Disease Name
Paroxysmal Supraventricular Tachycardia (PSVT)
1) Disease Description (Causes, Pathophysiology · Main Symptoms)
- Summary: PSVT refers to recurrent, sudden-onset tachycardia originating in the supraventricular region of the heart (the atria and area around the atrioventricular node). The representative mechanisms are atrioventricular nodal reentrant tachycardia (AVNRT) and atrioventricular reentrant tachycardia (AVRT) using an accessory pathway.
- Causes/Pathophysiology:
- AVNRT: A slow pathway and a fast pathway functionally coexist within the atrioventricular node, forming a circuit. A reentrant circuit is created through retrograde and antegrade conduction via the atrioventricular node.
- AVRT (including concealed accessory pathways): A muscular accessory pathway connecting the atria and ventricles, separate from the atrioventricular node, forms a reentrant circuit. Some accessory pathways have no evidence of conduction at rest and are not detected on a standard ECG (concealed accessory pathways).
- Main symptoms:
- Sudden rapid heartbeat (usually 150–250 beats/minute), palpitations
- Dizziness, shortness of breath (dyspnea), chest discomfort
- Many people can clearly feel when the episode starts and ends
- Rarely, low blood pressure, fainting, worsening heart failure, or chest pain (ischemic symptoms) may occur
2) Treatment Methods (Including Standard Treatment, Medication, Procedures/Surgery, and Lifestyle Management) and Precautions · Complications
- Acute phase (when symptoms occur)
- Nonpharmacological: Valsalva maneuver (the modified Valsalva maneuver has a higher success rate), applying ice to the face (infants), carotid massage (use cautiously in adults; contraindicated when cerebrovascular disease is suspected)
- Medication: Intravenous (IV) adenosine (first-line adult dose: rapid injection of 6 mg, followed by 12 mg if unsuccessful) — the first-choice medication for acute regular SVT with a narrow QRS. Preparation is necessary before use in patients with hemodynamic instability.
- Other options: IV beta-blockers (e.g., esmolol), IV calcium channel blockers (verapamil/diltiazem) — these induce AV block to terminate the tachycardia. However, if atrial fibrillation caused by an accessory pathway (evidence of electrical pre-excitation or WPW) is suspected, AV nodal blocking agents (beta-blockers/CCBs/digoxin) are contraindicated because they are dangerous and may cause rapid conduction to the ventricles.
- Emergency electrical treatment: In cases of hemodynamic instability (hypotension, shock, heart failure, or myocardial ischemia), synchronized electrical cardioversion (synchronized DC cardioversion) should be performed immediately.
- Prevention of recurrence (long term)
- Medication: Beta-blockers, nondihydropyridine calcium channel blockers, and antiarrhythmic drugs (such as propafenone and flecainide, when there is no structural heart disease) — the advantages, disadvantages, and side effects should be considered.
- Procedure: Radiofrequency catheter ablation (RFCA) — targets and eliminates the causative circuit (the slow pathway of the atrioventricular node or the accessory pathway). It has a high success rate (generally 85–95% or higher) in both adults and children and can provide a “curative treatment.” Risks of ablation include, rarely, atrioventricular block (if persistent, a pacemaker is required), vascular complications, and pericardiocentesis, among others.
- Surgical treatment: Very rare (when the procedure fails or concomitant cardiac surgery is required).
- Lifestyle management · Precautions
- Avoid factors that trigger episodes: caffeine, nicotine, excessive alcohol, some cold medicines (ingredients that stimulate the sympathetic nervous system), stress, and sleep deprivation.
- When an episode occurs, self-treatment such as the Valsalva maneuver may be attempted promptly (it is most effective within the first few minutes).
- When taking antiarrhythmic medication, side effects (hypotension, dizziness, cough, pulmonary or hepatic abnormalities, etc.) must be monitored.
- Complications
- Recurrent or prolonged episodes may cause fainting, worsening heart failure, or worsening ischemic heart disease.
- Procedure-related complications (as mentioned above)
- Prognosis
- It is generally not fatal, and when symptoms are mild, the course is favorable with management alone.
- Treatment with maintenance medication or ablation is determined according to the frequency of recurrence and quality of life. The cure rate is high after ablation.
3) Checklist Before an Outpatient Visit (Items to Bring · Materials to Show the Doctor · Example Questions to Prepare)
- Items/materials to bring or submit
- A list of all medications currently being taken (including prescription drugs, OTC medications, and dietary supplements) and medication times
- Previous electrocardiograms (ECGs), hospitalization/emergency room records, and Holter (24–48 h) or event monitor results, if available
- Symptom diary: time of episode onset, duration, triggers (food, beverages, activities), symptoms (dizziness, chest pain, etc.), self-treatment attempts, and responses
- History of previous cardiac procedures or surgery, allergies, and possibility of pregnancy (for women)
- Information to tell the doctor in advance during the outpatient visit
- Whether there has been any recent fainting or loss of consciousness
- Whether there is underlying heart disease (congenital abnormalities, valvular disease, or coronary artery disease)
- Whether anticoagulants are being taken (important when considering a procedure)
4) Examples of General Questions to Ask the Doctor
- What are the main side effects of this medication (or procedure), and what should I do if they occur?
- What is the likelihood of recurrence (prognosis) in my case?
- What warning signs indicate that I should go to the emergency room when symptoms occur?
- Are there any lifestyle factors I must avoid? (Exercise, alcohol consumption, driving, etc.)
- I am planning a pregnancy. How might this affect treatment (medication or ablation)?
5) Examples of Disease-Specific Questions (1–2)
- Can we determine with certainty whether the mechanism of my tachycardia is AVNRT (atrioventricular nodal reentry) or is caused by an accessory pathway (AVRT)? What tests are needed to confirm this?
- If you recommend catheter ablation (RF ablation), could you explain in detail the success rate, recurrence rate, and procedure-related risks (especially the possibility of atrioventricular block)? (Considering my age and underlying conditions, when would be the recommended time to undergo the procedure?)
If needed, we can briefly prepare a symptom-recording form, instructions for performing the Valsalva maneuver (including the modified method), or a list of documents to bring when visiting the hospital.