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Risk Stratification Using T Wave Morphological Variability

IP.com Disclosure Number: IPCOM000241137D
Publication Date: 2015-Mar-30
Document File: 6 page(s) / 1M

Publishing Venue

The IP.com Prior Art Database

Abstract

Reliable analysis of the electrocardiogram (ECG) of the patient is required for detecting arrhythmias of the human heart. In typical state of the art implantable medical devices (IMDs) for therapy of cardiac diseases, as e.g. cardiac pacemakers or implantable cardiac defibrillators (ICDs), the ECG of the patient is recorded and automatically evaluated via specific computing algorithms implemented within the signal processing unit of the cardiac pacemaker.

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Risk Stratification Using T Wave Morphological Variability

Reliable analysis of the electrocardiogram (ECG) of the patient is required for detecting arrhyth- mias of the human heart. In typical state of the art implantable medical devices (IMDs) for therapy of cardiac diseases, as e.g. cardiac pacemakers or implantable cardiac defibrillators (ICDs), the ECG of the patient is recorded and automatically evalu- ated via specific computing algorithms imple- mented within the signal processing unit of the cardiac pacemaker.

The most distinctive signal parts of a physiologi- cal ECG are the P-wave (represents atrial depolar- ization), the QRS-complex (represents ventricular contraction) and the T-wave (represents ventricu- lar repolarization). Most common automatic ECG detection algorithms are targeted on identification of these signal parts, wherein research is continu- ally performed in science in order to develop new strategies for optimization of such algorithms.

The T wave in ECG represents ventricular repo- larization. Abnormal T wave morphology usually indicates spatiotemporal heterogeneity in ventric- ular repolarization which can predispose an indi- vidual to lethal arrhythmias.

Known methods that assess the T wave variability either solely rely on the measurement of temporal variation of T wave, or solely rely on the measure- ment of T wave amplitude. There is no known technique in prior art that measures the variability of T wave in both time domain (i.e. duration) and scalar domain (i.e. amplitude). Theoretically, the spatiotemporal heterogeneity of ventricular repo- larization will be likely refLected in the variability of T wave morphology that is shown in both T wave duration and T wave amplitude.

In the following, a novel apparatus and method for assessing the risk of cardiac arrhythmia by means of quantitative analysis of T wave morphol- ogy are proposed. The apparatus and method pro- vide a novel strategy for an ECG or intracardiac electrogram (IEGM) monitoring device to stratify a patient's arrhythmic risk.

In particular, the proposed apparatus and method describes a novel method for risk stratification of ventricular arrhythmias in an ECG monitoring device based on a novel index that quantifies the T wave morphological variability.

The proposed apparatus and method relates to cardiac monitoring devices, including cutaneous ECG monitors (e.g. Holter monitors, ECG loop recorders, etc.), subcutaneous ECG monitors, and implantable pacemakers, defibrillators and cardiovertors.

According to the presented apparatus and method, the cardiac electrical signal is continu- ously recorded by a cardiac monitoring device. The device maintains multiple sets of ECG beats, where each set represents an ensemble of normal ECG cycles at specific heart rate. For each set of ECG waveform, a novel metric - termed T wave morphological variability (TWMV) - is calculated by quantifying the variation of T wave morphol- ogy among all cardiac cy...