What is a Defibrillator — How It Works
A defibrillator is a medical device that delivers an electrical shock to the heart to correct abnormal rhythms.
What is a Defibrillator? Types & Complete Guide — AED, ICD, Manual & More
A defibrillator is a medical device that delivers an electrical shock to the heart to reset abnormal rhythms. There are 5 main types — from AEDs that anyone can use, to surgically implanted ICDs for permanent protection. Each type serves a different purpose and user. This guide explains all types with clear comparisons.
5 Types of Defibrillators
Defibrillators come in 5 main types, each designed for different situations and users:
| Type | Full Name | User | Setting | |------|-----------|------|---------| | AED | Automated External Defibrillator | Anyone | Public places | | Manual | Manual External Defibrillator | Doctors/nurses | Hospitals | | ALS | Advanced Life Support Defibrillator | Paramedics | Ambulances | | ICD | Implantable Cardioverter-Defibrillator | High-risk patients | Implanted in body | | WCD | Wearable Cardioverter-Defibrillator | Patients awaiting surgery | Worn as vest |
Key distinction: Defibrillator ≠ Pacemaker - Defibrillator delivers high-energy shocks to "reset" dangerously abnormal rhythms (VF/VT) - Pacemaker delivers continuous low-energy pulses to regulate a slow or irregular heartbeat - Modern ICDs function as both defibrillator and pacemaker in one device
Details for each type follow below.
Type 1 — AED (Automated External Defibrillator)
AED (Automated External Defibrillator) is the most common type found outside hospitals. Designed for use by anyone without medical training.
Key features: - Automatic heart rhythm analysis — no ECG reading required - Step-by-step voice guidance (Thai/English) - Will not shock a normally beating heart — safe for laypersons - Lightweight and portable (1-3 kg)
Two subtypes: - Semi-Automatic: Analyzes automatically but user presses the shock button. Best for locations with trained personnel. - Fully Automatic: Analyzes and shocks without any button press. Best for public spaces.
Where they're installed: Airports, shopping malls, train stations, stadiums, schools, offices, condominiums, hotels, factories. Per Ministerial Regulation No. 69, high-rise (23m+) and extra-large buildings (10,000 sqm+) must provide AED installation points.
กพฉ. standard specs: - Energy: 50J (pediatric), ≥120J (adult) - Analysis and shock within 10 seconds - Thai and English voice guidance
AEDs available in Thailand: Amoul i-Series, Philips FRx, ZOLL AED 3, ZOLL AED Plus, Mindray C1A/C2, Yuwell HeartSave Y8, Heart Guardian
Compare AED brands: AED Brand Comparison — 5 Brands
Types 2-3 — Manual and ALS Defibrillators
Manual External Defibrillator
Used in hospitals by trained doctors and nurses. Unlike AEDs, the operator must: - Read and interpret ECG waveforms independently - Select energy levels manually (not automatic) - Decide whether and when to shock
Key features: - High flexibility — doctors adjust energy based on situation - Real-time ECG waveform display - Suitable for newborns — very low energy can be set - Often includes pacing function (heart rhythm stimulation)
ALS Defibrillator — Ambulance Defibrillator
ALS (Advanced Life Support) Defibrillators are heavy-duty machines used by paramedics/EMTs in ambulances.
Key features: - Rugged, designed for challenging environments (moving vehicles, weather) - Multi-parameter monitoring (ECG, SpO2, blood pressure) - Both Manual and AED modes in one device - Patient data recording during transport
Neither Manual nor ALS defibrillators are designed for general public use — they require specialized training.
Type 4 — ICD (Implantable Cardioverter-Defibrillator)
ICD (Implantable Cardioverter-Defibrillator) is a defibrillator permanently implanted inside a patient's body. It continuously monitors heart rhythm and shocks automatically 24/7.
