Under a cardiac arrhythmia (HRS) or cardiac arrhythmia , with the forms (cardiac) arrhythmia ( ancient Greek ἄρρυϑμος , "irregular"; irregular sequence of excitations and / or pulse beats) and cardiac dysrhythmia (deviation from the normal heart rate or disruption of the timing individual heart actions), one understands a disturbance of the normal heartbeat sequence, caused by irregular processes in the development and conduction of excitation in the heart muscle . Physiological changes in the heart rhythm, on the other hand, are referred to as heart rate variability . Among them there is an acceleration ( tachycardia ) and a slowdown ( bradycardia ) of the heart rate.
Classification of cardiac arrhythmias
- Speed (frequency) of the resulting heartbeat: bradycardiac (in adults less than 60 beats per minute) or tachycardiac arrhythmia,
- Dangerousness: benign (with hemodynamically stable symptoms) or malignant, potentially life-threatening arrhythmias due to unstable hemodynamics
- Development (mechanism): congenital (additional conduction pathways or focal impulse formation , circular excitation , cardiac muscle diseases , ion channel diseases) or acquired ( ischemic , thickening of the heart muscle, enlargement of the heart cavities) disorders.
- Place of origin: Supraventricular ( supraventricular tachycardia / supraventricular extrasystoles ) or ventricular ( ventricular tachycardia / ventricular extrasystoles ) arrhythmia.
- ECG criteria: width and appearance of the QRS complex , regular or irregular, atrial and ventricular frequency.
- Onset: Sudden ( paroxysmal ) or slowly increasing cardiac arrhythmia.
- Duration: Non-persistent (less than 30 seconds) or persistent.
Atrium (supraventricular arrhythmias)
Excitation conduction system
(schematic, in humans)
Important structures are
- Atrial fibrillation
- Atrial flutter
- Supraventricular tachycardia
- Sinoatrial block ( SA block )
Chamber (ventricular arrhythmias)
- Extra ventricular asthma
- Accelerated idioventricular rhythm
- Ventricular tachycardia (ventricular tachycardia), special form: torsade-de-pointes tachycardia
- Ventricular flutter
- Ventricular fibrillation
Excitation formation and excitation conduction system
Sick Sinus Syndrome (SSS, Diseased Sinus Node Syndrome)
- including z. E.g .: bradycardia-tachycardia syndrome
- (Pathological) sinus bradycardia
- Carotid Sinus Syndrome
- Supraventricular tachycardia
- Atrioventricular blocks (AV block)
- AV Nodal Reentry Tachycardia (AVNRT)
- Wolff-Parkinson-White syndrome (WPW syndrome)
- Ventricular reserve rhythm
Cardiac arrhythmias are common. Healthy people sometimes notice a stumbling of the heart ( palpitations ) or brief stopping of the heartbeat, caused by extra beats . A distinction is made between different forms of arrhythmia ( respiratory arrhythmia , absolute arrhythmia , extrasystole and atrioventricular conduction disorders). Palpitations, as in rapid atrial fibrillation or AVNRT , are often described as regular or irregular throbbing "down to the throat". If a heart is previously damaged, an existing heart failure can worsen due to the high heart rate. This can be expressed, for example, by shortness of breath. In severe cases, pulmonary edema can result. Heart pain ( angina pectoris ) can also occur as well as a worsening of symptoms of a pre-existing poor cerebral blood flow (disorientation, dizziness, seizures, temporary speech and vision disorders).
If there is a slow (bradycardic) arrhythmia (SSS, SA block, AV block), dizziness, collapse states and even complete fainting ( syncope ) can result. In rare cases, fatal asystole can also occur with a third degree AV block without an alternate rhythm.
In the case of dangerous cardiac arrhythmias such as ventricular tachycardia, the ejection capacity of the heart is usually so restricted that adequate circulation is no longer possible, and the patient loses consciousness. A mechanically absent heart action is present in ventricular flutter or fibrillation with complete cardiac arrest (asystole). If these arrhythmias occur for no apparent reason, one speaks of sudden cardiac death .
