Chapter 22
Palpitations

Marc A. Probst¹ and Christopher R. Carpenter²

¹ Department of Emergency Medicine, Columbia University Irving Medical Center, New York, NY, USA

² Department of Emergency Medicine, Washington University School of Medicine, St. Louis, MO, USA

Highlights

Relatively little research has been published on palpitations in the emergency care setting. Thus, clinical management regarding diagnostic and prognosis is extrapolated from the primary care setting.
History and physical exam do not accurately identify clinically significant dysrhythmias as the etiology of palpitations, so emergency clinicians rely on clinical gestalt and electrocardiographic testing to aid in diagnosis, as opposed to clinical risk scores or patient decision aids.
Attributing anxiety and other psychiatric conditions as the etiology of palpitations could delay diagnostic testing, and should be a diagnosis of exclusion.
Emerging ambulatory cardiac monitors may provide alternative post‐ED monitoring to identify preventable or potentially dangerous precipitants of palpitations.

Background

Palpitations are the subjectively unpleasant awareness of heartbeats. In this chapter, we will review palpitations without syncope since syncope is discussed in this chapter. Between 2001 and 2010 palpitations represented approximately 0.58% of emergency department (ED) visits in the United States.¹ Most individuals with cardiac dysrhythmias do not report palpitations, and approximately 40% of patients with palpitations who present for evaluation are found to have a dysrhythmia.^1,2 The 1‐year mortality rate for individuals evaluated for palpitations is 1.6%.²

The differential diagnosis for palpitations is broad (Table 22.1).³ Some elements of the history may provide clues as to the etiology of palpitations, allowing focused additional diagnostic testing to be obtained. Patients who present with new‐onset palpitations at a younger age are likely to have developed paroxysmal supraventricular tachycardia (PSVT). In older adults, atrial fibrillation and ventricular tachycardia (VT) are more often associated with structural heart disease.⁴ The onset of symptoms with exercise or stress (due to catecholamine surges) can imply VT or sinus tachycardia,⁵ while symptoms that occur during periods of increased vagal tone or while sleeping can be associated with atrial fibrillation or prolonged QT syndrome (an inherited abnormality of myocardial repolarization).⁶ Medications associated with prolonged QT and subsequent Torsades de Pointes include antiarrhythmics, antimicrobials, antihistamines, psychotropics, diuretics, protease inhibitors, and gastrointestinal motility agents.^7,8 Young adults consumers of energy drinks high in caffeine are more likely to report palpitations than nonconsumers.^9,10 Inappropriate sinus tachycardia is characterized by atypical increases in sinus rates and occurs most frequently in young women during minimal exertion or with emotional stress, possibly due to a hypersensitivity to beta‐adrenergic stimulation.¹¹

Table 22.1 Differential diagnosis of palpitations

Source: Data from [3].

Dysrhythmia

Supraventricular

Atrial fibrillation or atrial flutter

AV node re‐entry

Premature atrial complex

Ventricular

Ventricular tachycardia

Premature ventricular complex

Sinus tachycardia

Hyperthyroidism

Hypovolemia

Stimulants (e.g., caffeine, nicotine, cocaine, or amphetamines.)

Hypoglycemia

Pheochromocytoma

Medications (e.g., sympathomimetic agents, vasodilators, anticholinergic drugs, or withdrawal from beta blockers.)

Anxiety or panic disorder

Although anxiety and panic disorders can be associated with palpitations, these psychiatric conditions must remain diagnoses of exclusion in the ED. One investigation of 107 consecutive PSVT patients found that 67% fulfilled DSM (Diagnostic and Statistical Manual of Mental Disorders) criteria for panic disorder and that true dysrhythmias were misdiagnosed for a median of 3.3 years.¹² About half of patients referred for Holter monitoring will have at least one anxiety or depressive disorder if tested using DSM criteria.¹³ At 6 months, 84% of palpitation patients have recurrent palpitations with significantly higher rates of psychosocial morbidity and physician visits.¹⁴ A 10‐item screening instrument derived in primary care settings to distinguish patients whose palpitations are more likely to result from panic disorder and in whom monitoring might be avoided awaits validation in ED settings.¹⁵ The panic disorder modules of the Patient Health Questionnaire and Psychiatric Diagnostic Screening Questionnaire are weak predictors of panic attacks or panic disorder among ED adults with chest pain or palpitations.¹⁶

