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. - - - and/or Physicians 3 amily questions F of copyright Academy for Although frequently cause This article describes the more common Of these patients, 43 percent had palpita .org palpitations, most patients with arrhyth presentations of palpitations and a rational patientevaluation, to approach andprovides evidence for making decisions about ambu at at a university medical center who com tions, and 4 percent had palpitations caused by other noncardiac cause causes. of the palpitations could be identified No specific percentin of the16 patients. Psychiatric and emotional illnesses such as , and somatization panic, disorders may be underly ing problems in many patients. mias do not actually notice their mia arrhyth and are palpitations. unlikely to report having latory monitoring. plained palpitations of and for followed were one year, an etiology was determined in 84 percent of the patients. tions caused by cardiac causes (40 had percent an , cardiac 3 causes), 31 percent percent had palpitations had percent 6 other disorder, panicanxiety or by caused had palpitations caused by street drugsprescription or and over-the-counter medica

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of 190 patients 190 of 1 .org/afp reserved. .aafp . in a family practice set rights 2 www at other Consensusevidence-based or site All guidelines for diagnosing and with noncardiac causes as such , , or drug use, and can occur in anxious but otherwise normal persons. The differential diagnoses of pitations pal are summarized 1 Table in

. eb ness of the tions heartbeat,are a common symptom in palpita patients presenting to family phy n n increased or abnormal aware W site

eb W the Physician Keck School of Medicine of the University of Southern California, Los Angeles, California of Although there are many possible cardiac managing palpitations have not been devel oped. However, oped. recent However, studies of palpitation etiology provide evidenceimproved that can guide a family physician through diagnosis. prospective Instudya cohort sicians. Palpitations can be symptomatic of life-threatening cardiac arrhythmias. ever, most palpitations are benign. In retrospective study one ting, there was no difference in the rates of morbidity or mortality among patients with palpitations compared with matched control subjects. etiologies, palpitations can be associated A Family user

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ziness, near-, or syncope because they sug- Palpitations are potentially more serious when they are associated with diz- gest tachyarrhythmia. Patient information:

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ALLAN ABBOTT, M.D., V. of a Palpitations—sensations rapid or irregular heartbeat—are most often caused by cardiac arrhythmias or anxiety. ventricular Most premature fibrillation, atrial patients , sinus with including arrhythmia, any arrhythmias However, do not complain of should be consid palpitations. Palpitations can cause palpitations. tachycardia, or ventricular contractions, Diagnostic Approach to Palpitations Diagnostic Approach pitations, written by the author of this article, is provided on page 755. ered as potentially more serious if they are associated with , near-syncope, or syncope. or syncope. near-syncope, with dizziness, if associated are serious they more as potentially ered Nonarrhythmic cardiac problems, such as hypo and syncope, prolapse, vasovagal , and congestive , as such problems, noncardiac and over-the- failure, heart and drugs, stimulant from result can also Palpitations palpitations. cause can glycemia, No cause for and medications. counter the can prescription palpitations be found in up to 16 if is usually indicated monitoring (ECG) electrocardiographic Ambulatory of percent patients. examina physical history, the patient’s from be determined cannot of the etiology palpitations an or initial do not unpredictably occur daily, occur palpitations When and ECG. tion, resting for monitoring Holter is indicated. recording event closed-loop of continuous course two-week 24 to 48 Fam (Am hours may event be in patients. appropriate most patients with Trans-telephonic for daily palpitations. monitors Holter than cost-effective and effective more are monitors Physicians.) of Family Academy American 2005 Copyright© 2005;743-50,755-6. Physician ▲ STRENGTH OF RECOMMENDATIONS

Key clinical recommendation Label References

Most patients with palpitations are diagnosed with an arrhythmia or C 1 . The identification of panic disorder in patients with palpitations can be C 9 assisted with the use of screening questionnaires. Unless palpitations occur daily, event monitors are more cost effective than 24-hour or 48-hour Holter monitors in the diagnosis of intermittent B 19 arrhythmias. Patients with palpitations caused by premature ventricular contractions, B 23 who have a normal heart evaluation, have no increased mortality.

A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-oriented evidence, usual practice, opinion, or case series. See page 639 for more information.

