Cardiac Arrhythmias

Many people have abnormal heart rhythms during their lifetime. Healthy people sometimes notice that a beat skips or the heart stumbles. Such extra blows (so-called extrasystoles) are to a certain extent harmless and harmless (especially for young people). But sometimes these stumbling blocks indicate serious heart disease. Here you will find everything about the symptoms, causes, and treatment of cardiac arrhythmias.

Definition

In the case of cardiac arrhythmias, the sequence of heartbeats is disturbed: the heart beats too fast, too slowly or too irregularly. In healthy adults, the heart beats about 60 to 80 times a minute when at rest and without exertion. With excitement, anger, fear, or stress, as well as physical strain, the heartbeat accelerates. On the other hand, it decreases during sleep. These changes are normal and important. In the case of cardiac arrhythmias, this adjustment of the heartbeat does not work properly.

Sinus nodes and AV nodes – clocks for the heart rhythm

The so-called sinus node in the heart indicates how fast and often the heart beats. However, this sinus node is not a palpable or tactile node. Rather, it is an accumulation of specialized heart muscle cells.

The sinus node is the first clock of the heartbeat. It is located in the upper area of ​​the right atrium and generates around 60 to 80 so-called excitations per minute. From there, these electrical impulses reach the AV node via the walls of the atria. This node lies at the transition between the atrium and the ventricle and steps in when the sinus node fails. It is like a downstream (secondary) pacemaker. However, the AV node produces only 40 to 50 excitations per minute. From the AV node, the electrical stimuli pass through specific conduction pathways into the muscles of the heart, which make the heartbeat.

Classification Of Cardiac Arrhythmias

Cardiac arrhythmias are classified according to their place of origin. They can arise in the atrium or the ventricle as well as in the stimulation and conduction system. There are also classifications according to speed and danger, as well as congenital and acquired cardiac arrhythmias. We limit ourselves to the classification of cardiac arrhythmias according to their place of origin.

Cardiac Arrhythmias

Atrial Arrhythmias

Arrhythmias that arise in the atrium of the heart are called supraventricular arrhythmias. As a rule, pathological changes in the sinus or AV node are the cause.

Typical atrial arrhythmias are:

    • Atrial fibrillation (most common significant cardiac arrhythmia. With atrial fibrillation, non-directional electrical excitations run across the atria at an immense speed.
    • Atrial flutter (abnormal heart rhythm in which the auricles beat regularly but very quickly per minute)
    • Conduction disorder from the sinus node to the atrial muscles (sinoatrial block).
    • Heartbeats outside the normal heart rhythm, originating in the atrium (supraventricular extrasystoles).

Cardiac Arrhythmias In The Ventricle

Arrhythmias that arise in the chambers of the heart are called ventricular arrhythmias. Typical cardiac arrhythmias in the ventricle are:

    • Heartbeats outside the normal heart rhythm from the ventricle (ventricular extrasystoles)
    • Rapid, sometimes life-threatening cardiac arrhythmias that originate in the ventricles (ventricular tachycardia)
    • Ventricular flutter (rapid sequence of relatively regular ventricular actions)
    • Ventricular fibrillation (life-threatening and pulseless cardiac arrhythmia with disordered ventricular excitation, whereby the heart muscle no longer beats properly. If left untreated, ventricular fibrillation leads directly to death due to the lack of pumping capacity).

Cardiac Arrhythmias Of The Excitation And Conduction System

    • Malfunction of the sinus node and conduction in the atria (e.g. sick sinus syndrome, sick sinus node syndrome)
    • Delayed or interrupted conduction of excitation at the AV node (AV blockages)
    • rapid and regular heartbeats that begin suddenly and end abruptly (AV node reentry tachycardia)
    • Wolff-Parkinson-White syndrome (WPW syndrome, a frequent cardiac arrhythmia in young people that is triggered by an electrical circuit between the auricles and the ventricles.)
    • Ventricular reserve rhythm after failure or blockage of sinus nodes or AV nodes.

Symptoms

A cardiac arrhythmia can also be seen when feeling the pulse wave, for example on the wrist. The pulse can really race, go very slowly or bump irregularly, be hard or flat and weakly palpable, and sometimes it can hardly be felt, if at all. Depending on the severity of the heart damage, shortness of breath, disorientation, dizziness, and temporary speech and vision disorders are possible. Very severe cardiac arrhythmias can lead to loss of consciousness or even death.

An overview of the symptoms of cardiac arrhythmias

    • slow, fast, or stumbling heartbeat (palpitations, palpitations)
    • Stopping the heartbeat (palpable pause in beat)
    • Feeling the heartbeat – sometimes up to the throat (palpitations)
    • Pulse changes (racing, slow, hard, soft, weak, or barely noticeable)
    • Heart pain, chest tightness (angina pectoris)
    • temporary speech and vision disorders
    • Difficulty breathing, disorientation, dizziness, drowsiness, confusion
    • Seizure, collapse, loss of consciousness.

Complications from cardiac arrhythmias

Arrhythmias can lead to dangerous complications. Vascular occlusions (embolisms), heart attacks, strokes, increasing heart failure or sudden cardiac death are particularly feared.

