A prospective randomized-controlled trial of ventricular fibrillation detection time in a DDDR ventricular defibrillator. Ventak AV II DR Study Investigators

Clinical experience of entirely subcutaneous implantable cardioverter-defibrillators in children and adults: cause for caution

AIMS

This paper describes our clinical experience of using an entirely subcutaneous implantable cardioverter-defibrillator (S-ICD) in children and adults. Maintaining lead integrity and long-term vascular access are critical challenges of ICD therapy, especially in younger patients. The S-ICD has considerable theoretical advantages in selected patients without pacing indications, particularly children and young adults. Although sensing in an S-ICD may be influenced by age, pathology, and posture, there are currently few published data on clinical sensing performance outside the setting of intra-operative testing or in younger patients.

METHODS AND RESULTS

Patients were selected by a multi-disciplinary team on clinical grounds for S-ICD implantation from a broad population at risk of sudden arrhythmic death. Sixteen patients underwent implantation [median age 20 years (range 10-48 years)]. Twelve had primary electrical disease and four had congenital structural heart disease. There were no operative complications, and ventricular fibrillation (VF) induction testing was successful in all cases. During median follow-up of 9 months (range 3-15 months), three children required re-operation. Eighteen clinical shocks were delivered in six patients. Ten shocks in four patients were inappropriate due to T-wave over-sensing. Within the eight shocks for ventricular arrhythmia, three were delivered for VF, among which two had delays in detection with time to therapy of 24 and 27 s.

CONCLUSION

The S-ICD is an important new option for some patients. However, these data give cause for caution in light of the limited published data regarding clinical sensing capabilities, particularly among younger patients.

Case report: Delayed detection of ventricular tachycardia due to intradevice interactions by implantable atrio-ventricular pacer/cardioverter defibrillator

Current generations of implantable cardioverter defibrillators are capable of providing sophisticated dual chamber atrioventricular and rate-responsive pacing therapies, and even cardiac resynchronization therapy. Appropriate programming of the devices is necessary for them to perform all such sophisticated tasks. In this report, we describe a case where detection of ventricular tachycardia was delayed due to intradevice interactions between the pacemaker and defibrillator components of the device.

Delayed Detection of Ventricular Tachycardia in a Dual Chamber Rate Adaptive Pacing Implantable Cardioverter Defibrillator:. A Case of Intradevice Interaction

Ventricular tachycardia detection is delayed due to concomitant programming of rate adaptive dual chamber pacing. Underlying timing cycle constraints as well as programming precautions and pitfalls are reviewed.

Cross-talk in a dual-chamber defibrillator presenting as pacemaker alternans

This case report highlights the occurrence of pacemaker alternans in a dual-chamber defibrillator. Pacemaker alternans occurs secondary to cross-talk. The sensing algorithm and basic timing cycles are reviewed.