Medications & Cardioversion

The treatment of choice for symptomatic patients with a stable blood pressure is IV administration of adenosine. The advantage of this drug is that it is relatively safe, has limited side effects, and has a half life of 5 to 10 seconds.

• The initial dose is 0.1mg/kg (maximum dose is 6 mg)
  • Due to the extremely short half life, it should be administered through the port closest to the hub of the IV catheter, or directly into the vein within 1 to 2 seconds and immediately followed with a 2-3 ml. bolus of normal saline.
• If there is no rhythm change within 1 to 2 minutes, a second dose should be administered at twice the first dose (up to 12 mg. maximum single dose) and immediately flushed through with a 2-3 ml. bolus of normal saline.
• Close cardiac monitoring is essential as new arrhythmias may occur such as PVCs, sinus bradycardia, dropped beats, or asystole. These arrhythmias are self limiting and usually resolve without intervention when the adenosine becomes deactivated.

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Watch the monitor with us in the Emergency Room. Examine nurse's notes as patient is treated for PSVT in the ER!

Intravenous propranolol and verapamil are commonly used to terminate PSVT in adults, but are used with greater caution in the pediatric patient. These medications result in long-duration adrenergic and calcium-channel blockade causing cardiovascular collapse, profound bradycardia, and death in the younger child. IV verapamil or propranolol can be used for the acute treatment of PSVT IF:

• The child is over 1 year of age.
• Has no underlying cardiac abnormalities.
• The child is not in CHF.
• The child is not on beta-blockers.

For the patient who is hemodynamically compromised, synchronized cardioversion is the treatment of choice. Ideally, prior to cardioversion, patients should:

• be intubated
• ventilated with 100% oxygen
• have secure venous or intraosseous access
• be considered for conscious sedation

Obviously though, if the child is quickly decompensating, cardioversion should not be delayed while the above therapies are performed.

The initial dose for synchronized cardioversion is 0.5 joules/kg. If PSVT persists the dose is doubled.

Long term medical treatment of most patients with PSVT often includes digoxin (except in those children with Wolff-Parkinson-White syndrome)

• If digoxin fails to control PSVT, a beta-blocker such as propranolol may be prescribed.
• Calcium-channel blockers are often ineffective for most patients, but may be tried in those patients who fail to respond to other medications first.

For more information on digoxin administration to children, click here

When the nurse provides discharge education for the patient and family, a careful review of the precipitating factors of PSVT must occur.

• The direct relationship between the avoidance of these factors and the decrease in the number of PSVT episodes must be stressed to the family and understood by them.
• Home management techniques should be taught to all members of the family with appropriate return demonstrations.
• Additional education for the family members should be encouraged, e.g. CPR and First Aid courses.
• Emergency numbers should be reviewed with the parent as well as follow up appointments for the child.

Instant Feedback:

If a second dose of Adenosine is indicated, it is to be the same amount as the first dose.

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