On average, the normal resting heartbeat of an adult is between 60 and 100 beats per minute. Any change in the usual rhythm and rate of the heartbeat is considered an arrhythmia. Different types of arrhythmias have different signs to be aware of.
Types
Bradycardia is diagnosed in people with a heart that beats slower than normal, while tachycardia is a heart rate that is faster. Fibrillation is when the heart quivers instead of contracts. This may occur in the upper heart chambers, the atria, or the lower chambers, the ventricles.
Causes
The muscular layer of the heart, or myocardium, has special myocardial cells that transmit an electrical impulse that stimulates the heart to contract. A defect anywhere along the route can result in an arrhythmia.
Bradycardia Symptoms
This slower heart rate may limit the blood supply to the brain and body tissues, resulting in fatigue or dizziness. In severe cases, bradycardia may cause fainting.
Tachycardia Symptoms
Palpitations and a pounding, racing heart characterize tachycardia. This arrhythmia may also cause dizziness and lightheadedness, because the heart may be pumping too fast to be effective.
Atrial Fibrillation Symptoms
Some symptoms of atrial fibrillation include palpitations, sweating, chest pressure or pain, weakness, difficulty catching your breath, fatigue during activity and fainting.
Ventricular Fibrillation Symptoms
Ventricular fibrillation is life-threatening. The heart is pumping little or no blood to the body. Collapse and sudden death will occur quickly if medical attention is not received immediately.
References
- The Human Body in Health and Illness; Barbara Herlihy, PhD, RN; 2003
- Body Structures & Functions; Ann Senisi Scott; 2004
- The American Heart Association
