"Ensine o aluno a observar"

William Osler

sábado, 26 de março de 2011

Palpitações - Up to date

INTRODUCTION — Palpitations are one of the most common problems of outpatients who present to internists and cardiologists, accounting for 16 percent of complaints in one study of 500 medical outpatients [1]. Although the cause is usually benign, palpitations are occasionally a manifestation of potentially life-threatening arrhythmia. As a result, the concern about missing a treatable condition may lead to the inappropriate use of expensive tests with little diagnostic and therapeutic value.
The common presentations of palpitations in adults and a guide to rational diagnostic testing and therapy are reviewed here. The approach to palpitations in children and the management of documented arrhythmias are discussed separately. (See "Approach to the child with tachycardia" and "Arrhythmia management for the primary care clinician".)
DEFINITION — Palpitations are a sensory symptom. They are defined as an unpleasant awareness of the forceful, rapid, or irregular beating of the heart. Patients may at times describe the sensation as a rapid fluttering in the chest, flip-flopping in the chest, or a pounding sensation in the chest or neck, and these descriptions may help elucidate the cause of the palpitations [2]. (See 'Description' below.)
ETIOLOGY — The differential diagnosis of palpitations is extensive (table 1), and the etiology varies depending upon the population studied. In a study of 190 patients presenting with a chief complaint of palpitations to a university medical center, an etiology was determined in 84 percent [3]. The cause was cardiac in 43 percent, psychiatric in 31 percent, and miscellaneous (eg, medication-induced, thyrotoxicosis, caffeine, cocaine, anemia, amphetamine, mastocytosis) in 10 percent. A cardiac etiology was more common in patients presenting to the emergency department than to the medical clinic (47 versus 21 percent), while psychiatric etiologies were more common in the medical clinic (45 versus 27 percent). Cardiac etiologies may also be more common among patients who present to a specialist [4].
Psychiatric disorders — Palpitations may be a feature of several psychiatric disorders, including panic attacks, generalized anxiety disorder, somatization, and depression [5,6]. (See "Treatment of panic disorder" and "Overview of generalized anxiety disorder" and "Clinical manifestations and diagnosis of depression".)
Palpitations are a symptom and can occur in the absence of a cardiac arrhythmia [7]. When palpitations are associated with anxiety or panic, it is frequently difficult for the patient to discern whether the feeling of anxiety or panic preceded or resulted from the palpitations.
Psychiatric illness may coexist in patients with another etiology of palpitations [3,8]. As an example, in the university study cited above, 24 of the 190 patients (13 percent) were assigned more than one etiology for palpitations; 21 were coexisting psychiatric illnesses [3]. A second report of 107 patients with electrophysiologically documented reentrant supraventricular tachycardia found that there was a median duration of 3.3 years between the initial presentation to a physician and the definitive diagnosis of supraventricular tachycardia; 67 percent of the patients also met the criteria for panic disorder [9]. Supraventricular tachycardia was not diagnosed during an initial medical evaluation in 59 patients and 32 received a diagnosis of panic, stress, or anxiety disorder; 65 percent of these individuals were women. These findings suggest that although there is good evidence that psychiatric disorders are a common cause of palpitations, this diagnosis should not be accepted until arrhythmic etiologies have been excluded.
Cardiac disorders — As mentioned, cardiac disorders are a common cause of palpitations, and their possible presence generates the most concern among physicians evaluating patients with this complaint. The spectrum of cardiac etiologies ranges from arrhythmias (virtually any new deviation from normal sinus rhythm or a significant change in the rate of a stable arrhythmia, such as atrial fibrillation, can cause palpitations), to valvular heart disease (eg, mitral or aortic insufficiency, mitral valve prolapse), the pacemaker syndrome, cardiomyopathy, and atrial myxoma (table 1).
Most patients with palpitations who undergo ambulatory monitoring are found to have benign supraventricular or ventricular ectopy or normal sinus rhythm [10-12]; normal sinus rhythm is found in up to one-third. Ventricular premature contractions and nonsustained ventricular tachycardia are also found in a substantial proportion of patients with palpitations; they are not associated with increased mortality in patients with structurally normal hearts [13]. (See "Prevalence and evaluation of ventricular premature beats" and "Supraventricular premature beats".)
