The complaint of heart palpitations is extremely common. While palpitations are rarely indicative of a serious cardiac problem, they are occasionally a manifestation of potentially life-threatening conditions. Zimetbaum and Josephson describe the presentation of common palpitations and offer a guide to diagnostic testing.
Heart palpitations are often described by patients in a variety of ways, including sensations of “flip-flopping” (premature atrial or ventricular contractions) or a rapid “fluttering” (atrial or ventricular arrhythmias) in the chest. Some people report a “pounding” in the neck. This sensation is most typical of a reentrant supraventricular arrhythmia.
Although palpitations are frequently associated with anxiety or panic attacks, they should not be attributed to psychiatric disorders until more serious causes have been excluded. In one study of 107 patients with electrophysiologically documented reentrant supraventricular tachycardia, 67 percent met the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria for panic disorder. In addition, there was a median time of 3.3 years from initial presentation to a physician and a definitive diagnosis.
Idiopathic ventricular tachycardias occur during periods of catecholamine excess, such as during exercise or emotional stress. This disorder often presents during the second or third decades of life as palpitations, dizziness or syncope. In patients with atrioventricular nodal tachycardia, the onset of symptoms may occur when they stand up straight after bending over, and symptoms often end when they lie down. Patients who experience dizziness, presyncope or true syncope often have a supraventricular arrhythmia. Their symptoms are caused by acute vasodilation, a rapid heart rate with low cardiac output, or both.
The evaluation of any patient who complains of palpitations should include a thorough history and physical examination, and a 12-lead electrocardiogram (ECG). The history should focus on the description of the palpitations as well as the patient's age at onset. The patient who has had symptoms since childhood is likely to have a supraventricular tachycardia. The physician may ask the patient to tap out the rhythm with his or her fingers, as it is critical that the patient give a detailed description of the symptoms. Providing examples of various cardiac rhythms to the patient is sometimes helpful. Palpitations described as abrupt in onset and termination are often caused by ventricular or supraventricular tachycardias.
It is unlikely that the physician will examine a patient during an episode of palpitations. Consequently, the cardiac examination should focus on detecting abnormalities such as the midsystolic click of mitral valve prolapse. Virtually every type of arrhythmia has been described with this disorder, and many patients have premature atrial or ventricular contractions. A holosystolic murmur heard along the left sternal border that increases when the Valsalva maneuver is performed suggests hypertrophic obstructive cardiomyopathy. Atrial fibrillation is a common cause of palpitations in patients with this disorder.
The ECG will help limit the differential diagnosis of palpitations in patients with normal sinus rhythm. For example, a short PR interval or delta waves suggest ventricular preexcitation and the substrate for supraventricular tachycardia (Wolff-Parkinson-White syndrome).
The authors recommend further diagnostic testing for the following patients: those whose initial evaluation suggests an arrhythmic cause for the palpitations; those at high risk for organic heart disease or any myocardial abnormality that can lead to serious arrhythmias (usually determined by history); and those who remain anxious and need an explanation for their symptoms. Ambulatory 24-hour Holter monitoring has been recommended. However, continuous-loop event recorders have proved more efficacious and cost-effective for the evaluation of palpitations. These devices are worn by the patient for two weeks (previously four weeks) and constantly record data. Unlike the Holter monitor, the information is only saved when the patient manually activates the device. When the monitor is activated, it saves the patient's cardiac rhythm for the preceding two minutes and the subsequent two minutes.
If, after the history, physical examination and 12-lead ECG, there is no evidence of heart disease and the palpitations are unsustained and well tolerated, ambulatory monitoring or reassurance is recommended. In patients whose evaluation suggests underlying heart disease and whose palpitations are unsustained, ambulatory monitoring is again recommended. If palpitations are sustained or poorly tolerated, electrophysiologic testing is recommended, even if there is no overt evidence of heart disease.
The authors have found that most outpatients evaluated for palpitations have a benign cause and will not require an extensive evaluation or medical treatment. In the few patients who need pharmacotherapy, the preferred treatment options are beta blockers or calcium channel blockers. Other antiarrhythmic medications are usually avoided because of the associated risks of proarrhythmia. Most patients found to have a supraventricular arrhythmia can be cured with radio-frequency ablation.