Supraventricular Tachycardia (SVT)
Supraventricular Tachycardia (SVT)
Source: JCS Task Force 2025– EP Session, Dr. Munir Zaqqa (Interventional EP Cardiologist)
Keynotes :
1. Definition
• SVT = abnormal heart rhythm > 100 bpm.
• Originates from the His bundle or above (atrial or AV nodal tissue).
2. Clinical Presentation
• Main symptom: palpitations.
• Other possible symptoms: dyspnea, fatigue, light-headedness, chest discomfort, syncope, or may be asymptomatic.
3. Initial Assessment Algorithm
1. Assess patient → Check vital signs and hemodynamic stability.
2. Obtain ECG to confirm tachycardia type.
3. If sinus rhythm: search for underlying cause (anxiety, volume depletion, PE, etc.).
4. If SVT: determine if patient is stable.
4. Unstable Patient
• Immediate cardioversion (50–200 J synchronized).
5. Stable Patient – Stepwise Treatment
1. Assess mechanism on ECG:
A regular narrow-complex tachycardia usually indicates a reentry mechanism, while an irregular pattern suggests atrial fibrillation or other non-reentrant causes (e.g., AF, MAT).
2. Regular SVT (reentry type):
• Perform Valsalva maneuver (first step).
• If not converted → Adenosine 6–18 mg rapid IV bolus with escalation.
• If still not converted → AV-nodal blocking agents (beta-blocker or non-DHP CCB).
• If ineffective → Antiarrhythmic agents (flecainide, propafenone, amiodarone) — avoid contraindications.
• Cardioversion if pharmacologic treatment fails.
3. Irregular tachycardia: manage according to specific protocol (e.g., AF or MAT).
6. Long-Term Management
a. Patient Education
• Avoid caffeine, alcohol, and stress triggers.
• Regular follow-ups for symptom control and drug side effects.
• Monitor heart rhythm and adherence to therapy.
• Watch for recurrence or complications.
b. Pharmacologic Therapy
• β-blockers (metoprolol 25–100 mg daily; bisoprolol 2.5–10 mg daily).
• Calcium-channel blockers (diltiazem 120–360 mg; verapamil 120–240 mg).
• Antiarrhythmics (flecainide, propafenone, amiodarone) — reserve for refractory cases under specialist supervision.
c. Electrophysiologic Study & Ablation
• Recommended to avoid long-term medications and prevent recurrent hospitalizations.
• Curative success rates > 95 % for AVNRT/AVRT with low risk of complications.
7. Key Take-Home Messages
• Follow a structured algorithm for SVT recognition and management.
• Early ECG confirmation and stability assessment are crucial.
• Adenosine remains the first-line acute drug for regular narrow complex tachycardia.
• Catheter ablation is the definitive therapy for recurrent SVT.
