A 57-year-old man with a history of presumed infarct-related cardiomyopathy, ventricular tachycardia(VT), and implantable cardioverter-defibrillator (ICD)presented with 2 ICD shocks. He was using the bath-room while at work and was shocked by his ICD. Hethen walked out of the bathroom and once again wasshocked, prompting a call to emergency services. Hepresented to the emergency room with normal vitalsigns and without distress; interrogation of his ICD
EARNING OBJECTIVES
To appreciate that, even when coronaryartery disease is present, not all VT is due toischemia or infarction.To understand the benefits of CMR in evalu-ating scar-related VT.To understand the benefits of FDG PET indiagnosing and monitoring cardiacsarcoidosis.
N 2666-0849
m the Department of Cardiology, Allegheny General Hospital, Pittsburgh
ve no relationships relevant to the contents of this paper to disclose.
e authors attest they are in compliance with human studies committe
titutions and Food and Drug Administration guidelines, including patien
it the JACC: Case Reports author instructions page.
nuscript received February 18, 2020; revised manuscript received April 1
revealed appropriately treated episodes of poly-morphic VT (Figure 1).
MEDICAL HISTORY
One year prior to the current presentation, the patientpresented to his local hospital with an episode ofsyncope while driving. In the hospital, the patienthad recurrent ventricular arrythmias on cardiacmonitoring. Work-up at that time had revealed asignificant stenosis in the left anterior descendingartery (LAD), and it was presumed that LAD territoryischemia was responsible for the VT and syncope. Thepatient received 2 drug-eluting stents and was dis-charged on amiodarone and with an external defi-brillator—ejection fraction (EF) was noted to be 35%with an inferior wall motion abnormality onechocardiography.
A few months later, the patient’s echocardiogramrevealed normal chamber size, grade I diastolicdysfunction, and EF of 30% despite revascularizationand medical therapy. Electrocardiography revealed
https://doi.org/10.1016/j.jaccas.2020.04.037
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T-wave inversions in the inferior leads. An ICD wasimplanted, and amiodarone was discontinued toprevent long-term adverse effects.
Three months after implantation, he experiencedan ICD shock but did not seek medical attention.Two months later, he experienced a second shockand presented to his local hospital for evaluation.Device interrogation showed multiple episodes ofnonsustained VT and polymorphic VT, with poly-morphic VT episodes being treated by his device. Itwas presumed that the VT was scar mediated froma prior infarct, with premature ventricular contrac-tions (PVCs) being the trigger based on deviceinterrogation. Electrophysiology study and VTablation was performed, with PVCs in the mid andapical inferoseptum mapped as triggers for poly-morphic VT. The mid inferoseptal PVCs were abla-ted; however, the apical PVCs were not completelyablated, as they were associated with hemody-namically unstable VF; the facility did not havecapability to complete the ablation with hemody-namic support.
Two months after ablation, he had recurrent VTand ventricular fibrillation and once again presentedto his local hospital. Cardiac catheterization wasperformed at that time, which revealed patent LADstents and no significant coronary artery disease. Hewas started on antiarrhythmic therapy with mex-iletine 200 mg 3 times a day but 2 months later pre-sented to our hospital with recurrent ICD shocks forVT and ventricular fibrillation. Notably, the patienthas a family history of sudden cardiac death in hismother when she was in her 60s, as well as in 2 sib-lings who were in their 50s.
FIGURE 1 Device Interrogation
Intracardiac electrocardiogram’s from the patient’s implantable cardiove
ventricular arrhythmias. In this representative example, a premature ven
break the rhythm with antitachycardia pacing. The rhythm eventually se
DIFFERENTIAL DIAGNOSIS
The differential diagnosis for recurrent VTincludes ischemic heart disease, end-stageheart failure, and congenital heart diseaseincluding arrhythmogenic right ventriculardysplasia, hypertrophic cardiomyopathy, andinfiltrative heart disease.
