Cardiac arrhythmias and conduction disturbances

The article was professionally consulted with Specialist Doctor II Nguyen Quoc Viet - Interventional Cardiologist - Department of Medical Examination & Internal Medicine - Vinmec Danang International General Hospital.

In a healthy heart, cardiac signaling is usually smooth, with a normal resting heart rate of 60-100 beats/min. In people with arrhythmias, the heart rate may be faster or slower than the normal heart rate. This can cause uncomfortable, life-threatening signs and symptoms.

An arrhythmia is an irregular heartbeat. Heart rhythm problems (arrhythmias) happen when the electrical signals that coordinate the heartbeat of the heart don't work properly. The faulty signal causes the heart to beat too fast (tachycardia), too slow (bradycardia), or abnormally.
Arrhythmias can feel like a pounding or fluttering heart and can be harmless. However, some arrhythmias can cause unpleasant, life-threatening signs and symptoms that can also be normal. For example, the heart rate may increase during exercise or slow down during sleep.
Treatment for arrhythmias may include medications, catheterization procedures, implanted devices, or surgery to control or eliminate fast, slow, and irregular heartbeats.

A conduction disturbance is an abnormality in the heart's electrical impulse conduction system that causes your heart to beat irregularly. This system is called the cardiac conduction system. Normally, the electrical signal that makes your heart beat travels from the medulla oblongata (at the base of the heart) along a conduction system down to the apex of the heart. The signal that activates the heart muscle causes your heart to beat, pumping blood to your lungs and entire body. In conduction disorders, electrical signals are not generated properly or are not transmitted properly through the heart.
In intraventricular conduction disturbances (such as atrioventricular - AV block) and bundle branch block, which vary depending on where they occur in the conduction system. Certain medications can cause conduction disturbances as well as ischemic heart disease or heart attack.... Your doctor can diagnose a conduction disorder with an electrocardiogram (EKG or ECG), which is a measurement of your heart's electrical activity.
Conduction disorders may require no treatment or can be treated with medications, pacemakers, implantable defibrillators (ICDs), and surgical procedures. Treatment depends on the location, type, and severity of the conduction disturbance. Your doctor will look at how the disorder affects your heart and symptoms, which can vary from person to person. Sometimes an irregular heartbeat is the first sign of a conduction disorder. If left untreated, serious conduction disturbances can lead to sudden cardiac arrest.

Arrhythmias are grouped by the speed of the heart rate, which is tachycardia (greater than 100 beats per minute), bradycardia (which is a resting heart rate of less than 60 beats per minute), and premature heart rate.
Common types of tachycardia include:
Atrial fibrillation: Chaotic heart signals that cause a fast, uncoordinated heartbeat. The condition may be temporary, but some episodes of atrial fibrillation may not stop unless treated. Atrial fibrillation is associated with serious complications such as stroke. Atrial flutter: Atrial flutter is similar to atrial fibrillation, but the heart rate is more organized. Atrial flutter has also been linked to stroke. Supraventricular tachycardia: A broad term that includes arrhythmias that begin in the lower chambers of the heart (ventricles). Supraventricular tachycardia causes episodes of pounding heart (palpitations) that end abruptly. Ventricular fibrillation: This type of arrhythmia occurs when rapid, chaotic electrical signals cause the lower heart chambers (ventricles) to quiver instead of coming into concerted contact to pump blood to the rest of the heart. body. This serious problem can lead to death if a normal heart rhythm is not restored within minutes. Ventricular tachycardia: This rapid, regular heartbeat begins with faulty electrical signals in the lower heart chambers (ventricles). Tachycardia does not allow the ventricles to fill with blood properly. As a result, the heart cannot pump enough blood to the body. Ventricular tachycardia may not cause serious problems in people with healthy hearts. In people with heart disease, ventricular tachycardia can be a medical emergency that requires immediate medical treatment. If you're healthy enough, your heart can still pump enough blood to your body at less than 60 beats a minute at rest. If the heart rate is slow and the heart is not pumping enough blood, you may have one of the following types of bradycardia:
Sinus node syndrome: If it is not working properly, the heart rate may alternate between being too slow (rhythmic) bradycardia) and too fast (tachycardia). Sick sinus syndrome can be caused by scarring near the sinus node that slows, interrupts, or blocks the passage of impulses. Conduction block: A blockage of the heart's electrical pathways can cause the signals that trigger the heart rate to slow or stop.

Premature heartbeat:
An extra beat that occurs one beat at a time, sometimes in an alternating pattern with a normal heartbeat. The extra beats can come from the top chamber of the heart (premature contraction atria) or the lower chamber (premature contraction ventricle). Premature heartbeat can feel like your heart is out of rhythm. These extra beats are usually not cause for concern and they rarely mean you have a more serious condition. However, premature beats can cause arrhythmias to last longer, especially in people with heart disease. Very frequent premature beats that last for several years can lead to a weak heart. Premature heartbeat can occur at rest. Sometimes a premature heartbeat is caused by stress, strenuous exercise, or a stimulant, such as caffeine or nicotine.

Your doctor may notice an irregular heartbeat when examining you for another health reason. Signs and symptoms of an arrhythmia may include:
Shivering in the chest Tachycardia Slow heart rate Chest tightness Shortness of breath Other symptoms may include anxiety, fatigue dizziness, fainting sweating, fainting. If you feel your heart is beating too fast or too slow, make an appointment with your doctor. Seek medical help right away if you experience shortness of breath, weakness, dizziness, lightheadedness, chest pain or discomfort.

In a healthy heart, cardiac signaling is usually smooth, resulting in a normal resting heart rate of 60 to 100 beats per minute.
Things that can cause an irregular heartbeat (arrhythmia) include:
Existing heart attack or scarring from a previous heart attack Clogged arteries in the heart (coronary artery disease) Changes to the structure of your heart structure of the heart, such as due to cardiomyopathy Diabetes High blood pressure COVID-19 infection Overactive thyroid (hyperthyroidism) Sleep apnea Underactive thyroid (hypothyroidism) Certain medications, including cold and allergy medicines bought without a prescription Drinking too much alcohol or caffeine; drug abuse; genetics; smoke; stress or anxiety Sleep apnea: This condition causes breathing stops during sleep. It can lead to bradycardia and irregular heartbeat, including atrial fibrillation. Electrolyte imbalance: Substances in the blood called electrolytes, such as potassium, sodium, calcium, and magnesium help trigger and send electrical impulses in the heart. An imbalance in electrolytes can interfere with the heart's signaling and lead to an irregular heartbeat. Some prescription and over-the-counter cough and cold medicines can cause arrhythmias.

Complications will depend on the type of arrhythmia. However, the most common complications of arrhythmias are stroke, sudden death, and heart failure.
Cardiac arrhythmias associated with blood clot formation. If the clot breaks off, it can travel from the heart to the brain, causing a stroke. Blood thinners can reduce the risk of strokes associated with atrial fibrillation and other heart rhythm disorders. Your doctor will determine if a blood thinner is right for you.
If an arrhythmia is causing symptoms of heart failure, methods of controlling the heart rate can improve heart function.
Lifestyle changes to reduce your risk of heart disease can help prevent arrhythmias. You should therefore:
Have a heart-healthy diet Maintain physical activity and a healthy weight Don't smoke Limit or avoid caffeine and alcohol Use medications as directed and talk to your doctor about all the medicines you take, including those bought without a prescription. Most people with an irregular heartbeat can lead a normal life if it is diagnosed and treated properly. Therefore, if you have abnormal signs in your heart such as shortness of breath, fast or slow heart rate, palpitations, etc., you should see a doctor for timely diagnosis and treatment.
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