A short story: what would you do?
Follow Tita Linda to learn the warning signs and what to do. Turn on your sound for the narration.
What happens in an arrhythmia
Each heartbeat starts with an electrical signal from a small group of cells in the upper right chamber, called the sinus node. It is the heart's natural pacemaker. The signal spreads across the upper chambers (atria), passes through a gate called the AV node, then travels down special wiring to the lower chambers (ventricles), which squeeze and pump blood to the body. [Ref: ACC/AHA/HRS 2018 Bradycardia]
At rest, a normal heart beats in a steady rhythm, usually 60 to 100 times a minute. An arrhythmia happens when the signal starts in the wrong place, is blocked, or goes around in a loop. [Ref: ESC 2019 SVT] [Ref: ACC/AHA/HRS 2018 Bradycardia]
Too slow: bradyarrhythmia
The heart beats too slowly, usually under 50 beats a minute at rest, so the body may not get enough blood. A slow rate can be normal in fit people and during sleep.
Too fast or irregular: tachyarrhythmia
The heart beats faster than 100 beats a minute at rest, or unevenly. A fast rate is normal during exercise, fever or fear, but not when you are resting.
[Ref: ACC/AHA/HRS 2018 Bradycardia] [Ref: ESC 2019 SVT]
Slow and fast heart rhythms
Doctors name an arrhythmia by its speed and by where in the heart it starts. An ECG (electrocardiogram) shows the pattern. [Ref: ESC 2019 SVT] [Ref: ESC 2022 VA]
Slow rhythms (bradyarrhythmias)
Sinus node dysfunction ("sick sinus")The natural pacemaker fires too slowly, pauses, or cannot speed up with activity. It is more common with older age. Some people swing between slow and fast rhythms.
Heart block (AV block)The signal is delayed or blocked on its way from the upper to the lower chambers. Mild forms often need no treatment. In complete heart block, no signals get through, and a pacemaker is usually needed.
[Ref: ACC/AHA/HRS 2018 Bradycardia] [Ref: ESC 2021 Pacing]
Fast rhythms (tachyarrhythmias)
Atrial fibrillation (AF)The most common long-lasting arrhythmia. The upper chambers quiver instead of beating, so the pulse is irregular and often fast. Blood can pool and form clots that travel to the brain and cause a stroke.
Atrial flutterA fast, regular loop in the upper chambers. It carries a stroke risk like AF and is often treated the same way.
Supraventricular tachycardia (SVT)Sudden attacks of a very fast, regular heartbeat that start and stop suddenly. It is usually caused by an extra electrical pathway or a short loop in the heart's wiring, often near the AV node. It is often seen in younger people and is usually not dangerous. But tell your doctor if you have fainted, or if you were told you have an extra pathway (WPW).
Extra beats (premature beats)A skipped or extra beat that feels like a flutter or thump. They are very common and usually harmless in a healthy heart.
Ventricular tachycardia (VT)A fast rhythm from the lower chambers, often in people with a weak or scarred heart, for example after a heart attack. It can cause fainting and can turn into VF.
Ventricular fibrillation (VF)The lower chambers quiver and stop pumping. This is cardiac arrest. Without CPR and a shock from a defibrillator within minutes, it is fatal.
[Ref: ESC 2024 AF] [Ref: ESC 2019 SVT] [Ref: ESC 2022 VA]
Why atrial fibrillation matters
People with AF are about five times more likely to have a stroke than people without it. Taking the right blood thinner lowers this risk a lot. [Ref: AHA AFib and Stroke] [Ref: ESC 2024 AF]
In the Philippines, a study of PhilHealth claims from 2017 to 2018 found that about 19 of every 10,000 adult hospital admissions were due to AF. The typical patient was in their late 60s. [Data: PJC 2026 AF]
Causes and risk factors
Things that strain the heart
Older age, high blood pressure, heart attack or blocked heart arteries, heart failure, heart valve disease, and heart problems present from birth.
Things you can change
Excess weight, drinking alcohol, smoking, too little physical activity, diabetes, and untreated sleep apnea (loud snoring with pauses in breathing).
Causes that can be reversed
Some medicines that slow the heart, an overactive or underactive thyroid, and high or low potassium. Fixing these may fix the rhythm.
