We describe the case of a patient with ventricular pre-excitation who underwent dobutamine
stress echocardiography to evaluate atypical chest pain. The patient safely underwent the
procedure with interesting electrocardiographic findings during pharmacological stress. The
risks of dobutamine stress testing, along with possible explanations of this observed event, are
discussed. In conclusion, the safety of dobutamine stress testing in patients with ventricular
pre-excitation has not been established; further prospective studies are needed to decide whether
dobutamine stress testing is safe in certain subsets of this population. (Cardiol J 2011; 18, 4:
437&#8211;440

Birnbaum, Yochai

Ware, David L.

Yamani, Hussein N.

English

Via Medica Journals

www.cardiologyjournal.org 437CASE REPORTCardiology Journal2011, Vol. 18, No. 4, pp. 437–440Copyright © 2011 Via MedicaISSN 1897–5593Address for correspondence: Dr. Hussein N. Yamani, The University of Utah Health Sciences Center, Cardiology Division,30 North 1900 East, Salt Lake City, Utah 84132–2401, USA, tel: 801 585 1686, fax: 801 581 7735,e-mail: h.yamani@alumni.utexas.netReceived: 16.02.2010 Accepted: 27.04.2010Dobutamine stress echocardiography ina patient with Wolff-Parkinson-White syndromeHussein N. Yamani1, David L. Ware1, Yochai Birnbaum21Division of Cardiology, The University of Texas Medical Branch, Galveston, Texas, USA2Section of Cardiology, Baylor College of Medicine, Houston, Texas, USAAbstractWe describe the case of a patient with ventricular pre-excitation who underwent dobutaminestress echocardiography to evaluate atypical chest pain. The patient safely underwent theprocedure with interesting electrocardiographic findings during pharmacological stress. Therisks of dobutamine stress testing, along with possible explanations of this observed event, arediscussed. In conclusion, the safety of dobutamine stress testing in patients with ventricularpre-excitation has not been established; further prospective studies are needed to decide whetherdobutamine stress testing is safe in certain subsets of this population. (Cardiol J 2011; 18, 4:437–440)Key words: dobutamine, stress test, pre-excitationIntroductionExercise stress testing may provide some in-sight into the physiological behavior of the acces-sory pathway in patients with Wolff-Parkinson--White (WPW) syndrome and it may estimate theirrisk of sudden arrhythmic death, as abrupt (i.e. notgradual) loss of pre-excitation may indicate that theaccessory pathway could not conduct rapidly dur-ing atrial fibrillation (AF) [1]. However, the role ofpharmacological stress testing, specifically with do-butamine, in arrhythmic risk stratification of pa-tients with WPW, has not been described, nor hasthe risk for developing an arrhythmia during suchtesting been fully ascertained. A small study sug-gested that dobutamine can facilitate anterogradeaccessory pathway conduction, which could in-crease the risk of ventricular fibrillation in patientsduring testing if they were to go into AF [2]. A pa-tient with ventricular pre-excitation who underwentdobutamine stress echocardiography (DSE) at ourinstitution for evaluation of atypical chest pain hasprovided an opportunity to discuss the risks of do-butamine stress testing and whether the test mightpredict sudden death in individuals with WPW.Theoretically, inducing tachyarrhythmia by dobu-tamine infusion could potentially be used for riskstratification of asymptomatic patients with WPW.However, it is unclear whether disappearance of thepre-excitation delta wave during dobutamine infu-sion carries the same prognostic significance aswhen it occurs during exercise test. This importantquestion should be further investigated in a pro-spective study.Case reportA 44 year-old African American man with hy-pertension, hyperlipidemia, prior alcohol abuse, anda questionable previous myocardial infarction wasreferred to our institution for further evoluation ofchest pain. He stated that the ‘knife-like’ pain be-gan in the sub-xyphoid area and then moved aroundhis chest, and that it was associated with shortness438Cardiology Journal 2011, Vol. 18, No. 4www.cardiologyjournal.orgof breath and arm numbness. Cardiac biomarkerswere normal and his electrocardiogram (ECG)showed sinus rhythm with abnormal ST-T wavechanges. Given the atypical features of his historyand the ST-T wave changes, the managing teamelected to perform non-invasive testing. As it wasfelt that the patient may not be able to achieve histarget heart rate with treadmill exercise, DSE wasordered. This is preferred to adenosine or dipyrida-mole radionuclinde pharmacological stress testing atour institution. At baseline, the patient was in sinusbradycardia (52 bpm) with obvious pre-excitationand ST-T wave abnormalities, due at least in partto his abnormal (pre-excited) depolarization se-quence (Fig. 1). With dobutamine infusion, the pa-tient achieved a heart rate of 150 bpm and deve-loped premature ventricular contractions with 1 mmST depression in II, AVF, V5, and V6. Delta