How it works: - Surgeon implants ICD beneath the collarbone - Thin wires (leads) connect from the device to the heart - The device continuously monitors heart rhythm - If VF or VT is detected → automatic shock delivery - Modern ICDs also function as pacemakers
Who needs an ICD: - Cardiac arrest survivors (secondary prevention) - High-risk patients: cardiomyopathy, Long QT Syndrome (primary prevention) - Severe heart failure patients
Lifespan: - ICD battery lasts approximately 5-10 years, requiring surgical replacement - High cost — ICD devices cost hundreds of thousands of baht (Thai social security and universal coverage may apply)
ICD ≠ AED: ICDs are implanted in specific patients, while AEDs are external devices for use on anyone in cardiac arrest. Both use the same principle (electrical shock to reset heart rhythm) but are designed for different situations.
Type 5 — WCD (Wearable Cardioverter-Defibrillator)
WCD (Wearable Cardioverter-Defibrillator) is an external defibrillator worn as a vest or harness underneath clothing.
How it works: - Sensors continuously monitor heart rhythm - If ventricular arrhythmia is detected → alerts the patient first - If patient is unresponsive (unconscious) → automatic shock - If patient responds (conscious) → they can cancel the shock (preventing false alarms)
Who uses WCD: - Patients awaiting ICD implant surgery - Patients whose ICD was removed to treat infection - Post-heart attack patients still being risk-assessed - Patients awaiting heart transplant
Key features: - No surgery required — put on and take off - Temporary solution while awaiting permanent treatment - Survival rate exceeds 90% when arrhythmia occurs - Patients can continue daily activities normally
WCD in Thailand: WCDs are not yet as common in Thailand as AEDs or ICDs, but some cardiac centers have adopted them. For the general public, AED is the most relevant defibrillator type.
Comparison of All 5 Defibrillator Types
| Criteria | AED | Manual | ALS | ICD | WCD | |----------|-----|--------|-----|-----|-----| | User | Anyone | Doctors/nurses | Paramedics | Surgically implanted | Patient wears it | | Placement | External (chest pads) | External (chest pads) | External (chest pads) | Internal (under skin) | External (vest) | | Analysis | Automatic | Operator reads ECG | Both modes | Automatic | Automatic | | Training needed | Not required | Required | Required | N/A (automatic) | Basic orientation | | Reusable | Yes (replace pads) | Yes | Yes | Yes (replace battery) | Yes | | Duration | Temporary (emergency) | Temporary (emergency) | Temporary (emergency) | Permanent | Temporary (weeks-months) |
For organizations and public venues: AED is the only appropriate choice — it's the only type designed for use by non-medical personnel without specialized training.
Read more: What is an AED — Complete Guide | Thai AED Law | CPR + AED Guide
Frequently Asked Questions
How many types of defibrillators are there?
There are 5 main defibrillator types: 1) AED — automatic, anyone can use 2) Manual — doctors in hospitals 3) ALS — ambulances 4) ICD — permanently implanted 5) WCD — worn as temporary vest. For public venues, AED is the only appropriate type.
What is a defibrillator? How do you pronounce it?
A defibrillator (dee-FIB-rih-lay-ter) is a medical device that delivers an electrical shock to the heart to reset abnormal rhythms. In Thai, it's called เครื่องกระตุ้นหัวใจ or เครื่องกระตุกหัวใจ.
What is the difference between a defibrillator and a pacemaker?
A defibrillator delivers high-energy shocks to "reset" dangerously abnormal rhythms (like VF). A pacemaker delivers continuous low-energy pulses to regulate a slow or irregular heartbeat. Modern ICDs combine both functions in one device.
How long does an ICD last?
ICD batteries last approximately 5-10 years depending on how frequently the device activates. When the battery nears depletion, surgery replaces the device unit while leads can often be reused. Costs are high but may be covered by Thai social security or universal healthcare.
Which defibrillator type can the general public use?
AED (Automated External Defibrillator) is the only type designed for public use. It features voice guidance, automatic analysis, and will not shock a normal heart. No training required. Thailand's Emergency Medical Act protects good-faith users.
Interested in AEDs for Your Organization?
Thunder Venture Group distributes Amoul AEDs with comprehensive after-sales service. Contact us for pricing and specifications.