Cardiac arrhythmia

Disease Description (Causes and Symptoms)

• Definition summary: A condition in which the pulse becomes abnormally fast (tachycardia), slow (bradycardia), or irregular due to abnormalities in the generation or conduction of the heart’s normal beats. It is classified according to the site of origin, such as the atria, atrioventricular junction, or ventricles.
• Major causes: Abnormalities of the cardiac conduction system (sinoatrial node, atrioventricular node, His bundle, and Purkinje system), ischemic heart disease (acute or chronic myocardial infarction), electrolyte abnormalities (low/high potassium or magnesium), hyperthyroidism, medications (antiarrhythmics, antipsychotics, antibiotics, etc.), acute or chronic structural heart disease, congenital abnormalities (such as WPW), metabolic or acid–base abnormalities, aspiration or submersion, and hyperventilation or stress.
• Pathophysiology (brief): Abnormal automaticity, formation of reentry circuits, and conduction block distort cardiac impulse generation and conduction, resulting in abnormal rhythms.
• Major symptoms: Palpitations, dizziness, syncope (or presyncopal symptoms), shortness of breath, chest pain, fatigue, and, rarely, no symptoms. In the case of atrial fibrillation, the risk of stroke increases.

Treatment Methods

• General principles: Treatment is selected based on the mechanism (tachycardia vs. bradycardia, supraventricular vs. ventricular), patient stability (hemodynamic instability), and whether underlying heart disease is present.
• Emergency treatment (unstable patients): Immediate synchronized cardioversion (electrical cardioversion); ventricular fibrillation and sustained ventricular tachycardia require defibrillation and medications (such as epinephrine and amiodarone) according to ACLS guidelines.
• Drug treatment
  • Rate control for tachycardia: Beta-blockers (e.g., metoprolol) and non-DHP calcium channel blockers (diltiazem, verapamil)—particularly for atrial tachycardia.
  • Rhythm control (atrial or supraventricular): Amiodarone, sotalol, propafenone, and flecainide (structural heart disease must be absent), among others.
  • Anticoagulation (to prevent stroke in atrial fibrillation and other conditions): Based on the CHA2DS2-VASc score, a DOAC (such as rivaroxaban or apixaban) or warfarin (target INR 2.0–3.0).
  • Treatment of bradycardia: A pacemaker (permanent pacemaker) when symptoms or hemodynamic problems are present.
  • Acute correction of electrolyte and metabolic abnormalities: Potassium or magnesium supplementation, thyroid function control, and so on.
• Procedures/Surgery
  • Electrical cardioversion: To restore rhythm when drug or non-drug treatments are used.
  • Percutaneous radiofrequency or cryoablation (catheter ablation): Recommended as first-line treatment or when drug treatment fails for indications such as persistent or recurrent atrial fibrillation, AVNRT, and WPW.
  • Mechanical support: A permanent pacemaker (for bradycardia or complete atrioventricular block) and an implantable cardioverter-defibrillator (ICD; for patients at high risk of ventricular tachycardia or ventricular fibrillation)—for patients with recurrent life-threatening ventricular tachycardia and heart failure.
• Lifestyle management and precautions
  • Avoid triggers: Avoid caffeine, excessive alcohol, amphetamines, and some cold medicines (sympathomimetic agents); prevent dehydration, maintain regular sleep, and treat sleep apnea.
  • Medication use and interaction management: Check the side effects and interactions of prescribed antiarrhythmics and anticoagulants (particularly avoid concomitant use of medications that can cause QT prolongation).
  • Follow-up testing: ECG, Holter monitoring (24–48 hours) or an event monitor, electrolyte and thyroid function tests, and echocardiography (to assess structural heart disease).
• Risk of complications: Stroke (particularly with atrial fibrillation), worsening heart failure, cardiomyopathy caused by persistent tachycardia (tachycardia-induced cardiomyopathy), and syncope or sudden death (ventricular arrhythmias).

Checklist Before an Outpatient Visit (Including Items to Bring and Example Questions)

• Items to bring
  • List of current medications and supplements (including doses and administration times)
  • Recent test results (electrocardiogram ECG, Holter monitoring, echocardiography, blood tests (electrolytes, thyroid function, kidney function), and records of previous surgeries or procedures)
  • Symptom diary: Time of symptom onset, duration, triggers (exercise, stress, food, medications), and accompanying symptoms (syncope, shortness of breath)
  • Family history: Sudden death at a young age or hereditary heart disease
• Useful records before the appointment
  • When palpitations began and how often they occur; heart rate measured during symptoms, if possible
  • Recent records of alcohol, caffeine, and medication use
• Materials to show the doctor at the outpatient visit
  • Previous ECGs (originals, if possible), Holter report, and medication prescriptions
• Things to know before the outpatient visit
  • If you are taking an anticoagulant, check in advance about instructions before tests or procedures (bleeding risk)
  • Record symptoms as soon as possible when they occur (a mobile-phone audio or video recording, smartwatch ECG, etc., can be useful)

Examples of General Questions to Ask the Doctor

• What are the side effects of this medication? (Especially anticoagulants and antiarrhythmics)
• Do I need anticoagulant treatment to prevent stroke given my current condition? (Please explain the CHA2DS2-VASc criteria.)
• What do you think is causing my heart rhythm problem?
• In what situations should I go to the emergency room because of these symptoms?
• What should I be careful about during daily activities, exercise, alcohol consumption, and work?
• How often should I have follow-up tests?

Examples of Disease-Specific Questions

• Regarding anticoagulation: "How is my CHA2DS2‑VASc score calculated, and which is more suitable for me, a DOAC or warfarin? What is my bleeding risk (e.g., HAS‑BLED)?"
• Regarding procedures: "If drug treatment does not control the condition, is catheter ablation (or a pacemaker/ICD) recommended? What are the expected success rate and potential complications of the procedure?"

(Emergency signs: If chest pain, loss of consciousness or syncope, severe shortness of breath, severe dizziness, or persistent tachycardia or hypotension occurs, visit the emergency room immediately.)