wavesgradually became smaller but were still present(Fig. 2). In recovery (Fig. 3), with a heart rate of81 bpm, the delta waves returned to their baselineappearance, but non-diagnostic changes in the ST-Twaves persisted. Transthoracic echocardiographyrevealed normal left ventricular size and functionat rest and no regional wall motion abnormalitiesduring dobutamine stress. The left ventricular ejec-tion fraction increased from 55 to > 70%, with nearcavity obliteration and hyperdynamic contractility.Figure 2. Peak stress ECG (note less obvious pre-excitation).Figure 1. Baseline ECG prior to dobutamine stress echocardiography.439Hussein N. Yamani et al., Dobutamine stress testing in WPW patientswww.cardiologyjournal.orgDuring his hospitalization, the patient mentionedthat in addition to chest pain, he previously hadepisodes of near-syncope and possible syncope. Hewas therefore referred to the ElectrophysiologyService, and underwent successful accessory path-way ablation. After discharge, the patient was seenin the cardiology clinic about two months later. Hereported some chest pain symptoms, but denied anysyncopal episodes. There was sufficient concern toadmit the patient for further evaluation. However,the patient did not want to be admitted at that time.DiscussionVentricular pre-excitation (short PR-intervalwith delta waves) occurs when one or more acces-sory pathways enable conduction from the atriumto the ventricle to bypass the atrio-ventricular (AV)node and activate a portion of the ventricle prema-turely, widening and distorting the QRS complex.The delta waves become larger as the amount ofpre-excited tissue increases. Patients with WPWsyndrome have both ventricular pre-excitation andarrhythmias, which may be AF, AV re-entry, orboth. Patients with the WPW pattern have charac-teristic ECG findings of pre-excitation but no sub-jective or objective evidence of arrhythmia. TheWPW pattern may occur intermittently and evendisappear over time [3–5].Although the mechanism is not entirely under-stood, ventricular pre-excitation is associated witha higher incidence of AF [6]. A minority of indivi-duals with both pre-excitation and AF are at somerisk of sudden arrhythmic death, if during AF thephysiological properties of the accessory pathwayallow it to conduct from the atrium to the ventricleso rapidly that ventricular fibrillation occurs. Atrialfibrillation will present as an irregular, wide com-plex tachycardia (each QRS usually with varyingdegrees of pre-excitation) at exceedingly fast rates.In this setting, the shortest interval from one pre-excited QRS to another may be used to estimatethe risk of sudden death [7].The degree of pre-excitation may also changewith exercise stress testing. Mulpuru et al. [8]described a patient with a WPW pattern withparadoxical septal wall motion on baselineechocardiography that disappeared along with thedelta wave during peak exercise on treadmill;both reappeared on recovery. Such a sudden dis-appearance of pre-excitation during exercise mayindicate poor atrial to ventricular conduction viathe accessory pathway, and so be associated witha lower risk of sudden death.Plain treadmill exercise stress test for assess-ment of ischemia is contraindicated in patients withWPW pattern, as baseline repolarization changespreclude accurate assessment of ischemia [9]. Thus,these patients should undergo stress test with non--invasive imaging (echocardiographic or radionu-clide). The treating team felt that the patient maynot be able to achieve the target heart rate duringtreadmill exercise stress test, and ordered a DSE.Recently, a concern was raised that radionuclidestress tests are associated with high exposure toradiation [10, 11]. Therefore, echocardiographicimaging is usually preferred over radionuclide testsin our institution.Figure 3. ECG on recovery with baseline appearance of delta waves.440Cardiology Journal 2011, Vol. 18, No. 4www.cardiologyjournal.orgDobutamine is a synthetic b-1 selective cate-cholamine that increases heart rate, myocardialcontractility, and systolic blood pressure. It is in-dicated when patients needing non-invasive stressimaging cannot tolerate (or have contraindicationsto) other testing modalities including adenosine ordipyridamole. Dobutamine has been known tocause arrhythmias during pharmacological stresstesting such as: premature atrial and ventricularcontractions, atrial fibrillation and flutter, su-praventricular tachycardias, junctional rhythms,non-sustained ventricular tachycardia and rate-related left or right bundle branch blocks [12, 13].The safety of dobutamine stress testing, and itsvalue in assessing the risk of sudden death in pa-tients with pre-excitation, have not been thorough-ly investigated. However, Molenda et al. [2] stud-ied 15 patients with intermittent ventricular pre-excitation and found that dobutamine significantlyshortened the refractory periods, improved acces-sory pathway conduction, and increased the inci-dence of arrhythmias.In our patient, the extent of pre-excitation less-ened