss the use of echocardiography in the OR

4. Rhythm Issues in the OR • Tachyarrhythmias • Supraventricular tachycardia (SVT) • Atrial flutter/fibrillation (AF/Fib) • VT/VF • Junctional Rhythm • Too fast OR too slow • Conduction abnormalities • Advanced 2° or 3° (complete) heart block

5. Diagnosis: Monitor Strips • Evaluate rate, regularity, rhythm • Is every QRS preceded by a P wave? • Narrow or wide complex? • What is the rate compared to what you expect?

6. Normal Sinus Rhythm • Look for a P wave in front of every QRS • But not so far in front that it is ‘behind’ • Change leads to be sure

7. Junctional Ectopic Tachycardia • Common post-operative arrhythmia • Originates from AV node • Particularly in postop TOF/Fontan patient • Heart rates >150 beats per minute • Loss of AV synchrony • Look for AV dissociation • Slower P wave rate • Easy to diagnose with pacing wires postop

8. Junctional Ectopic Tachycardia

9. Junctional Ectopic Tachycardia • Treat with IV Amiodarone • Load 5-10 mg/kg IV • Drip infusion of total of 10 mg/kg/24 hrs • Alternative or complimentary • Cooling • Reduction of sympathetic stimulation (Epinephrine) • Correct Ca++ and Mg+ levels • Volume replacement

10. AV Node Independent Re-Entry • Atrial fibrillation • Irregularly irregular • No organized atrial contractility • Easy to see on direct visualization or by TEE • Atrial flutter • Regular atrial rate, variable conduction • Also can be seen by TEE or visualization

11. DiagnosisAV node independent re-entry Atrial flutter Cardiovert

12. Complete AV Block • Common postop complication • 3.7-6% incidence of surgical postoperative complete AV block • Recognition of AV dissociation with slower escape rate • P wave rate is greater than QRS rate • Otherwise this may be AV dissociation with accelerated junctional rhythm!

13. Postoperative Complete AVB

14. Complete AV Block • Temporary pacing wires used in interval • Daily threshold checks • Pulse oximeter monitoring • ECG monitor picks up pacing spike • Recommendation for observation to see if resolves within 7-10 days • If not, permanent pacing system warranted

15. Objectives • Rhythm issues encountered in the operating room • Discuss the use of echocardiography in the OR

16. Echo: Background • Echo has been utilized in the OR for the last 20 years • Miniaturization of probe allows application of TEE to all pts coming to the OR for CHD surgery • Mini-TEE, mini-multiplane, Acunav longitudinal imaging • Performed by either the cardiologist or the anesthesiologist • The key to this is proper training and experience with the diagnosis and evaluation of congenital heart disease

17. Echo in the OR • Echocardiography is a key part of non-invasive imaging in the operating room • Evaluate the preoperative anatomy • Be sure nothing was ‘missed’ • Confirm the surgical plan • Evaluate the repair before leaving the OR • Residual defects • Guide revision • Available modalities: TTE or Epicardial

18. Randolph G, Hagler D et al J Thorac Cardiovasc Surg 2003 Utility of TEE? • Mayo Clinic: 1002 pts during CHD surgery • Mean age 9 yrs; range 4d to 85 yrs • Prebypass or postbypass major impact in ~14% of cases • 52 pts had immediate revision (“cost-effective”) • Most useful in complex valve repairs or in complex outflow tract reconstructions • Less impact in PAPVR, ASD, simple tricuspid valve repair, aortic arch repair

19. Echo in the OR • Pre-operative echo evaluation • Document baseline ventricular function • Assessment of AV valve function • Confirmation of anatomy and surgical plan • Are there any additional defects that need to be addressed surgically? • Especially atrial septal defect • ?Bubble study to confirm intact atrial septum

20. Post-Bypass Echo: Function • Evaluation of air in the left heart • Adequate venting • Ventricular function • Comparison with pre-bypass imaging • Evaluation of intervention with medications and inotropic support • Volume status • Is the heart underfilled or distended?

21. Post-Bypass Echo: Anatomy • Critical for evaluation of residual defects • Outflow tract stenosis • Alignment as parallel as possible (often transgastric views needed) • Valve repair • Be sure volume status is sufficient, BP stable • Residual shunts • Atrioventricular valve • Critical if repair undertaken • Leaflet motion/paravalve leak in replacement

22. Post-operative Evaluation • Echo can be correlated with surgeon’s evaluation • Pressure line monitoring • i.e. RV to PA pressure post-TOF repair • Blood gas sampling for shunt • i.e. SVC line and PA blood gas sampling

23. Review of TEE and applications to pediatric CHD • Intraoperative TEE • Catheterization and TEE guidance • TEE during non-cardiac surgery in the CHD patient • Description of typical probe positions and views obtained Kamra K, et al, Pediatr Anes, 2011

24. Mid-Esophageal View (0-30º) • Typical 4-chamber view • AV valves • Ventricular function • Atrial septum • Segments of ventricular septum • Inlet

25. Mid-Esophageal View (60-90º) • Typical long-axis view • AV valves in different plane • Ventricular function • Atrial septum • Segments of ventricular septum • Outflow tracts • RVOT and LVOT

26. Mid-Esophageal (30º) • Typical view to see aortic leaflets • Coronary origins • Proximal RVOT and pulmonary valve • PA bifurcation

27. Deep Trans-Gastric View (0º) • Left ventricle • LVOT • Right ventricle (rotate rightward) • RVOT • Ventricular function

28. Deep Trans-Gastric View (90º) • Anteflex probe and rotate right/left • LVOT and aortic valve • Outlet ventricular septum • Tricuspid valve inflow/function

29. Epicardial Echo • When TEE not available • Standard use transthoracic probes • Sterile sleeve • Surgeon images in epicardial position • Image orientation may not be quite ‘standard’ • Understanding of baseline anatomy and surgical repair

30. Epicardial Echo • Reported use of Epicardial or Epi+TEE in 8% of CHD OR cases • May be useful for difficult to see ‘areas’ such as PA branches and coronaries Use of Epicardial Echo JCVTS Hospital for Sick Children Toronto 2007-2009 Dragalescu A, et.al, JCVTS 2011 in press

31. Epicardial Echo RVOT Free wall: “PLAX view” Aorto-PA Sulcus: “PLAX view”

32. Epicardial Echo RVOT Free wall: “PLAX view” Aorto-PA Sulcus: “PLAX view”

33. Epicardial Echo RV Free wall: “Subcostal view” SVC-Aorto Sulcus: “Subcostal long axis”

34. Epicardial Echo RV Free wall: “Subcostal view” SVC-Aorto Sulcus: “Subcostal long axis”

35. Conclusion • One must pay careful attention to rhythm issues in the operating room • Most will involve a decision about placement of pacing wires • Intraoperative echo is very useful for pre and post-bypass evaluation of anatomy, surgical repair and cardiac function • Epicardial echo may be used if TEE is unavailable