Although sometimes arrhythmias (abnormal heart rhythms) cause no symptoms at all, the most common reason that people seek advice is that they have developed troublesome symptoms that are affecting their lifestyle, exercise capacity and sense of well-being. Arrhythmias may result in a variety of different sensations and effects on the body and it is not always obvious that the heart is to blame. If the arrhythmia is paroxysmal (i.e. it comes and goes) the symptoms will also be intermittent, only occuring when the rhythm is abnormal. Some of the common symptoms are described below.
Palpitations refer to an awareness of the heartbeat. During a normal rhythm, most people are unaware of their heart beat and they only become aware of the sensation during exercise, stress or excitement when it naturally beats harder and stronger. The normal heartbeat is like the steady, regular ticking of a clock which will naturally speed up or slow down depending on your activity levels. Arrhythmias are often sensed as palpitations as they cause inappropriately fast heartbeats or alterations in the natural timing. If you have a clock in your house that regularly ticks once a second you are probably so used to it that you blank out the ticking and don't consciously hear it. If that clock suddenly accelerated to 180 ticks a minute rather than the usual 60, or became erratic and irregular, you would become aware of it straight away.
The speed, timing and regularity of the palpitations can tell your doctor a lot about the type of arrhythmia you may be experiencing. If there is a senstation of a brief pause, missed beat or single heavy thump, that may be due to ectopic beats. Very rapid and regular racing of the heart that starts and stops suddenly may indicate supraventricular or ventricular tachycardia or atrial flutter. A rapid but chaotic heartbeat that is jumping all over the place is a typical feature of atrial fibrillation. Sometimes this is so subtle that people describe feeling "jittery" without being aware that it is their heart.
Arrhythmias may make the heartbeat less efficient and reduce the amount of blood that is pumped around the body. This is usually most obvious when trying to perform physical activity. People may notice that they have become short of breath when performing normal daily activities which previously had been no effort. Others notice that their regular exercise and sporting activities have become much harder. Atrial fibrillation can cause very non-specific symptoms of low energy and fatigue that are not immediately attributable to a change in heart rhythm.
Rapid arrhythmias can cause chest pain or discomfort, usually felt as a diffuse tightness, as they make the heart muscle work harder than it needs to. For the majority of people twho have chest pain during arrhythmias do not have angina and furring up of the coronary arteries. For those whose arrhythmias do result in chest pain, it is usually accompanied by palpitations and breathlessness.
The sudden onset of a very rapid heart beat may cause a dramatic drop in the blood pressure and a lack of blood to the brain. If it takes more than a few seconds for the body to react by tightening up blood vessels in the arms and legs, this may cause dizziness or even a brief loss of consciousness (syncope). Falling to the ground allows the brain to receive more blood so people usually recovery consciousness quickly. A sudden loss of consciousness should be taken seriously and be investigated promptly to find the cause as in a few rare circumstances it may be due to a dangerous condition. If unexplained it may also mean that the person should not drive for a period of time.