How do arrhythmias occur?

The heart works at a rate ranging from 60 to 100 beats per minute. The heart rate adjusts according to the body’s needs, manifesting a smooth change. However, many times this orderly function is disturbed by arrhythmias, which can lead to bradycardia (decreased heart rate), tachycardia (increased heart rate), atrial fibrillation (irregular atrial beats) or ectopic contractions (momentary interruptions in the normal rhythm).

“The mechanisms of arrhythmias are stimulus re-entry (where electrical stimulation follows a circular motion) repetitively and cyclically depolarizing an area that cells have just recovered from a previous depolarization, and pathological automaticity where a cell automatically depolarizes without being stimulated by an adjacent one cell,” he says Mr. Georgios Vassilopoulos Deputy Director Cardiologist Metropolitan Hospital.

What symptoms do arrhythmias cause?

Many times, arrhythmias may show no symptoms and be discovered accidentally during a medical examination. However, there are cases where the patient may feel temporary interruptions in the heart rhythm, or changes with some more intense pulses but also tachycardias that last for a few seconds and are repeated.

“In cases of paroxysmal tachycardia, supraventricular or ventricular, patients suddenly feel a strong tachycardia that is often unbearable. This condition can last from a few minutes to a few hours or even days, and it always stops abruptly, either automatically, or by vasotonic manipulations (tightening, pressure of the carotid arteries, coughing, etc.) or finally by drugs usually administered intravenously . In addition, sometimes arrhythmias can manifest with a feeling of weakness, dizziness, fatigue, shortness of breath or general discomfort.

If the tachycardia is particularly high (especially in patients with severe heart disease) or if the ventricles stop contracting due to cardiac arrest or AV block, blood flow to the brain is reduced, causing loss of consciousness and what we know as syncope.” , he explains.

What are the causes of arrhythmias?

Heart arrhythmia can be caused by a number of factors, including:

• Coronary artery disease
• Heart failure
• Hypertension
• Diabetes
• Sleep apnea
• Excessive use of alcohol
• Smoking
• Consumption of narcotic substances
• Thyroid diseases
• Excessive coffee consumption

Often the arrhythmia occurs in a healthy heart without any trigger.

What are the types of arrhythmias?

Irregular heartbeats are divided into two categories, tachycardias or tachyarrhythmias, when the heart rate exceeds 100 beats per minute, and bradycardias or bradyarrhythmias, when the heart rate is less than 60 beats per minute.

How do we distinguish tachycardias?

The category of arrhythmias is distinguished according to whether their source is the atria or ventricles of the heart and are called supraventricular or ventricular respectively.

Supraventricular arrhythmias are distinguished into:

• Early atrial spontaneous contractions
• AV nodal re-entrant tachycardia (AVNRT)
• Tachycardias with accessory bundle involvement (as in Wolff-Parkinson-White syndrome)
• Atrial fibrillation
• Atrial flutter
• Atrial tachycardia

Ventricular arrhythmias are divided into:

• Abnormal abdominal contractions
• Ventricular tachycardia
• Ventricular fibrillation

What are bradyarrhythmias and what types are there?

Bradycardias represent conditions where the heart rate is abnormally low. In many cases, apparent bradycardia can be completely normal, such as in athletes or during sleep. In pathological cases, the low pulse rate is due to disturbances in the production of impulses from the sinus or in the transmission of impulses through the conduction system. Thus, bradyarrhythmias are divided into the following types:

• Sinus dysfunction (or sinus disease)
• AV block

What arrhythmias should we be concerned about?

“Arrhythmias that occur in people without heart disease can cause significant symptoms, although they are usually not dangerous. In these cases, attention is focused on managing symptoms and preventing flare-ups. However, their appearance in patients with structural or electrical heart diseases requires immediate treatment, since they can cause sudden cardiac death. Special mention should be made of atrial fibrillation due to the risk of stroke, especially in patients with risk factors such as old age, diabetes mellitus, heart failure, hypertension”, Mr. Vassilopoulos points out.

How are arrhythmias diagnosed?

Various diagnostic methods are used to evaluate arrhythmias, such as electrocardiogram, Holter, stress test, echocardiogram, and electrophysiological study.

• The electrocardiogram remains a useful tool for diagnosing arrhythmias, particularly in supplementary bundles or when performed during the paroxysm.
• The Holter provides heart rate information throughout the day.
• The fatigue test used to detect arrhythmias that occur during physical fatigue.
• The heart ultrasound offers a comprehensive picture of cardiac function.
• H electrophysiological studya minimally invasive procedure, allows control of the cardiac electrical impulse generation and conduction system, as well as the induction of arrhythmias for further evaluation.

How are arrhythmias treated?

Treatment of cardiac arrhythmias depends on the type and severity of the arrhythmia. Available options may include:

• Pharmaceutical treatment: Medicines are used to control the heart rhythm or restore the heart’s normal rhythm.
• Cardioversion: This is an invasive procedure aimed at restoring the heart rhythm.
• Pacemaker: It is a device that delivers electrical pulses and is used in cases of bradycardia, heart block and heart failure.
• Implantable cardioverter-defibrillator (ICD): This is a device that provides a steady heartbeat and is usually used in cases of ventricular tachycardia or heart failure.
• Ablation: Modern treatment of arrhythmias is invasive. With the use of small electrode catheters, which are inserted into the heart cavities through the femoral and internal jugular veins under local anesthesia, receiving electrical potentials, while in parallel with modern mapping systems, a three-dimensional imaging of the heart is performed, thus accurately locating the arrhythmogenic focus. Then again with the use of a special catheter ablation of the arrhythmia is applied by the administration of radio frequency waves. Arrhythmia ablation can also be performed by applying cryocoagulation, such as in patients with atrial fibrillation, while recently the administration of pulsed field energy (PFA Ablation) is applied for atrial fibrillation with quite good results.

“The above operations ensure a complete cure for a significant number of arrhythmias (supraventricular tachycardia atrial flutter), while for several others they significantly reduce the arrhythmological burden, improving the quality of life of the patients with a minimal rate of complications,” concludes Mr. Vassilopoulos.

*The Metropolitan Hospital has a modern and fully equipped Cardiology Clinic, which compares with the leading cardiology centers abroad. The clinic is certified according to the ISO standard and has won the trust of the medical community in Greece. Also, for the last 15 years, it has proven its scientific excellence in the care and treatment of complex cardiac cases. With a highly qualified scientific and nursing staff, as well as advanced equipment, the Cardiology Clinic serves patients 24 hours a day, ready to deal with acute or chronic cardiac cases with exemplary thoroughness.