Method and apparatus for controlling cardiac resynchronization therapy using cardiac impedance
First Claim
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1. A machine-assisted method for monitoring a heart having first and second ventricles, the method comprising:
- measuring a first impedance signal, the first impedance signal being substantially indicative of a volume of the first ventricle as the first ventricle expands and contracts during a cardiac cycle of the heart;
measuring a second impedance signal, the second impedance signal being substantially indicative of a volume of the second ventricle as the second ventricle expands and contracts during the cardiac cycle;
computing a first slope of the first impedance signal at a first predetermined type point on the first impedance signal;
computing a second slope of the second impedance signal at a second predetermined type point on the second impedance signal; and
producing a first resynchronization index parameter as a function of a difference between the first and second slopes using a processor circuit, the first resynchronization index parameter indicative of a degree of cardiac mechanical synchrony or asynchrony between the first and second ventricles.
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Abstract
This document discusses, among other things, systems, devices, and methods for measuring cardiac impedances and producing one or more resynchronization index parameters each indicative of a cardiac synchrony or asynchrony using the measured cardiac impedances. In one example, the one or more resynchronization index parameters are used to adjust one or more pacing parameters of a cardiac resynchronization therapy.
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12 Claims
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1. A machine-assisted method for monitoring a heart having first and second ventricles, the method comprising:
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measuring a first impedance signal, the first impedance signal being substantially indicative of a volume of the first ventricle as the first ventricle expands and contracts during a cardiac cycle of the heart; measuring a second impedance signal, the second impedance signal being substantially indicative of a volume of the second ventricle as the second ventricle expands and contracts during the cardiac cycle; computing a first slope of the first impedance signal at a first predetermined type point on the first impedance signal; computing a second slope of the second impedance signal at a second predetermined type point on the second impedance signal; and producing a first resynchronization index parameter as a function of a difference between the first and second slopes using a processor circuit, the first resynchronization index parameter indicative of a degree of cardiac mechanical synchrony or asynchrony between the first and second ventricles. - View Dependent Claims (2, 3, 4, 5)
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6. A machine-assisted method for monitoring a heart having first and second ventricles, the method comprising:
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measuring a first impedance signal, the first impedance signal being substantially indicative of a volume of the first ventricle as the first ventricle expands and contracts during a cardiac cycle of the heart; measuring a second impedance signal, the second impedance signal being substantially indicative of a volume of the second ventricle as the second ventricle expands and contracts during the cardiac cycle; detecting a first peak of the first impedance signal during the cardiac cycle, the first peak being a first point at which the first impedance signal reaches its maximum value during the cardiac cycle; detecting a second peak of the second impedance signal during the cardiac cycle, the second peak being a second point at which the second impedance signal reaches its maximum value during the cardiac cycle; detecting a first ventricular depolarization of the first ventricle during the cardiac cycle; detecting a second ventricular depolarization of the second ventricle during the cardiac cycle; measuring a first time interval between the first ventricular depolarization and the first peak; measuring a second time interval between the second ventricular depolarization and the second peak; computing a difference between the first and second time intervals; and producing a first resynchronization index parameter as a function of the difference between the first and second time intervals using a processor circuit, the first resynchronization index parameter indicative of a degree of cardiac mechanical synchrony or asynchrony between the first and second ventricles. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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Specification