What is Arrhythmia?

Almost everyone regardless of age and gender has felt a fluttering in their chest or thought that their heart has skipped a beat; many would have felt their heart rate fast and for some it may present as slow. These signs may indicate an arrhythmia, or abnormal or irregular heartbeat, or you may understand them simply as palpitations. Don’t panic if you occasionally experience any of these symptoms, as arrhythmias are extremely common and do become more prevalent as we age. Millions of people worldwide experience and live with an arrhythmia, and in most cases it is often a benign (non life threatening) condition, but there are some arrhythmias that are extremely dangerous and require active treatment and management – in all cases if you experience an abnormal heart beat, you should attend your G.P for consultation and referral if necessary.

When is an irregular heartbeat dangerous?

When your heart is beating normally (between 60-100 times per minute) you can’t feel it, it’s beating away up to a 100,000 times a day pumping blood and delivering oxygen to the body. A heart rhythm abnormality (arrhythmia) occurs when the electrical impulses in your heart that coordinates the heartbeats is interrupted by other cells misfiring, this can cause your heart to beat too fast (tachycardia), too slow (bradycardia) or irregularly. An occasional skipped beat would not usually indicate an underlying pathology but if you experience prolonged bouts of fluttering or irregularity that lasts for some time and produces accompanying symptoms then it may flag a dangerous heart condition that needs investigation.

What are some common types of irregular heartbeats?

Atrial Fibrillation: A-fib or AF is the most common type of sustained cardia arrhythmia. AF occurs when there are too many electrical signals that normally control the heart beat and rate, causing the upper chambers of the heart (the atria) to beat extremely rapidly (up to more than 400 beats per minute) and quiver (fibrillate). AF is often described as an irregular, most often rapid heartbeat.

Supraventricular Tachycardia: (SVT) Tachycardia means a fast heart rate. Superventricular means coming from above the ventricle. During an episode of SVT, the heartbeat is no longer controlled by the SA node (the hearts natural pacemaker), another cell misfires overriding the SA node and producing faster impulse. The trigger or source of the impulse during and SVT episode originate above (supra) the ventricles from somewhere in the atria and the spreads to the ventricles. There are three main types of SVT: Atrioventricular nodal re-entry tachycardia (AVNRT), Atrial Tachycardia and Wolff-Parkinson-White (WPW) syndrome.

PACS (Premature Atrial Contractions) & PVC’s (Premature Ventricular Contractions): It is thought up to 99% of all people experience both PACs and PVCs, often thought as a normal variant, they occur when the atrium (PAC) or the ventricle (PVC) beats early. Most people are unaware of their occurrence, however many people do become quite aware of their presence and may report a palpitation felt in the neck, chest, throat or stomach. Often described as a “thump” or “thud”, in otherwise healthy individuals and those with a structurally normal heart they are classified as benign and do not pose any health risks.

Ventricular tachycardia (V-tach): Ventricular tachycardia is another rapid heart rate that originates from the bottom of the heart in the ventricles. VT can be sustained or non-sustained, and is a rapid heartbeat caused by a malfunction of one of the heart’s ventricles. The pulse is usually felt at over 100 beats per minute with at least three irregular heartbeats in a row (this definition is open to interpretation), if left untreated this can lead to Ventricular Fibrillation which is a medical emergency. VT can occur with or without heart disease but is usually due to structural abnormalities, disease or trauma.

Symptoms of Arrhyhmias:

Arrhythmias can produce a wide range of symptoms, from barely perceptible to collapse,medical emergency and even death.

• Fatigue
• Skipped beats
• Fluttering
• Dizziness
• Lightheadedness
• Fainting (syncope) or near-fainting spells
• Rapid heartbeat or pounding
• Shortness of breath
• Chest pain
• In extreme cases, collapse and sudden cardiac arrest.

How are irregular heartbeats typically diagnosed?

For many when experiencing palpitations or a racing heart for the first time they will quite rightly visit A & E or their GP.In arriving at a correct diagnosis they will perform an ECG (electrocardiogram), this painless procedure will help to identify the type of abnormal rhythm you may be experiencing. If an abnormal rhythm is documented you will be referred to a Cardiologist. Where further tests will be carried out, these may include:

• An ECG or EKG records the electrical activity of the heart and shows abnormal rhythms (arrhythmias or dysrhythmias).
• Ambulatory cardiac monitoring. A Holter monitor may be used for 24 hours. Other monitors may be worn in excess of two weeks.
• An “echo” uses ultrasound waves to produce a moving picture of the heart and heart valves.
• Coronary angiography. An X-ray of the heart’s blood vessels may be performed to evaluate possible narrowing of the coronary arteries, which can cause palpitations. In this procedure a tiny catheter is inserted into an artery of a leg or arm and threaded up into the coronary arteries. A contrast material is then injected from the end of the catheter into the coronary arteries, and X-rays are taken.

Common causes of arrhythmias

Palpitations can be caused by factors including:

• Overexertion or exercise.
• Genetic/inherited cardiac arrthythmia.
• Caffeine, alcohol, tobacco or diet pills.
• Overactive thyroid.
• Hormone changes associated with menstruation, pregnancy or menopause.
• Low blood pressure.
• Heart disease or heart valve abnormalities.
• Medications such as thyroid pills, cold medicines, asthma drugs, beta blockers for high blood pressure or heart disease, or anti-arrhythmics (medications for irregular heart rhythm).

Arrhythmia Support and Information

Speak to an Irish Heart Foundation nurse in confidence on theirr National Heart and Stroke Helpline on 1890 432 787 , Monday – Friday, 10am-5pm.

CRY: Cardiac Risk in the Young

CRYP Centre, Adelaide and Meath Hospital

Tallaght, Dublin 24,

Ireland

CRYP Centre: + 353 1 414 3058
CRY Helpline: + 353 1 839 5438
CRY Charity: + 353 1 452 5482

Email: info@cry.ie