Others can develop something called POTS, which stands for postural orthostatic tachycardia syndrome, and can cause sharp spikes in the heart rate and dizziness.

In many cases of supraventricular tachycardia, the abnormal heart rhythm is caused by a small short-circuit in the heart's electrical circuitry.

A complex condition, heart failure can have diverse triggers, including a past heart attack, viral infection or chronic arrhythmias such as ventricular tachycardia.

A couple of days later, graver symptoms started to appear: gastrointestinal issues, tachycardia, panic attacks, and extreme fatigue that kept him sleeping 20 hours a day.

She had heart surgery last fall to treat supraventricular tachycardia, an irregularly fast heartbeat.