Disturbances of the rhythm of the heart are extremely common, and the vast majority of these are not sinister. Some arrhythmias can be quite dangerous however, and even some of the less dangerous ones can - in certain situations - be debilitating.
In order to accurately diagnose most rhythm problems it is important to have a recording of the activity of the heart at the time of symptoms. This is achieved by ECG recordings; the most common way of doing this is using a device called a "24 hour tape" to record the heart rhythm over 24 hours. If the symptoms are less frequent than that, longer term monitoring can be achieved with event recorders or even by implanting small heart rhythm recorders which can last up to 3 years (a "Reveal Device").
Your cardiologist or G.P. may also request an echocardiogram when assessing rhythm problems. This is because understanding the structure and function of a patient's heart is important in the initial assessment of a rhythm problem (if it likely to be a dangerous problem, for example), and also in the treatment of rhythm problems (some drug treatments should be avoided in cases where the heart function is not normal).
There are many ways of treating cardiac rhythm problems. Often the symptoms will settle with time and reassurance, but in some cases treatment with medications, pacemakers or procedures such as cardiac ablations might be appropriate.