A healthy heart is an organ that pumps approximately five liters of blood per minute to the entire body. Our heart beats 60 to 100 times per minute under normal circumstances while it can be up to 150 times in case of physical activity and excitement. Our heart functions highly rhythmic and if it loses this rhythmic order for various reasons, this is called arrhythmia, i.e. rhythm disturbance. Each heartbeat is initiated by electrical wave from natural stimulant center (sinoatrial node) located right upper corner of the heart. This wave encapsulates the whole heart in about one second through intracardiac electrical pathways, and the entire heart contracts almost at the same time to pump the blood inside to the body.
This state which is called normal sinus rhythm can lose its harmony in various ways. Every person occasionally experiences irregular heartbeat and this type of rare, sporadic beats are harmless. Conspicuously, slower (bradycardia) or faster (tachycardia) than normal, or irregular betas are detected. Arrhythmia can be felt fast, irregular, or malfunctioning heartbeats in the chest; lead to dizziness and syncope; besides there are patients reporting chest pain and shortness of breath. Although some arrhythmias cannot be felt by the patient, they may be severe. Generally, arrhythmias are common when the heart is unable to function physiologically, e.g. coronary heart disease, pathological cardiac valves, or heart failure.
The blood pressure may drop to life-threatening levels because the heart, as a pump, is unable to pump the blood at sufficient level with the rhythm being sometimes too slow or sometimes too fast. On the other hand, occurrence of arrhythmia alone does not indicate a heart disease. Many healthy people may experience arrhythmia in their daily life.
Some persons have congenital arrhythmic basis. In addition to many heart diseases, hypertension may also cause arrhythmia. Due to their specific characters, caffeine, smoking, some drugs, alcohol, and stress are known to cause arrhythmia even in healthy people. Therefore, one should remember that the cause of arrhythmia may be very simple, or there may be an important underlying factor in those who present with arrhythmia.
Some persons have no complaints, however those who present with arrhythmia usually have complaints of palpitaions, dizziness, blackout, chest pain, or dyspnea and air hunger. The patients often express complaints of palpitaions that as if a bird is fluttering in their chest, or sometimes a feeling of having a hole or they do feel their heartbeat. This can take a few seconds or hours. Complaint of dizziness associated with arrhythmia is rather common and sometimes blackout may occur. Particularly blackout is a good reason to visit a doctor immediately.
Human heart has four chambers, adjoining and one under the other. Arrhythmias originating from top two chambers (atria) are called supraventricular while arrhythmias originating from lower two chambers (ventricles) are called ventricular arrhythmia. The other arrhythmias are categorized by heart rate: it is bradycardia when the rate is under 60 per minute; it is tachycardia when it is over 100. The most irregular and the fastest arrhythmia is the fibrillation. Each muscle fiber contracts independently and fast during fibrillation. Arrhythmias can be felt an innocent palpitaions, however the blood pressure may drop further and result in sudden death in cases such as ventricular tachycardia, and fibrillation.
It is essential to identify the cause accurately for a correct treatment. There are various causes for rhythm disturbances:
1- Causes related to myocardium:
a- Coronary artery disease, myocardial infarction b- Myocarditis and cardiomyopathy
2- Hemodynamic causes
a- Heart valve disease, congenital abnormalities, exposing the heart to pressure and volume load
3- Other causes
a- Accessory transmission pathways (e.g. WPW)
c- Imbalance of electrolytes
d- Some drugs
e- Abuse of some pleasure-giving substances (e.g. nicotine, alcohol, coffee, and drugs)
f- Carotid sinus syndrome
h- Cardiac surgery
It is also important whether rhythm disturbances occur during resting or effort. Rhythm disturbances that occur during resting and disappear with effort are quite benign; however arrhythmias that occur with effort in particular should be paid attention.
An extensive blood test is required for those that present with arrhythmia. This examination that can detect imbalance of electrolytes measures potassium and magnesium levels which sometimes enough to solve the problem.
The blood level of thyroid-stimulating hormone should be determined. Hyperfunction of thyroid may lead to arrhythmia.
