Synonyms: ectopic beats, premature beats, premature atrial or ventricular complexes

The normal heart rate and rhythm are determined by the sino-atrial node in the right atrium, which acts as the pacemaker for the heart. This node discharges electric current through the atria causing them to contract. The electric current then passes through the atrioventricular (AV) node which lies within the lower interatrial septum. Electrical impulses pass from here into the Purkinje's network, along the right and left bundles of His, and excite the ventricular muscles causing their contraction. The conduction system and myocardium have a nerve supply and are hormone sensitive (to catecholamines), which allows regulation of the heartbeat according to different activities, stress and excitement.¹

Extrasystoles are essentially extra beats, or contractions, which interrupt the normal regular rhythm of the heart. They occur when there is electrical discharge from somewhere in the heart other than the sino-atrial node. They are classified as atrial or ventricular extrasystoles (VEs) according to their site of origin.

Epidemiology²

Both atrial and ventricular asystoles are common at all ages.

Atrial extrasystoles

• These are common in healthy people with normal hearts, e.g. they may occur on 24-hour Holter monitoring in over 60% of healthy adults.³
• They can also occur when there is increased pressure on the atria such as in cardiac failure or mitral valve disease and, in such cases, may occur prior to the development of atrial fibrillation. They are exacerbated by alcohol and caffeine.⁴

Ventricular extrasystoles (VEs)

• These are common and can occur at any age.
• Ventricular asystoles are found in 1% healthy people on standard ECG and 40-75% of healthy people on 24-48-hour ambulatory ECG recording.
• They are more common in those with structural heart disease. VEs are the most common type of arrhythmia that occurs after myocardial infarction. They may also occur in severe left ventricular (LV) hypertrophy, hypertrophic cardiomyopathy and congestive cardiac failure.⁴

There are various classification systems for ventricular ectopics, in terms of their clinical risk, frequency or focus of origin.⁵

Children⁶

• Atrial extrasystoles are very common and only rarely associated with any disease.
• VEs are also common. In a structurally normal heart, they are almost always benign.
• Both are usually abolished by exercise.

Significance of extrasystoles

Extrasystoles can occur frequently in people with completely normal hearts and often do not cause any problems. However, they can also be a feature of certain cardiac diseases.

Significance of atrial extrasystoles

• Usually, atrial extrasystoles do not cause problems.
• In some cases, runs of atrial ectopy can lead to paroxysms of atrial fibrillation.⁷

Significance of ventricular extrasystoles (VEs)⁸

Patients without cardiac disease

VEs are often found in clinical practice. In the absence of heart disease, they are usually benign and the prognosis is good. Previous research found that in normal hearts, there were no excess cardiovascular events or mortality in patients with VEs.² However, more recent research has revealed possible adverse affects of VEs, even in those without known cardiac disease:

• There is conflicting evidence regarding the effect of VEs on mortality.⁹
• Extrasystoles induced during exercise testing, particularly those arising during the recovery phase, may indicate an increased mortality risk.^10,11,12
• In patients with frequent ventricular ectopics (>1,000 per 24 hours), there may be an adverse effect on ventricular function:⁸
  • There may be subtle impairment of left ventricular (LV) function, despite a normal LV ejection fraction.
  • Frequent VEs may be linked to a slow decline in ventricular function in the long-term (over several years or decades). However, it was rare for overt LV dysfunction to develop - most patients had ejection fractions in the normal range.

With cardiac disease

In the presence of significant structural heart disease, frequent VEs indicate an increased risk of sudden cardiac death, and specialist advice should be sought.¹³

Risk factors for extrasystoles^2,5

• Can occur in normal hearts, where the prevalence of extrasystoles increases with age
• Hypertension
• Heart disease, including acute myocardial infarction, valvular heart disease, cardiomyopathy, ventricular hypertrophy and cardiac failure
• Electrolyte disturbances, including hypokalaemia,¹³ hypomagnesemia, hypercalcaemia
• Drugs, including digoxin, aminophylline, tricyclic antidepressants, cocaine, amfetamines
• Alcohol excess
• Infection
• Stress
• Surgery
• Hyperthyroidism
• Possibly, central sleep apnoea is linked to ventricular ectopics¹⁴
• Stimulants such as caffeine may have a role, although this has not been proven for ventricular extrasystoles (VEs)²

Presentation^5,15

May be a coincidental finding on a routine ECG.