In the university study cited above, four variables were independent predictors of a cardiac etiology of palpitations [3]:
  • Male sex
  • Description of an irregular heart beat
  • History of heart disease
  • Event duration >5 minutes
None of the patients with zero predictors had a cardiac etiology, compared with 26, 48, and 71 percent of patients with 1, 2, and 3 predictors, respectively.
Despite the relatively high prevalence of cardiac disorders in this study, the short-term prognosis was excellent; mortality during one year of follow-up was documented in only three women, all over age 70, and none of the deaths was sudden or directly related to the original etiology of palpitations [3]. The one-year stroke rate was also low (1.1 percent).
A second outcome study reported similar findings. In this retrospective cohort study of 109 patients with palpitations evaluated in a primary care setting, there was no difference in morbidity or mortality compared with age and sex matched controls over a mean 42 month follow-up [14]. Ventricular tachycardia was responsible for palpitations in only four patients.
Arrhythmias during catecholamine excess — A number of sustained supraventricular and ventricular tachyarrhythmias may be provoked by sympathetic stimulation and catecholamine excess, as occurs during exercise or at times of stress. Studies in which exercise testing was performed revealed that nonsustained supraventricular and ventricular premature beats are more common than sustained arrhythmias, and the incidence of any arrhythmia is increased in patients with underlying heart disease. (See "Clinical significance and treatment of ventricular premature beats", section on 'Exercise-induced' and "Exercise ECG testing to determine prognosis of coronary heart disease", section on 'Ventricular arrhythmias' and "Exercise ECG testing to determine prognosis of coronary heart disease", section on 'Atrial arrhythmias'.)
On the other hand, idiopathic ventricular tachycardia (VT), especially when it arises from the right ventricular outflow tract, can occur during exercise in patients with structurally normal hearts; this arrhythmia most often presents during the second and third decades of life as palpitations, dizziness, or syncope [15]. (See "Monomorphic ventricular tachycardia in the absence of apparent structural heart disease".)
Supraventricular tachyarrhythmias, including atrial fibrillation (AF), can be induced during exercise or at the termination of exercise when the withdrawal of catecholamines is coupled with a surge in vagal tone [16]. AF occurring during this relative increase in vagal tone is particularly common in athletic men in the third to sixth decade of life [17]. (See "Paroxysmal atrial fibrillation", section on 'Autonomic dysfunction'.)
Catecholamine excess resulting in arrhythmia may also occur during emotionally startling experiences. As an example, patients with the long QT syndrome, especially congenital type 1 or 2 (an inherited abnormality of myocardial repolarization), characteristically present with palpitations during periods of vigorous exercise or emotional stress; the mechanism is often a polymorphic VT known as torsades de pointes [18]. (See "Clinical features of congenital long QT syndrome".)
Inappropriate sinus tachycardia is a rare disorder that manifests as palpitations during minimal exertion or with emotional stress. This arrhythmia is characterized by an inappropriate increase in the sinus rate and is most frequently seen in young women; it may result from a hypersensitivity to beta-adrenergic stimulation. (See "Sinus tachycardia", section on 'Inappropriate sinus tachycardia'.)
DIAGNOSTIC EVALUATION — In the vast majority of outpatients with palpitations, the cause of the palpitations is benign, and extensive and costly investigation is not warranted. Attention to characteristics that identify patients at high risk for serious causes of palpitations will help define the much smaller percentage of patients with palpitations who require more extensive diagnostic testing and management of their condition.
The diagnostic evaluation of all patients with palpitations should include a detailed history, physical examination, and 12-lead electrocardiography. This, plus some limited laboratory testing, is sufficient to make a definitive diagnosis in more than one-third of patients [3]. Ambulatory monitoring is helpful in the remainder, and rare patients need more specialized testing.
History — The history should include information on the characteristic presentation of the palpitations, associated sensations, and the patient's age at the onset of palpitations.
Age of onset — Age does not appear to be an independent predictor of the presence or absence of a cardiac etiology of palpitations [3]. On the other hand, age may help narrow the differential diagnosis of certain arrhythmias. As an example, a patient who has had rapid palpitations since childhood is most likely to have a supraventricular tachycardia, particularly one that uses a bypass tract, although atrioventricular nodal reentrant tachycardia (AVNRT) is also possible. Other types of paroxysmal supraventricular tachycardia, such as atrial tachycardia or AF, are more likely to occur as the subject ages. (See "Overview of the evaluation and management of atrial fibrillation".)
