• Bradycardia. Too slow a heartbeat, or bradycardia, can result in dizziness, fatigue and/or fainting spells. It is the most common reason for pacemaker therapy.
• Atrial Fibrillation. Sometimes referred to as AFib, atrial fibrillation , is another common heart arrhythmia that can affect people of all ages. During AFib, the SA Node in the right atrium (where the electrical signals of the heart begin) sends out extra electrical signals that are not coordinated. Your atria beat so fast they may quiver instead of contracting fully. When this happens, blood is not effectively pumped into the ventricles, and they in turn do not pump enough blood out to your body.

Since your atria are not emptying effectively, some blood may pool there and form a blood clot, which increases your risk for stroke. To help prevent this, people suffering from AFib often take a "blood thinner" medication such as coumadin (Warfarin).

People who have high blood pressure, a history of heart or valve disease, coronary artery disease or hyperthyroidism are at risk for AFib.

• Ventricular Fibrillation. VFib is similar to atrial fibrillation only it affects the ventricles. During ventricular fibrillation, your ventricles do not contract effectively or in a coordinated fashion. Thus, freshly oxygenated blood is not circulated to you body. A person in VFib will lose consciousness and soon die if not treated with emergency procedures such as electrical shock and/or medications immediately.
• Premature Ventricular Contractions (PVCs). When the electrical signals of your heart cause your ventricles to contract before they are filled with blood from the atria, less blood is pumped out to your body. Symptoms of PVC include lightheadedness, weakness, fainting, shortness of breath and chest pain. If this happens frequently or over an extended period of time, it can lead to ineffective blood circulation, exhausted ventricles and even death.

Multiple PVCs occurring in a row is called ventricular tachycardia, or V-tach, and can be life threatening.