Etiology of Palpitations arteriovenous block, or ventricular tachy- CARDIAC ARRHYTHMIAS cardia. Episodes of Palpitations can result from many arrhyth- and supraventricular tachycardia may be mias, including any and tachy- perceived as palpitations but also can be cardia, premature ventricular and atrial asymptomatic or lead to syncope. Palpita- contractions, sick sinus syndrome, advanced tions associated with dizziness, near-syn-

TABLE 1 of Palpitations

Arrhythmias Nonarrhythmic cardiac causes /flutter Atrial or ventricular septal defect Bradycardia caused by advanced arteriovenous block or Congenital heart disease Bradycardia-tachycardia syndrome Congestive (sick sinus syndrome) Multifocal atrial tachycardia Pacemaker-mediated tachycardia Premature supraventricular Pericarditis or ventricular contractions Valvular disease (e.g., , or arrhythmia stenosis) Supraventricular tachycardia Extracardiac causes Ventricular tachycardia Anemia Wolff-Parkinson-White syndrome imbalance Psychiatric causes Fever Hyperthyroidism Panic attacks Drugs and medications Alcohol Pulmonary disease Certain prescription and over-the-counter Vasovagal syndrome agents (e.g., digitalis, phenothiazine, theophylline, beta agonists) Street drugs (e.g., ) Tobacco

NOTE: The categories of palpitations are arranged from most common to least common; within the categories, condi- tions are listed in alphabetical order.

744 American Family Physician www.aafp.org/afp Volume 71, Number 4 ◆ February 15, 2005 Palpitations Panic Disorder Questionnaire

Question Circle one

Do you think there is something seriously wrong with your body? 1 2 3 4 5 Do you get the feeling that people are not taking your illness seriously 1 2 3 4 5 enough? Do you find that you are bothered by many different symptoms? 1 2 3 4 5 In the past month, how much have you been aware of a sudden 1 2 3 4 5 feeling of unsteadiness or loss of balance? In the past month, how much have you been aware of being short 1 2 3 4 5 of breath? In the past six months, how much have you been bothered by the following: Feeling faint or dizzy? 1 2 3 4 5 Pains in your heart or chest? 1 2 3 4 5 Numbness, tingling, or burning in parts of your body? 1 2 3 4 5 Feeling weak in parts of your body? 1 2 3 4 5 Not feeling well most of the time in the past few years? 1 2 3 4 5

Scoring: 1 = not at all; 2 = a little bit; 3 = moderately; 4 = quite a bit; 5 = a great deal. A total score of more than 21 suggests underlying panic disorder (57 percent positive predictive value and 93 percent negative predictive value in a typical population where 25 percent of patients with palpitations have a panic disorder).

Figure 1. Questionnaire to identify panic disorder in patients with palpitations.

Adapted with permission from Barsky AJ, Ahern DK, Delamater BA, Clancy SA, Bailey ED. Differential diagnosis of palpitations: preliminary development of a screening instrument. Arch Fam Med 1997;6:244. cope, or syncope suggest tachyarrhythmia A screening questionnaire (Figure 1)9 to and are potentially more serious. help identify patients whose palpitations are Some patients notice “pounding” or “jump- more likely to result from panic disorder was ing” palpitations when they are quietly sitting validated among patients referred for Holter or lying down. This symptom may result monitoring. A score of more than 21 points from premature contractions, especially pre- on the questionnaire is 81 percent sensitive mature ventricular contractions. Orthostatic and 80 percent specific for panic disorder. intolerance or inadequate cerebral perfusion To explain it another way, if, overall, 25 per- on upright posture may result in palpitations, cent of patients have panic disorder as the tachycardia, altered mentation, , cause of their palpitations, then 57 percent nausea, pre-syncope, and, occasionally, syn- with more than 21 points have panic disor- cope. is most com- der compared with only 7 percent of those mon in women of childbearing age.4 with 21 or fewer points.9 A simpler screening tool for panic disor- ANXIETY OR PANIC DISORDER der, consisting of a single question, also has The prevalence of panic disorder in patients been developed. The question is, “Have you with palpitations is 15 to 31 percent.1,5,6 experienced brief periods, for seconds or Panic disorder is diagnosed on the basis minutes, of an overwhelming panic or terror of information in the patient’s history and that was accompanied by racing heartbeats, is characterized by recurrent unexpected , or dizziness?”10 The panic attacks. Panic disorder is more likely physician must remember that panic dis- to be diagnosed in women of childbearing order and significant arrhythmias are not age because these patients somatize more mutually exclusive, and that cardiac evalu- frequently, present to emergency depart- ation still may be necessary in patients with ments more often, and have increased hypo- suspected panic disorder. In addition, some chondriacal concerns about their health.7 patients or physicians may find it difficult to Palpitations are most persistent in persons determine whether the feeling of anxiety or who have many minor daily irritants and are panic started before or after the palpitations. highly sensitive to bodily sensations.8 Therefore, true arrhythmic causes must be

