Introduction: Hypertrophic cardiomyopathy (HCM) is the commonest inherited heart disease. Implantable cardioverter defibrillators (ICDs) are routinely implanted to protect against risk of sudden cardiac death (SCD) in those patients (pts) who meet criteria. Whilst the consequence of not having an ICD when needed is clear, the implantation of cardiac devices is not without short and long-term risks to the patient. We sought to report the ICD complication rate in HCM patients and place them in context with the frequency of appropriate therapies delivered.
Methods: We retrospectively assessed consecutive patients who underwent ICD implantation between July 2016 and October 2018 and were coded as hypertrophic cardiomyopathy in the device database (Mediconnect™). HCM diagnosis was confirmed by reviewing implant referral and procedure notes, with only new device implants included. Complications were described according to timing, with acute considered in the same admission and late being post-discharge.
Results: Between July 2016 and October 2018, 136 HCM patients underwent ICD implantation, 127 (93%) for primary prevention of SCD. Over a mean follow-up of 1.9 ± 0.7 years, there were 3 deaths, 2 from cardiac cause (myocardial infarction). 8 pts (5.9%) received appropriate therapies. 7 pts had both an appropriate shock and anti-tachycardic pacing (ATP), and one pt had ATP alone. 6 pts (4.4%) received an inappropriate shock. There were 4 procedural complications (2.9%), including a pericardial effusion / tamponade, torn cephalic vein after difficult access, right atrial lead displacement/loss of function requiring revision, and finally high lead impedance with a new lead required. 6 pts (4.4%) experienced a late complication, including right ventricular lead displacement with loss of function requiring revision (2 pts), atrial lead displacement (2 pts), superficial wound infection requiring antibiotics (1 pts), and high shock impedance at follow-up (1pt). Adverse ICD events (inappropriate shocks and / or device complications) were seen in 16 pts (12%).
Conclusions/implications: Over a short follow-up period, occurrence of appropriate device therapy and adverse event rate was in line with published data, with infection rate extremely low. The occurrence of inappropriate shocks suggests this may be an important potential complication to include in pre-implant discussion with patients