[Ref: ESC 2024 AF] [Ref: ACC/AHA 2023 AF] [Ref: ACC/AHA/HRS 2018 Bradycardia]
Symptoms
Some people feel nothing, and the arrhythmia is found on a routine ECG or a smartwatch. Others notice: [Ref: ESC 2024 AF] [Ref: ACC/AHA/HRS 2018 Bradycardia]
PalpitationsA racing, pounding, fluttering or skipping heartbeat.
Dizziness or faintingFeeling light-headed, or blacking out for a moment.
Tiredness and shortness of breathGetting tired or breathless easily, especially with activity.
Chest discomfortPressure or pain in the chest during an attack. This needs urgent care.
Write it down
When symptoms come, note the time, what you were doing, how long it lasted, and your pulse if you can check it. If you can, go to a clinic or hospital to get an ECG while the symptoms are happening. This is the best way to find the cause.
What happens at your check-up
Only an ECG and a doctor's examination can tell which rhythm you have and whether it needs treatment. Depending on your symptoms, your doctor may use these tests.
12-lead ECG
The main test. Small stickers on the chest record the heart's electrical signals in a few minutes.
Holter or patch monitor
A small recorder you wear for 1 to 14 days to catch rhythms that come and go.
Event or implanted recorder
For rare symptoms, such as fainting spells, a recorder can be worn for weeks, or placed under the skin for up to a few years.
Echocardiogram and blood tests
An ultrasound shows the heart's structure and pumping. Blood tests check the thyroid, potassium and kidneys.
Exercise test
Shows how the heart rate and rhythm respond to activity, and whether symptoms come with effort.
Electrophysiology (EP) study
Thin wires are passed into the heart through a vein to map the electrical system. It is often done together with an ablation.
[Ref: ESC 2024 AF] [Ref: ACC/AHA/HRS 2018 Bradycardia] [Ref: ESC 2019 SVT]
Smartwatches and phone ECGs can warn of an irregular rhythm. But a diagnosis of AF needs an ECG tracing reviewed by a doctor, so bring the recording to your visit. [Ref: ESC 2024 AF]
Your doctor decides which tests you need and explains what the results mean for you.
Palpitations, dizziness or a slow pulse? Get your heart rhythm checked.
Only an ECG and a doctor's examination can tell which rhythm you have and whether it needs treatment. Dr. Aaron Christopher P. Novales sees patients with heart rhythm problems.
Fainting, chest pain, or a racing heartbeat with breathlessness? Do not wait for a clinic visit. Go to the emergency room now →
How it is treated
About the medicines on this page
Medicines are described here only to help you understand your doctor's plan. Do not buy or take any medicine because you read about it here. Take only what your doctor prescribes for you, and never start, stop or change a dose on your own.
Treatment depends on the type of arrhythmia, your symptoms and your heart's health. Some extra beats and mild slow rhythms need no treatment at all. [Ref: ACC/AHA/HRS 2018 Bradycardia] [Ref: ESC 2022 VA]
Slow rhythms
First, your doctor looks for causes that can be fixed, such as a medicine that slows the heart, thyroid problems, high potassium or sleep apnea. If the slow rhythm causes symptoms, or if you have a serious type of heart block, a pacemaker is recommended. It is a small device placed under the skin below the collarbone, with a wire to the heart, that sends a signal whenever the heart is too slow. [Ref: ACC/AHA/HRS 2018 Bradycardia] [Ref: ESC 2021 Pacing]
Atrial fibrillation: the AF-CARE plan
The 2024 European guideline organizes AF care in four parts: [Ref: ESC 2024 AF]
C, Conditions: treat high blood pressure, diabetes, sleep apnea and excess weight, and cut down on alcohol. This makes AF come back less.
A, Avoid stroke: your doctor scores your stroke risk. If it is raised, your doctor will prescribe the blood thinner that is right for you.
R, Reduce symptoms: medicines that slow the heart rate, and treatments that restore a normal rhythm, such as medicines, an electric shock (cardioversion) or catheter ablation.
E, Evaluate: regular check-ups, because AF and the risks that come with it change over time.
