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Updated: Jul 27, 2025

A New Single Chamber Implantable Defibrillator with Atrial Sensing: A Practical Demonstration of Sensing and Ease of Implantation
Published on: February 28, 2012
Performance of a multisensor implantable defibrillator algorithm for heart failure monitoring related to
Vincenzo Ezio Santobuono1, Stefano Favale1, Antonio D'Onofrio2
1Interdisciplinary Department of Medicine, Cardiology Unit Polyclinic of Bari, University of Bari 'Aldo Moro', Bari, Italy.
Insights
The HeartLogic algorithm effectively predicts heart failure decompensation in ICD patients, even with co-morbidities like atrial fibrillation and chronic kidney disease. This tool enhances patient monitoring and risk stratification for better outcomes.
Area of Science:
- Cardiology
- Biomedical Engineering
- Medical Devices
Background:
- The HeartLogic algorithm uses implantable cardioverter-defibrillator (ICD) sensor data to predict heart failure (HF) decompensation.
- Its efficacy has been established in cardiac resynchronization therapy with defibrillator (CRT-D) patients.
- This study aimed to assess its performance in non-CRT ICD patients and those with co-morbidities.
Purpose of the Study:
- To evaluate the HeartLogic algorithm's performance in predicting heart failure decompensation in patients with standard ICDs, not just CRT-D devices.
- To assess the algorithm's effectiveness in the presence of co-morbidities such as atrial fibrillation (AF) and chronic kidney disease (CKD).
- To determine if the algorithm's predictive capability varies based on device type or specific co-morbidities.
Main Methods:
- The HeartLogic algorithm was activated in 568 ICD patients across 26 centers, including 410 with CRT-D.
- Patient data were followed for a median of 26 months, recording hospitalizations, deaths, and HeartLogic alerts.
- Statistical analyses, including incidence rate ratios and hazard ratios, were used to assess the algorithm's predictive accuracy and the impact of patient characteristics.
Main Results:
- HeartLogic alerts were associated with a 13.35-fold increased risk of cardiovascular hospitalization or death.
- Atrial fibrillation and chronic kidney disease independently predicted a higher burden of HeartLogic alerts.
- The algorithm's ability to identify high-risk periods was consistent across different patient groups (CRT-D/ICD, AF/non-AF, CKD/non-CKD).
Conclusions:
- The HeartLogic algorithm reliably predicts increased risk for clinical events in ICD patients, irrespective of device type (CRT-D vs. ICD).
- Patients with atrial fibrillation and chronic kidney disease experienced more alerts but the algorithm's predictive power remained robust.
- HeartLogic demonstrates continued value in monitoring and risk stratification for heart failure decompensation across diverse patient populations.
Aims:
The HeartLogic algorithm combines multiple implantable defibrillator (ICD) sensor data and has proved to be a sensitive and timely predictor of impending heart failure (HF) decompensation in cardiac resynchronization therapy (CRT-D) patients. We evaluated the performance of this algorithm in non-CRT ICD patients and in the presence of co-morbidities.
Methods And Results:
The HeartLogic feature was activated in 568 ICD patients (410 with CRT-D) from 26 centres. The median follow-up was 26 months [25th-75th percentile: 16-37]. During follow-up, 97 hospitalizations were reported (53 cardiovascular) and 55 patients died. We recorded 1200 HeartLogic alerts in 370 patients. Overall, the time IN the alert state was 13% of the total observation period. The rate of cardiovascular hospitalizations or death was 0.48/patient-year (95% CI: 0.37-0.60) with the HeartLogic IN the alert state and 0.04/patient-year (95% CI: 0.03-0.05) OUT of the alert state, with an incidence rate ratio of 13.35 (95% CI: 8.83-20.51, P < 0.001). Among patient characteristics, atrial fibrillation (AF) on implantation (HR: 1.62, 95% CI: 1.27-2.07, P < 0.001) and chronic kidney disease (CKD) (HR: 1.53, 95% CI: 1.21-1.93, P < 0.001) independently predicted alerts. HeartLogic alerts were not associated with CRT-D versus ICD implantation (HR: 1.03, 95% CI: 0.82-1.30, P = 0.775). Comparisons of the clinical event rates in the IN alert state with those in the OUT of alert state yielded incidence rate ratios ranging from 9.72 to 14.54 (all P < 0.001) in all groups of patients stratified by: CRT-D/ICD, AF/non-AF, and CKD/non-CKD. After multivariate correction, the occurrence of alerts was associated with cardiovascular hospitalization or death (HR: 1.92, 95% CI: 1.05-3.51, P = 0.036).
Conclusions:
The burden of HeartLogic alerts was similar between CRT-D and ICD patients, while patients with AF and CKD seemed more exposed to alerts. Nonetheless, the ability of the HeartLogic algorithm to identify periods of significantly increased risk of clinical events was confirmed, regardless of the type of device and the presence of AF or CKD.
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