Long-term performance of submammary defibrillator system.

AIMS

There are various implantation techniques that have been used to minimize the cosmetic effect of implantable cardioverter defibrillator (ICD) implantation, including submammary implantation. There are limited data on submammary ICD implantation and no data on long-term follow-up. We report the long-term performance of submammary ICD systems implanted in young females.

METHODS AND RESULTS

We gathered data from August 1994 to September 2009 on all submammary ICD implantations undertaken at two institutes in Melbourne, Australia. Twenty submammary ICDs were implanted. Mean age at implantation was 21 +/- 10 years. Fifteen single chamber (VR) and five dual chamber (DR) systems were implanted. Twenty-five per cent were implanted for primary prophylaxis. Implantable cardioverter defibrillator implantation was predominantly for non-cardiomyopathy indications. Mean follow-up duration was 60 +/- 46 months. There were no deaths during follow-up. There were two early lead dislodgements and three late lead revisions. No extractions were performed. Five patients had appropriate and five patients had inappropriate ICD therapy. Mean duration to first appropriate therapy was 58 +/- 40 months. Stable sensing and high voltage (HV) lead performance were demonstrated (mean lowest effective defibrillation at implant vs. follow-up: 13 +/- 6 vs. 14 +/- 4 J, P = 0.8; R-wave amplitude: 9 +/- 3 vs. 8 +/- 2 mV, P = 0.6; HV lead impedance: 52 +/- 6 vs. 44 +/- 9 ohm, P = 0.1). A clinically insignificant rise in ventricular pacing threshold (0.6 +/- 0.2 V at implant vs. 1.6 +/- 0.6 V at follow-up, P < 0.001) and a decrease in pacing impedance (621 +/- 223 vs. 471 +/- 89 ohm, P = 0.02) were noted.

CONCLUSION

Submammary ICD implantation in young females is feasible and safe. Long-term follow-up data reveal stable sensing and HV lead performance.