Intracardiac Defibrillation Catheter Dynamic Refractory Period Control
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Solution Overview
Problem
Existing intracardiac defibrillation catheter systems cannot reliably prevent defibrillation from being performed in synchronization with a T wave, especially when heart rate varies, leading to potential adverse effects such as inducing ventricular fibrillation.
Innovation Solution
An intracardiac defibrillation catheter system that dynamically adjusts the refractory period based on the heart rate, ensuring that defibrillation is only performed in synchronization with an R wave by calculating and updating the heart rate and adjusting the refractory period to avoid T wave synchronization, regardless of the heart rate level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed refractory period is used for defibrillation synchronization, then the device complexity is reduced, but the reliability deteriorates when heart rate varies
Solution Approach 1:
The patent implements a dynamic refractory period adjustment mechanism where the refractory period is automatically modified based on real-time heart rate detection. When heart rate increases, the refractory period is shortened; when heart rate decreases, the refractory period is lengthened. This dynamic adaptation ensures reliable R-wave synchronization across varying physiological conditions without requiring complex manual configuration
Solution Approach 2:
The system continuously monitors cardiac rhythm and uses this feedback to adjust the refractory period in real-time. The control unit detects R-waves and T-waves, calculates the current heart rate, and dynamically modifies the refractory period setting based on the detected rhythm, creating a closed-loop control system that maintains defibrillation synchronization accuracy
2Object-affected harmful factors
If the refractory period is extended to avoid T wave synchronization, then the safety is improved, but the productivity deteriorates due to missed defibrillation opportunities
Solution Approach 1:
The system dynamically adjusts the refractory period length based on real-time heart rate measurement. During tachycardia (high heart rate), the refractory period is automatically shortened to prevent missed defibrillation opportunities, while during bradycardia (low heart rate), it is extended to ensure T-wave avoidance. This dynamic adjustment optimizes both safety and treatment efficiency across different physiological states
Solution Approach 2:
The patent changes the temporal parameter (refractory period duration) based on the physiological parameter (heart rate). By establishing a relationship where refractory period = f(heart rate), the system automatically optimizes the balance between avoiding T-wave synchronization and capturing R-wave defibrillation opportunities according to the patient's current cardiac state
3Productivity
If the refractory period is shortened to increase defibrillation opportunities, then the productivity is improved, but the safety deteriorates due to increased T wave synchronization risk
Solution Approach 1:
The system employs dynamic refractory period adjustment that responds to heart rate changes. When tachycardia is detected, the refractory period is shortened to maximize defibrillation opportunities during rapid heart rates. When bradycardia is detected, the refractory period is extended to maintain safety margins for T-wave avoidance, thus optimizing the safety-productivity balance adaptively
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system reliably avoids performing defibrillation in synchronization with a T wave, ensuring safe and effective defibrillation in synchronization with an R wave, even when heart rates change during surgery.
Implementation Method 1
direct-current voltages having different polarities are applied to the first electrode group and the second electrode group from the DC power supply unit through the output circuit of the arithmetic processing unit, the switching unit, and the catheter connection connector
Implementation Method 2
the arithmetic processing unit sequentially detects an R wave and a T wave from an electrocardiogram input from the electrocardiograph through the electrocardiogram input connector
Data Source
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AI summary
Provided is an intracardiac defibrillation catheter system including a defibrillation catheter (100), a power supply device (700), and an electrocardiograph (800), in which an arithmetic processing unit of the power supply device sequentially senses an event estimated to be an R wave from an electrocardiogram input from the electrocardiograph through an electrocardiogram input connector, calculates a heart rate each time sensing is performed, and, when, after an event (Vn) is sensed and after an application execution switch is input, an event (Vn+m) is sensed, performs arithmetic processing so that a direct-current voltage is applied in synchronization with the event (Vn+m) only in a case where the event (Vn+m) is sensed after a lapse of a refractory period whose length corresponds to 50% of a reciprocal of a heart rate (An) at a sensing time point of the event (Vn), to control a DC power supply unit. According to this defibrillation catheter system, it is possible to reliably avoid performing defibrillation in synchronization with a T wave without being affected by the level of the heart rate of a patient.