Wide-complex tachycardia
Background
- 3 wide complexes in a row is considered ventricular tachycardia; non-sustained if lasts less than 30 seconds
- Sustained ventricular tachycardia is ventricular tachycardia >30 seconds
Etiology[1][2][3]
- WCT is due to true ventricular tachycardia in 80% of cases
- For patients with underlying cardiac disease, this number increases to > 90%
- Multiple other causes must be considered, including Hyperkalemia, Digoxin toxicity, severe metabolic acidosis, and others
Clinical Features
- Usually symptomatic, depending on etiology
- May have cardiac arrest or unstable vitals
Differential Diagnosis
Wide-complex tachycardia
Assume any wide-complex tachycardia is ventricular tachycardia until proven otherwise (it is safer to incorrectly assume a ventricular dysrhythmia than supraventricular tachycardia with abberancy)
- Regular
- Monomorphic ventricular tachycardia
- PSVT with aberrant conduction:
- PSVT with bundle branch block^
- PSVT with accessory pathway
- Atrial flutter with bundle branch block^
- Sinus tachycardia with bundle branch block^
- Accelerated idioventricular rhythm (consider if less than or ~120 bpm)
- Metabolic
- Irregular
- Atrial fibrillation/atrial flutter with variable AV conduction AND bundle branch block^
- Atrial fibrillation/atrial flutter with variable AV conduction AND accessory pathway (e.g. WPW)
- Atrial fibrillation + hyperkalemia
- Polymorphic ventricular tachycardia
^Fixed or rate-related
Evaluation
- Assume ventricular tachycardia until proven otherwise
- See V Tach vs. SVT
Management
Pulseless: see Adult pulseless arrest
Unstable
- Regular: Synchronized cardioversion 100-200J
- Irregular: Unsynchronized cardioversion (defibrillation) 200J
Stable
- Procainamide 100 mg q5min at max rate of 25-50 mg/min[4]
- Until termination of arrhythmia, then start 2-6 mg/min (or 1-2 mg/min for renal/cardiac failure) OR
- Max 17 mg/kg total dose given (12 mg/kg if renal failure) OR
- If QRS widens > 50%
- Favored over Amiodarone in PROCAMIO trial; termination of tachycardia in 67% of procainamide group vs 38% of amiodarone group, adverse cardiac events 9% vs 41%, respectively [5]
- Amiodarone, agent of choice in setting of AMI or LV dysfunction
- 150 mg over 10min (15 mg/min), followed by 1 mg/min drip over 6hrs (360 mg total)[6]
- Then 0.5 mg/min drip over next 18 hrs (540 mg total)
- Oral dosage after IV infusion is 400 -800 mg PO daily
- Lidocaine 1-1.5mg/kg IV q5min, repeat PRN until up to 300mg/hr
Recurrent
- ≥3 episodes within 24 hours considered electrical storm and may require alternate treatment (i.e. beta blockade, sedation, ablation)
Other considerations
- True Vtach generally has rate >120bpm. If rate <120bpm or refractory to other therapy, consider other causes
- When in doubt, use cardioversion for treatment of regular WCT. In irregular WCT, consider Afib with WPW in which Procainamide is the treatment of choice.
- In very wide complex (>0.2 msec) and <120 bpm in a patient with significant history, consider giving calcium chloride to treat hyperkalemia
- Consider Acidosis
- Sodium channel blockade (e.g. from benadryl, TCA, or cocaine toxicity) may cause very wide complex (>0.2msec) tachycardia with rate <120bpm
- Treat with sodium bicarbonate
- Lidocaine, Procainamide, Amiodarone all block Na channels and may result in asystole in patients with intrinsic or extrinsic Na-channel blockade
Disposition
- Admit all patients (even if converted to NSR in ED)
See Also
- ACLS: Tachycardia
- ACLS (Main)
- V Tach vs. SVT
- Paroxysmal supraventricular tachycardia
- Nonsustained ventricular tachycardia
- Polymorphic ventricular tachycardia
References
- ↑ Gupta AK, Thakur RK. Wide QRS complex tachycardias. Med Clin North Am. 2001;85(2):245–66– ix–x.
- ↑ Akhtar M, Shenasa M, Jazayeri M, Caceres J, Tchou PJ. Wide QRS complex tachycardia. Reappraisal of a common clinical problem. Ann Intern Med. 1988;109(11):905–912.
- ↑ Stewart RB, Bardy GH, Greene HL. Wide complex tachycardia: misdiagnosis and outcome after emergent therapy. Ann Intern Med. 1986;104(6):766–771.
- ↑ Procainamide. GlobalRPH. http://www.globalrph.com/procainamide_dilution.htm.
- ↑ Ortiz M, Martín A, Arribas F, et al. Randomized comparison of intravenous procainamide vs. intravenous amiodarone for the acute treatment of tolerated wide QRS tachycardia: the PROCAMIO study. Eur Heart J. 2017 May 1;38(17):1329-1335
- ↑ Amiodarone. GlobalRPH. http://www.globalrph.com/amiodarone_dilution.htm.