What is cardiac arrhythmia?

A Cardiac arrhythmia is any condition in which the electrical activity of the heart is altered by either being irregular or it is faster or slower than normal. Some arrhythmias are life-threatening medical emergencies that can cause cardiac arrest and sudden death such as Ventricular Tachycardia / Fibrillation; causes include LQTS and LVH. Others cause aggravating symptoms, such as an awareness of a different heart beat, or palpitation, which can be worrisome; these include PAC's, PVC's, SVT, Atrial Fibrillation and WPW syndrome. There is an arrhythmia known as Sinus arrhythmia: it is characterized by acceleration of the heart during respiration, this is also a sign of a healthy heart and vagal response. Typically there are also deviations from the normal heart rates (60-90): any lower than 60 is regarded as a brachycardia and any above 99 is regarded as a tachycardia.