Tachycardia
Tachycardia refers to a heart rate of more than 100 beats per minute. Tachycardia can occur normally during and post exercise or during emotional stress and do not represent danger for a healthy individuals. However in some cases, tachycardia occurs without underlying cause or can occur as a complication of a myocardial infarction (heart attack) or heart disease and is an arrhythmia, which is a pathological deviation from the normal rhythm of the heartbeat. Most arrhythmias are caused by irregularities in the electrical stimuli which results the heart to beat. Generally these pacemaking stimuli begins with the sinoatrial node. The fundamental symptoms of tachycardia are fatigue, dizziness, faintness, shortness of breath, and a sensation of palpitation in the chest. Tachycardia can be controlled by administering an electrical shock to the heart to stabilize regular heart rhythm or by the administration of such antiarrhythmic drugs like procainamide, lidocaine, or quinidine.