Possible symptoms:

• Palpitations are the main reported symptom:
  • There is an awareness of a change in the force, rate or rhythm of the heartbeat. Extrasystoles usually occur after a normal heartbeat and are followed by a pause until the normal heart rhythm returns. Therefore, they may be felt as 'missed' or 'skipped' beats or 'feeling the heart has stopped'. Alternatively, they can be felt as a thud or strange sensation like a somersault in the chest, or as extra beats. They can be uncomfortable and cause significant anxiety in some people.
• Symptoms are usually worse at rest and may disappear with exercise. Symptoms which increase on exercise are more worrying and significant.
• Other possible symptoms are:
  • Syncope or near syncope (dizziness)
  • Atypical chest pain
  • Fatigue
  • There are case reports in which chronic cough cough ± syncope were the presenting symptoms of extrasystoles^3,16,17

Possible signs:

• There may be none.
• Variable or decreased intensity of heart sounds; the augmented beat following a dropped beat may be heard.
• Variable pulse rhythm.
• Visible jugular pulse (cannon a wave) from loss of atrioventricular synchrony.

Assessment^15,18

History:

• Detailed history of the presenting symptom - including onset, duration, associated symptoms and recovery.
• Check for other cardiac symptoms including chest pain, breathlessness, syncope or near syncope (e.g. dizziness), and arrhythmia symptoms, e.g. sustained fast palpitations.
• If there is history of syncope, note that:
  • Exertional syncope should always raise alarm of a sinister cause.¹⁹
  • Rapid recovery after the syncopal event, without confusion or drowsiness, is characteristic of cardiac syncope.¹⁹
• Family history - for early cardiac disease or sudden death.
• Previous cardiac disease or coronary heart disease (CHD) risk factors.

Examination:

• Cardiovascular system including blood pressure, heart murmurs and any signs of cardiac failure.

Investigations

In patients presenting with palpitations, initial investigations are:¹⁵

• Resting 12 lead ECG
• Full blood count and thyroid function tests
• Electrolytes¹³

Other investigations:

• Serum calcium and magnesium.
• If symptoms have a long duration (many hours), advise the patient to attend their GP surgery or A&E for a 12 lead ECG during the next episode.
• Ambulatory ECG monitoring:
  • If symptoms are short-lived but frequent (>2-3 times per week), use a 24-hour Holter monitor
  • If symptoms are short-lived and infrequent (<1 per week), use an event monitor or transtelephonic recorder
• Echocardiography - to assess left ventricular (LV) function and heart structure.
• Exercise stress testing - the relation of extrasystoles to exercise may have prognostic importance (above).

ECG findings

Atrial extrasystoles are premature P waves which look different from a normal P wave. They may be hidden in the ST segment or T wave of the preceding sinus beat. They may be followed either by a normal QRS complex, or the PR interval may be prolonged, or the impulse may not be conducted at all.⁴

Ventricular extrasystoles (VEs) are wide, abnormally-shaped QRS complexes. Extrasystoles occurring at every second or third beat are called bigeminy or trigeminy respectively.

For examples see the ECG library (link provided under Internet and further reading).

Which patients need referral from primary care?^15,18

In the context of palpitations or suspected arrhythmia, referral is required for:

• Urgent symptoms, e.g. chest pain, breathlessness or loss of consciousness - usually merit admission for assessment.
• Syncope or near syncope (especially exertional syncope, which is a serious symptom¹⁹).
• Symptoms suggesting a pathological tachycardia, e.g. if there is an accurate description of very rapid heartbeat with sudden onset and offset.
• Significant ECG abnormality.
• Significant cardiac disease.
• Heart murmur.
• Significant underlying problem, e.g. endocrine or metabolic disorder, infection.
• Family history of sudden death or heart disease at a young age:²⁰
  • Unexplained sudden death at age >30, and all sudden deaths at age < 30, should trigger cardiovascular evaluation of first-degree relatives (for heritable arrhythmias or cardiomyopathies).
  • A family history of early cardiac disease (age <40) suggests possible increased cardiac risk and further assessment may be warranted.
• Also refer if symptoms are troublesome, so that treatment options can be considered.

The urgency of referral depends on clinical judgement, taking into account the frequency and duration of symptoms and other medical conditions. Discussion with a specialist may be helpful if there is uncertainty about the urgency or usefulness of referral. Usually, refer to an arrhythmia clinic, if available.

