All heart diseases, including congenital structural abnormalities (eg. B. accessory atrioventricular bundle) and functional (z. B. inherited ion channel disorders) may cause cardiac arrhythmia. And systemic factors can cause cardiac arrhythmia or contribute to. These include electrolyte derailments (v. A. Low potassium or Magnesimspiegel), hypoxia, hormonal fluctuations (eg. As hypo- or hyperthyroidism), drugs and toxins such as alcohol and caffeine.

The healthy heart beats regularly and coordinates; as electrical impulses that are generated by myocardial cells with unique electrical properties and forwarded, trigger a series of organized myocardial contractions. Cardiac arrhythmias arise due to malfunctions in the energization forming or conduction of electrical pulses, or a combination of both. All heart diseases, including congenital structural abnormalities (eg. B. accessory atrioventricular bundle) and functional (z. B. inherited ion channel disorders) may cause cardiac arrhythmia. And systemic factors can cause cardiac arrhythmia or contribute to. These include electrolyte derailments (v. A. Low potassium or Magnesimspiegel), hypoxia, hormonal fluctuations (eg. As hypo- or hyperthyroidism), drugs and toxins such as alcohol and caffeine. Anatomy of the conduction system at the junction of the superior vena cava to the upper lateral part of the right atrium (RA) is called a cluster of cells the sinoatrial node (SA node), the sinus node which generates the first electrical pulse of each normal heart beat. The electrical discharge of pacemaker cells stimulates the subsequent cells and leads to the subsequent cardiac regions are stimulated in an ordered sequence. The pulses are transferred (AV node) via the atrium to the atrioventricular node. This is preferably done via internodal conduction paths and unspecialized Vorhofmyokardzellen. The AV node is situated on the right side of the atrial septum. It forwards the excitations slowly, thereby delaying the impulse conduction. The AV nodal conduction time is dependent on the heart rate and is regulated by the autonomic tone and circulating catecholamines to maximize cardiac output at any atrial rate. With the exception of the region anteroseptal the atria are electrically insulated from the ventricles through the annulus fibrosus. In the anteroseptal region the bundle of His in the upper Ventrikeseptum occurs as a continuation of the AV node and is divided there into a left and a right leg, the both ends in the Purkinje fibers. The right leg passes pulses to the anterior and apical Endokardregionen of the right ventricle (RV). The left leg fans out over the left side of the interventricular septum and and a posterior (left-posterior fascicles) divides into an anterior (left-anterior fascicle) part. Both stimulate the left side of the interventricular septum, the first region of the ventricle, which is electrically activated. Thus, the ventricular septum is depolarized from left to right. Subsequently, both ventricles of the endocardial surface by the ventricular walls are activated almost simultaneously to the epicardial surface. Heart Physiology An understanding of normal cardiac physiology is important for the understanding of arrhythmia. Electrophysiology The passage of ions through the membrane of myocardial cells is regulated by means of specific ion channels that cause a cyclic de- and repolarization of the cell, the so-called. Action potential. The action potential of a working myocardial starts when the cell of its diastolic transmembrane potential (-90 mV) depolarized to a potential of about -50 mV. In this emerging potential, the fast voltage-dependent sodium channels open and run by a sodium influx in a rapid depolarization. The concentration gradient here is high. The fast sodium channel is rapidly inactivated and sodium influx stops, but other time- and voltage-dependent ion channels open and allow the entry of calcium through slow calcium channels (one Depolarisationsvorgang) and the exit of potassium through potassium channels (one Repolarisationsvorgang). First, are these two processes in balance, keep a positive transmembrane potential in and extend the plateau phase of the action potential. one during this phase occurs calcium, which is responsible for the electro-mechanical coupling and for the contraction of the myocardial cells in the cell. Finally, the calcium influx ends, potassium flow increases from the cell and thus causes a rapid repolarization of the cell back to the resting potential of -90 mV. During the depolarization of a myocardial cell can not be depolarized by a further Depolarisationsvorgang (it is refractory). Initial subsequent depolarization is not possible (absolute refractory period), after a partial but incomplete repolarization subsequent depolarization is possible, but takes place slowly (relative refractory period). There are generally two types of cardiac tissue: Tissue with fast-conductive cell passages (atrial – and Ventrikelarbeitsmyokard, His-Purkinje system) have a high density of conductive fast sodium channels. Tissue quickly with conductive channels cell tissue with slow-conducting ion channels with quickly conductive tissue cell passages (atrial – and