Serious ventricular arrhythmias typically occur in older patients with structural heart disease. However, idiopathic VT occasionally occurs in adolescence and many cases of torsades de pointes due to congenital long QT syndrome occur before the age of 20. (See "Monomorphic ventricular tachycardia in the absence of apparent structural heart disease" and "Clinical features of congenital long QT syndrome".)
Description — Palpitations are described in many ways, but some specific sensations are common and useful for narrowing the differential diagnosis. Thus, it is critical that the patient give a detailed description of the sensation associated with the symptom of palpitation. In particular, it is important to establish the rate and degree of regularity of the palpitations; it may be helpful to have the patient tap out the rhythm with the fingers. It may also be useful for the physician to provide examples of rapid and regular rhythms, rapid and irregular rhythms, slow and regular rhythms, and slow and irregular rhythms. Rapid and regular rhythms are suggestive of paroxysmal supraventricular tachycardia or VT. Rapid and irregular rhythms suggest atrial fibrillation, atrial flutter, or tachycardia with variable block.
Other descriptions can also provide helpful information:
  • Flip-flopping in the chest — In some cases the palpitations are sensed as the heart seeming to stop and then start again, producing a pounding or flip-flopping sensation. This type of palpitation is generally caused by supraventricular or ventricular premature contractions. The sensation that the heart has stopped results from the pause following the premature contraction, and the pounding or flipping sensation results from the forceful contraction following the pause, ie, post extrasystolic potentiation of ventricular inotropy. (See "Supraventricular premature beats" and "Prevalence and evaluation of ventricular premature beats".)
  • Rapid fluttering in the chest — A feeling of rapid fluttering in the chest often results from a sustained ventricular or supraventricular arrhythmia, including sinus tachycardia. The regularity or irregularity of the palpitation may indicate the probable arrhythmic etiology; as examples, atrial fibrillation is irregular while sinus tachycardia and AVNRT are regular.
  • Pounding in the neck — An irregular pounding feeling in the neck is caused by atrioventricular dissociation, with independent contraction of the atria and ventricles, resulting in occasional atrial contraction against a closed tricuspid and mitral valve. This produces cannon A waves, which are intermittent increases in the "A" wave of the jugular venous pulse. Cannon A waves may be seen with ventricular premature contractions, third degree or complete heart block, or ventricular tachycardia (VT). (See "Examination of the jugular venous pulse".)
Rapid and regular neck pulsations, which are due to prominent and regular A waves, may be seen as a bulging in the neck, sometimes termed a "frog sign" [19]. The sensation of rapid and regular pounding in the neck is most typical of reentrant supraventricular arrhythmias, particularly AVNRT or atrioventricular reentrant tachycardia due to a preexcitation syndrome. AVNRT is the most common form of paroxysmal supraventricular tachycardia and is three times as common in women as in men [20]. In the typical form of atrioventricular nodal tachycardia, the atria and ventricles are activated simultaneously at an average rate of 160 to 180 beats per minute; as a result of simultaneous atrial and ventricular contraction, the atria are always contracting against a closed or partially closed mitral and tricuspid valve. (See "Atrioventricular nodal reentrant tachycardia (junctional reciprocating tachycardia)" and "Tachyarrhythmias associated with accessory pathways".)
Onset and offset — The mode of onset and termination of the palpitations sometimes indicates their cause. Palpitations that occur randomly and episodically and last for an instant are generally due to premature beats, while a gradual onset and offset suggests a sinus tachycardia. Palpitations described as abrupt in onset and termination may be caused by supraventricular or ventricular tachycardias.
Patients often become adept at terminating their own palpitations with carotid sinus massage or other vagal maneuvers, such as the Valsalva maneuver. This mode of termination is suggestive of supraventricular tachycardias, particularly atrioventricular nodal tachycardia or those using a bypass tract. (See "Atrioventricular nodal reentrant tachycardia (junctional reciprocating tachycardia)" and "Tachyarrhythmias associated with accessory pathways".)
