What is the appropriate workup and management for a patient with recurrent episodes of tachycardia (heart rate of 125), associated with symptoms of heart palpitations, sweating, and shoulder pain, who recently finished a prescription for prednisone (corticosteroid)?

Workup and Management for Recurrent Tachycardia Episodes After Prednisone

For a patient with recurrent episodes of tachycardia (HR 125) associated with sweating, heart burning, shoulder pain, and "flutters" after completing prednisone, a 12-lead ECG, 48-hour ambulatory ECG monitoring, and echocardiography are essential for diagnosis and management.

Initial Evaluation

Immediate Assessment

• Obtain a 12-lead ECG during symptoms if possible 1
• Assess vital signs including blood pressure and oxygen saturation
• Review medication history, particularly focusing on the recently completed prednisone course

Diagnostic Testing

1. 12-lead ECG (resting) - to identify baseline abnormalities or pre-excitation 1
2. 48-hour ambulatory ECG monitoring - essential for capturing the paroxysmal episodes 1
   • If episodes are less frequent, consider an event recorder or implantable loop recorder (ILR) 1
3. Echocardiography - to exclude structural heart disease that may be contributing to arrhythmias 1
4. Exercise stress test - particularly if symptoms are exercise-related 1

Differential Diagnosis

Primary Considerations

• Supraventricular tachycardia (SVT) - most likely given the paroxysmal nature, heart rate of 125, and abrupt onset/termination 1

  • AVNRT (AV nodal reentrant tachycardia)
  • AVRT (AV reciprocating tachycardia)
  • Atrial tachycardia

• Corticosteroid-induced arrhythmia - prednisone can cause bradycardia and potentially tachyarrhythmias 2, 3

• Sinus tachycardia - less likely given the abrupt onset and termination 1

• Ventricular tachycardia - consider if ECG shows wide complex tachycardia 4

Secondary Considerations

• Atrial fibrillation - especially if the patient describes irregular palpitations 1
• Myocardial ischemia - given the shoulder pain and "heart burning" symptoms 5, 6
• Thyroid dysfunction - can be exacerbated by recent steroid use

Management Plan

Immediate Management

1. If currently symptomatic with stable vital signs:

   • Attempt vagal maneuvers (Valsalva, carotid sinus massage) if regular tachycardia is present 1
   • Document rhythm with 12-lead ECG during symptoms

2. If hemodynamically unstable during an episode:

   • Immediate synchronized cardioversion is indicated 4

Pharmacological Management

1. For documented SVT:

   • Beta-blockers (first-line) if no contraindications 1
   • Calcium channel blockers (verapamil, diltiazem) as alternatives 1
   • Avoid digoxin if pre-excitation is present 1

2. For documented ventricular arrhythmias:

   • Amiodarone (150 mg IV over 10 minutes, followed by infusion) for unstable VT 4
   • Procainamide for stable monomorphic VT 4

Referral Criteria

Refer to a cardiac electrophysiologist if:

• Sustained tachycardia episodes are documented 1
• ECG shows pre-excitation (WPW syndrome) 1
• Patient has severe symptoms (syncope, dyspnea) during episodes 1
• Tachycardia is drug-resistant or patient desires to be free of drug therapy 1

Follow-up Recommendations

1. Close monitoring during the first few weeks after prednisone discontinuation

2. Electrophysiology study (EPS) if:

   • Recurrent symptomatic episodes are documented 1
   • Diagnosis remains unclear after non-invasive testing 1
   • Patient has persistent or recurrent SVT 1

3. Consider catheter ablation for definitive treatment of recurrent SVT 1

Special Considerations

• The temporal relationship with prednisone completion is significant - corticosteroids can cause cardiac arrhythmias including both bradycardia and tachycardia 2, 3
• The shoulder pain during episodes raises concern for possible cardiac ischemia, which should be evaluated 5, 6
• The combination of "heart burning," sweating, and shoulder pain during tachycardia episodes warrants careful evaluation for acute coronary syndrome