Premature atrial contraction

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Premature atrial contraction
Other namesSupraventricular extra systole (SVES), Supraventricular ectopy (SVE)
PAC.png
Two PACs with a compensatory pause seen on an EKG rhythm strip. A "skipped beat" occurs and rhythm resumes 2 P-to-P intervals after the last normal sinus beat.
Specialty Cardiology, electrophysiology   OOjs UI icon edit-ltr-progressive.svg

Premature atrial contraction (PAC), also known as atrial premature complexes (APC) or atrial premature beats (APB), are a common cardiac dysrhythmia characterized by premature heartbeats originating in the atria. While the sinoatrial node typically regulates the heartbeat during normal sinus rhythm, PACs occur when another region of the atria depolarizes before the sinoatrial node and thus triggers a premature heartbeat, [1] in contrast to escape beats, in which the normal sinoatrial node fails, leaving a non-nodal pacemaker to initiate a late beat.

Contents

The exact cause of PACs is unclear; while several predisposing conditions exist, single isolated PACs commonly occur in healthy young and elderly people. Elderly people that get PACs usually don't need any further attention besides follow ups due to unclear evidence. [2] [3]

PACs are often completely asymptomatic and may be noted only with Holter monitoring, but occasionally they can be perceived as a skipped beat or a jolt in the chest. In most cases, no treatment other than reassurance is needed for PACs, although medications such as beta blockers can reduce the frequency of symptomatic PACs. [4]

Risk factors

Hypertension, or abnormally high blood pressure, often signifies an elevated level of both psychological and physiological stress. Often, hypertension goes hand in hand with various atrial fibrillations including premature atrial contractions (PACs). [5] Additional factors that may contribute to spontaneous premature atrial contractions could be: [4]

Diagnosis

Normal sinus rhythm and ectopic beats - premature ventricular contractions (PVC) and premature atrial contractions (PAC) shown on an EKG NSR and Ectopic beats (PVC and PAC).svg
Normal sinus rhythm and ectopic beats - premature ventricular contractions (PVC) and premature atrial contractions (PAC) shown on an EKG

Premature atrial contractions are typically diagnosed with an electrocardiogram, Holter monitor, long-term continuous monitor, cardiac event monitor, or with a smartwatch with an ECG functionality.[ citation needed ]

Electrocardiogram

On an electrocardiogram (ECG), PACs are characterized by an abnormally shaped P wave in different ECG leads. Since the premature beat initiates outside the sinoatrial node, the associated P wave appears different from those seen in normal sinus rhythm. Typically, the atrial impulse propagates normally through the atrioventricular node and into the cardiac ventricles, resulting in a normal, narrow QRS complex. However, if the atrial beat is premature enough, it may reach the atrioventricular node during its refractory period, in which case it will not be conducted to the ventricle and there will be no QRS complex following the P wave.[ citation needed ]

In some people, PACs occur in a predictable pattern. Two PACs in a row are called doublets and three PACs in a row are triplets. Depending whether there are one, two, or three normal (sinus) beats between each PACs, the rhythm is called atrial bigeminy, trigeminy, or quadrigeminy. If 3 or more consecutive PACs occur in a row and at a frequency of 100 or more beats per minute, it may be called atrial tachycardia.

Treatment

Premature atrial contractions are often benign, requiring no treatment. Occasionally, the patient having the PAC will find these symptoms bothersome, in which case the doctor may treat the PACs. Sometimes the PACs can indicate heart disease or an increased risk for other cardiac arrhythmias. In this case, the underlying cause is treated. Often a beta blocker will be prescribed for symptomatic PACs. [6]

Prognosis

In otherwise healthy patients, occasional single premature atrial contractions are a common finding and most of times do not indicate any particular health risk. Rarely, in patients with other underlying structural heart problems, PACs can trigger a more serious arrhythmia such as atrial flutter or atrial fibrillation. [7] In otherwise healthy people, PACs usually disappear with adolescence.[ citation needed ]

Supraventricular extrasystole

A supraventricular extrasystole (SVES) is an extrasystole or premature electrical impulse in the heart, generated above the level of the ventricle. This can be either a premature atrial contraction or a premature impulse from the atrioventricular node. SVES should be viewed in contrast to a premature ventricular contraction that has a ventricular origin and the associated QRS change. Instead of the electrical impulse beginning in the sinoatrial (SA) node and propagating to the atrioventricular (AV) node, the signal is conducted both to the ventricle and back to the SA node where the signal began. [8]

See also

Related Research Articles

<span class="mw-page-title-main">Bradycardia</span> Heart rate below the normal range

Bradycardia is a slow resting heart rate, commonly under 60 beats per minute (BPM) as determined by an electrocardiogram. It is considered to be a normal heart rate during sleep, in young and healthy or elderly adults, and in athletes.

