Arrhythmia is a condition characterised by the heart's failure to contract or beat at the correct time. Some people are able to feel an arrhythmia when it happens, while others cannot. Arrhythmias can be divided into two main groups: tachyarrhythmias, where the heart beats faster than normal; and bradyarrhythmias, where the heart beats slower than normal.
Tachyarrhythmias include:
Bradyarrhythmias include:
The occurance of arrhythmia is common; as many as 2.2 million Americans are living with atrial fibrillation (one type of arrhythmia). A recent study has also suggested that 1 in 4 Adult Americans over the age of 40 could develop an irregular heartbeat.
Heart disease (coronary artery disease): The coronary arteries are blood vessels that surround the heart and carry oxygenated blood to the hard-working heart muscle that is performing the pump function for itself and the rest of the body. Blood is also necessary to maintain a biologically sound electrical conduction system within the heart. Cardiac valvular disease: Deposits in the cardiac valves can also involve the heart wall between the 2 large pumping chambers - the ventricles. Without the unrestricted use of the valves, regular heart rate becomes difficult at best. Heart failure: Heart failure results in the inability of the heart to efficiently and consistently pump, causing excess fluid to collect in the legs and lung. Conductive tissue disease: A number of diseases can cause excessive amounts of substances to circulate in the bloodstream, including proteins and calcium. These substances may be deposited in different locations including the kidneys, connective tissue, and the specialized conducting tissues in the heart. When these deposits do form, the conducting tissue may become abnormal in turn affecting heartbeat. Ingested substances: Caffeine, tobacco, alcohol, cocaine, amphetamines, certain over-the-counter medications such as some cold medications, and prescribed medications may contribute to arrhythmia. Most of these substances act as artificial stimulants. Physical or psychological demands placed upon the heart due to exercise, fatigue and stress. These demands generate a cariety of hormones and stimulants which are common in people with irregular heartbeats.Symptoms include:
A sensation of feeling ones own heart beat (palpitations); Fainting; Light-headedness, dizziness; Chest pain; Shortness of breath; Paleness; Temporarily absence of ability to breath.Blood tests may be done in an attempt to idenitfy the cause of the arrhythmia;ECG;Chest x-ray;Ambulatory cardiac monitoring;Echocardiogram.The outcome is dependent on several factors:
The form the arrhythmia takes;Whether it is an atrial arrhythmia (originating from the atrium) or a more dangerous arrhythmia such as ventricular tachycardia or ventricular fibrillation, which are potentially fatal;The overall pumping ability of the heart. In other words, the percentage of blood that the heart pumps from the ventricles to the body with each beat; andThe individual patient's health.When an arrhythmia is serious, there may be insufficient bloodflow to the body's vital organs, such as the brain, kidneys and the coronary arteries of the heart. When these cases exist, treatment is urgent and may include electrical "shock" (defibrillation or cardioversion), the implantation of a temporary pacemaker to interrupt the arrhythmia by making the heart beat faster (overdrive supression), or the immediate administration of intravenous medications.
For long-term treatment of arrhythmias, daily medications become part of everyday life. These include antiarrhythmic medications, medications to increase or decrease heart rate and others. Over the past decade, life-threatening arrhythmias have been increasingly treated with an implantable cardioverter-defibrillator (ICD). As soon as an arrhythmia begins, the ICD can detect it and send an automatic electrical shock to terminate it, or it can activate a pacemaker function to overdrive the arrhythmia.
Arrhythmia [online]. Dallas, TX: American Heart Association; 1998 [cited 15 September 2004]. Available from: URL linkArrhythmia [online]. Washington DC: American College of Cardiology; 2004 [cited 15 September 2004]. Available from: URL linkArrhythmias [online]. Omaha ,NE: eMedicine; 2004 [cited 15 September 2004]. Available from: URL link
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