Related Experiment Video
Updated: Oct 13, 2025
Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System
Published on: April 11, 2025
Heart rate score and outcomes in ICD patients: insights from the prospective randomized INTRINSIC RV trial
Rakesh Gopinathannair1, Arjun Sharma2, Paul Jones3
1Kansas City Heart Rhythm Institute, 5100 W 110th St, Ste 200, Overland Park, KS, 66211, USA. drrakeshg@yahoo.com.
Insights
Heart rate score (HRSc) and mean intrinsic heart rate (MIHR) independently predict mortality and heart failure hospitalizations in implantable cardioverter-defibrillator patients. Higher HRSc and MIHR levels are associated with increased risk.
Area of Science:
- Cardiology
- Biomedical Engineering
- Clinical Trials
Background:
- Implantable cardioverter-defibrillators (ICDs) are crucial for managing heart failure (HF) and preventing sudden cardiac death.
- Previous studies suggested heart rate score (HRSc) and mean intrinsic heart rate (MIHR) predict survival in ICD patients.
- The INTRINSIC RV trial provides a robust dataset to validate these predictors in a prospective, randomized setting.
Purpose of the Study:
- To evaluate if HRSc and MIHR independently predict mortality and HF hospitalization in patients with dual-chamber ICDs.
- To assess the association between baseline MIHR and HRSc and their combined predictive value for adverse cardiovascular events.
Main Methods:
- Analysis of 1471 patients from the prospective, randomized INTRINSIC RV trial with dual-chamber ICDs.
- Utilized multivariate regression and Cox modeling to assess the relationship between pre-randomization MIHR, HRSc, and the primary endpoint (all-cause mortality and HF hospitalization).
- Defined high MIHR as >70 bpm and high HRSc as >70% for categorical analysis.
Main Results:
- A 1% increase in HRSc was associated with a 1% increase in death/HF hospitalization risk (p=0.01).
- Higher MIHR was associated with higher HRSc (1.8% increase in HRSc per 1 bpm increase in MIHR, p=0.01).
- Both high MIHR (>70 bpm) and high HRSc (≥70%) independently predicted the primary endpoint (HR: 1.39, p=0.005 for MIHR; HR: 1.654, p=0.01 for HRSc).
Conclusions:
- HRSc is a robust and independent predictor of death and HF hospitalization in a large, prospectively studied ICD population.
- High MIHR and high HRSc, while associated, each independently predict adverse outcomes in ICD patients.
- These findings support the use of HRSc and MIHR as valuable prognostic markers in ICD management.
Background:
Heart rate score (HRSc), the percentage of atrial sensed and paced beats in the largest 10 beat/min bin of a device histogram and mean intrinsic heart rate (MIHR), predicted survival in nonrandomized studies of implantable defibrillator (ICD) patients. We evaluated whether HRSc and MIHR independently predicted mortality and heart failure (HF) hospitalization in the prospective, randomized, controlled INTRINSIC RV trial.
Methods And Results:
The INTRINSIC RV trial enrolled 1530 patients receiving dual-chamber ICDs. This analysis involves patients (n = 1471) for whom MIHR and HRSc data were available. Mean follow-up was 10.4 months. The relationship between pre-randomization MIHR and HRSc on the primary endpoint of all-cause mortality and HF hospitalization was assessed using multivariate regression and Cox modeling. As categorical variables, MIHR > 70 bpm and HRSc > 70% were considered high.
Results:
The median baseline MIHR and HRSc were 74 (IQR = 16) and 50% (IQR = 20) respectively. As a continuous variable, for every 1% increase in HRSc, death/HF hospitalization increased by 1% (95%CI: 1.002-1.017; p = 0.01). Regression analysis showed baseline MIHR was associated with HRSc (p = 0.01); for every 1 beat/min increase in MIHR, HRSc increased by 1.8%. A MIHR > 70 bpm and HRSc ≥ 70% predicted, but were independently associated with, the primary endpoint (HR: 1.39; 95%CI: 1.10-1.76, p = 0.005 for MIHR and HR: 1.654; 95%CI: 1.11-2.46, p = 0.01 for HRSc). Male gender (HR: 0.75), history of HF (HR: 1.29), and atrial fibrillation (HR: 1.37) also predicted death/hospitalization in the Cox model.
Conclusions:
In this large, prospectively studied ICD population, HRSc was a robust and independent predictor of death/HF hospitalization. High MIHR and high HRSc were associated but each predicted outcomes independently.
More Related Videos
12:45Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
Published on: December 11, 2017
08:01Semi-Minimal Invasive Method to Induce Myocardial Infarction in Rats and the Assessment of Cardiac Function by an Isolated Working Heart System
Published on: June 11, 2020
Related Concept Videos
01:30Heart Failure IV: Classification and Diagnostic Evaluation
01:19Cardiac Output I:Effect of Heart Rate on Cardiac Output
Cardiac output (CO) refers to the total amount of blood ejected by one of the ventricles in liters per minute (L/min). In a resting adult, CO ranges from 5 to 6 L/min, adjusting according to the body's metabolic requirements.
Effect of Heart Rate on Cardiac Output
Cardiac output adapts to metabolic demands during stress, physical activity, or illness. The autonomic nervous system regulates heart rate via the sinoatrial node. The parasympathetic nervous system decreases heart...
01:30Acute Coronary Syndrome III: Diagnostic Studies