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Arrhythmia: Types, Symptoms, Causes, and When to Seek Care

Definition

An arrhythmia is any deviation from the normal sinus rhythm: too fast (tachycardia), too slow (bradycardia), or irregular (atrial fibrillation, ectopic beats).

Common Types

  • Atrial fibrillation (AFib): Irregularly irregular; stroke risk.
  • Atrial flutter: Regular atrial tachycardia (~300 bpm).
  • SVT (AVNRT, AVRT): Sudden onset/offset palpitations.
  • Ventricular tachycardia/fibrillation: Life-threatening; requires immediate defibrillation.
  • Bradyarrhythmias: Sinus node dysfunction, AV block.
  • Premature beats (PACs, PVCs): Often benign.

Symptoms

  • Palpitations, skipped beats, racing heart
  • Dizziness, syncope, near-syncope
  • Shortness of breath, chest discomfort
  • Fatigue, exercise intolerance
  • Asymptomatic (incidental finding)

Causes/Triggers

  • Heart disease (CAD, cardiomyopathy, valve disease)
  • Electrolyte imbalance (K+, Mg2+, Ca2+)
  • Thyroid dysfunction (hyper/hypo)
  • Medications (beta-blockers, digoxin, QT-prolonging drugs)
  • Caffeine, alcohol, stimulants, stress
  • Sleep apnea
  • Genetic channelopathies (Long QT, Brugada)

When to Seek Immediate Care

  • Chest pain, dyspnea, syncope with palpitations
  • Heart rate >150 bpm or <40 bpm with symptoms
  • Known heart disease + new arrhythmia

Diagnosis and Management

ECG, Holter/event monitor, echo, EP study. Treatment: rate/rhythm control, anticoagulation (AFib), ablation, devices (pacemaker, ICD), lifestyle modification.

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