Cardiac arrhythmias

What are they

In medicine, cardiac arrhythmias are defined as alterations in the heartbeat that may concern frequency or rhythm. They occur when the heart beats too fast, too slow, or in an irregular rhythm.

When the heartbeat is too fast, i.e. more than 100 beats per minute, we speak of tachycardia, when it is too slow, ie less than 60 beats per minute, it is called bradycardia.

There are different types of arrhythmia, depending on the site involved and the type of electrical anomaly.

Hyperkinetic arrhythmias

An arrhythmia of this type can be supraventricular or ventricular type.

Supraventricular arrhythmias

1. Extrasystoles. They are characterized by an anticipated contraction of the cardiac or muscle. The typical symptom is the sensation of “missing heartbeat” or “flickering”, with brief episodes of palpitations. They are usually not dangerous and asymptomatic forms are frequent.
2. Atrial fibrillation (AF). It is a very common tachyarrhythmia, suffering from it more than 5 percent of the population over 70 years and 10 percent of over 80. It consists of a very rapid contraction (fibrillation) of the atrial walls, with a variable frequency in the transmission of the impulse and, consequently, irregularity of the heartbeator. It is divided into paroxysmal (spontaneous regression), persistent (when the restoration of sinus rhythm is achieved with drugs or electrical cardioversion), permanent (when it is now resistant to all therapies and has become chronic). The main complication of atrial fibrillation is stroke, which can occur with equal frequency even in paroxysmal fibrillation, so a patient suffering from AF must take anticoagulants. This type of arrhythmia can also increase the risk of heart failure.
3. Atrial flutter. It is similar to atrial fibrillation, but in this case the signal, instead of spreading chaotically through the atria, moves as if it were a circular wave in a fast and regular manner. Among tachyarrhythmias, it is a less frequent form than the previous one, although sometimes it evolves into atrial fibrillation. It gives the same symptoms and complications.
4. Nodal reciprocating tachycardia (TRN). To cause it is a slow conduction pathway at the level of the atrioventricular nodeand: it begins and ends suddenly and is of variable duration. It is usually not dangerous, it is typical of young age, it is widespread especially among girls.
5. Wolff-Parkinson-White syndrome. The electrical signal travels from the atria to the ventricles following an alternative path to the physiological one. It is one of the most dangerous forms of arrhythmia.

Ventricular arrhythmias

1. Ventricular extrasystoles. Arrhythmias involving the ventricles: there is a prematur ventricular contraction. When they are single contractions, or in pairs, and are not associated with other heart defects, they have the same relevance as supraventricular extrasystoles.
2. Ventricular tachycardia. It consists of a rapid, but regular, beating of the ventricles that can last from a few seconds to a few hours. If it’s a short episode, it doesn’t pose any problems. If, on the other hand, it is prolonged over time, it can be dangerous. In some cases it evolves into more severe forms of arrhythmia, such as ventricular fibrillation.
3. Ventricular fibrillation. It occurs when disorganized electrical signals prompt the ventricles to quiver and tremble. And as a result they can no longer pump blood around the body. When this happens, you usually lose consciousness after a few seconds. If you do not intervene promptly with electric shock to the heart or defibrillation, death occurs within a few minutes.

Hypokinetic arrhythmias

1. Disease of the sinus node. It is part of the bradyarrhythmias and in this case, the frequency of the beat is slower than normal. When it is too slow, the brain may no longer receive enough blood. Typical symptoms are dyspnea and asthenia for minimal effort.
2. Atrioventricular blocks. They are divided into first, second and third degree blocks depending on the severity and type of pulse block. In severe cases, syncope and cardiac arrest may occur.

Symptoms

In many cases, arrhythmias do not give signs or symptoms of their presence. In all other circumstances, the following may occur:

1. Palpitations
2. slow beat
3. irregular heartbeat
4. missing beat
5. Flicker

Other symptoms may be:

1. anxiety
2. weakness
3. dizziness
4. Stunning
5. faint
6. excessive sweating
7. Shortness
8. Chest pain

Causes

Arrhythmias are usually caused by non-physiological activity on the part of heart cells that specialize in producing electrical signals.

In other cases it is the signal that it does not “travel” as it should through the heart.

Some risk factors that favor the onset of arrhythmia have also been identified:

1. cigarette smoke
2. alcohol abuse
3. use of drugs such as cocaine or amphetamines
4. excessive caffeine intake
5. taking certain medications
6. digestive disorders
7. COPD.

Even a strong emotional stress or an attack of anger can induce an acceleration of the heartbeat, an increase in blood pressure values and the release of stress hormones. And consequently trigger an arrhythmia.

Le patologie che possono portare, tra le loro conseguenze, a un’aritmia sono:

1. infarto cardiaco
2. ipertensione
3. patologie coronariche
4. disfunzioni tiroidee
5. patologie reumatiche del cuore.

In alcune forme di aritmia c’è una dimostrata componente genetica.

Terapie

Non tutte le aritmie richiedono un trattamento farmacologico. Qualora il cardiologo lo ritenga opportuno, i farmaci più utilizzati per la cura delle aritmie sono:

Esistono anche trattamenti non farmacologici per alcune aritmie. Ecco le principali procedure chirurgiche, interventi comuni nei reparti di cardiologia di ogni ospedale.

Prevention and diagnosis

In light of the multiple causes that can trigger an alteration of the heart rhythm, prevention passes through a series of measures aimed at keeping heart health under control.

The diet must be as balanced and varied as possible. In particular, the consumption of alcoholic beverages, sweets and high-fat foods, especially if of animal origin, should be limited. It is also good to practice constant and regular physical activity, do not smoke and avoid stressful situations as much as possible.

In the presence of congenital risk factors or diseases (hypertension, ischemic heart disease) that can facilitate the onset of cardiac arrhythmias, constant monitoring of cardiovascular activity is essential. If the medical examination, including clinical history and auscultation of the heart, shows problems in the heartbeat, further investigations may be prescribed.

Blood tests can help identify possible causes: some alterations in electrolytes (especially calcium, magnesium and potassium) can give rise to arrhythmias. The same happens for the thyroid, whose failure may depend on the altered heart rhythm.

One of the most widespread and accurate tests from a diagnostic point of view is the electrocardiogram (ECG). The trace of an ECG is able to accurately identify a possible disturbance of the heart rhythm and allows doctors to intervene promptly. There are different variants of ECG, depending on the type of arrhythmia suspected and diagnostic needs.

The ECG according to Holter allows to record cardiac activity within 24/48 hours, in order to highlight transient arrhythmias or in any case of short duration. If there is a need to monitor cardiac activity for longer times, a small implantable device (loop recorder) can be used.

Stress ECG and myocardial scintigraphy allow to discover undetectable ischemia at rest, which can give rise to cardiac arrhythmias. Finally, through the echocardiogram, it is possible to measure the diameter of the heart chambers and their functionality.

Some syncope patients may then undergo the tilt test, which consists of monitoring the pressure and heart rate in the transition from a vertical (orthostatic) to a horizontal position.