An arrhythmia is caused by irregular electrical signals in the heart. This means that the heart has an irregular heartbeat (skipping a beat, beating too quickly or too slowly). Some types of arrhythmia can increase risk of cardiac arrest, stroke and blood clots. People with arrhythmia may experience symptoms like: shortness of breath, dizziness or lightheadedness. An electrical signal, that runs down through the ventricles, from the right atrium is essential for normal heartbeat. If something like: heart attack, infection or inherited condition, disturb this electrical signal, a person may develop arrhythmia.
Every part of the heart can start electrical impulse that drives the beat. But, if it starts a new signal too soon, it may disturb the normal rhythm. Nicotine, drugs and even caffeine may be responsible for short-term arrhythmias. In most cases, they are harmless, but it is known that people may die from ventricular fibrillation due to drug overdose. Arrhythmias that starts in the atria may cause trouble, but they aren’t lethal (usually). Atrial fibrillation is the most common condition that requires hospitalization for arrhythmia. It can increase the risk of a stroke and it cause blood clotting and pooling.
An unusually slow heartbeat (less than 60 bpm) is called Bradycardia. It also starts in the atria. People who are fit, have a low heart rate, because their heart is efficient and strong. Those arrhythmias that start in the ventricles are very dangerous. 300.000 people in America die from ventricular fibrillation every year. In ventricular tachycardia, the heart may reach 200 bpm! This will cause breathless and dizziness. In many cases a person will lose consciousness. The normal heart rate (for adults) is from 60 bpm to 100 bpm.