A premature heart beat or extrasystole is a heart rhythm disorder corresponding to a premature contraction of one of the chambers of the heart. Premature heart beats come in two different types:

premature atrial contraction 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 typic ...

s and premature ventricular contractions. Often they cause no symptoms but may present with fluttering in the chest or a skipped beat. They typically have no long term complications. They most often happen naturally but may be associated with caffeine, nicotine, or stress. Usually no treatment is needed. They are the most common

arrhythmia 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 ...

Physiopathology

The normal heart contraction comes from a cyclic membrane

depolarization In biology, depolarization or hypopolarization is a change within a cell, during which the cell undergoes a shift in electric charge distribution, resulting in less negative charge inside the cell compared to the outside. Depolarization is esse ...

(reversal of the electrical polarity of the cell membrane) of a group of cells located on the upper part of the right

atrium Atrium may refer to: Anatomy * Atrium (heart), an anatomical structure of the heart * Atrium, the genital structure next to the genital aperture in the reproductive system of gastropods * Atrium of the ventricular system of the brain * Pulmona ...

, the

sinoatrial node The sinoatrial node (also known as the sinuatrial node, SA node or sinus node) is an oval shaped region of special cardiac muscle in the upper back wall of the right atrium made up of cells known as pacemaker cells. The sinus node is approximat ...

. This depolarization spreads to the whole heart and causes muscle cells to contract. It is followed by a "refractory period", a short time when the cells are no longer stimulable. The heart rate is controlled by this node.

Diagnosis

Premature heart beat revealed by laser Doppler holography of the eye fundus

Premature heart beats can be asymptomatic (the patient does not complain about anything). The subject may experience

palpitations Palpitations are perceived abnormalities of the heartbeat characterized by awareness of cardiac muscle contractions in the chest, which is further characterized by the hard, fast and/or irregular beatings of the heart. Symptoms include a rapi ...

, a feeling of cardiac "pause". Taking (prolonged)

pulse In medicine, a pulse represents the tactile arterial palpation of the cardiac cycle (heartbeat) by trained fingertips. The pulse may be palpated in any place that allows an artery to be compressed near the surface of the body, such as at the nec ...

may result in a rhythm that seems irregular.

Electrocardiography Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording of the heart's electrical activity. It is an electrogram of the heart which is a graph of voltage versus time of the electrical activity of the hear ...

and

laser Doppler imaging Laser Doppler imaging (LDI) is an imaging method that uses a laser beam to scan live tissue. When the laser light reaches the tissue, the moving blood cells generate doppler components in the reflected ( backscattered) light. The light that comes ...

allow to visualize Premature heart beats. From their appearance, their location can be assessed. The

Holter monitor In medicine, a Holter monitor (often simply Holter) is a type of ambulatory electrocardiography device, a portable device for cardiac monitoring (the monitoring of the electrical activity of the cardiovascular system) for at least 24 hours. T ...

allows to quantify them, to specify their characteristics and their repetition.

Types

Premature atrial contraction 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 typic ...

(PAC) ** Supraventricular extrasystoles (SVES) * Premature ventricular contraction (PVC) ** Ventricular extrasystoles (VES) * Premature junctional contraction

References

External links

{{Medical resources , DiseasesDB = , ICD10 = {{ICD10, Xxx.x , ICD9 = {{ICD9, xxx , ICDO = , OMIM = , MedlinePlus = , MeSH = , GeneReviewsNBK = , GeneReviewsName = Cardiac arrhythmia Premature events