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Updated: Mar 19, 2026
A New Single Chamber Implantable Defibrillator with Atrial Sensing: A Practical Demonstration of Sensing and Ease of Implantation
Published on: February 28, 2012
Evaluating real-world mortality risk after defibrillator implantation
Lisa W M Leung1, Zaki Akhtar2, Oswaldo Valencia3
1Consultant Cardiologist and Electrophysiologist.
Insights
Implantable cardioverter-defibrillators protect against sudden cardiac death. However, early death risk in candidates may be better predicted using biomarkers like red cell distribution width (RDW), alongside age and ejection fraction.
Area of Science:
- Cardiology
- Medical Devices
- Biomarkers
Background:
- Implantable cardioverter-defibrillators (ICDs) are crucial for preventing sudden cardiac death (SCD) from ventricular arrhythmias.
- Current guidelines often contraindicate ICD implantation for patients with less than one year life expectancy.
- Assessing prognosis in ICD candidates remains challenging, potentially leading to suboptimal device selection.
Purpose of the Study:
- To evaluate outcomes of ICD recipients, focusing on early mortality (<12 months post-implant).
- To identify predictors of early death in ICD recipients, particularly non-arrhythmic causes.
- To explore the utility of biomarkers, such as red cell distribution width (RDW), in refining prognostic assessment for ICD candidates.
Main Methods:
- Retrospective analysis of 235 patients who received transvenous ICDs in 2015 for primary or secondary SCD prevention.
- Data collection included patient demographics, device information, and mortality outcomes over a mean follow-up of 66.2 months.
- Statistical analysis, including univariate and multivariate analyses and Receiver Operator Characteristic (ROC) curve analysis, was used to identify mortality predictors.
Main Results:
- Out of 235 patients, 77 (32.8%) died during follow-up; 20 (8.5%) died within 12 months post-implant.
- None of the early deaths were directly attributed to arrhythmias.
- Significant predictors of mortality included older age, ejection fraction <35%, and elevated red cell distribution width (RDW >14.75%).
- RDW demonstrated strong association with early mortality risk (p<0.001) with good diagnostic performance (AUC 0.75).
Conclusions:
- Current prognostic assessments for ICD candidates have limitations.
- Red cell distribution width (RDW) is a significant predictor of early, non-arrhythmic death in ICD recipients.
- Integrating biomarkers like RDW into clinical frailty scores could improve pre-assessment and risk stratification for ICD candidates.
Abstract:
Protection against the increased risk of sudden cardiac death (SCD) due to ventricular arrhythmias is offered by the implantation of cardiac defibrillators. A life-expectancy of less than one year is usually a contraindication to the implantation of these devices. We evaluated the outcomes of all those who received defibrillator implantation for any clinical indication at our centre in the same year that early (<12 months) death notifications occurred. This is a single-centre retrospective study on the outcomes of all patients who had a transvenous defibrillator implant in 2015. All transvenous defibrillator devices implanted for both primary and secondary prevention of SCD were included. Patient demographic data and device data were studied. Data from 235 patients were analysed. In a follow-up period of 66.2 ± 3.8 months, 77 (32.8%) of the study cohort died; 20 (8.5%) of these patients died less than 12 months post-implant. None of the deaths were directly arrhythmia related. Factors that were significant in predicting mortality included age and ejection fraction <35% (p<0.01). From a preprocedure biomarker perspective, an increased red cell distribution width (RDW) was strongly associated with early mortality risk on univariate and multi-variate analysis (p<0.001). Receiver operator characteristics (ROC) curve analysis found that the optimal cut-off for RDW was 14.75% (area under curve 0.75; sensitivity 0.69; specificity 0.77; p<0.001). In conclusion, there are limitations in fully assessing patient prognosis despite current guidance. Universal clinical frailty scores that incorporate biomarkers may be helpful in enhancing this pre-assessment process to improve the evaluation of the risk of early non-arrhythmic-related death for implantable cardioverter defibrillator candidates.
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