Positional palpitations — Patients who have a history of AVNRT frequently experience the arrhythmia upon standing up straight after bending over; the arrhythmia may end when lying down.
Often a patient notes an intermittent pounding sensation while lying in bed, particularly in the supine or left lateral decubitus position. This symptom is commonly the result of supraventricular or ventricular premature beats, which occur more frequently at slow heart rates, as when a person is resting in bed. In the left lateral decubitus position, the apex of the heart is closer to the chest wall, which may account for the greater awareness of palpitations in this position.
Palpitations associated with syncope or presyncope — Dizziness, presyncope, or syncope may accompany palpitations and should prompt a search for a hemodynamically significant and potentially serious arrhythmia, most importantly VT. Short runs of nonsustained VT can cause syncope as well as a sensation of palpitations.
Occasionally syncope is associated with a supraventricular tachycardia, particularly at the beginning of the tachycardia. This type of syncope is believed to result from acute vasodilation, rapid heart rate with low cardiac output, or both [21,22]. (See "Pathogenesis and etiology of syncope".)
Psychiatric illness — There is no optimal screening tool for psychiatric causes of arrhythmia. In one study of 125 outpatients referred for ambulatory electrocardiographic monitoring to evaluate a complaint of palpitations, patients with psychiatric disorders were significantly younger and more disabled, somatized more, and had more hypochondriacal concerns about their health [23]. Their palpitations were more likely to last longer than 15 minutes, were accompanied by more ancillary symptoms, were described as more intense, and were associated with more emergency department visits.
Diagnostic criteria for the major psychiatric disorders associated with palpitations (panic attacks, generalized anxiety disorder, somatization, depression) have been established (table 2 and table 3). (See "Treatment of panic disorder" and "Overview of generalized anxiety disorder" and "Clinical manifestations and diagnosis of depression".)
Medications and habits — A history of all medications, including over-the-counter medications, should be obtained. In particular, palpitations may occur with the use of sympathomimetic agents, vasodilators, anticholinergic drugs, or during withdrawal from beta blockers.
Illicit drug use (eg, cocaine or amphetamines) and nicotine use should also be established. Any temporal relationship between palpitations and excessive caffeine intake should also be sought.
Other medical disorders — A history of or symptoms consistent with any of the medical disorders that can be associated with palpitations (eg, hypoglycemia, thyrotoxicosis, pheochromocytoma) should be determined. (See "Diagnostic approach to hypoglycemia in adults" and "Overview of the clinical manifestations of hyperthyroidism in adults" and "Clinical presentation and diagnosis of pheochromocytoma".)
Some studies suggest that palpitations can occur more frequently in pregnancy.
Physical examination — The physician rarely has an opportunity to examine a patient during an episode of palpitations, but the physical examination is still useful in defining potential cardiovascular abnormalities that could serve as a substrate for arrhythmias and in identifying some other medical disorders that may be associated with palpitations. A notable example is the midsystolic click and occasionally murmur associated with mitral valve prolapse. (See "Definition and diagnosis of mitral valve prolapse".) Virtually every type of supraventricular arrhythmia, as well as ventricular premature depolarizations and nonsustained ventricular tachycardia, has been described with mitral valve prolapse, and palpitations are nearly ubiquitous in the subset of patients with mitral valve prolapse who have the mitral valve prolapse syndrome, even in patients who do not have an identifiable arrhythmia [24]. (See "Arrhythmic complications of mitral valve prolapse" and "Mitral valve prolapse syndrome", section on 'Palpitations'.)
A harsh 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 this disorder, but it is also associated with ventricular tachycardia. (See "Clinical manifestations of hypertrophic cardiomyopathy".)
Clinical evidence of a dilated cardiomyopathy and heart failure raise the possibility of ventricular tachycardia as well as atrial fibrillation. (See "Pathogenesis of ventricular arrhythmias in heart failure and cardiomyopathy".)
The physical examination can be very useful for evaluating patients with chronic atrial fibrillation and palpitations. Although palpitations may not be present at rest, when the ventricular response is slow, a brisk walk down the corridor, which results in sympathetic activation and an increase in catecholamines, will enhance atrioventricular nodal conduction and may unmask a poorly controlled ventricular response and resultant palpitations. (See "Overview of the evaluation and management of atrial fibrillation".)
