Cardiac Arrhythmia

The heart functions as an electrical pump that circulating blood through its four chambers throughout the body in a controlled sequence of muscular contractions. Each electrical pump is originated from special cells in the right atrium of the heart called the sinus node or Sino-atrial node or SA node, allowing the heart to beat in a coordinated way. When there is an abnormal electrical activity in the heart, cardia arrhythmias occur.

Read also about Pericardial Mesothelioma, an inflammation of the lining of the heart.

Arrhythmias are irregular rhythms of the heart caused by disturbances in transmission of electrical impulses through cardiac tissue, resulting in the heart beating that may be too fast or too slow, and may be regular or irregular.

Some cases of arrhythmias may lead to cardiac arrest and sudden death while in other only cause heart palpitations. Some are not too significant and do not considered as abnormal variants. In fact, most people will sometimes feel some degree of heart palpitations, their heart may be skipping a beat or producing an occasional extra heartbeat which is not a medical emergency.

However, some asymptomatic arrhythmias are associated with adverse events. They may increase the risk of developing blot clot, insufficient blood supply, embolism, stroke, heart failure and sudden death.

Heart arrhythmia symptoms

The term cardiac arrhythmia covers a very large number of very different conditions and produces a broad range of symptoms. The most common symptom of arrhythmia is heart palpitations. It is an abnormal awareness of heartbeat that feel like a rapid thumping in the chest. They may be infrequent, frequent, or continuous. If an cardiac arrhythmia results in a heartbeat that is too fast, too slow or too weak to supply the body's needs, it will manifest as a lower blood pressure and may cause dizziness or lightheadedness. This is also a possible cause of blackouts and fainting.

When arrhythmias last long enough to affect how well the heart works, more serious heart arrhythmia symptoms may develop:

• Rapid heartbeat / pounding heart beat / heart palpitations, fatigue
• Dizziness, lightheadedness symptoms
• feeling tired
• Blackouts, fainting or near-fainting spells
• Chest pain, shortness of breath with chest pressure
• Loss of consciousness
• In extreme cases, collapse and sudden cardiac arrest

Normal, tachycardia, bradycardia, automaticity, reentry and fibrillation
Cardiac arrhythmia can be categorized by rate, which could be normal, tachycardia or bradycardia and by mechanism, which could be automaticity, reentry or fibrillation.

Bradycardias
Bradycardia is a type of arrhythmia in which the heart beats more slowly than it should, usually less than 60 beats per minute. When bradycardia / slow heartbeat occurs, the brain and other body parts may not get sufficient amount of oxygen. This may lead to various heart arrhythmia symptoms like feeling tired, dizziness, blackouts, fainting, chest pain, shortness of breath sometimes with chest pressure, light-headedness and confusion. Generally, a slow heart beat is normal in athletes and those with trained hearts.

Tachycardias
Tachycardia / fast heartbeat is a condition in which the heart contracts at a rate faster than 100 beats per minute. The main symptom is heart palpitations, a fluttering, racing beat in the chest. It may also feel like a strong pulse in the neck. Depending on the cause and extent of the tachycardia, other symptoms of this type of heart arrhythmia may include dizziness, blackouts, fainting, chest pain, shortness of breath, sweaty, severe anxiety and feelings of discomfort.

Automaticity
Automaticity refers to a cardiac muscle cell firing off an impulse on its own. It may cause a single premature beat now or produce a sustained abnormal rhythm because of the poorly coordinated contraction. This may result in a decrease in the heart’s pumping efficiency. The resulting heart rhythm can be normal but rapid or dysrhythmia may ensue.

Re-entry
Re-entry arrhythmias occur when an electrical impulse recurrently travels in a tight circle within the heart, rather than moving from one end of the heart to the other and then stopping. This can produce a sustained abnormal circuit rhythm that often responsible for atrial flutter, most paroxysmal supraventricular tachycardia, and dangerous ventricular tachycardia.

Fibrillation
Fibrillation commonly refers to the rapid, irregular, and unsynchronized contraction of the muscle fibers of the heart. Fibrillation can affect the atrium (atrial fibrillation) or the ventricle (ventricular fibrillation).

Atrial fibrillation
Atrial fibrillation is a condition in which rapid, uncoordinated firing of electrical impulses from multiple sites in the atrium causing decreased efficiency of the heart. Atrial fibrillation may be due to serious underlying medical conditions, and should be evaluated by a physician. It is not typically a medical emergency.

The symptoms of this type of cardiac arrhythmia vary from person to person. Some people with atrial fibrillation have no symptoms at all. The most common symptom of atrial fibrillation is heart palpitations that feel like a racing, uncomfortable, irregular heart beat or a flopping in the chest. Other symptoms are decreased blood pressure, symptoms of weakness and sweating, lightheadedness or fainting, confusion, fatigue, chest pain, shortness of breath and no energy.

Ventricular fibrillation
Ventricular fibrillation is an irregular heartbeat characterized by uncoordinated contractions of the ventricle. It is a medical emergency that cause sudden collapse in seconds. If left untreated, it can result in death within minutes. Common heart arrhythmia symptoms such chest pain, shortness of breath with chest pressure, rapid heartbeat / heart palpitations, dizziness, nausea and lightheadedness may be felt within one hour before the sudden failure.

Triggered beats
Triggered beats occur when problems at the level of the ion channels in individual heart cells result in abnormal propagation of electrical activity and can lead to sustained abnormal rhythm. They are relatively rare, but can result from the action of anti-arrhythmic drugs.

Diagnosing cardiac arrhythmia

Medical assessment of the abnormality using an electrocardiogram is the best way to diagnose and evaluate the risk of any given arrhythmia. The assessment should be done immediately in a condition of abnormal heart palpitations, particularly when accompanied by shortness of breath with chest pressure, sweating, blackouts or fainting.

Treatment of arryhytmia

Treatment of cardiac arrhythmia depends on the type of arrhythmia, the patient’s age, physical condition and age. Because arrhythmias are such a heterogeneous group of conditions, treatment should be carefully selected by the physician and patient. Some arrhythmias require no treatment at all. Others require immediate emergency treatment if death is to be avoided. This is especially true in the case where the cardiac arrhythmia causes blackouts, fainting, abnormal heart palpitations and shortness of breath with chest pressure. Treatments include physical maneuvers, antiarrhythmic drugs, other drugs, electricity shock, and electro or cryo cautery.