<span class="mw-page-title-main">Electrocardiography</span> Examination of the hearts electrical activity

Electrocardiography is the process of producing an electrocardiogram, a recording of the heart's electrical activity through repeated cardiac cycles. It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the heart using electrodes placed on the skin. These electrodes detect the small electrical changes that are a consequence of cardiac muscle depolarization followed by repolarization during each cardiac cycle (heartbeat). Changes in the normal ECG pattern occur in numerous cardiac abnormalities, including cardiac rhythm disturbances, inadequate coronary artery blood flow, and electrolyte disturbances.

<span class="mw-page-title-main">Premature ventricular contraction</span> Skipped beat with ventricular origin

A premature ventricular contraction (PVC) is a common event where the heartbeat is initiated by Purkinje fibers in the ventricles rather than by the sinoatrial node. PVCs may cause no symptoms or may be perceived as a "skipped beat" or felt as palpitations in the chest. PVCs do not usually pose any danger.

Systole is the part of the cardiac cycle during which some chambers of the heart contract after refilling with blood.

<span class="mw-page-title-main">Wolff–Parkinson–White syndrome</span> Medical condition

Wolff–Parkinson–White syndrome (WPWS) is a disorder due to a specific type of problem with the electrical system of the heart involving an accessory pathway able to conduct electrical current between the atria and the ventricles, thus bypassing the atrioventricular node. About 60% of people with the electrical problem developed symptoms, which may include an abnormally fast heartbeat, palpitations, shortness of breath, lightheadedness, or syncope. Rarely, cardiac arrest may occur. The most common type of irregular heartbeat that occurs is known as paroxysmal supraventricular tachycardia.

<span class="mw-page-title-main">Sinus node dysfunction</span> Medical condition

Sinus node dysfunction (SND), also known as sick sinus syndrome (SSS), is a group of abnormal heart rhythms (arrhythmias) usually caused by a malfunction of the sinus node, the heart's primary pacemaker. Tachycardia-bradycardia syndrome is a variant of sick sinus syndrome in which the arrhythmia alternates between fast and slow heart rates.

<span class="mw-page-title-main">Third-degree atrioventricular block</span> Medical condition

Third-degree atrioventricular block is a medical condition in which the electrical impulse generated in the sinoatrial node in the atrium of the heart can not propagate to the ventricles.

<span class="mw-page-title-main">Cardiac conduction system</span> Aspect of heart function

The cardiac conduction system(CCS) (also called the electrical conduction system of the heart) transmits the signals generated by the sinoatrial node – the heart's pacemaker, to cause the heart muscle to contract, and pump blood through the body's circulatory system. The pacemaking signal travels through the right atrium to the atrioventricular node, along the bundle of His, and through the bundle branches to Purkinje fibers in the walls of the ventricles. The Purkinje fibers transmit the signals more rapidly to stimulate contraction of the ventricles.

<span class="mw-page-title-main">Supraventricular tachycardia</span> Abnormally fast heart rhythm

Supraventricular tachycardia (SVT) is an umbrella term for fast heart rhythms arising from the upper part of the heart. This is in contrast to the other group of fast heart rhythms – ventricular tachycardia, which start within the lower chambers of the heart. There are four main types of SVT: atrial fibrillation, atrial flutter, paroxysmal supraventricular tachycardia (PSVT), and Wolff–Parkinson–White syndrome. The symptoms of SVT include palpitations, feeling of faintness, sweating, shortness of breath, and/or chest pain.

<span class="mw-page-title-main">AV nodal reentrant tachycardia</span> Medical condition

AV-nodal reentrant tachycardia (AVNRT) is a type of abnormal fast heart rhythm. It is a type of supraventricular tachycardia (SVT), meaning that it originates from a location within the heart above the bundle of His. AV nodal reentrant tachycardia is the most common regular supraventricular tachycardia. It is more common in women than men. The main symptom is palpitations. Treatment may be with specific physical maneuvers, medications, or, rarely, synchronized cardioversion. Frequent attacks may require radiofrequency ablation, in which the abnormally conducting tissue in the heart is destroyed.