Twelve-lead ECG — The etiology of palpitations should be clear in the few patients in whom an arrhythmia correlating with palpitations is captured on a 12-lead electrocardiogram (ECG). If the arrhythmia is documented on ECG (eg, atrial fibrillation or ventricular tachycardia), the patient should be managed according to the underlying arrhythmia. (See "Arrhythmia management for the primary care clinician".)
However, most patients are in sinus rhythm when the ECG is obtained; in this situation the 12-lead electrocardiography (ECG) may help narrow the differential diagnosis of palpitations (table 4) [20].
  • The electrocardiogram should be scrutinized for the presence of a short PR interval and delta waves (the Wolff-Parkinson-White syndrome), which confirms the presence of ventricular preexcitation and suggests it as the cause of supraventricular tachycardia (figure 1).
  • Marked left ventricular hypertrophy with deep septal Q waves in I, aVL, and V4 through V6 suggests the presence of hypertrophic obstructive cardiomyopathy. (See "Clinical manifestations of hypertrophic cardiomyopathy".) Left ventricular hypertrophy with evidence of left atrial abnormality (as indicated by a terminal P-wave force in V1 more negative than 0.04 msec and notched in lead II) suggests a likely substrate for atrial fibrillation.
  • The presence of Q waves characteristic of a prior myocardial infarction warrants a more extensive search for nonsustained or sustained ventricular tachycardia. (See "Pathogenesis and diagnosis of Q waves on the electrocardiogram".)
  • Isolated supraventricular and/or ventricular ectopy may occasionally be seen on the 12-lead ECG. The morphology of the ventricular premature beats, particularly in patients with normal hearts, may suggest that an idiopathic ventricular tachycardia is the cause of the palpitations.
  • Prolongation of the QT interval and abnormal T wave morphology may suggest the presence of the long QT syndrome (figure 2). (See "Clinical features of congenital long QT syndrome".)
  • A bradycardia of any etiology can be accompanied by ventricular premature depolarizations and associated palpitations. In particular, complete heart block can be associated with ventricular premature depolarizations or a prolonged QT interval and torsades de pointes.
Laboratory testing — There are no evidence-based guidelines to direct the laboratory work-up of patients with palpitations. Limited laboratory testing to rule out anemia and hyperthyroidism is reasonable, in addition to testing for specific disorders that may be suggested by the history and physical examination.
Further diagnostic testing — While most patients with palpitations do not have a life-threatening condition, the majority have recurrent symptoms that can adversely effect quality of life [3]. Thus, when the history, physical examination, electrocardiogram, and laboratory testing do not establish a definitive diagnosis, additional testing can serve several purposes: to rule out a serious condition; to possible identify a treatable cardiac dysrhythmia (eg, atrial fibrillation); and to reassure the patient.
Diagnostic testing is recommended for three groups of patients:
  • Those in whom the initial diagnostic evaluation (history, physical examination, and electrocardiogram) suggests an arrhythmic cause. Testing is particularly important in patients who experience syncope or presyncope in association with palpitations.
  • Those who are at high risk for an arrhythmia. Patients are considered at high risk if they have organic heart disease or any myocardial abnormality that can lead to serious arrhythmias, including scar formation from myocardial infarction, idiopathic dilated cardiomyopathy, clinically significant valvular regurgitant or stenotic lesions, and hypertrophic cardiomyopathy. These disorders have all been shown to be associated with the development of ventricular tachycardia [25]. Other high-risk patients are those with a family history of arrhythmia, syncope, or sudden death from cardiac causes, such as from a cardiomyopathy or the long QT syndrome. Low-risk patients are those without a potential substrate for arrhythmias.
  • Those who remain anxious to have a specific explanation for their symptoms.
In low-risk patients, we use ambulatory monitoring only if the history or ECG is suggestive of a sustained arrhythmia or the patient needs the reassurance of a documented benign cause for the palpitations. Additional diagnostic procedures in high-risk patients include ambulatory or transtelephonic monitoring devices, and ultimately invasive electrophysiologic testing if clinically significant arrhythmias are recognized or are suspected but not recorded by ambulatory monitoring devices.
Ambulatory monitoring — Ambulatory ECG monitoring devices are the most important tools for the diagnosis of unexplained recurrent palpitations [26]. (See "Ambulatory monitoring in the assessment of cardiac arrhythmias".)