with dobutamine, but the delta waves did notcompletely disappear. This was probably, at least inpart, because dobutamine facilitated AV nodal con-duction and increased the amount of ventricular tis-sue activated in the normal (His-Purkinje) fashion,relative to the amount of tissue activated via the ac-cessory pathway. Theoretically however, the acce-lerated sinus rate may be approaching the refractoryperiod of the accessory pathway, thus revealing someintrinsic property of the latter. If a rate of 150 bpm isbeginning to cause conduction block in the pathway,then the pathway would probably not conduct rapid-ly during AF. (The reader is reminded that these pos-sible scenarios do not take into account the electro-physiology of atrial tissue between the sinus nodeand the accessory pathway, which can also affect thedegree of pre-excitation.)Whether pharmacological stress testing withdobutamine is safe in patients with WPW syndromehas not been established. The sudden loss of pre-excitation during dobutamine stress testing may nothave the same prognostic implications as it doeswhen it occurs during exercise stress testing,where it has been associated with a lower risk ofsudden death. Given the arrhythmic complicationsattributed to dobutamine, exercise stress testingwith either echocardiographic or radionuclide ima-ging would, if possible, be the preferred option fornon-invasive cardiac evaluation in these patients.However, exercise may also induce arrhythmia.It has not been studied whether the risk of arrhyth-mia for patients with WPW is greater with dobu-tamine than with exercise. During exercise stresstesting, information regarding the patient’s func-tional capacity would be obtained. This is somethingthat in itself has prognostic implications, in additionto assessment of perfusion or regional function.AcknowledgementsThe authors do not report any conflict of inte-rest regarding this work.References1. Jezior MR, Kent SM, Atwood JE. Exercise testing in Wolff-Par-kinson-White syndrome: Case report with ECG and literaturereview. Chest, 2005; 127: 1454–1457.2. Molenda W, Telichowski C, Petruk J et al. Effect of stimulationof adrenergic beta receptors on electrophysiologic properties ofthe bundle of Kent in patients with intermittent Wolff-Parkin-son-White syndrome. Kardiol Pol, 1989; 32: 311–318.3. Krahn AU, Manfreda J, Tate RB, Mathewson FA, Cuddy TE. Thenatural history of electrocardiographic preexcitation in men. TheManitoba Follow-up Study. Ann Intern Med, 1992; 116: 456–460.4. Munger TM, Packer DL, Hammill SC et al. A population studyof the natural history of Wolff-Parkinson-White syndrome in Ol-mstead County, Minnesota, 1953–1989. Circulation, 1993; 87:866–873.5. Klein GJ, Yee R, Sharma AD. Longitudinal electrophysiologicalassessment of asymptomatic patients with the Wolf-Parkinson--White electrocardiographic pattern. New Engl J Med, 1989; 320:1229–1233.6. Centurion OA, Shimizu A, Isomoto S, Konoe A. Mechanisms forthe genesis of paroxysmal atrial fibrillation in the Wolff-Parkin-son-White syndrome: Intrinsic atrial muscle vulnerability vs.electrophysiological properties of the accessory pathway. Eu-ropace, 2008; 10: 294–302.7. Sharma AD, Yee R, Guiraudon G, Klein GJ. Sensitivity and spe-cificity of invasive and noninvasive testing for risk of suddendeath in Wolff-Parkinson-White syndrome. J Am Coll Cardiol,1987; 10: 373–381.8. Mulpuru SK, Vasavada BC, Hejmadi PS, Sahni G. Unique wallmotion abnormalities on stress echocardiogram associated withWolff-Parkinson-White pattern electrocardiogram: A case re-port. Int J Cardiol, 2007; 119: E68–E70.9. Gibbons RJ, Balady GJ, Bricker JT et al. American College ofCardiology/American Heart Association Task Force on PracticeGuidelines. Committee to Update the 1997 Exercise TestingGuidelines. ACC/AHA 2002 guideline update for exercise test-ing: Summary article. A report of the American College of Cardio-logy/American Heart Association Task Force on Practice Guide-lines (Committee to Update the 1997 Exercise Testing Guide-lines). J Am Coll Cardiol, 2002; 40: 1531–1540.10. Fazel R, Krumholz HM, Wang Y et al. Exposure to low-doseionizing radiation from medical imaging procedures. N Engl JMed, 2009; 361: 849–857.11. Bedetti G, Pizzi C, Gavaruzzi G et al. Suboptimal awareness ofradiologic dose among patients undergoing cardiac stress scin-tigraphy. J Am Coll Radiol, 2008; 5: 126–131.12. Mertes H, Sawada SG, Ryan T et al. Symptoms, adverse effects,and complications associated with dobutamine stress echocardio-graphy. Experience in 1118 patients. Circulation, 1993; 88: 15–19.13. Mathias W, Arruda A, Santos FC et al. Safety of dobutamine-atropine stress echocardiography: A prospective experience of4,033 consecutive studies. J Am Soc Echocardiogr, 1999; 12:785–791.

Dobutamine stress echocardiography in a patient with Wolff-Parkinson-White syndrome

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Dobutamine stress echocardiography in a patient with Wolff-Parkinson-White syndrome

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