Palpitations

Palpitations are the subjective awareness of the heart beating and are usually the result of a change in heart rate, heart rhythm, or the force of cardiac contraction.

Etiologies

A wide variety of disorders can produce palpitations (Table 3-1). The most common causes are arrhythmias, medications, and psychiatric disorders.

Clinical Manifestations

History
Patients may describe palpitations as a fluttering, skipping, or pounding sensation in their chests and may have associated lightheadedness, dizziness, or dyspnea.

Arrhythmias are the predominant cause and include supraventricular (SVT) and ventricular (VT) tachycardias, and premature atrial (PAC) and ventricular (PVC) contractions. The pattern of palpitations may suggest the underlying cause. Patients can often reproduce the rhythm by tapping their fingers on a table-a rapid regular rhythm suggests sinus tachycardia, SVT, or VT, whereas a rapid, irregular rhythm suggests atrial fibrillation (AF), or frequent premature beats.

Abrupt onset and termination suggests SVT or VT. Associated syncope is more likely with VT than SVT. Single “missed heats” or “flip-flops” are usually from atrial or ventricular premature contractions. Rapid regular palpitations associated with a pounding sensation in the neck suggests a specific type of SVT called AV nodal re-entrant tachycardia (AVNRT). A very slow rate suggests sinus bradycardia or heart block. Palpitations triggered by mild exertion suggest underlying heart failure, valvular disease, anemia, thyrotoxicosis, or poor physical fitness. Occasionally, VT that arises from the right ventricle (RV) outflow tract may present as exercise-induced palpitations. Although anxiety can cause palpitations (typically owing to sinus tachycardia), other more worrisome diagnoses should be excluded. Many young women with SVT are wrongly labeled with anxiety or panic disorder as the cause of their palpitations.

A history of excessive caffeine intake or of cocaine use suggests SVT or PACs as the cause. A thorough review of the patient’s medications should be performed to exclude pro-arrhythmic medications (e.g., antiarrhythmic agents, antipsychotic agents) or stimulants (e.g., beta-agonists, theophylline).

Physical Examination
The examination of the person with palpitations is frequently unrevealing; however, clues to the underlying disease may be found and include:

  • murmurs (valvular heart disease)

  • elevated jugular venous pressure (JVP), rales (heart failure)

  • enlarged thyroid gland (thyrotoxicosis)

    Diagnostic Evaluation (see Figure 3-1)

    The most helpful diagnostic study in the evaluation of palpitations is a 12-lead ECG performed during the patient’s symptoms. Unfortunately, a routine ECG performed in the absence of symptoms is rarely diagnostic. The routine ECG may, however, provide clues to the presence of cardiac conditions such as pre-excitation syndrome (short PR, delta wave), cardiomyopathy (Q waves, ventricular hypertrophy), or valvular heart disease (ventricular hypertrophy, atrial enlargement).

    Prolonged monitoring with a 24-hour ambulatory ECG, ambulatory event monitor, or an implantable loop recorder is usually necessary to determine the cause of infrequent palpitations. An echocardiogram should be performed if underlying heart disease is suspected. A serum TSH level should be routinely obtained to exclude hyperthyroidism as a cause of PACs or SVT. A very aggressive diagnostic strategy should be pursued in those patients with a high likelihood of VT -this includes those with significant valvular disease, myocardial disease, or prior myocardial infarction, and those with a family history of syncope or sudden death. Rarely, electrophysiological studies may be necessary to determine the cause of palpitations.

    KEY POINTS
    1. Although they are often the result of benign conditions, palpitations may indicate the presence of life-threatening disorders.
    2. The history is crucial to identifying possible etiologies of palpitations.
    3. An ECG (12 lead or rhythm strip) during symptoms is essential to confirm the diagnosis.
    4. Prolonged ECG monitoring may be required before the diagnosis is established.

    Provided by ArmMed Media
    Revision date: July 3, 2011
    Last revised: by Sebastian Scheller, MD, ScD