Inclusion criteria, setting, procedures, and ethics

To cover essential aspects of the heterogeneous disease HCM we predefined the following maximum variation sampling variables: sex, age, time since diagnosis, primary/secondary indication of ICD, and a history of appropriate or inappropriate shock (Table ​(Table1).1). All patients, aged ≥18 years with at least 2 years history of a transvenous ICD due to HCM, were identified from the Swedish ICD Registry which has a complete coverage of all implants [15]. Patients with a postal address in the Region Gävleborg or Umeå University hospital and their affiliated hospitals were recruited.

Characteristics of 26 interviewed HCM patients with history of ICD

M Male, F Female, NYHA New York Heart Association, ICD Implantable cardioverter defibrillator, HCM Hypertrophic cardiomyopathy

ICD duration refers to time (years) with an ICD and Diagnosis time (years) since first known diagnosis of HCM

^aheart transplant due to NYHA IV, at the time of interview NYHA I

Medical data were validated using medical records (PM, SM). The patients were contacted by phone by the investigators (PM or SM) and scheduled for an appointment with the interviewer (JJ). All patients came to the appointment, consented, and were subsequently interviewed (sample size, n = 26) between February and June 2015 either at the research department, outpatient clinic, or at home. The study was approved by the Regional Ethical committee in Uppsala (Dnr 2015/060). References to patients’ identities have been omitted due to confidentiality.