title: Myocardial ultrasound tissue characterization in patients with hypertrophic cardiomyopathy: noninvasive evidence of electrical and textural substrate for ventricular arrhythmias.
abstract: BACKGROUND
  Although in patients with hypertrophic cardiomyopathy (HCM) pathologic studies seem to suggest a correlation between morphologic findings and arrhythmias, it has never been confirmed in the clinical setting.
  
  
  OBJECTIVE
  We sought to noninvasively assess the electrical and textural properties of the myocardium and to define their potential relationship in patients with HCM.
  
  
  METHODS
  We studied 48 patients: 22 with HCM (mean age: 22 +/- 5.1 years) and 26 age- and body surface area-matched healthy patients. They underwent a standard echocardiographic examination to assess left ventricular size and thickness. In addition, by integrated backscatter analysis, we assessed textural properties of left ventricular myocardium with calibrated averaged intensity (IB) and to assess functional properties of the myocardium with cyclic variation, both at the interventricular septum (IVS) and posterior wall. Finally, we studied ventricular late potentials (VLPs) by signal-averaged electrocardiography and performed a 24-hour electrocardiography Holter monitoring to respectively define electrical instability and ventricular arrhythmias.
  
  
  RESULTS
  Compared with control patients, patients with HCM had, both at IVS and posterior wall, increased IB (-28.8 +/- 10 vs -35 +/- 4 dB [P =.007] and -29 +/- 8 vs -33 +/- 5 dB [P <.035], respectively) and decreased cyclic variation (6.8 +/- 2.7 vs 10.3 +/- 2.3 dB [P <.001] and 8.2 +/- 2.9 vs 11.4 +/- 2.1 dB [P <.001], respectively). In all, 5 patients with HCM had positivity of VLPs, and 4 of them showed nonsustained ventricular tachycardia (nsVT) on the Holter monitoring. Compared with patients who had HCM without VLPs and nsVT, patients with positivity of VLPs and nsVT showed higher IB both at IVS (-15.8 +/- 8.4 vs -32.6 +/- 5.9 dB [P <.001] and -16.6 +/- 9.5 vs -31.5 +/- 7.5 dB [P =.002], respectively) and at posterior wall (-19.08 +/- 8.42 vs -32.5 +/- 4.2 dB [P <.001] and -22.4 +/- 4.6 vs -31 +/- 7.5 [P =.04], respectively). A multivariate analysis showed IB at IVS (P =.042; odds ratio = 1.19) and positivity of VLPs (P =.026; odds ratio = 3.67) as independent predictors of nsVT.
  
  
  CONCLUSIONS
  Patients with HCM showed abnormal morphologic and electrical properties of the myocardium. The correlation between VLPs and IB at IVS and their relationship with nsVT suggests a link between textural and electrical nonhomogeneity of myocardial fibers, a potential substrate of nsVT in patients with HCM.
authors.affiliation: Cattedra di Cardiologia Pediatrica, Seconda Università, A.O. Monaldi, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Limongelli
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pacileo
authors.forename: Fabiana
authors.initials: F
authors.lastname: Cerrato
authors.forename: Marina
authors.initials: M
authors.lastname: Verrengia
authors.forename: Andrea
authors.initials: A
authors.lastname: Di Simone
authors.forename: Sergio
authors.initials: S
authors.lastname: Severino
authors.forename: Berardo
authors.initials: B
authors.lastname: Sarubbi
authors.forename: Raffaele
authors.initials: R
authors.lastname: Calabrò
mesh_terms: D000293:Adolescent; D000328:Adult; D001145:Arrhythmias, Cardiac / Q000145:classification / Q000000981:diagnostic imaging / Q000453:epidemiology; D002312:Cardiomyopathy, Hypertrophic / Q000145:classification* / Q000000981:diagnostic imaging* / Q000453:epidemiology; D004452:Echocardiography; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000000981:diagnostic imaging / Q000473:pathology; D006352:Heart Ventricles / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D007558:Italy; D008297:Male; D015999:Multivariate Analysis; D009206:Myocardium / Q000473:pathology* / Q000648:ultrastructure*; D015588:Observer Variation; D011237:Predictive Value of Tests; D013223:Statistics as Topic