Disease Description (Causes and Symptoms)
- Definition: Ventricular fibrillation (VF) is a condition in which the electrical activity of the ventricles is extremely rapid and disorganized (approximately 350–600 times per minute), so effective ventricular contractions do not occur. Because the heart cannot pump out blood, it immediately causes circulatory failure and pulseless cardiac arrest (sudden cardiac arrest).
- Main causes: Acute myocardial infarction (ischemia) is the most common cause. Other causes include coronary artery disease, cardiomyopathy, heart failure, after cardiac surgery, electrolyte abnormalities (low potassium or low magnesium), medications (such as excessive antiarrhythmic use), severe hypothermia, thyrotoxicosis, pericarditis, and excessive alcohol consumption. Primary (idiopathic) ventricular fibrillation that occurs without structural heart abnormalities also rarely exists.
- Pathophysiology: Multiple ectopic foci and reentry circuits cause the entire ventricles to become activated in a disorganized manner, resulting in the loss of effective contraction (cardiac output).
- Symptoms: Sudden fainting or loss of consciousness, cessation of breathing or abnormal breathing (gasping), and an impalpable pulse; in emergency situations, it can occur without warning. Palpitations, chest pain, or shortness of breath may occur for several seconds to several minutes before the episode.
Treatment Methods
- Emergency treatment (highest priority)
- Immediately contact the emergency medical system (such as 119) and begin cardiopulmonary resuscitation (CPR) as soon as possible.
- Use an automated external defibrillator (AED) or defibrillator (DC shock) as soon as possible — defibrillation is the most decisive treatment.
- In-hospital treatment and ACLS (advanced cardiac life support)
- Maintain high-quality CPR while performing repeated defibrillation.
- Medication: Epinephrine (1 mg intravenously, repeated every 3–5 minutes) is recommended. Consider using amiodarone as an antiarrhythmic (initially 300 mg intravenously, with an additional 150 mg if necessary) or lidocaine as an alternative.
- Correction of causes: Correct electrolyte abnormalities (potassium and magnesium), treat drug intoxication, correct hypothermia, and so on.
- Treatment after ROSC (return of spontaneous circulation)
- Consider targeted temperature management (therapeutic hypothermia) to protect neurological outcomes.
- If an ischemic cause is suspected, perform emergency coronary angiography and, if necessary, percutaneous coronary intervention (PCI).
- Monitor myocardial function and electrolytes and provide multisystem supportive care.
- Secondary prevention
- If the cause can be corrected (e.g., electrolyte correction or temporary drug-induced arrhythmia), address it and then assess the risk of recurrence.
- In cases of irreversible causes or high risk of recurrence: Implantation of an implantable cardioverter-defibrillator (ICD) is recommended, as determined by a cardiologist.
- Standard treatment for underlying heart disease (coronary artery disease, cardiomyopathy, etc.), such as beta-blockers, ACE inhibitors/ARBs, and statins.
- Lifestyle management and precautions
- In an emergency, quickly contact 119 or go to the emergency room; family members and colleagues are encouraged to learn the location of the AED and CPR.
- Avoid excessive alcohol consumption and illegal drugs, and take prescribed medications regularly.
- After ICD implantation, undergo regular device checks and follow the medical team's instructions.
- Complications and prognosis
- Neurological damage due to cerebral hypoxia, multiple organ failure, recurrent ventricular arrhythmias, and worsening heart failure may occur.
- Prognosis is greatly influenced by the initial response (immediate defibrillation and high-quality CPR) and the cause (e.g., whether there is acute ischemia that can be treated with reperfusion).
Outpatient Visit Checkpoints (Including Example Questions)
- Items to prepare (bring with you)
- A list of currently taken medications (including doses and administration times) and a history of allergies
- Copies or summaries of previous test results (electrocardiogram, echocardiogram, coronary angiography/PCI findings, etc.)
- The hospital discharge summary (including records of cardiac arrest and defibrillation)
- If you have an ICD, the device card or the company name/model information
- The time, circumstances, and duration of the episode or symptoms, and a witness statement (brief notes)
- Family history (sudden death at a young age or inherited heart disease)
- Examples of self-records before an outpatient visit
- Frequency and characteristics of symptoms (palpitations, dizziness, presyncope symptoms)
- Recent alcohol or drug intake and symptoms related to electrolyte abnormalities (such as vomiting or diarrhea)
- Information to tell the doctor in advance during the outpatient visit
- Any recent fainting or defibrillation, whether an ICD has been implanted, and any history of cardiovascular surgery or procedures
Examples of General Questions to Ask the Doctor
- What are the side effects of this medication (e.g., amiodarone or beta-blockers), and how will they be monitored?
- What is the presumed cause of this event, and how high is the risk of recurrence?
- What is the expected prognosis (neurological recovery and survival rate)?
- What should be prioritized in cardiac rehabilitation or lifestyle improvement?
- Are there any restrictions on driving, work (such as operating heavy equipment), or sports participation?
Examples of Disease-Specific Questions
- In my case, is ICD (implantable cardioverter-defibrillator) implantation recommended? If so, when should it be performed and what benefits can be expected?
- Are there any additional tests I should undergo to reduce the risk of recurrence (such as genetic testing, an electrophysiology study, or coronary artery testing)?
- If acute ischemia (myocardial infarction) was the cause in my case, how long is coronary reperfusion treatment (PCI) effective? Is additional treatment needed after the acute phase?
(In an emergency, calling emergency medical services without delay and immediately performing CPR/defibrillation are crucial to improving the survival rate.)