Cardiac Arrhythmias: When the Heart Gets Out of Rhythm

Suddenly it rumbles in the chest, then absolute radio silence. Such short-lived attacks are usually harmless – but sometimes they are harbingers of a heart condition. A healthy heart muscle contracts about 60 to 80 times a minute, then relaxes again shortly afterwards to pump blood through the circulatory system. A miniature power plant, the sinus node in the right ventricle, ensures that this rhythm of life is maintained. This small plexus of tendons regularly sends out electrical impulses that set the heart‘s beat. Thus, the human heart has specialized cells that serve, on the one hand, to generate electrical impulses and, on the other hand, to spread these impulses throughout the heart muscles.

What happens when the heart beats?

If the sinus node fails, there is far from radio silence. Another area of the electrical pathway, called the AV node, steps in. If this emergency supply also fails, the His fiber bundle can take over the role of the clock generator, but with a significantly reduced pulse rate of only 40 beats per minute. In the long run, this is too little. Doctors then speak of dangerous bradycardia. The circulation comes to a standstill and the person can even lose consciousness. If the heartbeat sequence is continuously turbulent (tachycardia), there is also something wrong with the heart’s electrical system. 13 tips for a healthy heart

Cardiac arrhythmias: Causes

Cardiac arrhythmias may be an expression of organic disease of the heart muscle or isolated damage to the stimulus-forming and conduction structures of the heart. In some cases, the organic or functional basis for cardiac arrhythmias may be established at a person’s birth. In this case, cardiac arrhythmias can occur either in early childhood or later in life. However, the following causes are much more common – especially in Western industrialized nations:

  • High blood pressure
  • Circulatory disorders of the coronary arteries
  • Heart attack
  • Heart valve defect
  • Heart muscle inflammation or
  • A pathologically weakened heart

But also an overactive thyroid or potassium deficiency sometimes bring the life motor out of step. To some extent, electrolyte disorders or side effects of drugs are also considered as triggers of cardiac arrhythmias. Since cardiac function is also strongly influenced by the autonomic nervous system, psychological factors can also play a significant role in the development of cardiac arrhythmias. But: Not behind every stumble and irregular heartbeat is a disease. Stress and physical exertion, caffeine and alcohol, and even certain medications can disrupt the “power supply” in the heart. The consequences are heart palpitations and extra beats, called extrasystoles in technical language.

Symptoms and characteristics of cardiac arrhythmias

If the heart permanently deviates from the normal pumping rhythm, there is a risk of serious damage to health and sometimes even complete heart failure. The problem: In cardiac arrhythmias, there is often a marked difference between the physician’s assessment of the disorder and the patient’s impairment. Thus, it can happen that even life-threatening cardiac arrhythmias lasting several minutes are hardly noticed by patients. Other patients, on the other hand, may feel that their condition is severely impaired even by sporadically recurring extra beats of the heart that are in themselves completely harmless. Depending on the type and duration, cardiac arrhythmias may cause the following symptoms:

  • Palpitations and palpitations
  • Irregular pulse beat
  • Dizziness
  • Collapse
  • Fainting spells

In extreme cases, a malignant arrhythmia or sudden cardiac death may occur. Important distinguishing criteria for cardiac arrhythmias are, on the one hand, their place of origin (atrium or ventricle), on the other hand, their duration and also whether they occur in the context of an acute heart disease, for example, in myocardial infarction, or in a chronically damaged heart.

Common: atrial flutter

As a general rule, arrhythmias originating in the atrium tend to be of a harmless nature, whereas arrhythmias originating in the ventricle can sometimes assume life-threatening proportions, especially in cases of advanced organic heart disease.The uncoordinated and rapid twitching of the atria is the most common form of cardiac arrhythmia. Elderly people and people with heart failure are particularly affected by such atrial fibrillation or flutter. Although the underlying disease should always be treated first, atrial fibrillation must also be stopped so that heart failure does not worsen. This is done through a procedure called cardioversion, in which the heart is restored to its normal beating sequence with medication or with the help of an electric shock. However, there are also cases in which treatment for atrial fibrillation is not necessary. These can be patients, for example, who have a normal heart rate despite arrhythmia and are symptom-free. However, the increased risk of blood clots, which can clog vessels and, in the worst case, trigger a stroke, must always be averted in these patients.

Life-threatening ventricular fibrillation

Clock disturbances of the heartbeat always become dangerous when they lead to a drastic drop in pumping capacity. This happens when a racing heartbeat does not give the heart muscle time to fully contract, and the heart chambers can no longer fill with blood. The extreme case is the dreaded ventricular fibrillation, in which the heart muscle only twitches in an uncoordinated manner. The pace can increase to up to 300 such irregular beats per minute. At this infernal speed, the heart cannot even come close to supplying the circulatory system with blood. Without rapid intervention, the result is heart failure. Rescue comes with an electric shock delivered by a defibrillator. The small device can virtually eliminate the risk of dying from a life-threatening arrhythmia.

Progression of cardiac arrhythmias

As far as the course of arrhythmias is concerned, it is not possible to make accurate predictions in individual cases. Cardiac arrhythmias can either be lifelong or occur only at a certain stage of life, or they can become permanent, unpleasant companions as organic heart disease progresses. In order to assess their character more accurately and to establish a possible treatment plan, it is essential for the physician to document the cardiac arrhythmia in a resting or long-term ECG. This means that an electrocardiogram must be written at the time of the ongoing arrhythmia. Once the arrhythmia has been clearly diagnosed, the physician can decide whether immediate drug therapy should be considered and the patient can subsequently go home symptom-free or whether a longer hospital stay is necessary for further evaluation.