Wide Complex Tachycardia Uncertain Origin

Section 4 - CARDIAC

4.10 WIDE COMPLEX TACHYCARDIA – UNCERTAIN ORIGIN (Heart rate >150 beats/minute)

• INITIAL MEDICAL CARE (2.01) - OXYGEN @ 100% via NRB mask or assist with BVM.

STABLE and SVT highly likely:

• Administer ADENOSINE 6 mg RAPID IVP, administered at a port closest to the IV site, followed immediately by a rapid 10-20 ml saline flush
• If NO response in 2 minutes, ADENOSINE 12 mg RAPID IVP followed immediately by a rapid 10-20 ml saline flush (Maximum dose 18 mg)

STABLE and unknown wide complex or ventricular tachycardia likely:

• LIDOCAINE 1 to 1.5 mg/kg IV over 3-5 minutes
  • If no response, LIDOCAINE 0.5-0.75 mg/kg IV over 3-5 minutes (may repeat to a maximum of 3 mg/kg administered)
  • In patients over age 70 or in those with known hepatic disease limit the use of LIDOCAINE to a maximum of 1.5 mg/kg)

UNSTABLE WIDE COMPLEX TACHYCARDIA:

Definition of Unstable: Persistent Wide Complex Tachyarrhythmia causing:
Hypotension or signs of decreased tissue perfusion Significant dyspnea or significant compromise of the airway Acute mental status change Signs/symptoms of shock Acute heart failure Ischemic chest discomfort

• SYNCHRONIZED CARDIOVERSION
  • Initial recommended doses:
    • If narrow and regular complexes 50-100 Joules biphasic
    • If narrow and irregular complexes 120-200 Joules biphasic
    • If wide and regular complexes 100 Joules biphasic
    • If wide and irregular complexes – use defibrillation dose (not synchronized)
• If IV established prior to patient becoming UNSTABLE, may administer VERSED 2-5 mg IVP, IO or IN AND REPEAT 2 mg every 30 seconds to one minute if patient is conscious.
• If NO response, SYNCHRONIZED CARDIOVERSION @ 200 Joules.
• If NO response, SYNCHRONIZED CARDIOVERSION @ 360 Joules.

DEFIBRILLATION should be considered instead of synchronized cardioversion if the patient is deteriorating rapidly to avoid delays associated with synchronization.

Following electrical cardioversion if no antiarrythmic agent was given:

• Administer LIDOCAINE 1.0 mg/kg IV bolus.
  • Use ½ above dose if hypotensive.
  • Follow with continuous infusion at 2-4 mg/min
  • Contraindicated if ventricular escape rhythm
• If LIDOCAINE was given previously
  • Follow with continuous infusion at 2-4 mg/min
  • Contraindicated if ventricular escape rhythm.
• If HYPERKALEMIA suspected in any wide complex Tachycardia:
  • Suspect in patients with any of the following:
    • Diagnosis of Renal Failure or any form of Kidney insufficiency
    • Widening QRS
    • Increased K+ in diet (excessive consumption of cherries, bananas, melons or citrus), Acidosis, or Shock.
  • Note last dialysis TX.
  • CALCIUM CHLORIDE 1 gm IV (Avoid if patient is on digoxin/lanoxin)
  • SODIUM BICARBONATE 1 mEq/kg IV

Physician's Orders: If no response, contact Medical Control for consult.

Discontinue boluses in patients who now manifest tachycardia with hypotension, altered mental status, or widening of the QRS complex.