February 15, 2005 ◆ Volume 71, Number 4 www.aafp.org/afp American Family Physician 745 TABLE 2 Key Clinical Findings with Palpitations and Suggested Diagnoses

Finding Suggested diagnosis nized arrhythmia on the initial evaluation; this was particularly true among young Single “skipped” beats Benign ectopy women. Feeling of being unable to catch Ventricular premature contractions one’s breath increase at times of intense Single pounding sensations Ventricular premature contractions emotional experience, with intense , Rapid, regular pounding in neck Supraventricular arrhythmias and in conditions such as pheochromocy- Palpitations that are worse at night Benign ectopy or atrial fibrillation toma. Ventricular or supraven- Palpitations associated with Psychiatric etiology or tricular tachycardias can be triggered by this emotional distress -sensitive arrhythmia catecholamine increase. An increase of vagal Palpitations associated with activity Coronary heart disease tone after exercise occasionally can lead to General anxiety Panic attacks episodes of atrial fibrillation.14 Thus, even Medication or recreational drug use Drug-induced palpitations in cases where panic disorder is suggested, Rapid palpitations with exercise Supraventricular arrhythmia, atrial (ECG) or ambulatory fibrillation ECG monitoring is important. Positional palpitations Atrioventricular nodal tachycardia, pericarditis NONARRHYTHMIC CARDIAC CAUSES Heat intolerance, tremor, Hyperthyroidism Conditions in this category include valvu- thyromegaly lar diseases such as aortic insufficiency or Palpitations since childhood Supraventricular tachycardia stenosis, atrial or ventricular septal defect, Rapid, irregular rhythm Atrial fibrillation, tachycardia with congestive heart failure, cardiomyopathy, variable block and congenital heart disease. These condi- Palpitations terminated by vagal Supraventricular tachycardia maneuvers tions can predispose the patient to arrhyth- Heart valve disease mia and to palpitations. Pericarditis, a rare Midsystolic click Mitral valve prolapse cause of palpitations, can cause Friction rub Pericarditis that may change with position.

NOTE: The information in this table is based on clinical experience and not on the EXTRACARDIAC CAUSES results of clinical trials. The physician should examine the patient for extracardiac causes. The patient may have obvious associated illness with fever, ruled out before the diagnosis of anxiety or , hypoglycemia, anemia, or evi- panic disorder can be accepted as the cause dence of thyrotoxicosis. Use of drugs such as of the palpitations.1,11,12 cocaine, and alcohol, caffeine, and tobacco Some physicians may prematurely blame can precipitate palpitations. The use of ephe- palpitations on anxiety. In one study13 of dra and ephedrine also has been associated patients with supraventricular tachycardia, with palpitations.15 Many prescription med- two thirds of the patients were diagnosed ications, including digitalis, phenothiazine, with panic, stress, or anxiety disorder, and theophylline, and beta agonists, can cause one half of the patients had an unrecog- palpitations.

Initial Clinical Evaluation HISTORY AND The Author The cause of palpitations often can be deter- ALLAN V. ABBOTT, M.D., is professor of clinical family medicine at the Keck mined through a careful history and physical School of Medicine of the University of Southern California, Los Angeles, where he is associate dean for curriculum and continuing medical education. Dr. examination. Patients may describe palpita- Abbott received his medical degree from Indiana University School of Medicine tions in a variety of ways, such as a fluttering, and completed a residency in family medicine at UCLA San Bernardino Medical pounding, or uncomfortable sensation in the Center, Calif. chest or neck, or simply an increased aware- Address correspondence to Allan V. Abbott, M.D., 1975 Zonal Ave., KAM 317, ness of the heartbeat. Because the patient’s Los Angeles, CA 90033 (e-mail: [email protected]). Reprints are not available from description is often vague, knowing the cir- the author. cumstances, precipitating factors, and asso-

746 American Family Physician www.aafp.org/afp Volume 71, Number 4 ◆ February 15, 2005 Figure 2. Sinus tachycardia with electrical alternans.

