Ventricular Fibrillation Detection by Intramyocardial Pressure Gradients
Ventricular fibrillation recognition is a major problem before automatic implantable defibrillators (AID) will become useful on a large scale. In this work a pressure gradient measurement is proposed instead of using some kind of ECG processing. Endo- and epicardial pressures in the left ventricular wall were measured with high fidelity tip transducers. The intramyocardial wall gradient was determined by digital subtraction of these pressures.
Measuring endo- and epicardial pressures in the left ventricular wall permits to differentiate between ventricular arrhythmias with and without haemodynamic repercussion. During a normal sinus beat an intramyocardial pressure gradient exists with a maximum near the endocardium during systole and a maximum at the epicardium during diastole. This gradient decreases to a constant level without cyclic changes when left ventricular aclivity becomes uncoordinate. Our method permits to monitor left ventricular performance without an intraventricular transducer. Furthermore by using differential pressure measurements, the influence of transducer baseline drift is easily eliminated. Further study is needed to evaluate the system in long term experiments.
KeywordsVentricular Arrhythmia Ventricular Fibrillation Left Ventricular Wall Cyclic Change Pressure Gradient Measurement
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