Aspirin is not used to prevent stroke in AF. [Ref: ESC 2024 AF] [Ref: ACC/AHA 2023 AF]
SVT
An attack can often be stopped with a vagal maneuver, a simple technique your doctor can teach you. In the hospital, doctors can also give a medicine through a vein to stop it. For repeated attacks, catheter ablation is often the first choice because it can cure most types of SVT. Medicines are another option. [Ref: ESC 2019 SVT]
Ventricular arrhythmias
VT and VF are emergencies. They are treated with an electric shock, medicines and treatment of the heart disease behind them. People at high risk of sudden cardiac arrest may need an implantable cardioverter-defibrillator (ICD), a device that watches the heartbeat and gives a shock to restore a normal rhythm. [Ref: ESC 2022 VA]
| Treatment | What it does | Used for |
|---|---|---|
| Pacemaker | Keeps the heart from beating too slowly | Slow rhythms with symptoms, serious heart block |
| Catheter ablation | Burns or freezes the tiny area causing the extra signals, through thin tubes from a vein in the groin | SVT, atrial flutter, AF, some VT |
| Cardioversion | A controlled electric shock, given under sedation, to reset the rhythm | AF, atrial flutter, VT |
| ICD | Watches the heartbeat and shocks a dangerous rhythm back to normal | People who survived or are at high risk of VT or VF |
[Ref: ESC 2021 Pacing] [Ref: ESC 2024 AF] [Ref: ESC 2019 SVT] [Ref: ESC 2022 VA]
Never stop your blood thinner on your own
Tell every doctor and dentist that you take it, and seek care for unusual bleeding, such as black stools, blood in the urine, or bleeding that will not stop. Do not lower your dose on your own. [Ref: ESC 2024 AF]
Daily self-care
Learn to check your pulsePlace two fingers on your wrist and count the beats for 30 seconds, then double it. If the beat feels uneven, count for a full 60 seconds instead. Notice if it is regular.
Keep a healthy weightIf you are overweight, losing 10% of your weight can reduce AF attacks.
Limit alcoholFor AF, keep it to 3 standard drinks a week or less. Less is better.
Stay activeAim for 150 to 300 minutes of moderate activity a week, as your doctor advises.
Control blood pressure and sleep apneaTake your medicines, and ask about a sleep test if you snore loudly or feel sleepy in the day.
If you have a deviceCarry your device card and keep your follow-up checks. Tell your doctor before any MRI or surgery.
[Ref: ESC 2024 AF] [Ref: ESC 2021 Pacing]
Talk to your doctor about
Bring these questions to your visit.
- What type of arrhythmia do I have, and is it dangerous?
- What is causing it, and can that cause be treated?
- Do I need a blood thinner to prevent stroke?
- Would ablation, a pacemaker or an ICD help me?
- Which symptoms mean I should go to the emergency room?
- Is it safe for me to drive and exercise?
Related conditions
Guideline sources for this page
- ESC 2024 AF: Van Gelder IC, Rienstra M, Bunting KV, et al. 2024 ESC Guidelines for the management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS). Eur Heart J 2024;45:3314–3414.
- ACC/AHA 2023 AF: Joglar JA, Chung MK, et al. 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation. Circulation 2024;149:e1–e156.
- ACC/AHA/HRS 2018 Bradycardia: Kusumoto FM, Schoenfeld MH, et al. 2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients With Bradycardia and Cardiac Conduction Delay. Circulation 2019;140:e382–e482.
- ESC 2021 Pacing: Glikson M, Nielsen JC, et al. 2021 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy. Eur Heart J 2021;42:3427–3520.
- ESC 2019 SVT: Brugada J, Katritsis DG, Arbelo E, et al. 2019 ESC Guidelines for the management of patients with supraventricular tachycardia. Eur Heart J 2020;41:655–720.
- ESC 2022 VA: Zeppenfeld K, Tfelt-Hansen J, et al. 2022 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. Eur Heart J 2022;43:3997–4126.
- AHA AFib and Stroke: American Heart Association. AFib and stroke: understanding the fivefold increase in risk. 23 May 2024.
- PJC 2026 AF: Fadreguilan EC, Tumanan-Mendoza BA, Mendoza VL, Gervacio GG. Epidemiologic burden of atrial fibrillation-related hospitalization in the Philippines. Philippine Journal of Cardiology 2026;54(1).