Ventrikelarbeitsmyokard, His-Purkinje system) have a high density of conductive fast sodium channels. The action potentials are characterized by little or no ability to spontaneous diastolic depolarization (thus a pacemaker activity at low frequencies), by very rapid initial Depolarisationsfrequenzen (thus a high wire speed) and by a decrease in refractoriness, which coincides with the repolarisation (hence a short refractory period and the ability of repeated pulses having high frequencies to pass). Fabric with slow-conducting ion channels (sine and AV node) have a low density quickly conductive sodium channels. The action potentials are characterized by a faster spontaneous diastolic depolarization (thus a pacemaker activity at higher frequencies), by slow initial Depolarisationsfrequenzen (thus, a slow line speed) and by a decrease in refractoriness, the delay occurs after repolarization (thus a long refractory period and the inability to repetitive pulses at high frequencies to pass). Normally the sinus node has the highest spontaneous diastolic Depolarisationsfrequenzen. Its cells therefore generate spontaneous action potentials with a frequency higher than other tissues. Thus, the tissue of the sinus node is the dominant Automatiezentrum (pacemakers) of healthy heart. Creates the sinus node no pulses, takes over the fabric with the second highest Automatiefrequenz, usually the AV node, the pacemaker function. The Sympatikusstimulation increases the discharge frequency of the pacemaker tissue, stimulating the parasympathetic nervous system decreases heart rhythm sie.Normaler the rest frequency of sinus node in adults is normally between 60 to 100 beats / min. Lower frequencies (sinus bradycardia) can be found among young people, v. a. in athletes, and in his sleep. Faster frequencies (sinus tachycardia) occur during physical stress, illness or emotional events circulating through activation of the sympathetic nervous system and a distribution catecholamines. Normally, a classic daily rhythm with the lowest heart rates found in the early morning hours before waking. These differences result from variations in vagal tone and find themselves in particularly in healthy young people. A slight increase in the frequency of inhalation with a slight drop in the exhalation (respiratory sinus arrhythmia) is also normal. The fluctuations have to grow older, but not disappear completely. An absolutely regular frequency of the sinus node is pathological and occurs in patients with autonomic denervation (z. B. in advanced diabetes mellitus), or in severe heart failure. The majority of the electrical activity of the heart is in the ECG visible (diagram of the cardiac cycle, with pressure curves of the heart chambers, cardiac murmurs, Jugularvenenpulswelle and ECG.), Although not enough to the depolarization of the sine, the AV node and His-Purkinje system tissue is involved to establish them. The P-wave represents the atrial depolarization, the ventricular depolarization, the QRS complex and the T wave, the Ventrikelrepolarisation. The PR interval (from the start of the P wave to the beginning of the QRS complex) is the time from the beginning of the atrial activation to the beginning of ventricular activation. A large part of this interval is the attenuation of the momentum transfer in the AV node. The RR interval (time between two QRS complexes) shows the ventricular rate. The QT interval (from the start of the QRS complex to the end of T-wave), the duration of ventricular depolarization. The normal QT intervals are slightly longer than in men in women. Even with a slower heart rate, the QT intervals are extended. The QT interval is after the heart rate corrected (QTc). The most common formula for calculating the QTc interval (all intervals measured in seconds) is Clinical calculator: QT interval correction (ECG) pathophysiology arrhythmias due to deviations in the energization forming or the excitation line, or some combination of both. Bradyarrhythmias result from a reduced intrinsic pacing or conduction blocks, predominantly within the AV node or the His-Purkinje system. Most tachyarrhythmias occur due to a re-entrant mechanism, some due to an increased (normal) automatism or as a result of disturbed Automatiemechanismen. The reentry mechanism is circular excitation spread over two interconnected pathways with different conduction properties and refractory periods (typically reentry mechanism). Overview of the conduction system var model = {videoId: ‘4605515990001’ playerId: ‘H1xmEWTatg_default’ imageUrl: ‘http://f1.media.brightcove.com/8/3850378299001/3850378299001_4829229481001_CH20-49-AV-Node.jpg?pubId = 3850378299001 & videoId = 4605515990001 ‘, title:’ Overview of the conduction system ‘, description:’ u003Ca id = “v38395678 ” class = “”anchor “” u003e u003c / a u003e u003cdiv class = “”para “” u003e u003cp u003eZwei types of cardiac muscle cells work together to achieve a normal heartbeat. First contract contractile cells that make up the bulk of the myocardium to reduce the chamber volume and to drive blood from the chambers out. initiate it and distribute conductive cells specialized heart muscle cells

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