Management^15,18

As an overview:

• Low-risk patients with no other cardiac problems and no symptoms (or minor symptoms only) can be reassured.
• Other patients (those with cardiac disease, cardiac risk or significant symptoms) will usually need further assessment, treatment or follow-up.
• Treatment options are:
  • Drugs - betablockers, e.g. atenolol, metoprolol.
  • Radiofrequency catheter ablation of the ectopic focus (in suitable cases).
  • Patients with a high intake of caffeine or other stimulants may be advised to try reducing their intake, to see whether or not this improves their symptoms or the extrasystoles.²

Management of atrial extrasystoles

• If symptoms are troublesome, try betablockers (atenolol or metoprolol).^3,18
• Atrial extrasystoles arising from the pulmonary veins may be treatable by the procedure of pulmonary vein isolation.²¹
• Catheter ablation may be a feasible option for some atrial ectopics in future, using specialised techniques.^7,21

Management of ventricular extrasystoles²

Management depends on:

• Whether there is underlying heart disease
• The frequency of the extrasystoles and whether ventricular tachycardia has been documented
• The frequency and severity of symptoms

Document references

1. Kumar P; Clarke M; Clinical Medicine, 6th Ed, (2005). WB Saunders: London.
2. Ng GA; Treating patients with ventricular ectopic beats. Heart. 2006 Nov;92(11):1707-12.
3. Odeh M, Oliven A; A man who coughed for 15 years before a doctor took his pulse. Lancet. 1996 Aug 10;348(9024):378.
4. Extrasystoles, Chapter 2.5.6. Oxford Textbook of Medicine 4th edition.
5. Dave J; Ventricular Premature Complexes. eMedicine. Last updated August 2009.
6. Goodacre S, McLeod K; ABC of clinical electrocardiography: Paediatric electrocardiography. BMJ. 2002 Jun 8;324(7350):1382-5.
7. Kaye GC; Percutaneous interventional electrophysiology. BMJ. 2003 Aug 2;327(7409):280-3.
8. Wilber DJ; Ventricular ectopic beats: not so benign. Heart. 2009 Aug;95(15):1209-10. Epub 2009 May 7.
9. Zipes DP, Camm AJ, Borggrefe M, et al; ACC/AHA/ESC 2006 guidelines for management of patients with ventricular Europace. 2006 Sep;8(9):746-837. Epub 2006 Aug 25.
10. Frolkis JP, Pothier CE, Blackstone EH, et al; Frequent ventricular ectopy after exercise as a predictor of death. N Engl J Med. 2003 Feb 27;348(9):781-90. [abstract]
11. Morshedi-Meibodi A, Evans JC, Levy D, et al; Clinical correlates and prognostic significance of exercise-induced ventricular premature beats in the community: the Framingham Heart Study. Circulation. 2004 May 25;109(20):2417-22. Epub 2004 May 17. [abstract]
12. Dewey FE, Kapoor JR, Williams RS, et al; Ventricular arrhythmias during clinical treadmill testing and prognosis. Arch Intern Med. 2008 Jan 28;168(2):225-34. [abstract]
13. FF90 Factfile: Ventricular arrhythmias. British Heart Foundation, March 2005.
14. Borgel J, Mugge A; Images in cardiovascular medicine. Central sleep apnea induces ventricular Circulation. 2008 Sep 23;118(13):1398-401.
15. Palpitations referral guidelines. Cardiothoracic Services, Oxford Radcliffe Hospitals NHS Trust, 2009. Accessed March 2010.
16. Brandon N; Premature atrial contraction as an etiology for cough. Chest. 2008 Mar;133(3):828.
17. Stec S, Dabrowska M, Zaborska B, et al; Premature ventricular complex-induced chronic cough and cough syncope. Eur Respir J. 2007 Aug;30(2):391-4. [abstract]
18. Palpitations, Clinical Knowledge Summaries (March 2009)
19. Abrams DJ, Perkin MA, Skinner JR; Long QT syndrome. BMJ. 2010 Jan 8;340:b4815. doi: 10.1136/bmj.b4815.
20. FF102 Factfile: Arrhythmias and sudden death – implications for GPs. British Heart Foundation, March 2006.
21. Yamada T, Murakami Y, Okada T, et al; Electroanatomic mapping in the catheter ablation of premature atrial contractions Europace. 2008 Nov;10(11):1320-4. Epub 2008 Aug 28. [abstract]

Internet and further reading

• Bhushan M, Asirvatham SJ; The conundrum of ventricular arrhythmia and cardiomyopathy: which abnormality Curr Heart Fail Rep. 2009 Mar;6(1):7-13. [abstract]
• Beaufort-Krol GC, Dijkstra SS, Bink-Boelkens MT; Natural history of ventricular premature contractions in children with a Europace. 2008 Aug;10(8):998-1003. Epub 2008 May 6. [abstract]
• ECG Library; © Stephen Gerred (Medical Registrar Auckland, New Zealand) Dean Jenkins (Specialist Registrar, Llandough Hospital, Cardiff, Wales)

Acknowledgements