The type and form of the complaint depends on the condition of the heart and type of arrhythmia. Frequency and duration of arrhythmia as well as its severity are the factors to feel the complaints. Some arrhythmias may not present any symptoms. Contrary to popular belief, feeling palpitaions does not always indicate the presence of arrhythmia.
Although arrhythmias have similar symptoms, sometimes tips can be obtained to help for distinction. Tiredness, dyspnea, dizziness, and syncope are expected when heart functions slow (bradycardia). There is a feeling on the neck and chest that the heart is functioning fast or palpitation when heart functions fast (tachycardia), furthermore disturbance, weakness, sweating, dyspnea, and feeling faint may occur in the chest.
Many diagnostic methods are currently used to diagnose heart diseases, which quite detailed information can be derived. Generally, many are used together, and the following methods are particularly used to detect arrhythmia:
1- Electrocardiography (ECG):
Basic information about arrhythmias can be derived by a standard ECG. An ECG provides information on the electrical activity of heart and is useful to determine the type of arrhythmia, imbalance of electrolytes, or previous heart attack.
2- Holter Monitoring:
The rate and rhythm of the heart can be monitored for 24 hours. This system includes a device size of a radio that is attached to the waist, electrodes, and cables and is used to monitor rhythm disturbances during the day.
3- Event Recorder:
In case the complaints are rarer than 24 hours, event recorder, which is smaller than Holter device, can be used. This device remains attached to the body for several days and becomes activated and starts recording the rhythms when the symptom is felt. The newer models are able to record one minute forward or backward from activation of the device. Some types of this device allow instant monitoring of rhythms vie a telephone.
4- Loop Recorder:
It is used to capture much more infrequent symptoms of arrhythmia. This device can be implanted just under the skin and is about the size of thin long chewing gum. It can record up to 18 to 24 months and is very useful to detect vary rare rhythm disturbances.
5- T Wave Alternans Test:
Some ventricular arrhythmia occurred following a myocardial infarction in particular is known to cause sudden cardiac deaths. As a result of various searches to simply capture this type of arrhythmias, fluctuations of T wave in ECG appear to be a significant indication. Because these fluctuations, rarely visible, are often in microvolts, they can be detected by having patient performed effort for short period and measurements made by very precise devices. Until very recently, only electrophysiological method, an interventional method, has been performed in suspicion of this type of arrhythmia. The results of T wave alternans test have shown to be highly reliable and suggestive to detect life-threatening arrhythmias.
6- Electrophysiological Study:
An extensive study including a detailed examination of arrhythmias under sterile laboratory conditions by means of catheters. It is possible to obtain information on heart’s electrical activity using flexible, thin and long devices called catheter which is implanted in the heart through inguinal vessels. So, character and origin of arrhythmia can be determined. The effect of various drugs over arrhythmia and if they can treat it can be accurately studied. As in developed countries, in addition to classical electrophysiological studies in our country, electroanatomic mapping, a high technology used by today’s medicine, method is actively used to diagnose and treat complicated arrhythmias which are difficult to detect. This method allows a detailed examination of electrical currents in the heart and optimizes the treatment planning under modern conditions. After identifying characters of electrical disturbances, radiofrequency waves are delivered to ailing tissues to treat arrhythmias.
7- Tilt Table Test:
It is useful to detect syncope associated with arrhythmia. Some individuals may develop pathologies leading to fainting caused by a change in the blood pressure and pulse from standing up for long. Tilt table test is performed by having the patient lie flat on a special table then changing in posture from lying to standing 65 degrees to monitor the blood pressure and pulse. Patient’s anomaly related to receptor failure from standing up for long is attempted to stimulate. If no satisfactory result is obtained then the test is repeated with delivering drugs.
1- Pharmacotherapy: Specific pharmacologic agents and anti- arrhythmic drugs are used to resolve arrhythmia problems and to treat cardiac problems, e.g. coronary artery disease, myocarditis, heart failure, and problems, e.g. thyroid diseases, imbalance of electrolytes, and intoxications.