Figure 3. Sinus bradycardia with premature atrial contractions.

Figure 4. Atrial fibrillation with premature ventricular contractions.

Figure 5. Sinus bradycardia. A “slurred upstroke” of the QRS, or delta wave, suggests Wolff-Parkinson-White syndrome. This finding is associated with paroxysmal atrial tachycardia and other supraventricular arrhythmias. ciated symptoms may be helpful for the of the patient after he or she may physician in diagnosis. For example, a patient reveal an arrhythmia or murmur that is who describes single “skipped” beats is likely exacerbated by the resulting increased heart to be having benign premature ventricular rate and cardiac output. contractions. The physician should consider the differential diagnoses of palpitations ECG EVALUATION (Table 1) while questioning the patient. Cer- A 12-lead ECG evaluation is appropriate in tain clinical findings and possible associated all patients who complain of palpitations. conditions are listed in Table 2. In the event that the patient is experienc- Because physicians usually do not get ing palpitations at the time of the ECG, the the chance to examine the patient dur- physician may be able to confirm the diag- ing an episode of palpitations, the physical nosis of arrhythmia. Many ECG findings examination primarily serves to determine warrant further cardiac investigation. These if there are cardiac or other abnormalities findings include evidence of previous myo- present that might predispose the patient cardial infarction, left or right ventricular to palpitations. Careful examination of the hypertrophy, atrial enlargement, atrial ven- heart may reveal murmurs, extra sounds, or tricular block, short PR interval and delta cardiac enlargement. Mitral valve prolapse, waves (Wolff-Parkinson-White syndrome), which is commonly associated with palpita- or prolonged QT interval. Occasionally, the tions, is suggested by a midsystolic click.16 finding of an isolated premature ventricular The physician should look for evidence of contraction or premature atrial contrac- hyperthyroidism (e.g., nervousness, heat tion warrants further monitoring or exercise intolerance), drug use, or other serious ill- testing. Some common arrhythmias associ- nesses. Finally, in the occasional patient who ated with palpitations are shown in Figures has palpitations with exercise, examination 2 through 5.

February 15, 2005 ◆ Volume 71, Number 4 www.aafp.org/afp American Family Physician 747 ECG exercise testing is appropriate in patients who have palpitations with physical exertion and patients with suspected Further Diagnostic Testing nary disease or myocardial . or In patients at low risk for coro- Findings from the physical examination or myocardial ischemia. nary heart disease who have no ECG may suggest the need for echocardiog- palpitation-associated symp- raphy to evaluate structural abnormalities toms such as dizziness, and who and ventricular function. have negative physical examination and ECG High-risk patients, who require ECG findings, palpitations may need no further monitoring, include those with organic evaluation unless the episodes persist or the heart disease or any heart abnormality that patient remains anxious for an explanation. could predispose the patient to arrhythmias. Blood tests may be appropriate in the fol- Patients with a family history of arrhyth- lowing conditions: complete blood cell count mia, syncope, or sudden death also may be for suspected anemia or , electro- at higher risk. The results of one study17 of lytes for arrhythmia from suspected elec- 24-hour ECG monitoring showed that ven- trolyte imbalance, and -stimulating tricular tachycardia was associated with hormone for suspected hyperthyroidism or previous , idiopathic hypothyroidism. dilated cardiomyopathy, significant valvular ECG exercise testing is appropriate in lesions, and hypertrophic . patients who have palpitations with physical If the etiology of palpitations is not appar- exertion and patients with suspected coro- ent after the history, physical examination,

Evaluating a Patient with Palpitations

Patient presents with complaints of palpitations

Take history, perform physical examination, obtain ECG Evidence of

Extracardiac cause No structural heart disease diagnosed Obtain , or event or Holter monitoring Obtain complete blood cell count, chemistry profile, and Treat drug use, thyroid-stimulating hormone level; screen for drug use if Treat etiology or hyperthyroidism, etc. appropriate appropriately refer to cardiologist

Daily palpitations Palpitations are less than daily

Begin transtelephonic event Begin transtelephonic monitoring or continuous event monitoring ambulatory monitoring (Holter) for two weeks

Palpitations during Nonventricular Ventricular normal sinus rhythm arrhythmia arrhythmia