Causes

The cause of an arrhythmia can be in the heart itself or it can be a disease outside the heart. For example, febrile infectious diseases are often accompanied by a heartbeat that is too fast. An underactive thyroid usually causes a slow heartbeat.

Furthermore, electrolyte deficiencies (such as potassium deficiency or calcium deficiency) or an excess of minerals (such as potassium excess) can trigger cardiac arrhythmias of all kinds. For some people, eating 6 bananas is enough to cause cardiac arrhythmias. Because bananas contain a lot of potassium.

There are also congenital disorders of the cardiac excitation or everyday situations that change the heart rhythm (for example excessive alcohol or coffee consumption). Heart diseases that cause irregular heartbeat include:

Other diseases that can cause irregular heartbeat to include:

Hypersensitive carotid sinus in carotid sinus syndrome. The carotid sinus is a receptor on the main artery in the neck that can be irritated by pressure (for example when shaving, by a tight scarf or collar, or when the head is overstretched). As a result, the heartbeat slows down so much that the person affected sometimes passes out.

The following situations can trigger cardiac arrhythmias:

    • Fear, anger, nervousness
    • emotional stress and physical strain
    • excessive consumption of caffeine or teine ​​(coffee, tea, or cola)
    • excessive alcohol consumption
    • Smoke
    • Use of drugs or other poisons
    • Taking medication (e.g. side effects of thyroid hormones or antidepressants).

Examination

The typical complaints and previous or concomitant illnesses point the doctor to the diagnosis of cardiac arrhythmia. To confirm the diagnosis, the doctor will listen to your heart and measure your pulse, followed by a resting electrocardiogram (resting ECG) and, if necessary, a stress ECG. As a rule, these examinations are sufficient to determine cardiac arrhythmias.

Treatment

The doctor decides on an individual basis whether a cardiac arrhythmia needs treatment at all. Sometimes cardiac arrhythmias do not require treatment. Otherwise, the therapy depends on the type and cause of the cardiac arrhythmia. If illnesses are responsible for the disturbed heartbeat sequence, these must first be treated. There are many treatment approaches for cardiac arrhythmias themselves.

Drug Therapy For Cardiac Arrhythmias

Drugs for arrhythmias are called antiarrhythmics. Active ingredients from the following groups are used to treat cardiac arrhythmias with drugs:

    • Class I antiarrhythmics: sodium channel blockers such as ajmaline or quinidine
    • Class II antiarrhythmics: beta-blockers, e.g. bisoprolol, nebivolol, or metoprolol
    • Class III antiarrhythmics: potassium channel blockers, e.g. amiodarone, dronedarone or sotalol
    • Class IV antiarrhythmics: calcium antagonists, such as diltiazem and verapamil.

Other antiarrhythmics are:

    • Adenosine (is often used for the acute therapy of cardiac arrhythmias of the AV node)
    • Digitalis glycosides (strengthen the heart muscles, typical representatives are digoxin and digitoxin)
    • Parasympatholytics (such as atropine and ipratropium bromide)
    • Sympathomimetics (such as adrenaline and noradrenaline)
    • If channel inhibitors (a new group of active substances with the only representative so far ivabradine)

Cardioversion To Restore Normal Heart Rhythm

Cardioversion is designed to restore the heart’s normal sinus rhythm. This rhythmization is mainly used as an emergency treatment for ventricular flutter, ventricular fibrillation, and supraventricular or ventricular tachycardias. Cardioversion can be medicated or electrically (with the help of a defibrillator or cardiac shock). A strong current surge interrupts the electrical activity of the heart. This time-out allows the sinus node to resume its function and then rhythmically pace the heartbeat.

Ablation In Cardiac Arrhythmias

In the case of cardiac arrhythmias such as WPW syndrome, AV node reentry tachycardias, or with certain ventricular tachycardias, high-frequency current ablation can be useful. The starting point of the cardiac arrhythmia or additional conduction pathways (as in the WPW syndrome) is obliterated by electricity via a cardiac catheter.

Pacemaker For Cardiac Arrhythmias

Sometimes a pacemaker (Pacer, Pacemaker) is implanted if the heartbeat is too slow. In the case of life-threatening cardiac arrhythmias, the use of an implantable cardioverter-defibrillator (ICD) may be necessary to prevent cardiac arrest.

The pacemaker works like a pulse generator. It monitors the heartbeat and gives electrical impulses to the heart if it beats too slowly. The cardioverter-defibrillator is slightly larger than the pacemaker and monitors the heart rhythm. Depending on the rhythm disturbance, electrical impulses are emitted and over-or under-stimulation corrected. If necessary, cardiac shock therapy is carried out: defibrillation.

Both devices are implanted under the collarbone during a minor surgical procedure. Electrodes connect the devices to the heart. If the heartbeat drops too much, the pacemaker steps in. An implantable cardioverter-defibrillator (ICD) is used, among other things, for atrial flutter and atrial fibrillation as well as for ventricular fibrillation.