<span class="mw-page-title-main">Atrioventricular block</span> Medical condition

Atrioventricular block is a type of heart block that occurs when the electrical signal traveling from the atria, or the upper chambers of the heart, to ventricles, or the lower chambers of the heart, is impaired. Normally, the sinoatrial node produces an electrical signal to control the heart rate. The signal travels from the SA node to the ventricles through the atrioventricular node. In an AV block, this electrical signal is either delayed or completely blocked. When the signal is completely blocked, the ventricles produce their own electrical signal to control the heart rate. The heart rate produced by the ventricles is much slower than that produced by the SA node.

<span class="mw-page-title-main">Ventricular escape beat</span>

In cardiology, a ventricular escape beat is a self-generated electrical discharge initiated by, and causing contraction of the ventricles of the heart; normally the heart rhythm is begun in the atria of the heart and is subsequently transmitted to the ventricles. The ventricular escape beat follows a long pause in ventricular rhythm and acts to prevent cardiac arrest. It indicates a failure of the electrical conduction system of the heart to stimulate the ventricles.

Lown–Ganong–Levine syndrome (LGL) is a pre-excitation syndrome of the heart. Those with LGL syndrome have episodes of abnormal heart racing with a short PR interval and normal QRS complexes seen on their electrocardiogram when in a normal sinus rhythm. LGL syndrome was originally thought to be due to an abnormal electrical connection between the atria and the ventricles, but is now thought to be due to accelerated conduction through the atrioventricular node in the majority of cases. The syndrome is named after Bernard Lown, William Francis Ganong, Jr., and Samuel A. Levine.

<span class="mw-page-title-main">Lorcainide</span> Antiarrythmic agent

Lorcainide is a Class 1c antiarrhythmic agent that is used to help restore normal heart rhythm and conduction in patients with premature ventricular contractions, ventricular tachycardiac and Wolff–Parkinson–White syndrome. Lorcainide was developed by Janssen Pharmaceutica (Belgium) in 1968 under the commercial name Remivox and is designated by code numbers R-15889 or Ro 13-1042/001. It has a half-life of 8.9 +- 2.3 hrs which may be prolonged to 66 hrs in people with cardiac disease.

<span class="mw-page-title-main">Multifocal atrial tachycardia</span> Fast heart rhythm associated with exacerbations of COPD

Multifocal atrial tachycardia (MAT) is an abnormal heart rhythm, specifically a type of supraventricular tachycardia, that is particularly common in older people and is associated with exacerbations of chronic obstructive pulmonary disease (COPD). Normally, the heart rate is controlled by a cluster of cells called the sinoatrial node. When a number of different clusters of cells outside the SA node take over control of the heart rate, and the rate exceeds 100 beats per minute, this is called multifocal atrial tachycardia.

<span class="mw-page-title-main">Junctional rhythm</span> Medical condition

Junctional rhythm describes an abnormal heart rhythm resulting from impulses coming from a locus of tissue in the area of the atrioventricular node(AV node), the "junction" between atria and ventricles.

<span class="mw-page-title-main">Ectopic pacemaker</span> Cardiac condition

An ectopic pacemaker, also known as ectopic focus or ectopic foci, is an excitable group of cells that causes a premature heart beat outside the normally functioning SA node of the heart. It is thus a cardiac pacemaker that is ectopic, producing an ectopic beat. Acute occurrence is usually non-life-threatening, but chronic occurrence can progress into tachycardia, bradycardia or ventricular fibrillation. In a normal heart beat rhythm, the SA node usually suppresses the ectopic pacemaker activity due to the higher impulse rate of the SA node. However, in the instance of either a malfunctioning SA node or an ectopic focus bearing an intrinsic rate superior to SA node rate, ectopic pacemaker activity may take over the natural heart rhythm. This phenomenon is called an escape rhythm, the lower rhythm having escaped from the dominance of the upper rhythm. As a rule, premature ectopic beats indicate increased myocyte or conducting tissue excitability, whereas late ectopic beats indicate proximal pacemaker or conduction failure with an escape 'ectopic' beat.