Reassure patient, Treat arrhythmia Refer for electrophysiologic consider panic disorder or refer to cardiologist evaluation and treatment

Figure 6. Algorithm for evaluating patients with palpitations. (ECG = electrocardiography)

748 American Family Physician www.aafp.org/afp Volume 71, Number 4 ◆ February 15, 2005 Palpitations

and ECG are completed, the physician should Evidence supports the use of an initial consider ambulatory cardiac monitoring. two-week course of continuous closed-loop Figure 6 is an algorithm that can be used in event recording to monitor for palpitations. the evaluation of patients with palpitations. Holter monitoring for 24 hours is an alter- native to event monitoring in patients who CONTINUOUS ECG MONITORS reliably experience palpitations every day, or The is a simple ECG moni- who are not willing to wear an event moni- toring device that is worn continuously to tor for two weeks, and if event monitoring is record data for 24 or 48 hours. The patient not available locally. When palpitations are must keep a diary of any symptoms that sustained or poorly tolerated, a referral to a occur during the monitoring.17 Holter moni- cardiologist for an electrophysiologic evalu- tors typically are the most expensive of the ation may be warranted.21 monitoring devices, and are maintained and operated by hospitals or larger outpatient Management clinics. In patients with arrhythmias, the most com- mon finding on ambulatory monitoring is TRANSTELEPHONIC EVENT MONITORS benign atrial or ventricular ectopic beats Transtelephonic event monitors transmit associated with normal sinus rhythm.20-22 recordings by telephone to a central sta- Normal sinus rhythm alone is found in tion. As with Holter monitors, patients wear about one third of patients. Many patients continuous-loop event monitors, but unlike with palpitations have ventricular prema- Holter monitors, these save data only for the ture contractions or brief episodes of ven- previous and subsequent few minutes when tricular tachycardia; if the evaluation of the the patient manually activates the monitor. heart is otherwise normal, these findings are These monitors are smaller than a Holter not associated with increased mortality.23 monitor (i.e., the size of a beeper) and may Appropriate patient education is indicated miss arrhythmias that are asymptomatic, in these patients. The treatment of sus- or that occur during sleep or with syncope. tained arrhythmias involves pharmacologic Another type of transtelephonic monitor is or invasive electrophysiologic management not worn continuously but is carried by the and is beyond the scope of this article. patient and held to the chest when palpita- If the patient is diagnosed with a non- tions are perceived. This monitor records cardiac, psychiatric, or nonarrhythmia car- ECG data for about two minutes and is likely diac etiology, the underlying condition is to miss the onset of arrhythmia. managed according to the diagnosis. In some patients, a thorough history, physical Choosing an Ambulatory examination, diagnostic testing, and cardiac Monitoring Device monitoring all fail to reveal any abnormality The results of a review18 of studies comparing or etiology for palpitations. These patients Holter monitors and transtelephonic event should be advised to abstain from caffeine monitors in the diagnosis of palpitations and alcohol, as well as foods or stressful found that the diagnostic yield was 66 to situations that appear to trigger palpitations. 83 percent when event monitors were used Fortunately, the majority of patients with for monitoring, and 33 to 35 percent when palpitations have benign diagnoses and can Holter monitors were used. Furthermore, be treated with reassurance. event monitors have been found to be sig- The author indicates that he does not have any conflicts nificantly more cost effective than Holter of interest. Sources of funding: none reported. monitors.19,20 The results of retrospective and 19,20 Figures 2 through 5 used with permission from Allan V. prospective trials showed that 83 to 87 Abbott, M.D. percent of patients had diagnostic transmis- This article is one in a series on problem-oriented diagno- sions within the first two weeks of using a sis coordinated by the Department of Family Medicine at transtelephonic event monitor. the University of Southern California, Los Angeles, Calif.

