What is the diagnosis and treatment for a 15-year-old male with acute palpitations and tachycardia (180 bpm) triggered by emotional stress, without syncope or other symptoms?

Diagnosis: Supraventricular Tachycardia (SVT), Most Likely AVNRT

This 15-year-old male has supraventricular tachycardia (SVT) triggered by acute emotional stress, with a heart rate of 180 bpm—a classic presentation of atrioventricular nodal reentrant tachycardia (AVNRT) in an adolescent.

Clinical Reasoning

The presentation is textbook for SVT in a teenager:

• Heart rate of 180 bpm falls within the typical AVNRT range of 180-200 bpm 1
• Emotional stress trigger (hearing death news) is a known precipitant of AVNRT 1
• Absence of syncope, dizziness, or other symptoms indicates hemodynamic stability
• Young male without structural heart disease fits the typical AVNRT demographic 1

AVNRT is the most common SVT in young adults and is rarely life-threatening 1. The sudden onset of palpitations after emotional stress, without loss of consciousness, strongly supports this diagnosis over more dangerous arrhythmias like catecholaminergic polymorphic ventricular tachycardia (CPVT), which typically presents with syncope or cardiac arrest during stress 2, 3.

Immediate Treatment Algorithm

Step 1: Vagal Maneuvers (First-Line)

Start immediately with vagal maneuvers 1:

• Valsalva maneuver: Patient supine, bear down against closed glottis for 10-30 seconds (equivalent to 30-40 mmHg pressure)
• Ice-cold wet towel to face: Based on diving reflex
• Carotid sinus massage: Only after confirming no bruit, apply steady pressure for 5-10 seconds

Success rate is approximately 27.7% when switching between techniques 1.

Step 2: Adenosine (If Vagal Maneuvers Fail)

Adenosine is the recommended pharmacological first-line treatment 1:

• 95% success rate in terminating AVNRT 1
• Rapid IV push: 6 mg initial dose, followed by 12 mg if needed
• Short half-life with minimal negative inotropic effects 4
• Safe in adolescents and serves dual diagnostic/therapeutic purpose

Step 3: IV Beta-Blockers or Calcium Channel Blockers (If Adenosine Fails)

For hemodynamically stable patients, use IV beta-blockers, diltiazem, or verapamil 1:

• IV diltiazem or verapamil: Particularly effective (80-98% success rate) but contraindicated if any concern for pre-excited atrial fibrillation or ventricular tachycardia
• IV beta-blockers (esmolol): Excellent safety profile, preferred if any diagnostic uncertainty
• Critical caveat: Verapamil is contraindicated in patients <5 years old due to risk of electromechanical dissociation 4, but safe in this 15-year-old

Step 4: Synchronized Cardioversion (Last Resort)

Only if pharmacological therapy fails or is contraindicated 1.

Important Diagnostic Considerations

Must Obtain:

• 12-lead ECG during tachycardia: Narrow QRS complex confirms SVT
• Post-conversion ECG: Look for pre-excitation (delta waves) suggesting Wolff-Parkinson-White syndrome
• Family history: Rule out inherited arrhythmias like CPVT (though unlikely given presentation) 2, 3

Red Flags That Would Change Management:

• Wide QRS complex: Could indicate ventricular tachycardia—avoid calcium channel blockers
• History of syncope with exercise/emotion: Consider CPVT, requires cardiology referral 5
• Abnormal baseline ECG or family history of sudden death: Immediate cardiology consultation 5

Ongoing Management

If this is a first episode that terminates successfully, no prophylactic medication is needed initially. However:

• Cardiology referral for exercise stress test and Holter monitoring to assess for recurrence risk
• If recurrent episodes: Oral verapamil or diltiazem for ongoing management 1
• Definitive treatment: Radiofrequency catheter ablation has 90% permanent cure rate in adolescents and is preferred over long-term medication 4

Common Pitfalls to Avoid

1. Do not give verapamil or diltiazem if there is any possibility of ventricular tachycardia or pre-excited AF—can cause hemodynamic collapse 1
2. Do not dismiss as "anxiety" without ECG documentation—palpitations in teenagers warrant cardiac evaluation if associated with activity or concerning features 5
3. Do not use carotid massage without first checking for carotid bruits
4. Do not give epinephrine if CPVT is in differential—directly contraindicated 3

Bottom line: This patient needs vagal maneuvers immediately, followed by adenosine if unsuccessful, with ECG documentation before and after conversion.