Multiple diagnostic tests are used in an attempt to identify the etiology of palpitations and distinguish clinically significant sources. The initial test‐of‐choice is generally a standard 12‐lead electrocardiogram (ECG) (Table 22.2). If electrical or structural abnormalities are identified on the ECG, additional cardiac evaluation may be warranted. A Holter monitor simultaneously records two or three electrocardiographic leads and may record continuously (loop recorders) or be triggered at the time of symptoms (event recorders). Stored events on the Holter monitor can be transmitted through a telephone for physician review. Electrophysiological studies are more invasive tests of cardiac conduction that require a cardiology lab. Exercise treadmill testing or other types of provocative cardiac testing (also known as stress testing) may be useful if palpitations are precipitated by exercise or thought to be associated with myocardial ischemia.¹⁸ Echocardiography is indicated to evaluate suspected structural heart disease that may be associated with palpitations; however, identifying structural heart disease does not establish a causal relationship with palpitations.

Table 22.2 Electrocardiographic clues to palpitation etiology

Source: Data from [17].

ECG finding	Possible etiology
Complete heart block	PVC, VT
LVH (Q_I, aVL, V4–V6)	Hypertrophic cardiomyopathy with VT
P‐mitrale	Atrial fibrillation
Premature ventricular complexes	PVC, VT
Prolonged QT interval	VT
Q‐waves	PVC, VT
Short PR interval, delta waves	WPW syndrome, other re‐entrant tachycardia

Q_I = Q‐wave in lead I; PVC = premature ventricular contraction; VT = ventricular tachycardia; LVH = left ventricular hypertrophy; WPW = Wolff–Parkinson–White.

Clinical question

Can history, physical exam, and/or clinical risk scores accurately and reliably distinguish clinically significant dysrhythmia from other causes of palpitations?

Six studies have evaluated the diagnostic accuracy of history for significant dysrhythmias.³ The only useful clinical finding is the sensation of rapid pounding in the neck, which has a positive likelihood ratio (LR+) of 177 (CI 25–1251) and a negative likelihood ratio (LR−) of 0.07 (CI 0.03–0.19) for AV nodal re‐entry (Table 22.3).¹⁹

None of these studies were conducted in ED settings. Summerton et al. evaluated 139 adult patients with new‐onset palpitations from 36 primary care practices in the United Kingdom over 9 months using an event recorder as the criterion standard.²⁰ Hoefman et al. evaluated 127 consecutive patients with palpitations and lightheadedness from 41 general practice clinics in the Netherlands using a continuous event recorder as the criterion standard.²¹ Barsky et al. studied two cohorts of 131 and 145 patients who had been evaluated for palpitations using a 24‐hour Holter monitor and DSM criteria as the criterion standard for dysrhythmia and psychiatric disorder, respectively.^13,22 Gürsoy et al. assessed 244 patients referred for electrophysiology to assess AV nodal reentry tachycardia.¹⁹ Sakhuja et al. evaluated 239 patients referred for electrophysiology studies, cardiac ablation, or cardioversion using a combination of the electrophysiology studies, Holter monitoring, telemetry, and ECG for the criterion standard.²³

Clinical question

Can additional testing (ECG, Holter monitoring, electrophysiology lab) accurately distinguish clinically significant dysrhythmia from other causes of palpitations?

The 12‐lead ECG is the initial test of choice for palpitations, but in primary care, this is possible for only one‐third of patients.^20,24 If an ECG is performed while palpitations are being reported, 48% have a rhythm abnormality, including 19% with a clinically relevant dysrhythmia.²⁴ The diagnostic yield of ECG in the ED evaluation of palpitations has not been described, nor has the diagnostic yield of laboratory testing.