2- Electrical therapy: Pacemaker supporting the rhythm, shocking defibrillator therapy, and electrical cardioversion
3- Interventional treatment: Balloon angioplasty and stent implantation are used if stenosis and obstruction of coronary arteries have resulted in arrhythmia. If an anarchic focus or passage producing arrhythmia is present in myocardium, electrophysiological study is used to detect the focus mechanism and radiofrequency ablation is performed by a heating or freezing catheter.
4- Surgical treatment: Coronary artery bypass surgery is performed to help resolve arrhythmia associated with coronary disease. Surgical procedures might be performed to silence arrhythmic focus.
The patient presented with arrhythmia should be calmed down first, advised bed rest, delivered oxygen, hydrated if any loss of liquid and electrolyte, and the deficiencies should be remedied. Initially, coronary regurgitation or imbalance of electrolytes causing arrhythmia must be remedied in the treatment. With elimination of such pathologies leading to arrhythmia, rhythm disturbances are either completely corrected or suppressed by a simple medical therapy. If these do not provide a satisfactory result, a target-focused treatment is considered. Initially, correct anti-arrhythmic should be selected. It is critical to select a correct drug because some anti-arrhythmic agents might cause new arrhythmias related to their chemical nature if care is not taken when using some of the anti-arrhythmic drugs which have proarrhythmic character.
It is required to implant a pacemaker when heartbeats are under physiologic limits which reduces the quality of life or threatens the life. A pacemaker consists of a small computer and generator producing electrical currents and monitors the heart rate via an installed programme. It is activated when necessary to prevent the heart rate from dropping under the required level.
If some arrhythmias, e.g. atrial fibrillation, from upper portion of the heart do not have the required form and becomes intolerable by the patient despite delivered drug therapy, the patient will be anaesthetized to deliver electrical cardioversion (shock). This includes delivering heart low-power short-term electrical current to make irregular electrical current formed in the heart regular. Dangerous arrhythmias from the ventricles require urgent intervention, and electrical cardioversion must be performed within minutes.
ICD (implantable cardioverter defibrillator) implantation has an important role in treatment of arrhythmia. Ventricular fast heartbeats are life-threatening and require fast remedy. ICD devices are implanted under the skin below the right or left (preferentially left) clavicle, as with the pacemakers. The wires from the device are inserted specific location of the heart then ICD is activated. This system includes an advanced computer programme and generator producing current and aims at accelerating a slow rhythm as a pacemaker does, or unlike a pacemaker, interferes with an accelerated heart to have a regular rhythm; also it can play a life-saving role by activating automatically in case of ventricular fibrillation. Defibrillator devices include portable classical large types to deliver shock outside the body as well as modern types that can be carried in the patient’s bag or pocket.
Detection of source of many arrhythmias has been made possible by intracardiac mapping methods. Classically, electrical waves can be monitored for mapping, or electroanatomic mapping and sound waves have recently been used to derive clearer and detailed information about characteristic of arrhythmia. In the light of such information, catheter ablation is performed to remove arrhythmic focus or way. This method allows obtaining pleasing results in treatment of arrhythmias particularly from upper portion of the heart, i.e. atria. After mapping, the end of catheter is used to deliver heat to tissues to destroy arrhythmic tissue for prevention of leading to any rhythm disturbances. The recently developed catheters allow heating as well as cooling to treat more complicated arrhythmias.
Arrhythmias are also attempted to treat surgically. Electrical system in the left atrium can be surgically modified in treatment of fibrillation relatively often from the atrium. More rarely, after detecting the focus of arrhythmia electrophysiologically, the portion where this focus is located is surgically removed.
After performing basic examinations for patients that present with complaint of palpitaions, the detailed examinations we have just mentioned should be considered when or if necessary. For some individuals, even avoidance of caffeine, smoking and alcoholic beverages and changing into a healthier life style can actually help improve rhythm disturbances totally or largely. Many people are able to live a trouble-free life and return daily activities by these simple precautions, or by treatment or surgical procedure following detailed examinations.