• Holter monitor or event recorder. A portable EKG that is connected to a freely-moving (ambulatory) patient, usually for 24 hours, to measure the heart's electrical activity. Because the palpitations may occur only rarely during those 24 hours, a portable EKG is more likely to detect the palpitations and their source by recording the heart's activity continuously, rather than one random measurement at a physician's office or hospital visit.

    Other types of event recorders include continuous loop event recorders and relatively newer implantable recorders. A continuous loop event recorder constantly records data but only saves data for the preceding and subsequent two minutes after the patient manually activates the monitor after an episode of palpitation. This kind of recorder can be worn longer than a Holter monitor in the event of palpitations that occur less than daily. Implanted recorders can record the EKG for one year. As the name implies, they are implanted in the patient and activated by an abnormal heart rhythm. Implanted recorders have not yet been extensively tested.

  • Echocardiogram. This test uses sound waves to visualize the structures and functions of the heart. A moving image of the patient's beating heart is played on a video screen, where a physician can study the heart's thickness, size and function. The image also shows the motion pattern and structure of the four heart valves, revealing any potential leakage (regurgitation) or narrowing (stenosis). During this test, a Doppler ultrasound may be done to evaluate blood flow.

    Echocardiogram