title: Effectiveness of subcutaneous implantable cardioverter-defibrillator testing in patients with hypertrophic cardiomyopathy.
abstract: BACKGROUND
  Subcutaneous ICD (S-ICD) is a promising option for Hypertrophic Cardiomyopathy (HCM) patients at risk of Sudden Cardiac Death (SCD). However, its effectiveness in terminating ventricular arrhythmias in HCM is yet unresolved.
  
  
  METHODS
  Consecutive HCM patients referred for S-ICD implantation were prospectively enrolled. Patients underwent one or two attempts of VF induction by the programmer. Successful conversion was defined as any 65J shock that terminated VF (not requiring rescue shocks). Clinical and instrumental parameters were analyzed to study predictors of conversion failure.
  
  
  RESULTS
  Fifty HCM patients (34 males, 40±16years) with a mean BMI of 25.2±4.4kg/m2 were evaluated. Mean ESC SCD risk of was 6.5±3.9% and maximal LV wall thickness (LVMWT) was 26±6mm. In 2/50 patients no arrhythmias were inducible, while in 7 (14%) only sustained ventricular tachycardia was induced and cardioverted. In the remaining 41 (82%) patients, 73 VF episodes were induced (1 episode in 14 and >1 in 27 patients). Of these, 4 (6%) spontaneously converted. In 68/69 (98%) the S-ICD successfully cardioverted, but failed in 1 (2%) patient, who needed rescue defibrillation. This patient was severely obese (BMI 36) and LVMWT of 25mm. VF was re-induced and successfully converted by the 80J reversed polarity S-ICD.
  
  
  CONCLUSIONS
  Acute DT at 65J at the implant showed the effectiveness of S-ICD in the recognition and termination of VT/VF in all HCM patients except one. Extreme LVH did not affect the performance of the device, whereas severe obesity was likely responsible for the single 65J failure.
authors.affiliation: Referral Center for Cardiomyopathies, Univ Hosp of Careggi, Florence, Italy; Fondazione ARCARD, Florence, Italy. Electronic address: niccolo.maurizi@gmail.com.
authors.forename: Niccoló
authors.initials: N
authors.lastname: Maurizi
authors.affiliation: Referral Center for Cardiomyopathies, Univ Hosp of Careggi, Florence, Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Tanini
authors.affiliation: Referral Center for Cardiomyopathies, Univ Hosp of Careggi, Florence, Italy.
authors.forename: Iacopo
authors.initials: I
authors.lastname: Olivotto
authors.affiliation: AO dei Colli Monaldi Hosp, Naples, Italy.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Amendola
authors.affiliation: AO dei Colli Monaldi Hosp, Naples, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Limongelli
authors.affiliation: Advanced Biomedical Science, Federico II Univ Hosp, Naples, Italy.
authors.forename: Maria Angela
authors.initials: MA
authors.lastname: Losi
authors.affiliation: Conegliano General Hosp, Conegliano, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Allocca
authors.affiliation: Istituto Auxologico, Milan, Italy.
authors.forename: Giovanni Battista
authors.initials: GB
authors.lastname: Perego
authors.affiliation: Univ Hosp of Careggi, Florence, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Pieragnoli
authors.affiliation: Univ Hosp of Careggi, Florence, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Ricciardi
authors.affiliation: ASST Papa Giovanni XXIII, Bergamo, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: De Filippo
authors.affiliation: ASST Papa Giovanni XXIII, Bergamo, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Ferrari
authors.affiliation: ASST Papa Giovanni XXIII, Bergamo, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Quarta
authors.affiliation: Univ Hosp Pisa, Pisa, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Viani
authors.affiliation: Advanced Biomedical Science, Federico II Univ Hosp, Naples, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Rapacciuolo
authors.affiliation: Univ Hosp Pisa, Pisa, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Bongiorni
authors.affiliation: Fondazione ARCARD, Florence, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Cecchi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000628:therapy*; D016757:Death, Sudden, Cardiac / Q000209:etiology / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000295:instrumentation*; D004869:Equipment Safety; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014693:Ventricular Fibrillation / Q000150:complications / Q000628:therapy; D055815:Young Adult
keywords: Hypertrophic cardiomyopathy; S-ICD; Sudden death prevention