There are different types and forms of cardiac arrhythmias, for the diagnosis of which the EKG (electrocardiogram) - and here again the long-term EKG - is particularly useful . If the arrhythmia cannot be adequately diagnosed with these means, a so-called electrophysiological examination may be necessary.
Recognizing the cause is a prerequisite for proper therapy .
- Medical history (especially medication, previous illnesses and / or existing illnesses, family history)
- Resting ECG (recording of currently available HRS) and long-term ECG (recording of the time of day or situation-dependent HRS), if necessary event recorder (recording of sporadic episodes)
- Ergometry (recording of exercise-induced HRS and anomalies of the increase in heart rate, e.g. in the case of sick sinus syndrome )
- Electrophysiological examination (invasive, but very precise, e.g. using a mapping catheter); Detection of ectopic foci, accessory pathways (e.g. Mahaim fibers or Kent bundles in WPW syndrome )
- Pharmacological tests (e.g. ajmaline test to diagnose Brugada syndrome )
- Accessory (surplus) conduction pathways (WPW syndrome, AVNRT)
- Ion channel disorders (Brugada syndrome, congenital long QT syndrome )
- congenital heart defects (vitia with pressure or volume loads on the heart)
- Heart muscle damage
- Inflammation of the heart muscle and pericardium ( myocarditis , pericarditis )
- toxic dilated cardiomyopathy
Other (extracardiac) causes
- Electrolyte disorders ( potassium , magnesium , calcium )
- Medicines ( catecholamines , antiarrhythmics , cardiac glycosides , tricyclic antidepressants , some antibiotics )
- Electricity accident
- Carotid Sinus Syndrome (also "hyperreactive carotid sinus")
- psycho-vegetative (fear, stress, fatigue, increased vagal tone )
- Holiday Heart Syndrome
- Roemheld Syndrome
Cardiac arrhythmias require therapy only in those with heart disease. These include congenital or acquired heart muscle diseases, but also temporary diseases such as myocarditis and Holiday Heart Syndrome . The most common arrhythmias to be found in people with healthy heart are extrasystoles. These are benign and should not be treated with drugs in the sense of a “cosmetic of the EKG”.
Magnesium is used in the therapy of cardiac arrhythmias because of its antiarrhythmic properties. Its most important mechanisms of action include maintaining the electrolyte balance in the heart muscle cells, increasing the stimulus threshold , calcium antagonism and reducing the release of neurotransmitters and mediators (e.g. noradrenaline , adrenaline ), which preventively prevent arrhythmia or an existing cardiac arrhythmia can be eliminated relatively without side effects (by oral administration). The only contraindication for oral administration is severe renal insufficiency , whereby a controlled dose adjustment can be considered.
Depending on the type of arrhythmia, drugs that regulate and stabilize the frequency, so-called antiarrhythmics ( adenosine , ajmaline , amiodarone , atropine , beta blockers , digitalis , flecainide , calcium antagonists of the verapamil or diltiazem type, etc.) are given.
If the heartbeat is too slow, a pacemaker is implanted, and if dangerous rhythm disturbances occur again and again, an implantable defibrillator (ICD) is implanted . To restore a normal heart rhythm (sinus rhythm), an external electrical stimulus can be applied to the body in the case of atrial flutter and fibrillation and ventricular tachycardia (electrical cardioversion ). If there is ventricular fibrillation, this is called defibrillation when using higher energy .
If malignant arrhythmias occur as part of a worsening coronary artery disease (CHD) , it is important to improve the blood flow to the heart using a cardiac catheter or bypass surgery . Some arrhythmias (AVNRT, WPW syndrome, atrial flutter and fibrillation) can be eliminated by catheter ablation .
Extracardiac causes should be treated causally by treating the underlying disease ( hyper- , hypothyroidism , electrolyte disturbance , intoxication ). Supraventricular rapid heart rhythm disturbances can by lifting the vagal tone using the Valsalva maneuver or Carotisdruckversuch be affected.
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