  • The Holter monitor is a 24-hour monitoring system that records and saves data continuously. The device is worn for one or two days while the patient keeps a diary recording the time and characteristics of symptoms.
  • Continuous loop event recorders continuously record data, but save the data for the preceding and subsequent two minutes (or for other periods, as programmed) only when the patient manually activates the monitor. These recording devices are capable of direct transmission of the ECG as an audio signal via the telephone [27].
  • The implantable loop recorder (ILR) is a subcutaneous monitoring device for the detection of cardiac arrhythmias [28]. Such a device is typically implanted in the left pectoral region and stores events when the device is activated automatically according to programmed criteria or manually with magnet application. The ILR is most often used for patients with unexplained syncope, but it may have a role for those in whom other methods have failed to document the cause of palpitations. (See "Evaluation of syncope in adults", section on 'Electrocardiographic monitoring'.)
Holter monitors are inherently limited by the short duration of time available for monitoring. In addition, arrhythmias may be identified on a Holter recording that are unrelated to the palpitations. This was illustrated in a study of 1454 elderly patients aged 60 to 94 years, 8.3 percent of whom complained of palpitations [29]. Arrhythmias, predominantly conduction abnormalities and sinus bradycardia, were found in 12.6 percent. However, the prevalence of palpitations was similar in those with and without arrhythmias. In another study of 518 patients who had 24-hour electrocardiographic recordings, 34 percent had their typical symptoms at a time when the electrocardiogram was normal [7].
Continuous loop recorders can be used for longer periods than Holter monitors and, since most patients with palpitations do not have them every day, are more likely to record data during palpitations. Furthermore, symptoms can be directly correlated with the cardiac rhythm since the patient activates the monitor.
A review of four prospective and two retrospective studies of patients with palpitations found that the diagnostic yield was 66 to 83 percent for continuous loop devices, compared with 33 to 35 percent for Holter monitoring [30]. In addition, continuous loop recorders have proved more cost effective than Holter monitors for the evaluation of palpitations [10,31].
Two weeks of transtelephonic monitoring is sufficient to make a diagnosis in the vast majority of patients with palpitations and is less costly than the standard monitoring period of one month. As an example, in a retrospective analysis of 5,052 patients who had undergone event recording with a continuous loop monitor, 87 percent had an initial transmission corresponding to palpitations in the first two weeks of monitoring [32]. An additional 9 percent of initial transmissions occurred by four weeks of monitoring. In a second report of 105 outpatients referred for placement of a transtelephonic monitor for the evaluation of palpitations, the diagnostic yield was 1.04 diagnoses per patient in week one, 0.15 in week two, and 0.01 diagnoses per patient in week three and beyond [11]. The cost-effectiveness ratio increased from $98 per new diagnosis in week one, to $576 and $5832 in weeks two and three, respectively.
Thus, the data support two weeks of continuous loop event recording in patients with palpitations. A 24-hour Holter monitor can be used in patients with daily palpitations, particularly if the patient is likely to have trouble activating the loop recorder. An implantable event recorder can be used in selected patients with infrequent but symptomatic palpitations.
Electrophysiologic testing — Invasive cardiac electrophysiology is an established technique for the diagnosis of a suspected arrhythmia and is important for the therapy of certain rhythm abnormalities (eg, supraventricular tachycardia). It permits a detailed analysis of the mechanism underlying the cardiac arrhythmia and precise location of the site of origin. (See "Overview of invasive cardiac electrophysiology studies".) Electrophysiologic testing is indicated in patients with a high pretest likelihood of a serious arrhythmia (eg, patients with structural heart disease).
Diagnostic recommendations — The evaluation of patients with palpitations should begin with a history, physical examination, 12-lead ECG, and in some cases limited laboratory testing.
  • If there is no evidence of heart disease and the palpitations are unsustained and well tolerated, ambulatory monitoring or reassurance is recommended. Two weeks of transtelephonic monitoring is the optimal ambulatory monitoring technique in most cases.
  • If the initial evaluation suggests heart disease and the palpitations are unsustained, ambulatory monitoring is again recommended.
