Predicting inappropriate S-ICD® episodes by simple 12-lead surface ECG parameters

Area of Science:

• Cardiology
• Biomedical Engineering

Background:

• Subcutaneous Implantable Cardioverter-Defibrillators (S-ICD®) offer protection against sudden cardiac death.
• Inappropriate shocks from S-ICD® systems are a concern, often caused by oversensing.
• Predictive markers for these inappropriate episodes are crucial for patient management.

Purpose of the Study:

• To evaluate the predictive role of a preimplantation 12-lead electrocardiogram (ECG) for inappropriate S-ICD® episodes.
• To identify specific ECG parameters associated with oversensing and subsequent inappropriate shocks.

Main Methods:

• A cohort of 116 patients with S-ICD® and at least 6 months follow-up was analyzed.
• Preimplantation 12-lead ECGs were assessed for QRS and T-wave amplitude, concordance/discordance, and QRS/T wave ratio using Datinf® Measure software.
• Results were correlated with occurrences of inappropriate S-ICD® episodes due to oversensing.

Main Results:

• Of 116 patients, 17 (14.7%) experienced 27 inappropriate shocks, primarily due to T-wave oversensing.
• Hypertrophic cardiomyopathy (HCM) was a significant risk factor (OR 6.16, p=0.004).
• QRS-T wave discordance in lead I independently predicted inappropriate shocks (OR 6.5, p=0.003); the combination of HCM and lead I discordance increased risk 8.4-fold (p=0.003).

Conclusions:

• Preimplantation ECG analysis, specifically QRS-T wave discordance in lead I, is a valuable tool for predicting inappropriate S-ICD® shocks.
• This finding holds particular importance for patients with hypertrophic cardiomyopathy.
• Identifying these ECG patterns can help mitigate the risk of inappropriate therapy in S-ICD® recipients.