PALPITATIONS - Full extract 

Palpitations are those unpleasant sensations when your heart is thumping around inside your chest, either beating more rapidly than usual or with some irregularity. People vary greatly in the awareness of their own heartbeat; some people get agitated with a couple of extra beats, whilst others with an abnormal heart rhythm may hardly bat an eyelid. 

The automatic-timer of the heart is called the sino-atrial node. It is situated at the top of the heart in the wall of the right atrium, one of the heart's four chambers. Electrical impulses travel from the timer down nerve fibres to the rest of the heart setting off muscular contractions. With many palpitations, the timing mechanism is working fine but extra beats fire off sporadically in another portion of the heart. These extra beats frequently block out the next beat from the automatic timer; then follows a pause and a more forceful heart contraction. They are very common and some people find them quite distressing, especially when sitting quietly or trying to get off to sleep at night. 

Occasionally the automatic timer gets completely overridden by a new trigger somewhere else in the heart. When this happens the heart rate might suddenly jump from say 60 to 180 beats per minute, accompanied by a burst of palpitations lasting minutes or hours. At other times the impulses may come from many areas at once and the heart may beat in a rapidly irregular way. 

There are a variety of disturbances of heart rhythm, some more significant than others. Palpitations are the most common symptom but sometimes the abnormal rhythm might be so significant that it causes other symptoms such as chest pain, loss of consciousness or breathlessness. Any of these symptoms call for urgent cardiological assessment. 

It is important to establish exactly what sort of rate or rhythm disturbance has occurred with the palpitations. The only certain way this can be done is with a clear heart tracing at the time. It is a bit like hauling in a fish; if you have the cardiograph leads on and catch the tracing, you have a record for all time. It also helps if the person with palpitations can check the pulse; the actual heart rate and whether it is regular can assist with the diagnosis. Any other symptoms should also be recorded. 

Most cases of palpitations are well and truly settled by the time the patient sees the doctor and there is precious little to find. However, a careful history and examination is required to rule out some specific causes like stress, smoking, too much coffee, or an overactive thyroid gland. Sometimes the person might be noted to be taking a decongestant mixture or some other medication that could be aggravating things. Occasionally it will be noted that the person is on fluid tablets and the serum potassium level has become too low, making irregular heart rhythms more likely. It is unusual for evidence of heart disease to be found. 

Some basic blood tests might be organized, for instance a check on thyroid function and blood biochemistry. A standard cardiograph is done, although this is not as useful as when the palpitations are actually occurring. This might necessitate bowling into the doctor's surgery or into casualty at some odd time for a tracing. If someone is having persistent or recurrent palpitations, a Holter monitor is arranged; this is a portable continuous 24-hour heart tracing to see if any abnormal rhythms are recorded. Some patients require referral to a cardiologist for a precise diagnosis. 

The treatment of palpitations depends on the exact cause. Reassurance that there is no underlying heart disease is often all that is required. Certain palpitations can be eased by a straining, breathing-out exercise called the Valsalva manoeuvre. This increases the activity of a particular nerve that slows the heart down. 

Reducing tea and coffee intake may be helpful as might relaxation exercises. In some cases medications are required, either acutely to switch the palpitations off, or longer term to prevent them recurring. These days some people with intractable palpitations due to certain abnormal heart rhythms can also be cured by heart surgery. 

Health tip: 
* Palpitations usually do not indicate any underlying heart disease. However, it is a symptom that needs careful checking with your doctor.

Web links:
 ¹ www.heartfoundation.com.au

Dr. Andrew Pattison: Common Consultations
North East Valley Division General Practice, Melbourne, Australia.   Disclaimer
  - Last modified: August 18, 2001