INVESTIGATION
Electrocardiography on most recent presen-tation showed sinus bradycardia with inferiorT-wave inversions (Figure 2). Given therecurrence of VT despite revascularization,
VT ablation, and antiarrhythmic therapy, cardiacmagnetic resonance (CMR) with an ICD protocol wasperformed to investigate for infiltrative disease andscar burden (1).
The CMR showed normal left ventricle size withreduced function and a left ventricular EF of 32%,with mid to distal inferior, inferoseptal, and infero-lateral thinning with akinesis. Late gadoliniumenhancement was performed and was markedlyabnormal, with full-thickness transmural scarextending throughout the inferior, inferoseptal, andinferolateral walls (Figure 3).
Given that the scar location did not correspondto the patient’s treated coronary artery disease,infiltrative disease was suspected, with sarcoidosisbeing high on the differential. A cardiac fluo-rodeoxyglucose (FDG) positron emission tomogra-phy (PET) study was ordered to evaluate forinflammation, and showed increased FDG uptake in
VT =
rter-defibrillator showed multiple examples of premature ventricular contraction–triggered
tricular contraction triggers polymorphic ventricular tachycardia, and there is an attempt to
lf-terminated.
FIGURE 2 Electrocardiography
The patient’s electrocardiography showed sinus bradycardia with inferior T-wave inversions.
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the basal inferior, inferoseptal, and inferolateralwalls. There was also hilar lymph node uptakealong with mid to basal inferior and inferoseptalresting perfusion defects on the rubidium perfusionimages, indicative of scar and inflammation—find-ings consistent with sarcoidosis (Figures 4 to 6).Maximum standardized uptake values were 21.8 inthe inferoseptum and 5.1 in the hilar nodes. Thepatient underwent bronchoscopy with lymph nodebiopsy, which confirmed the diagnosis ofsarcoidosis.
FIGURE 3 Cardiac Magnetic Resonance
The patient’s cardiac magnetic resonance showed thinning of the inferio
indicates scar. Arrows indicate areas of late gadolinium enhancement.
MANAGEMENT
The patient continued on mexiletine in the short termfor VT suppression; meanwhile, the underlying causeof his VT, sarcoidosis, was treated with oralprednisone.
DISCUSSION
Sarcoidosis is a granulomatous disease that can affectany organ. Among patients with sarcoidosis, rates of
r and inferolateral wall. Late gadolinium enhancement in this area
FIGURE 4 Cardiac FDG PET Splash Images
The fluorodeoxyglucose (FDG) positron emission tomography showed a resting perfusion defect in the inferior, inferoseptal, and inferolateral walls, and increased
amount of FDG uptake in the matched area, consistent with sarcoidosis-mediated scar and inflammation.
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cardiac involvement have been reported to be as lowas 5% to as high as 27% in autopsy studies (2,3).
Making the diagnosis of cardiac sarcoidosis ischallenging, but perhaps even more difficult isinitially suspecting cardiac sarcoidosis and knowingwhen to screen for it. The 2014 Heart Rhythm ExpertConsensus Statement on the Diagnosis and Manage-ment of Arrhythmias Associated With CardiacSarcoidosis provides some guidance (4). Based onthat statement, individuals with diagnosed extrac-ardiac sarcoidosis should be screened with at least a12-lead electrocardiogram, a history with emphasis onsyncope and palpitations, and an echocardiogram.More advanced imaging modalities are noted to beappropriate only when those initial tests areabnormal.
The consensus is less clear when there is no priordiagnosis of extracardiac sarcoidosis. This is relevantnot only because there are cases of isolated cardiac
sarcoidosis, but also because even when extracardiacsarcoidosis is present, the initial presentation, asdemonstrated by our case, may still be cardiac (5).Small studies and case series have describedsarcoidosis patients who had an initial presentationof VT (6,7). This is still thought to be rare, leading todiscord among the experts; a majority of the writinggroup for the 2014 Heart Rhythm Society ExpertStatement recommended screening for sarcoidosis inpatients with unexplained monomorphic VT, but itdid not meet the threshold to be included as a formalrecommendation.
