Rapid heart rate (pulse) :
Typically a rapid pulse rate exceeding the normal resting rate is called as tachycardia i.e over 100 beats per minute (bpm) in adults. There are many different types of tachycardia manifesting in various forms namely atrial fibrillation, atrial flutter, sinus tachycardia, ventricular tachycardia, and ventricular fibrillation. However one can expect a rapid pulse greater or faster than 100 bpm in situations such as exercises and fear. Tachycardia is often characterised by symptoms such as fast pulse chest pain, confusion, shortness of breath, and fainting.
Tachycardia has various causes which may not always have a cause of concern such as anxiety, panic attack, fear, exercise, usage of drugs, a reaction to medications. Similarly a fast heart rate can also occur due to serious underlying medical conditions requiring prompt medical for example congenital cardiac irregularities, heart valve disorders, post heart surgery.