You cardiologist will try to evaluate to see if palpitations are brought on by heart’s natural response to stress or an electrical problem that causes the heart to beat abnormally at fast or irregular pace.
Is symptoms seem to come during times of stress or exertions and gradually improve, they may be due to stronger, faster beating that occurs during these episodes. However, if symptoms occur at rest, if they start suddenly at unpredictable times, or if they are associated with chest pain, dizziness, lightheadedness or feeling of passing out, then an abnormal electrical rhythm is more likely the cause.
The best way to diagnose an abnormal heart rhythm causing palpitations is to get an electrical recording of the heart at the time of the symptoms. Rarely are symptoms long enough for an ECG to be performed during an episode. Otherwise, your cardiologist who is investigating the cause of palpitations may give you a heart monitor to use at home. This may start out as a 24 hour Holter monitor and if needed longer term event monitor can be performed as well.
Additionally, blood tests will evaluate for hormonal or chemical abnormalities. A treadmill stress test may be used to bring out symptoms and abnormal rhythms with exercise. An ultrasound of the heart, Echocardiogram, can be helpful in evaluating for possible underlying structural heart abnormalities.
In order to discover more about palpitations and its potential causes and ramifications please view this PDF by the American Heart Association.