Even if that recommendation had been made astandard of care, our patient would have been missedbecause it was assumed that ischemic heart diseasewas the explanation for VT. Nonetheless, severalclues were present that led to the further work-up ofour patient’s VT. Notably, review of echocardiogra-phy from his initial presentation revealed inferior
yglucose uptake in the inferior, inferoseptal, and inferolateral
walls. This is consistent with cardiac sarcoidosis.
FIGURE 6 Fluorodeoxyglucose Positron Emission
Tomography
This also revealed increased fluorodeoxyglucose in the hilar
lymph nodes, consistent with systemic sarcoidosis.
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wall hypokinesis. This should have raised a questionabout his initial syncopal event, as his coronary dis-ease was only significant in the LAD territory, sug-gesting an alternate etiology for the inferior wallhypokinesis. The question could have been raisedagain during his VT ablation when he was found tohave isolated scar in the inferior wall, which wasablated.
The lack of correlation between the location of scarand coronary disease, combined with his incessantpolymorphic VT despite a lack of active ischemia,appropriate revascularization, and antiarrhythmictherapy led to the further work-up of his VT. CMR is auseful modality not only to show the scar location,but also to provide the scar burden, tissue charac-teristics, and a reproducible EF.
Although endomyocardial biopsy is the gold stan-dard for diagnosing cardiac sarcoidosis, and couldhave been considered after our CMR, the patchy na-ture of sarcoidosis gives the test a low sensitivity. Inthe right clinical scenario, FDG-PET imaging has highdiagnostic yield in cardiac sarcoidosis, and can also beused for prognostication. A metanalysis of 7 studieswith a total of 164 patients calculated a pooledsensitivity of 89% and a pooled specificity of 78% (8).When combined with resting perfusion imaging, car-diac PET has the ability to colocalize scar and in-flammatory burden in the myocardium. An importantconsideration before performing cardiac PET forsarcoidosis is to exclude significant coronary arterydisease, prior myocardial infarction, resting ischemia,
or hibernating myocardium. The presence of bothscar and inflammation is considered an adverseprognostic sign associated with a higher risk of deathor VT. FDG-PET can also identify extracardiac sarcoidand in fact, the Heart Rhythm Society criteria preferextracardiac tissue biopsy over endomyocardial bi-opsy because of the safety and higher yield of theformer to confirm the diagnosis. In addition, it ispossible to quantify inflammatory disease activityusing standardized uptake values, and these valuescan be used to monitor response to treatment (9,10).Our patient’s FDG-PET showed not only cardiacinflammation and scar, but also typical hilar lymph-adenopathy, and confirmatory diagnosis was thusmade by lymph node biopsy.
FOLLOW-UP
The patient continued on oral steroids with a gradualtaper toward a maintenance dose. At 3-month follow-up, device interrogation revealed no episodes ofsustained ventricular arrhythmias. A repeat PET scanshowed less inflammation than the initial diagnosticscan, with a maximum cardiac SUV of 8.4 (prior 21.8)and maximum hilar SUV of 2.9 (decreased from 5.1).He will continue on oral steroids and have his doseadjusted based on symptoms and serial PET scanning.
CONCLUSIONS
Sarcoidosis can be a hidden cause of VT, even in pa-tients with coronary artery disease. Presence of scar
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on CMR or resting perfusion imaging may not alwaysrepresent myocardial infarction. An infiltrative pro-cess can be the culprit and the cause of recurrentventricular arrhythmias, and should be suspectedwhenever there is a discrepancy between scar loca-tion and angiographic coronary artery disease.
ADDRESS FOR CORRESPONDENCE: Dr. Jayshiv T.Badlani, Allegheny General Hospital, Department ofCardiology, 320 East North Avenue, 4th Floor SnyderPavilion, Pittsburgh, Pennsylvania 15212. E-mail:[email protected].
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