Related Experiment Video
Updated: Mar 23, 2026
10:33
Expedited Radiation Biodosimetry by Automated Dicentric Chromosome Identification ADCI and Dose Estimation
Published on: September 4, 2017
16.7K
Reducing ICD Test Shocks with a Simplified Upper Limit of Vulnerability
Michael Pittaro1, William Deforge2, Mark W Kroll3
1Norwalk Hospital, Norwalk, Connecticut.
Pacing and Clinical Electrophysiology : PACE
|March 29, 2016
Summary
Determining the defibrillation safety margin for implantable cardioverter-defibrillators (ICDs) is simplified using a single electrogram coupling interval. This method accurately identifies patients needing higher or lower defibrillation thresholds, improving safety.
Area of Science:
- Cardiology
- Biomedical Engineering
- Electrophysiology
Background:
- Determining the defibrillation safety margin for implantable cardioverter-defibrillators (ICDs) is challenging.
- The upper limit of vulnerability (ULV) correlates with defibrillation thresholds.
- The vulnerable period is approximated by the T wave peak on the surface ECG.
Purpose of the Study:
- To assess if a single electrogram-derived coupling interval can accurately determine the vulnerable period.
- To evaluate a simplified method for approximating the defibrillation safety margin.
Main Methods:
- A single electrogram-derived coupling interval was used for T-shock timing.
- Intracardiac electrogram coupling intervals were compared to surface ECG T wave peaks.
Main Results:
- Coupling intervals were significantly longer on electrograms (365 ms ± 27) vs. surface ECG (347 ms ± 26).
- 96% of patients (69/72) were successfully defibrillated with the T-shock.
- Only 4% of patients failed the test criteria.
Conclusions:
- A simplified ULV testing protocol using a single electrogram channel is effective.
- This method accurately differentiates patients with low vs. high defibrillation thresholds.
Related Concept Videos
01:21Dose Response Curve: Conventional Versus Nonmonotonic
226
The correlation between a drug's dosage and its impact on a biological system is a cornerstone of pharmacology and toxicology. Conventional dose–response curves, which include graded and quantal relationships, are key to this understanding. Graded dose–response curves depict the spectrum of a biological reaction to different doses within an individual, indicating that as the drug dosage increases, so does the intensity of the response. On the other hand, quantal dose–response...
226
01:17Design Example: Analyzing Capacity Contours for Flood Risk Assessment
355
Flood risk assessment involves careful planning and analysis to ensure the safety of communities near water retention structures. Capacity contours are a vital tool in this process, as they illustrate the potential spread of water at specific levels in a given area. In the context of building a bund across a small valley, these contours play a critical role in evaluating the safety of nearby residential areas.In this example, the bund is intended to store stormwater in the valley. The engineers...
355
01:12Relative Risk
2.5K
Relative risk (RR) is a statistical measure commonly used in epidemiology to compare the likelihood of a particular event occurring between two groups. This metric is important for evaluating the relationship between exposure to a specific risk factor and the probability of a particular outcome. It plays a crucial role in medical research, public health studies, and risk assessment. Relative risk quantifies how much more (or less) likely an event is to occur in an exposed group compared to an...
2.5K