<span class="mw-page-title-main">Junctional ectopic tachycardia</span> Medical condition

Junctional ectopic tachycardia (JET) is a rare syndrome of the heart that manifests in patients recovering from heart surgery. It is characterized by cardiac arrhythmia, or irregular beating of the heart, caused by abnormal conduction from or through the atrioventricular node. In newborns and infants up to 6 weeks old, the disease may also be referred to as His bundle tachycardia or congenital JET.

<span class="mw-page-title-main">Arrhythmia</span> Group of medical conditions characterized by irregular heartbeat

Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults – is called tachycardia, and a resting heart rate that is too slow – below 60 beats per minute – is called bradycardia. Some types of arrhythmias have no symptoms. Symptoms, when present, may include palpitations or feeling a pause between heartbeats. In more serious cases, there may be lightheadedness, passing out, shortness of breath or chest pain. While most cases of arrhythmia are not serious, some predispose a person to complications such as stroke or heart failure. Others may result in sudden death.

Premature junctional contractions (PJCs), also called atrioventricular junctional premature complexes or junctional extrasystole, are premature cardiac electrical impulses originating from the atrioventricular node of the heart or "junction". This area is not the normal but only a secondary source of cardiac electrical impulse formation. These premature beats can be found occasionally in healthy people and more commonly in some pathologic conditions, typically in the case of drug cardiotoxicity, electrolyte imbalance, mitral valve surgery, and cold water immersion. If more than two such beats are seen, then the condition is termed junctional rhythm. On the surface ECG, premature junctional contractions will appear as a normally shaped ventricular complex or QRS complex, not preceded by any atrial complex or P wave or preceded by an abnormal P wave with a shorter PR interval. Rarely, the abnormal P wave can follow the QRS.

References

  1. US 5181511,Nickolls, Peter; Lu, Richard M. T.& Collins, Kenneth A.,"Apparatus and method for antitachycardia pacing using a virtual electrode",published Jan 26, 1993
  2. Brodsky M, Wu D, Denes P, Kanakis C, Rosen KM (March 1977). "Arrhythmias documented by 24 hour continuous electrocardiographic monitoring in 50 male medical students without apparent heart disease". Am. J. Cardiol. 39 (3): 390–95. doi:10.1016/S0002-9149(77)80094-5. PMID   65912.
  3. Folarin VA, Fitzsimmons PJ, Kruyer WB (September 2001). "Holter monitor findings in asymptomatic male military aviators without structural heart disease". Aviat Space Environ Med. 72 (9): 836–38. PMID   11565820.
  4. 1 2 Lin, Chin-Yu; Lin, Yenn-Jiang; Chen, Yun-Yu; Chang, Shih-Lin; Lo, Li-Wei; Chao, Tze-Fan; Chung, Fa-Po; Hu, Yu-Feng; Chong, Eric (2015-08-27). "Prognostic Significance of Premature Atrial Complexes Burden in Prediction of Long-Term Outcome". Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease. 4 (9): e002192. doi:10.1161/JAHA.115.002192. ISSN   2047-9980. PMC   4599506 . PMID   26316525.
  5. Healy, Jeff (2003). "Atrial fibrillation: hypertension as a causative agent, risk factor for complications, and potential therapeutic target". The American Journal of Cardiology. 91 (10): 9–14. doi:10.1016/S0002-9149(03)00227-3. PMID   12781903.
  6. Hueston, Kesh A. Hebbar|William J. (2002-06-15). "Management of Common Arrhythmias: Part I. Supraventricular Arrhythmias". American Family Physician. 65 (12): 2479–86. PMID   12086237 . Retrieved 2017-03-29.
  7. Jensen, Thomas J.; Haarbo, Jens; Pehrson, Steen M.; Thomsen, Bloch (2004-04-01). "Impact of premature atrial contractions in atrial fibrillation". Pacing and Clinical Electrophysiology. 27 (4): 447–52. doi:10.1111/j.1540-8159.2004.00462.x. ISSN   0147-8389. PMID   15078396. S2CID   32364061.
  8. Ernst, Mutschler (1995). Drug actions : basic principles and therapeutic aspects. Medpharm Scientific Publishers. ISBN   978-0849377747. OCLC   28854659.[ page needed ]