Atrial flutter

Disease Description (Causes and Symptoms)

• Definition summary: A general term for a condition in which the generation or conduction of the heart’s normal electrical impulses is delayed or blocked at one of the levels along the pathway from the sinoatrial node (SA) → atrioventricular node (AV) → the intraventricular conduction system (right bundle/left bundle), resulting in abnormalities of heart rhythm and conduction.
• Main causes: Coronary artery disease and myocardial injury (ischemia, cardiomyopathy), electrolyte abnormalities (low or high potassium, low calcium, etc.), medications (beta-blockers, calcium-channel blockers, digoxin, some antiarrhythmic drugs, etc.), alcohol, smoking, and caffeine, atrial or ventricular enlargement, acute infection, age-related degeneration of the conduction system, and others.
• Pathophysiology: Even when an impulse is generated, conduction delay or blockage occurs at the AV node or the intraventricular conduction system (right bundle/left bundle) → symptoms are caused by bradycardia, temporary or persistent segmental dyssynchrony, and impaired transmission of impulses to the ventricles.
• Main symptoms: It may be asymptomatic, but possible symptoms include dizziness, syncope (including symptoms before and after fainting), shortness of breath, a pounding or racing heartbeat (palpitations), fatigue, and worsening of symptoms during exercise. The prognosis and treatment vary depending on whether symptoms are present and on the location of the block (e.g., right bundle vs. left bundle, first-, second-, or third-degree AV block).

Treatment Methods (Standard Treatment, Medication, Procedures/Surgery, Lifestyle Management, and Precautions)

• Diagnostic procedures (before treatment)
  • Standard tests: 12-lead electrocardiogram (ECG), 24-hour Holter monitoring or an event monitor (to detect intermittent arrhythmias), echocardiography (to identify underlying heart disease), chest X-ray, exercise stress testing when necessary, and an electrophysiology study (EPS) to assess the location and mechanism of the lesion.
• Treatment of acute and correctable causes
  • Electrolyte correction (potassium, calcium, etc.), discontinuation or dose adjustment of causative medications (as directed by a doctor), treatment of ischemic causes (including coronary intervention), and treatment of infection.
• Mechanical treatment (implanted devices)
  • Permanent pacemaker (particularly for symptomatic bradycardia, high-grade AV block [Mobitz II, third-degree AV block], etc.) — according to the indications.
  • Temporary pacemaker: Temporary pacing in cases of acute cardiac symptoms (syncope, hypotension, risk of cardiac arrest).
  • In heart failure accompanied by cardiomyopathy and left bundle branch block, CRT (cardiac resynchronization therapy) may be considered as part of pacemaker treatment.
  • If necessary, an ICD (implantable cardioverter-defibrillator) may be added when the associated risk of ventricular arrhythmia is high.
• Medication treatment
  • Treatment of the underlying cause (medications for ischemia, heart failure, etc.). When AV block is present, use caution with medications that can worsen AV block, such as beta-blockers, non-dihydropyridine calcium-channel blockers, and digoxin.
  • Depending on high-rate ventricular tachycardia or accompanying arrhythmias, the use of antiarrhythmic drugs and anticoagulants (e.g., when AF is also present) should be assessed individually.
• Lifestyle management and preventive measures
  • Maintain electrolyte balance, limit excessive alcohol and caffeine intake, stop smoking, exercise regularly (as appropriate for your heart condition), and keep a record of medications taken.
  • When there is a risk of syncope, limit high-risk activities (such as driving and working at heights).
• Precautions and risk of complications
  • Asymptomatic right bundle branch block, for example, may be monitored, but there is a risk of a poor prognosis when left bundle branch block or high-grade AV block is present.
  • Possible risks include trauma caused by syncope, cardiac arrest and sudden death, pacemaker-related complications (infection and lead problems), and possible device dependence.
  • In an emergency (syncope, shortness of breath, loss of consciousness, etc.), seek emergency medical care immediately, including cardiopulmonary resuscitation and defibrillation.

Checkpoints Before an Outpatient Visit (Including Items to Bring, Records, and Example Questions)

• Items/documents to bring
  • A list of all medications currently being taken (including prescription drugs, OTC drugs, and herbal medicines) and the times they are taken
  • Copies of previous ECGs, Holter or event monitor results, and echocardiography or other test results, if available
  • Medical history (heart disease, myocardial infarction, history of pacemaker/ICD implantation, etc.)
  • Symptom diary: the time and duration of syncope, dizziness, or palpitations; the activity at the time (at rest or during exercise); and preceding symptoms
  • Lifestyle information: amount of alcohol, caffeine, and tobacco use, and recent changes in body weight
• Simple measurements during an outpatient visit
  • Current pulse and blood pressure, and an ECG recorded while symptoms are occurring, if possible
• Examples of questions to prepare in advance for the doctor
  • Recording the frequency and triggering circumstances of recent symptoms (during exercise, at rest, after taking medication, etc.) can help with diagnosis.

Examples of General Questions to Ask the Doctor

• “What are the possible side effects of this medication (or the prescription change)? Are there any interactions with my current medications?”
• “What is the prognosis (short-term and long-term) of my current condition? How should I manage lifestyle and exercise restrictions?”
• “Are there any medications or lifestyle habits I should stop immediately to reduce my symptoms?”

Examples of Condition-Specific Questions

• “Based on my ECG and test findings, where is the conduction disorder located, and how severe is it? (For example, first-, second-, or third-degree AV block, right or left bundle branch block, etc.)”
• “If I need a pacemaker (or CRT/ICD), which type would be most suitable, and what are the benefits and risks of the procedure?”