What should a patient expect after adenosine administration for Supraventricular Tachycardia (SVT)?

What to Expect After Adenosine Administration for SVT

Patients should expect transient but common side effects after adenosine administration, including flushing, dyspnea (shortness of breath), and chest discomfort, which typically resolve within seconds to minutes due to adenosine's very short half-life. 1

Immediate Effects to Expect

• Conversion to normal rhythm: 90-95% success rate for terminating SVT 1

• Common transient side effects:

  • Flushing (feeling of warmth, particularly in the face)
  • Dyspnea (feeling of breathlessness)
  • Chest discomfort or pressure
  • Sense of impending doom or anxiety
  • Dizziness or lightheadedness
  • Nausea (less common)
  • Headache (less common) 2, 1

• Duration of side effects: Very brief, typically lasting only seconds to minutes due to adenosine's extremely short half-life (less than 10 seconds) 2

Administration Process

Patients should be informed that:

• Adenosine is administered as a rapid IV push through a large vein
• It is followed immediately by a saline flush
• The effect is almost immediate
• Continuous ECG monitoring will be performed during administration
• They may feel a brief sensation of "impending doom" which resolves quickly 1

Special Considerations and Warnings

Contraindications

Patients with the following conditions should alert their healthcare providers:

• Asthma or COPD (adenosine should be avoided or used with extreme caution) 2, 3
• Taking medications such as:
  • Dipyridamole or carbamazepine (requires reduced dose)
  • Theophylline, caffeine, or theobromine (may require larger doses) 2, 4
• Heart transplant recipients (requires reduced dose) 2

Important Warnings

Patients should be informed that in rare cases, adenosine may cause:

• Bronchoconstriction (particularly in patients with asthma/COPD) 4, 3
• Brief heart block or other transient arrhythmias
• Hypersensitivity reactions
• Very rarely, seizures 4

After Conversion

• Monitoring period: Patients will be monitored for:

  • Recurrence of SVT (which occurs in some cases)
  • Vital sign stability
  • Resolution of symptoms 2

• Potential for recurrence: SVT may recur after initial conversion, which might require:

  • Additional doses of adenosine
  • Alternative medications (calcium channel blockers or beta-blockers)
  • Discussion of long-term management options 2, 1

Long-term Considerations

After successful acute treatment, patients should discuss:

• Electrophysiological study with possible catheter ablation (95% success rate for AVNRT)
• Oral medications for ongoing management if ablation is not pursued
• Lifestyle modifications to reduce triggers 1

Key Points for Patient Education

1. The side effects, while uncomfortable, are extremely brief
2. Adenosine is highly effective (90-95% success rate)
3. Patients should avoid caffeine prior to treatment as it can interfere with adenosine's effectiveness
4. Patients should always disclose their complete medical history, especially respiratory conditions and current medications 2, 1, 4