  • Regardless of the presence or absence of heart disease, if the palpitations are sustained or poorly tolerated, an electrophysiologic study, with or without prior ambulatory monitoring, is indicated. A Task Force of the ACC/AHA has published recommendations for electrophysiologic studies in patients with palpitations [33].
MANAGEMENT — The management of most sustained supraventricular or ventricular arrhythmias causing palpitations involves referral to a specialist trained in the pharmacologic and invasive electrophysiologic management of arrhythmias. Most types of regular supraventricular tachycardias and some types of ventricular tachycardias are now curable with radiofrequency ablation [34]. (See "Catheter ablation of cardiac arrhythmias: Overview and technical aspects".)
The most challenging cases of palpitations are those due to benign supraventricular or ventricular ectopy or associated with normal sinus rhythm. I attempt to reassure patients with these benign diagnoses that these rhythms are not life-threatening. (See "Prevalence and evaluation of ventricular premature beats" and "Supraventricular premature beats".)
In the rare cases in which the supraventricular or ventricular ectopy proves incapacitating, treatment with beta-blocking medications can be initiated (eg, metoprolol or atenolol 50 mg daily). The beta blocker may not suppress the arrhythmia, but it can eliminate the associated symptoms and make the patient more comfortable. Antiarrhythmic medications are not recommended, such as quinidine, flecainide, or sotalol because of the associated risks of proarrhythmia.
In general, radiofrequency ablation of isolated ventricular ectopy is not recommended. However, on rare occasions, ventricular bigeminy can produce palpitations with fatigue and near-syncope on exertion because of a slow effective heart rate and low cardiac output. Radiofrequency ablation may be considered in this circumstance, if the ventricular ectopy has uniform morphologic features and occurs incessantly. (See "Catheter ablation for ventricular arrhythmias".)
The management of inappropriate sinus tachycardia deserves special mention. The diagnosis of inappropriate sinus tachycardia can be made after secondary causes, such as hyperthyroidism or anemia, have been excluded and the patient has undergone electrophysiologic testing to rule out other forms of supraventricular tachycardia that may mimic sinus tachycardia, such as right atrial tachycardia and sinus node reentry [35]. The first line of therapy is pharmacologic treatment with beta blockers or calcium channel blockers. (See "Sinus tachycardia", section on 'Inappropriate sinus tachycardia'.)
If this strategy fails, radiofrequency ablation or modification of the sinus node can be attempted. However, these treatments are often unrewarding and may result in serious complications, such as complete destruction of the sinus node, requiring permanent pacing, or paralysis of the phrenic nerve [35]. (See "Catheter ablation of atrial tachycardia", section on 'Inappropriate sinus tachycardia'.)
SUMMARY
  • Palpitations are defined as an unpleasant awareness of the forceful, rapid, or irregular beating of the heart. The differential diagnosis of palpitations is extensive, but is most commonly due to cardiac and psychiatric illness (table 1). (See 'Etiology' above.)
  • In the majority of patients, the cause of palpitations is benign, and costly investigation is not warranted. Attention to characteristics that identify patients at high risk for serious causes of palpitations (eg, structural heart disease) will help identify the small percentage of patients who require more extensive diagnostic testing. (See 'Diagnostic evaluation' above.)
  • The diagnostic evaluation of all patients with palpitations should include a detailed history, physical examination, and 12-lead ECG. Limited laboratory testing to rule out anemia and hyperthyroidism is also reasonable. (See 'Diagnostic evaluation' above.)
  • For patients with bothersome and recurrent symptoms, ambulatory monitoring is helpful if the palpitations are unsustained and well tolerated. For most patients, two weeks of transtelephonic monitoring is the optimal ambulatory monitoring technique. A 24-hour Holter monitor can be considered in patients who have daily symptoms. (See 'Ambulatory monitoring' above.)
  • If the palpitations are sustained or poorly tolerated, an electrophysiologic study is indicated. Electrophysiologic testing is also useful in patients with a high pretest likelihood of a serious arrhythmia (eg, patients with structural heart disease). (See "Overview of invasive cardiac electrophysiology studies".)
  • The management of most sustained supraventricular or ventricular arrhythmias causing palpitations should be managed by a cardiologist trained in the pharmacologic and invasive electrophysiologic management of arrhythmias. (See 'Management' above.)
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REFERENCES

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