If the contraction of two atriums is disrupted, they will beat too fast – up to 400 time per minute. Ventricles can not beat faster than 160 beats per minute, and they cannot ”keep up” with the atriums; this disorder is known as atrial fibrillation. It reduces the effectiveness of the heart, partially because rapid gathering of atrium squeezes too little blood, and partly because the ventricles continue to beat much slower; the resulting loss of atrial and ventricular coordination reduces the volume of blood that the heart is pumping out.
Atrial flutter differs from atrial fibrillation only in that the muscle fibers are contracted somewhat slower (up to about 300 beats per minute). Both flutter and fibrillation come and go, alternating with periods of normal heart operation between seizures.
There are often no symptoms. The most common symptom is heartburn (i.e. feeling your heart beat too fast or too hard), sometimes dizziness, occasional attacks of angina pectoris and unconsciousness, and symptoms of cardiac decompensation may also occur.
Atrial flutter and atrial fibrillation are quite common. They usually occur as a result of coronary sclerosis or rheumatic fever. Flutter and fibrillation can be also caused by hyperthyroidism or high temperature. In about 10% of cases, especially among older people, there is no apparent cause of this condition.
The greatest danger is the risk of blood clots in the atriums; blood is clotted, so there is a danger of embolism. A clot in the atrium may break into fragments that can get (through the bloodstream) to places where they will not be able to continue their traveling due to their size. The embolism can stop the entire blood circulation behind the clots. The damage caused by this type of embolism depends on the dimensions and place of the embolus in the bloodstream.
Another possibility is a cardiac arrest. Usually, the ventricles themselves can carry out the task of pumping blood regardless of whether the function of the atriums is disturbed. However, if there are disturbances in the ventricles, they will not be able to withstand this, and the cardiac failure occurs soon after the atrial fibrillation.
What to do?
If you notice the symptoms of these disorders, contact your doctor who will refer you to the ECG to confirm the diagnosis. Since atrial fibrillation often occurs periodically, it may be necessary to continue ECG recording within 48 hours. This is done using a lightweight, portable device attached to the chest or waist belt, that captures the images while you are performing the usual tasks. Your doctor will probably point you to other diagnostic tests if there are any signs of some basic heart disease.
Treatment largely depends on the cause of the disorder. You may get a medication that improves the efficiency of ventricular contractions on which circulation is dependent if the atrial contractions are disturbed. Beta-blockers are also very effective if flutter and fibrillation are associated with basic thyroid disease. Anticoagulants are given to prevent embolism.
If your heart is basically healthy or if you have cured the underlying cause of atrial fibrillation, your doctor may also consider the type of treatment that is called electrical cardioversion. It consists of using an electro shock (under light anesthesia) which often establishes normal heart rhythm. The electro shock is provided with a defibrillator.