Cardiac arrhythmias at a glance

The heart has two ventricles and atria and is one of the strongest muscles in our bodies. Thousands upon thousands of muscle fibres contract and relax in sync thanks to an electrical impulse. Cardiac arrhythmias occur when the electrical impulses are not transmitted properly or when they propagate in the wrong way. These are manifested in an irregular, chaotic, overly fast or slow heart rhythm.

Nearly everyone will suffer from a heartbeat irregularity at some point in their life, often without even noticing. In most cases, these arrhythmias are completely harmless and pose no risk to the person. But these cardiac arrhythmias can also be caused by a cardiac disease, can diminish the capacity of the heart or, at worst, lead to sudden cardiac death. If the arrhythmias persist, they become bothersome and/or compromise the person’s quality of life until a cause for the irregularities can be found.

Atrial fibrillation: a lightning storm in the heart

 

Atrial fibrillation is among the most common types of cardiac arrhythmia. The trouble occurs when faulty electrical impulses in the atria of the heart cause the heart to beat too quickly, irregularly or, most notably, in an uncoordinated manner. The heart experiences a violent lightning storm of sorts. In the chaos of impulses, pumping activity in the atria and ventricles diminishes, reducing cardiac output.

It is possible to compensate for this weakness in the ventricles for a short time, so that there is initially no acute threat to the person’s life and limb. But if atrial fibrillation goes untreated, there is a risk of excess strain in the ventricles, eventually leading to cardiac insufficiency. Because atrial fibrillation causes excess blood clots to accumulate in the vessels, strokes may also result.

Anatomy of the heart
Cardiac arrhythmia

Sinus rhythm

The sinus rhythm refers to a person’s normal, regular heartbeat. They are a normal consequence of the “ignition sparks” or electrical impulses triggered by the body’s own internal pacemaker: the sinus node

Atrial fibrillation

Atrial fibrillation is among the most common types of cardiac arrhythmia. It causes irregular electrical impulses in the atria with more than 300 excitations per minute. This stress prevents the heart from functioning properly. It pumps less blood and the cardiac output diminishes.

Possible treatments: antiarrhythmic agents, cardioversion or catheter ablation. Because atrial fibrillation promotes the formation of blood clots, which can cause a stroke, patients also need to take blood-thinner medications.

Ventricular fibrillation

At more than 400 beats per minutes, the frequency in the main ventricles is extremely high. The heart merely spasms but is not pumping any more blood. This immediately renders the person unconscious and, without taking immediate emergency measures (cardiac massage, defibrillation and resuscitation), death.

Treatment: Implanting of a cardioverter / defibrillator (ICD) is required

Ventricular flutter and ventricular tachycardia
(ventricular tachycardias)

Beating in the main ventricles is very fast – up to 300 times per minute. In this case, not enough blood is pumped into circulation. It is often due to a recent heart attack or one further in the past, but it can also be caused by a cardiac insufficiency. Immediate defibrillation (cardioversion) is life-saving.

Treatment: Long-term treatment usually involves implanting a cardioverter/defibrillator (ICD).

Supraventricular tachycardia

Supraventricular tachycardia can have several causes, e.g. bypass between the atria and main ventricles, double paths in the normal transmission (A-V node) or improperly functioning natural pacemaker (“defective spark plugs). The heart beats between 150 and 220 times per minute. Symptoms include heart palpitations, rapid heartbeat, dizziness and, in rare cases, unconsciousness.

Treatment: Emergency medication to control cardiac rhythm followed by electrophysiological examination with catheter ablation.

Extrasystoles

In the case of extrasystoles, a “misfiring” from the atria or main ventricles disrupts the normal sinus rhythm. These extrasystoles are very often harmless and usually unnoticeable. In some cases, the person complains of irregular heartbeat or skips in heartbeat.

Treatment: Treatment is not required in most cases.

Atrial flutter

Atrial flutter circles the right atrium at a flutter speed of 220 to 300 per minute. Only every second to third atrial excitation is transmitted to the main ventricles.

Possible treatments: blood-thinner medications, antiarrhythmic agents, cardioversion, catheter ablation.

Sinus rhythm

The sinus rhythm refers to a person’s normal, regular heartbeat. They are a normal consequence of the “ignition sparks” or electrical impulses triggered by the body’s own internal pacemaker: the sinus node

Atrial fibrillation

Atrial fibrillation is among the most common types of cardiac arrhythmia. It causes irregular electrical impulses in the atria with more than 300 excitations per minute. This stress prevents the heart from functioning properly. It pumps less blood and the cardiac output diminishes.

Possible treatments: antiarrhythmic agents, cardioversion or catheter ablation. Because atrial fibrillation promotes the formation of blood clots, which can cause a stroke, patients also need to take blood-thinner medications.

Ventricular fibrillation

At more than 400 beats per minutes, the frequency in the main ventricles is extremely high. The heart merely spasms but is not pumping any more blood. This immediately renders the person unconscious and, without taking immediate emergency measures (cardiac massage, defibrillation and resuscitation), death.

Treatment: Implanting of a cardioverter / defibrillator (ICD) is required

Ventricular flutter and ventricular tachycardia
(ventricular tachycardias)

Beating in the main ventricles is very fast – up to 300 times per minute. In this case, not enough blood is pumped into circulation. It is often due to a recent heart attack or one further in the past, but it can also be caused by a cardiac insufficiency. Immediate defibrillation (cardioversion) is life-saving.

Treatment: Long-term treatment usually involves implanting a cardioverter/defibrillator (ICD).

Supraventricular tachycardia

Supraventricular tachycardia can have several causes, e.g. bypass between the atria and main ventricles, double paths in the normal transmission (A-V node) or improperly functioning natural pacemaker (“defective spark plugs). The heart beats between 150 and 220 times per minute. Symptoms include heart palpitations, rapid heartbeat, dizziness and, in rare cases, unconsciousness.

Treatment: Emergency medication to control cardiac rhythm followed by electrophysiological examination with catheter ablation.

Extrasystoles

In the case of extrasystoles, a “misfiring” from the atria or main ventricles disrupts the normal sinus rhythm. These extrasystoles are very often harmless and usually unnoticeable. In some cases, the person complains of irregular heartbeat or skips in heartbeat.

Treatment: Treatment is not required in most cases.

Atrial flutter

Atrial flutter circles the right atrium at a flutter speed of 220 to 300 per minute. Only every second to third atrial excitation is transmitted to the main ventricles.

Possible treatments: blood-thinner medications, antiarrhythmic agents, cardioversion, catheter ablation.