February 15, 2005 ◆ Volume 71, Number 4 www.aafp.org/afp American Family Physician 749 Palpitations

14. Coumel P. Clinical approach to paroxysmal atrial fibrilla- REFERENCES tion. Clin Cardiol 1990;13:209-12. 1. Weber BE, Kapoor WN. Evaluation and outcomes of 15. Shekelle PG, Hardy ML, Morton SC, Maglione M, Mojica patients with palpitations. Am J Med 1996;100:138-48. WA, Suttorp MJ, et al. Efficacy and safety of ephedra and ephedrine for weight loss and athletic performance: 2. Knudson MP. The natural history of palpitations in a a meta-analysis. JAMA 2003;289:1537-45. family practice. J Fam Pract 1987;24:357-60. 16. Duren DR, Becker AE, Dunning AJ. Long-term follow- 3. Barsky AJ. Palpitations, arrhythmias, and awareness of up of idiopathic mitral valve prolapse in 300 patients: a cardiac activity. Ann Intern Med 2001;134(9 pt 2):832-7. prospective study. J Am Coll Cardiol 1988;11:42-7. 4. Ali YS, Daamen N, Jacob G, Jordan J, Shannon JR, 17. Wolfe RR, Driscoll DJ, Gersony WM, Hayes CJ, Keane JF, Biaggioni I, et al. Orthostatic intolerance: a disorder of Kidd L, et al. Arrhythmias in patients with valvar aortic young women. Obstet Gynecol Surv 2000;55:251-9. stenosis, valvar pulmonary stenosis, and ventricular 5. Chignon JM, Lepine JP, Ades J. Panic disorder in cardiac septal defect. Results of 24-hour ECG monitoring. Cir- outpatients. Am J Psychiatry 1993;150:780-5. culation 1993;87(2 suppl):I89-101. 6. Barsky AJ, Cleary PD, Coeytaux RR, Ruskin JN. Psychi- 18. Zimetbaum PJ, Josephson ME. The evolving role of atric disorders in medical outpatients complaining of ambulatory monitoring in general clinical practice. Ann palpitations. J Gen Intern Med 1994;9:306-13. Intern Med 1999;130:848-56. 7. Jeejeebhoy FM, Dorian P, Newman DM. Panic disorder 19. Fogel RI, Evans JJ, Prystowsky EN. Utility and cost of and the heart: a perspective. J Psychosom event recorders in the diagnosis of palpitations, presyn- Res 2000;48:393-403. cope, and syncope. Am J Cardiol 1997;79:207-8. 8. Barsky AJ, Ahern DK, Bailey ED, Delamater BA. Predic- 20. Kinlay S, Leitch JW, Neil A, Chapman BL, Hardy DB, tors of persistent palpitations and continued medical Fletcher PJ, et al. Cardiac event recorders yield more utilization. J Fam Pract 1996;42:465-72. diagnoses and are more cost-effective than 48-hour 9. Barsky AJ, Ahern DK, Delamater BA, Clancy SA, Bailey Holter monitoring in patients with palpitations. A ED. Differential diagnosis of palpitations. Preliminary controlled clinical trial. Ann Intern Med 1996;124(1 pt development of a screening instrument. Arch Fam Med 1):16-20. 1997;6:241-5. 21. Zimetbaum PJ, Kim KY, Josephson ME, Goldberger 10. Ballenger JC. Treatment of panic disorder in the general AL, Cohel DJ. Diagnostic yield and optimal duration of medical setting. J Psychosom Res 1998;44:5-15. continuous-loop event monitoring for the diagnosis of 11. Barsky AJ, Cleary PD, Coeytaux RR, Ruskin JN. The clini- palpitations. A cost-effectiveness analysis. Ann Intern cal course of palpitations in medical outpatients. Arch Med 1998;128:890-5. Intern Med 1995;155:1782-8. 22. Zimetbaum PJ, Kim KY, Ho KK, Zebede J, Josephson 12. Zimetbaum P, Josephson ME. Evaluation of patients ME, Goldberger AL. Utility of patient-activated cardiac with palpitations. N Engl J Med 1998;338:1369-73. event recorders in general clinical practice. Am J Cardiol 13. Lessmeier TJ, Gamperling D, Johnson-Liddon V, Fromm 1997;79:371-2. BS, Steinman RT, Meissner MD, et al. Unrecognized 23. Kennedy HL, Whitlock JA, Sprague MK, Kennedy LJ, paroxysmal supraventricular tachycardia. Potential Buckingham TA, Goldberg RJ. Long-term follow-up of for misdiagnosis as panic disorder. Arch Intern Med asymptomatic healthy subjects with frequent and com- 1997;157:537-43. plex ventricular ectopy. N Engl J Med 1985;312:193-7.

750 American Family Physician www.aafp.org/afp Volume 71, Number 4 ◆ February 15, 2005