Tachycardia is a condition where the heart beats at a faster rate than normal (usually more than 100 beats per minute).
Heart arrhythmias are irregular heartbeats. The heart can beat too fast, too slow or irregularly — learn how to recognise the symptoms here.
Implantable cardioverter defibrillators
An ICD, also sometimes called an ACID (automated implantable cardioverter defibrillator) may be needed if you have an abnormally fast or irregular heartbeat.
Wolff-Parkinson-White syndrome is a possible cause of tachychardia (occasional or frequent episodes of very fast heartbeats). Learn more here.
Jellyfish stings are common and mostly painful. Some are so serious that you may need emergency medical attention. Read this page on jellyfish stings to hear what to do if you of someone you are with gets stung.