title: Electrogram guidance: a method to increase the precision and diagnostic yield of endomyocardial biopsy for suspected cardiac sarcoidosis and myocarditis.
abstract: OBJECTIVE
  The aim of this study was to describe the method used to perform electrogram-guided EMB and correlate electrogram characteristics with pathological and clinical outcomes.
  
  
  BACKGROUND
  Endomyocardial biopsy (EMB) is valuable in determining the underlying etiology of a cardiomyopathy. The sensitivity, however, for focal disorders, such as lymphocytic myocarditis and cardiac sarcoidosis (CS), is low. The sensitivity of routine fluoroscopically guided EMB is low. Abnormal intracardiac electrograms are seen at sites of myocardial disease. However, the exact value of electrogram-guided EMB is unknown.
  
  
  METHODS
  We report 11 patients who underwent electrogram-guided EMB for evaluation of myocarditis and CS.
  
  
  RESULTS
  Of 40 total biopsy specimens taken from 11 patients, 19 had electrogram voltage <5 mV, all of which resulted in histopathologic abnormality (100% specificity and positive predictive value). A voltage amplitude cutoff value of 5 mV had substantially higher sensitivity (70% vs. 26%) and negative predictive value (62%) than 1.5 mV. Abnormal electrogram appearance at biopsy site had good sensitivity (67%) and specificity (92%) in predicting abnormal myocardium. Normal signals with voltage >5 mV signified normal myocardium with no significant diagnostic yield. Biopsy results guided therapy in all patients, including 5 with active myocarditis or CS, all of whom subsequently received immunosuppressive therapy. There were no procedural complications.
  
  
  CONCLUSIONS
  In patients with suspected myocarditis or CS, electrogram-guided EMB targeting sites with abnormal or low-amplitude electrograms may increase the diagnostic yield for detecting abnormal pathological findings.
authors.affiliation: Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota.
authors.forename: Jackson J
authors.initials: JJ
authors.lastname: Liang
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
authors.forename: Virginia B
authors.initials: VB
authors.lastname: Hebl
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
authors.forename: Christopher V
authors.initials: CV
authors.lastname: DeSimone
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
authors.forename: Malini
authors.initials: M
authors.lastname: Madhavan
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
authors.forename: Sudip
authors.initials: S
authors.lastname: Nanda
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
authors.forename: Suraj
authors.initials: S
authors.lastname: Kapa
authors.affiliation: Division of Anatomic Pathology, Mayo Clinic, Rochester, Minnesota.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Maleszewski
authors.affiliation: Division of Anatomic Pathology, Mayo Clinic, Rochester, Minnesota.
authors.forename: William D
authors.initials: WD
authors.lastname: Edwards
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
authors.forename: Guy
authors.initials: G
authors.lastname: Reeder
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
authors.forename: Leslie T
authors.initials: LT
authors.lastname: Cooper
authors.affiliation: Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota; Department of Pediatrics and Adolescent Medicine Mayo Clinic, Rochester, Minnesota. Electronic address: asirvatham.samuel@mayo.edu.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Asirvatham
mesh_terms: D000293:Adolescent; D000328:Adult; D001706:Biopsy / Q000379:methods*; D009202:Cardiomyopathies / Q000175:diagnosis* / Q000473:pathology; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009205:Myocarditis / Q000175:diagnosis* / Q000473:pathology; D012507:Sarcoidosis / Q000175:diagnosis* / Q000473:pathology; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: cardiac sarcoidosis; cardiomyopathy; electrogram; endomyocardial biopsy; myocarditis