Tachycardia is defined as a heart rate greater than 100bpm. Tachycardia in the OR is not uncommon, and generally associated with severe hypovolemia, an inflammatory response or an inadequate anesthetic for surgical stimulus. The differential diagnosis for tachycardia in the OR is similar to that of bradycardia, including the 8H’s and 8T’s. Evolution of tachycardia to a more severe rhythm is rare in the absence of cardiac co-morbidities. Evaluation of the EKG rhythm is important to classify the tachycardia into separate categories: narrow vs. wide QRS and regular vs. irregular. Hemodynamic instability can occur with tachycardia (typically HR >150bpm) for which cardioversion is indicated.
Algorithm for Tachycardia in the OR1
- Give O2 if hypoxemic
- Monitor EKG, BP, oximeter, capnometry
- Light anesthesia
- Perform Echo if possible
- Unstable? (Altered mental status, chest pain, signs of shock, hypotension; usually HR >150)
- Perform immediate synchronized Cardioversion (Proscribed for clear sinus tachycardia)
- Verify IV access or obtain IV access
- Consider cardiology consult
- Verify IV access
- Obtain 12 lead EKG/rhythm strip
- Measure QRS complex
- Regular vs. Irregular rhythm
Narrow QRS, Regular Rhythm 1,2
- Consider vagal maneuver (listen to carotid first)
- Give Adenosine 6mg, IV push
- If no response, give 12mg Adenosine IV push
- Likely re-entrant SVT
- Observe for recurrence
- Treat recurrence with Adenosine or longer acting AV node blocker (ie: Beta blocker or diltiazem)
- Likely a-flutter, ectopic atrial tachycardia, or junctional tachycardia.
- Rate control with B blocker or CCB.
- Re-evaluate and treat underlying cause
Narrow QRS, Irregular Rhythm 1,2
- A-Fib, A-Flutter, or Multifocal atrial tachycardia
- Severe hypotension or low ejection fraction
- Load Amiodarone 150mg IV over 10min
- Normal EF and normal BP
- Beta blocker or CCB
Wide QRS, Regular Rhythm 1,2
- If V-tach or uncertain, give Amiodarone 150mg IV over a min, and CaCl 1g IV
- Lidocaine 1-1.5mg/kg IV q 3-5min x 3, is alternative to amiodarone
- Prepare for synchronized cardioversion
- If SVT with aberrancy, give adenosine 6 or 12mg IV push
Wide QRS, Irregular Rhythm 1,2
- If Torsades-de-Pointes, give Mg 2g IV over 5 min; consider repeat dose.
- If pre-excited a-fib (AF + WPW), consider amiodarone 150mg IV over 10min and cardiology consult; Avoid AV nodal blockers (adenosine, digoxin, CCBs)
- If A-fib with aberrancy, see irregular, narrow QRS algorithm
- Moitra, V et al. Anesthesia Advanced Circulatory Life Support. Can J Anesth/J Can Anesth (2012) 59:586-603.
- McEvoy, et al. 4-Step Approach to ACLS Management, pocket reference card. Medcial Univerisity of South Carolina, 2011.