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Inappropriate discharges by fourth generation implantable cardioverter defibrillators in patients with ventricular
T Washizuka1, M Chinushi, M Tagawa
1First Department of Internal Medicine, Niigata University School of Medicine, Japan. washi@med.niigata-u.ac.jp
Insights
Inappropriate therapies from implantable cardioverter-defibrillator (ICD) systems are common. Most issues, like tachycardia detection, can be managed by reprogramming or medication, but T-wave oversensing remains challenging.
Area of Science:
- Cardiology
- Biomedical Engineering
- Electrophysiology
Background:
- Fourth-generation implantable cardioverter-defibrillator (ICD) systems are crucial for managing cardiac arrhythmias.
- Inappropriate therapies, or shocks delivered erroneously, are a significant concern with ICDs.
- Understanding the causes and management of these events is vital for patient care.
Purpose of the Study:
- To investigate the incidence, causes, and management strategies for inappropriate discharges from fourth-generation ICD systems.
- To evaluate the effectiveness of reprogramming and pharmacological interventions in resolving inappropriate therapies.
- To identify challenges in managing specific causes of inappropriate ICD shocks, such as T-wave oversensing.
Main Methods:
- Prospective investigation of 45 patients with fourth-generation ICD systems.
- Analysis of follow-up data over a mean period of 27 months.
- Categorization of inappropriate therapies into sinus/supraventricular tachycardia and T-wave oversensing.
Main Results:
- 40% of patients (18 out of 45) experienced inappropriate therapies.
- Sinus and supraventricular tachycardia accounted for 15 cases, managed effectively with reprogramming and beta-blockers.
- T-wave oversensing occurred in 3 patients, with reprogramming improving but not completely eliminating discharges.
Conclusions:
- Inappropriate therapies are a common issue with fourth-generation ICDs, often manageable with dual-chamber systems.
- Reprogramming detection intervals and adjusting sensitivity are key management strategies.
- T-wave oversensing presents persistent challenges, making complete avoidance of inappropriate discharges difficult even with advanced ICD systems.
Abstract:
The study prospectively investigated the incidence, cause and efficient management of inappropriate discharge by the fourth generation implantable cardioverter-defibrillator (ICD) system in 45 patients (mean age, 57+/-16 years). During the follow-up period of 27+/-17 months, 18 patients (40%) experienced one or more inappropriate therapies: sinus and supraventricular tachycardia (15 patients) and T wave oversensing (3 patients). In the 15 patients, re-programming of the tachycardia detection interval and/or additional treatment with beta-blocking agents were effective. In the 3 patients with T wave oversensing, the arrythmia was associated with an increase in T wave amplitude, change in T wave morphology and decreased R wave amplitude, and re-programming of the sensitivity of the local electrogram or changing the number of intervals to detect ventricular tachycardia decreased the number of inappropriate discharges in all 3 patients. In conclusion, inappropriate therapies are common problems in patients treated with the fourth generation ICD system, but most of them can be resolved using the dual-chamber ICD system. However, in patients with T-wave oversensing, it is difficult to avoid inappropriate discharge completely, even if the dual-chamber ICD system is implanted.